[Solar Turbine] CFLR aiming options
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Ozheliguy
Apr 23, 2010, 10:07:23 AM4/23/10
to Solar Turbine, joseph....@gmail.com
Solar concentrator Reflector aiming Options:
Apologies for taking some time to get back to this. Have spent last
month and half being busy stuck in very unreliable internet access.
Then having to do a quick global circumnavigation to dodge volcanic
ash clouds. Have spent some time chasing various ideas and information
out there related to this subject.
(some different ‘out of the box’ ideas to ponder) Some so crazy they
might just work?
Control Sensors
Either- discrete on/ off or comparative with sensors and a control
circuit
1. Photo voltaic cells/panels- http://www.josepino.com/?simple_sun_tracker
very simple, no circuit needed, self powering. Or could use a circuit
and use comparative voltages. Have 2 panels with a ‘wall’ between and
or around them to cast a shadow to give differentiation. Even if this
principle isn’t used to aim the mirrors I believe it is a good option
to power, or partly power the system.
2. Thermal switches around USD$10 each, 100 or 150C so no spurious
activation (un concentrated full sun could only be say max 50 C ). Has
the advantage of searching for heat not light. No risk of picking up
wrong light sources or reflections etc. We are after all dealing with
a thermal system.
http://ly.rsdelivers.com/product/honeywell/2455rc-90820387/bi-metallic-thermostat-150degc-open-temp/4940851.aspx
Sensitivity could be adjusted by changing the distance of the sensors
or switches further out from or closer to the collector target.
3. Thermal probes- could either be Free Air Temp, or immersed in temp
sensor pipes parallel to and either side of collector target. These
could be just individual simple fluid filled sealed pipes. Could have
circuit comparing temps of both sides to keep concentrated solar heat
on target without actually having to touch sensor probes. I think
suitable probes? Are probably something like USD$35 ea
http://ly.rsdelivers.com/product/digitron/h0234/air-insertionprobe-for-2046t-thermometer/3107687.aspx
Would require a control circuit, but may be more accurate.
4. Hydraulic fluid pressure switches/ sensors- could be used in
temperature sensor pipes either side of collector target. As aiming
moves off target and onto sensor pipes. Is basically sensing
temperatures in a different way. Possibly more reliable or
controllable?
5. Light sensors/ resistors – seems to be the regular way to control
reflector positions on most other systems. Needs a mechanism to move
mirrors half sun movement. I have seen a multiplication lever used. I
am skeptical how successful this could be with wear slop in all
linkages. I have proposed a target mirror system- refer my pictures.
I’m not sure how successful this would be either. Many commercial
systems available like http://www.acrosolarlasers.com/acrosolarcatalog12.html
(USD$650) or http://heliotrack.com/Products.html#dualAxisTracker (USD
$175)
6. Aquaflector- http://www.aquaflector.com/technology.html very simple
system. Possibly not so robust but quite clever and may have something
to offer?
7. Computer calculated- from geographic position, date, etc. Does not
actually know where sun is only where it should be. Least desirable in
my humble opinion.
Motive forces
1. Electrical- electrical power from mains, generator, battery or PV
panel/s
DC rotary motors/ geared motors-
https://sdp-si.com/eStore/PartDetail.asp?Opener=Group&PartID=57804&GroupID=222
cheap , around USD$22, and common, actuated using a press or temp
switch, or may require relay as well if amperages or distances
excessive, driving a pinion to in turn drive a gear rack. The example
listed is 4300:1, but other ratios available. Large reduction ratios
give slow speed, more precise control, and more driving torque for a
smaller cheaper motor.
DC stepper motors around USD$30 as above but requires extra control
circuitry.
Geared stepper motors, https://sdp-si.com/eStore/PartDetail.asp?Opener=Group&PartID=68807&GroupID=933
(I don’t think these are required), USD$320 + stepper controller.
Linear actuators, we wont get sufficient range of movement to give the
accuracy we are after- that I know of. Looking for 785 mm, or more of
travel. Rack and pinion achieves the same thing.
2. Hydraulic-
Electrical 12 VDC pump driven haven’t followed up much on this option.
Could be controlled by temp or press switches or temp/ press sensors
and control circuit. If this option was considered I would think a
hydraulic motor controlled by temp or press switches.
Thermal expansion this option is quite interesting, but have not
followed up much on it yet. It would require no external power, very
simple.
Mechanical mechanism and linkages
1. Common actuation link- all reflectors move the same magnitude of
arc ie half of sun arc. However all reflectors will be at different
angles. Adjustment to individually aim each reflector. All Individual
reflector levers attached to actuation link by pivot bearings.
2. Rack and pinion- (pinions on common torque shaft) to reduce
inaccuracies from relectors twisting along their length from inputted
angle control. Mulitple rack sections can be used to get required
displacement and accuracy. Rack attached solidly to Common actuation
link. http://www.mcmaster.com/#rack-and-pinion-gears/=6s9l3b P/N
5170T1 4 foot section
Ready-Mnt Stl 14-1/2 Pressure Angle Gear Rack 24 Pitch, 1/4" Face
Width, 1/4" O'all Height
In stock at $49.29 Each
3. Individual Reflector actuation and adjustment levers- These are the
heart of the accuracy of our reflector rotational system. The longer
the more accurate ie smaller incremental movements. I suggest maybe 1
mtr (3 ft) A longer lever will move through a greater arc for the same
rotational change. Ie a 1m link will need to move 17.4 mm for one
degree (785mm for 45 deg) of rotation, which would be max required.
Attachment at the reflector end would be ‘solid’ so that play and
inaccuracy is reduced. The pivot attachments to the Common actuation
link and the adjustment for individual reflectors would be done at the
‘long’ common actuation link end to minimize any inaccuracy effect due
to pivot wear or slop. Refer my pictures. May need counterbalance
weights to lessen load on motor/s depending on installation
arrangement of array.
My thoughts and Recommendations
Simple and as low tech as practical, are the way to go. The aim is as
low tech, low cost and reliable as possible.
The AUSRA project in NSW, Australia, (company which has now moved to
California) http://www.physics.usyd.edu.au/app/research/solar/clfr.html
http://pointfocus.com/images/pdfs/shp_presentation_cep.pdf
Lessons to be learned from their experiences-
These guys quote AU$470/kW ie 47 Australian cents (approx 40 US cents)
per Watt. This is without the actual electrical generator because they
are utilizing the coal fired turbines at the existing facility.
Obviously this is a far larger scale so also benefits from economy of
scale. However this was built and has been running successfully since
1995, ie 15 years ago. Technology, particularly in this area has
progressed. We should be able to do better today after the experiences
learnt.
They are particularly interested in site concentration and have
developed a system of multiple receivers and tilt adjacent mirrors in
opposite directions to different receivers to reduce or eliminate
shading. Multiple receivers are probably not viable on a smaller
scale. However maximum area utilization is probably more critical in
more confined residential or urban areas. I believe that possible
repositioning to one receiver to outside the suns arc may be a
possible solution. Vertically, (or more), above the last (furthest
from the sun) collector, or horizontal (or below), in front of the
first reflector. Someone on the forum recently was saying they knew of
or are developing a program to calculate the optimum site coverage/
shading factors. I believe given a site opportunity of a building wall
the reflectors would suffer less shading in a vertical array, more so
the further from the equator. The optimum angle would be 45 deg
(slightly more) incline at the equator to vertical, or almost at the
poles. Using a wall or fence would also offer far more structural
support allowing a lighter cheaper structure not having to be self
supporting. Another AUSRA idea is to utilize the collector area as a
covered car park or car port. This sounds like a good idea to me.
They use a one electrical actuator per ‘row’ with all reflectors
linked together. They say this is to reduce complexity and expense. It
obviously works OK for 15 years. No point re inventing the wheel here.
They don’t specify the type of electrical actuator.
I suggest something along the following lines-
1. Powered by Solar Photo Voltaic panel/s. probably no need for
batteries because if there is enough sun to heat water there will be
enough sun light to generate PV power for motor to rotate reflectors.
Self sustaining system. Required panels reasonably small and
inexpensive?
2. Controlled by temp switches, or possibly temp sensors and control
circuit.
3. Geared 12 VDC motors driving a pinion,
4. Rack moving a common ‘rail’ moving 1m (or more if required)
individual reflector levers.
Have also done a good amount of research into the inter related areas
and come up with some possible ideas about Steam engines and their
consumption levels and valve timing issues. Also have made good
headway with my pet Solar air conditioning and atmospheric water
generation project. Scope with all of these is potentially huge.
Hopefully I have given the rest of you out there enough information
and motivation to run with and get some momentum going to get a head
of steam up with this project- pun intended.
Over to the rest of you out there for you comments, suggestions and
input,
Cheers.
--
To post to this group, send email to solar-...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/solar-turbine?hl=en
See http://openfarmtech.org/index.php?title=Solar_Power_Generator_Distillation_Transcript
Apologies for taking some time to get back to this. Have spent last
month and half being busy stuck in very unreliable internet access.
Then having to do a quick global circumnavigation to dodge volcanic
ash clouds. Have spent some time chasing various ideas and information
out there related to this subject.
(some different ‘out of the box’ ideas to ponder) Some so crazy they
might just work?
Control Sensors
Either- discrete on/ off or comparative with sensors and a control
circuit
1. Photo voltaic cells/panels- http://www.josepino.com/?simple_sun_tracker
very simple, no circuit needed, self powering. Or could use a circuit
and use comparative voltages. Have 2 panels with a ‘wall’ between and
or around them to cast a shadow to give differentiation. Even if this
principle isn’t used to aim the mirrors I believe it is a good option
to power, or partly power the system.
2. Thermal switches around USD$10 each, 100 or 150C so no spurious
activation (un concentrated full sun could only be say max 50 C ). Has
the advantage of searching for heat not light. No risk of picking up
wrong light sources or reflections etc. We are after all dealing with
a thermal system.
http://ly.rsdelivers.com/product/honeywell/2455rc-90820387/bi-metallic-thermostat-150degc-open-temp/4940851.aspx
Sensitivity could be adjusted by changing the distance of the sensors
or switches further out from or closer to the collector target.
3. Thermal probes- could either be Free Air Temp, or immersed in temp
sensor pipes parallel to and either side of collector target. These
could be just individual simple fluid filled sealed pipes. Could have
circuit comparing temps of both sides to keep concentrated solar heat
on target without actually having to touch sensor probes. I think
suitable probes? Are probably something like USD$35 ea
http://ly.rsdelivers.com/product/digitron/h0234/air-insertionprobe-for-2046t-thermometer/3107687.aspx
Would require a control circuit, but may be more accurate.
4. Hydraulic fluid pressure switches/ sensors- could be used in
temperature sensor pipes either side of collector target. As aiming
moves off target and onto sensor pipes. Is basically sensing
temperatures in a different way. Possibly more reliable or
controllable?
5. Light sensors/ resistors – seems to be the regular way to control
reflector positions on most other systems. Needs a mechanism to move
mirrors half sun movement. I have seen a multiplication lever used. I
am skeptical how successful this could be with wear slop in all
linkages. I have proposed a target mirror system- refer my pictures.
I’m not sure how successful this would be either. Many commercial
systems available like http://www.acrosolarlasers.com/acrosolarcatalog12.html
(USD$650) or http://heliotrack.com/Products.html#dualAxisTracker (USD
$175)
6. Aquaflector- http://www.aquaflector.com/technology.html very simple
system. Possibly not so robust but quite clever and may have something
to offer?
7. Computer calculated- from geographic position, date, etc. Does not
actually know where sun is only where it should be. Least desirable in
my humble opinion.
Motive forces
1. Electrical- electrical power from mains, generator, battery or PV
panel/s
DC rotary motors/ geared motors-
https://sdp-si.com/eStore/PartDetail.asp?Opener=Group&PartID=57804&GroupID=222
cheap , around USD$22, and common, actuated using a press or temp
switch, or may require relay as well if amperages or distances
excessive, driving a pinion to in turn drive a gear rack. The example
listed is 4300:1, but other ratios available. Large reduction ratios
give slow speed, more precise control, and more driving torque for a
smaller cheaper motor.
DC stepper motors around USD$30 as above but requires extra control
circuitry.
Geared stepper motors, https://sdp-si.com/eStore/PartDetail.asp?Opener=Group&PartID=68807&GroupID=933
(I don’t think these are required), USD$320 + stepper controller.
Linear actuators, we wont get sufficient range of movement to give the
accuracy we are after- that I know of. Looking for 785 mm, or more of
travel. Rack and pinion achieves the same thing.
2. Hydraulic-
Electrical 12 VDC pump driven haven’t followed up much on this option.
Could be controlled by temp or press switches or temp/ press sensors
and control circuit. If this option was considered I would think a
hydraulic motor controlled by temp or press switches.
Thermal expansion this option is quite interesting, but have not
followed up much on it yet. It would require no external power, very
simple.
Mechanical mechanism and linkages
1. Common actuation link- all reflectors move the same magnitude of
arc ie half of sun arc. However all reflectors will be at different
angles. Adjustment to individually aim each reflector. All Individual
reflector levers attached to actuation link by pivot bearings.
2. Rack and pinion- (pinions on common torque shaft) to reduce
inaccuracies from relectors twisting along their length from inputted
angle control. Mulitple rack sections can be used to get required
displacement and accuracy. Rack attached solidly to Common actuation
link. http://www.mcmaster.com/#rack-and-pinion-gears/=6s9l3b P/N
5170T1 4 foot section
Ready-Mnt Stl 14-1/2 Pressure Angle Gear Rack 24 Pitch, 1/4" Face
Width, 1/4" O'all Height
In stock at $49.29 Each
3. Individual Reflector actuation and adjustment levers- These are the
heart of the accuracy of our reflector rotational system. The longer
the more accurate ie smaller incremental movements. I suggest maybe 1
mtr (3 ft) A longer lever will move through a greater arc for the same
rotational change. Ie a 1m link will need to move 17.4 mm for one
degree (785mm for 45 deg) of rotation, which would be max required.
Attachment at the reflector end would be ‘solid’ so that play and
inaccuracy is reduced. The pivot attachments to the Common actuation
link and the adjustment for individual reflectors would be done at the
‘long’ common actuation link end to minimize any inaccuracy effect due
to pivot wear or slop. Refer my pictures. May need counterbalance
weights to lessen load on motor/s depending on installation
arrangement of array.
My thoughts and Recommendations
Simple and as low tech as practical, are the way to go. The aim is as
low tech, low cost and reliable as possible.
The AUSRA project in NSW, Australia, (company which has now moved to
California) http://www.physics.usyd.edu.au/app/research/solar/clfr.html
http://pointfocus.com/images/pdfs/shp_presentation_cep.pdf
Lessons to be learned from their experiences-
These guys quote AU$470/kW ie 47 Australian cents (approx 40 US cents)
per Watt. This is without the actual electrical generator because they
are utilizing the coal fired turbines at the existing facility.
Obviously this is a far larger scale so also benefits from economy of
scale. However this was built and has been running successfully since
1995, ie 15 years ago. Technology, particularly in this area has
progressed. We should be able to do better today after the experiences
learnt.
They are particularly interested in site concentration and have
developed a system of multiple receivers and tilt adjacent mirrors in
opposite directions to different receivers to reduce or eliminate
shading. Multiple receivers are probably not viable on a smaller
scale. However maximum area utilization is probably more critical in
more confined residential or urban areas. I believe that possible
repositioning to one receiver to outside the suns arc may be a
possible solution. Vertically, (or more), above the last (furthest
from the sun) collector, or horizontal (or below), in front of the
first reflector. Someone on the forum recently was saying they knew of
or are developing a program to calculate the optimum site coverage/
shading factors. I believe given a site opportunity of a building wall
the reflectors would suffer less shading in a vertical array, more so
the further from the equator. The optimum angle would be 45 deg
(slightly more) incline at the equator to vertical, or almost at the
poles. Using a wall or fence would also offer far more structural
support allowing a lighter cheaper structure not having to be self
supporting. Another AUSRA idea is to utilize the collector area as a
covered car park or car port. This sounds like a good idea to me.
They use a one electrical actuator per ‘row’ with all reflectors
linked together. They say this is to reduce complexity and expense. It
obviously works OK for 15 years. No point re inventing the wheel here.
They don’t specify the type of electrical actuator.
I suggest something along the following lines-
1. Powered by Solar Photo Voltaic panel/s. probably no need for
batteries because if there is enough sun to heat water there will be
enough sun light to generate PV power for motor to rotate reflectors.
Self sustaining system. Required panels reasonably small and
inexpensive?
2. Controlled by temp switches, or possibly temp sensors and control
circuit.
3. Geared 12 VDC motors driving a pinion,
4. Rack moving a common ‘rail’ moving 1m (or more if required)
individual reflector levers.
Have also done a good amount of research into the inter related areas
and come up with some possible ideas about Steam engines and their
consumption levels and valve timing issues. Also have made good
headway with my pet Solar air conditioning and atmospheric water
generation project. Scope with all of these is potentially huge.
Hopefully I have given the rest of you out there enough information
and motivation to run with and get some momentum going to get a head
of steam up with this project- pun intended.
Over to the rest of you out there for you comments, suggestions and
input,
Cheers.
--
To post to this group, send email to solar-...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/solar-turbine?hl=en
See http://openfarmtech.org/index.php?title=Solar_Power_Generator_Distillation_Transcript
...
Apr 25, 2010, 1:59:48 AM4/25/10
to solar-...@googlegroups.com
6. Aquaflector- http://www.aquaflector.com/technology.html very simple
system. Possibly not so robust but quite clever and may have something
to offer?
7. Computer calculated- from geographic position, date, etc. Does not
actually know where sun is only where it should be. Least desirable in
my humble opinion.
Immunity to sensor error is a pretty big advantage. How does a light sensing tracking system deal with 15 min of cloud cover? Thermal mass on temp sensors causes constant overcorrection and oscillations (related to the time constant of the thermal mass heating).
I think a micro-controller will be necessary in any tracking system for this project.
Do you think the rated torque load of the geared motor you link to is sufficient to drive the linked assembly you propose?
> https://sdp-si.com/eStore/PartDetail.asp?Opener=Group&PartID=57804&GroupID=222
For the rack and pinion actuator, what are the issues with tolerances? how precise could a rack and pinion system be?
I'll look into following this up with some estimations on how degree of accuracy will effect the utility/efficiency of the system.
-elliot
Ozheliguy
Apr 25, 2010, 10:56:50 AM4/25/10
to Solar Turbine
Yes,
I fully agree that overall this system is nowhere near the level of
precision or concentration required. I think the principles used are
quite clever and simple. Using water to create a precise level and a
large volume being controlled by a small flow. I cant see how we can
use that technology but it gives one possibilities to think on.
Yes you are correct that cloud cover (which can last for a day or more
easily), eclipses, do play havoc on light sensors. Perhaps this is
another benefit of a thermal system? If there is insuffient sun to
confuse a light sensor there is probably insufficient sun to
concentrate to heat water?
Thermal sensors, yes thermal mass could well cause lags and over
correcting and oscillating/ hunting- like any control system. Perhaps
a free air temp measurement would be better from the less thermal mass
issue. Like any system it would take some developing. If there was an
easy solution it would already have been done. Parameters like,
delays, sensitivity etc would definately have to be played with. But
maybe not much? Yes I agree that a micro- controller system is
definately a better way to go. I guess the question is could we
adequately get by with out one? We may be able to, so why bother with
one if we dont need one.
Having said all that, as you correctly point out any sensing system
has drawbacks. A computer calculated system may well work out to be
the most workable? I am just proposing options and alternatives as I
understand them. I am learning, but by no means profess to be an
authority. From the information I can find, most systems dont seem to
use them. I'm sure they are getting better though.
Having said what you consider to be drawback with the above concepts
what are your ideas on what might be most suitable?
Torque of motors. Yes I agree that the motor I used as an example is
most likely going to be too small for this application. I chose the
biggest on that particular site. I more intended it to be an example
of the type possible. There will be many questions related to motor
capacity size. How many we intend to use to share the load, how well
counter balanced the system is, total mechanical control system
friction and inertia etc etc. We are more at the workable concept
stage, than the particular specifications stage.
Accuracy/ precision/ tolerances- This all boils down to 2 factors-
1. Control precision of pinion rotation.
We control these by using gearing on our motors and stepper motors. Ie
a highly geared motor only outputs a little for a lot of motor input.
It then comes down to how fast the motor spins and how quickly we can
stop it. There is also the potential issue of gear backlash.
A stepper moves in indvidual rotational steps of typically say 1.8
degs/ 200 steps per revolution. So we can stop them very quickly to
move them very small amounts. Of course we can also have a combination
of the 2 ie a geared stepper.
Again it all comes down to what is the minimum we need to make this
work well. We can certainly go the biggest and best, but we are trying
to keeps things as simple, inexpensive and reliable as possible.
2. Gear mesh backlash between the rack and pinion. We have to
calculate allowing for an amount of backlash as a fact of practical
reality. We will obviously design our system with features to keep
backlash to a minimum. For example keeping some pressure on the gears
to force them into mesh. The normal trick is to have our motor mounted
on a pivoting base above the rack. The weight of the motor, perhaps
additional weight or spring pressure putting some pressure holding the
pinion tighter in mesh.
Reality is that the gear pitch, usually quoted in No of teeth per
inch/ pitch. If we allow for backlash the distance of our pitch as our
design worse case scenerio we are OK. If we ever had this much we
would have serious problems with our system, like missing gear teeth
etc. The rack I used as an an example had a pitch of 24. Ie 1/24th of
an inch- which is around 1mm for those that can speak metric or
between 1/16 and a 1/32" ie not much. In our example using our 1 metre
links this equates to around 0.057 deg/ 3.44 mins/ <0.001 radian
(1/1000th of a radian) of reflector rotation. We should also add any
other potential points of wear. In the arrangement I suggest we have a
pivot point where our individual 1m link attach to our common rail.
Also our any gear backlash in our geared motor. So a total of 3
potential slop areas if we use a geared motor. If we calculate our
maximum potential slop is greater than our required accuracy tolerance
we can easily increase our lever length. Ie if we uesd a 2 metre lever
instead on a 1 metre our accuracy would be twice. Ie we would get
<0.0005 radian reflector rotational slop for wear equivalent of 1
pitch of our rack. The most detrimental wear factor would be in the
reflector rotational pivots. I cant see any way around this, and all
other CLFR systems have this as well. Indeed compared with using
geared motors attached directly to relectors we would be capable of
far greater precision. Essentially only limited to the length of the
levers we use. A lever of course is a solid form of mulitplication not
like gearing. All our potential wear is reduced by a factor equivalent
to the ratio of mirror to pivot to lever length. Lever length is an
easy inexpensive way to get the accuracy we want. From what I can see
a far more difficult issue on how to get reflector accuracy are the
factors above the reflector pivot. Like twist in reflectors, sag,
accuracy of pivot alignment from support frame inaccuracies,
distortion from temp changes, wind, foundation subsidence, target
movement etc etc.
From what I have read I dont think this seems to be a showstopper
issue with existing projects. They seem to work so maybe these issues
arent as crucial as we think. But atleast as many alternatives are
being considered as possible.
Cheers.
On Apr 25, 2:59 am, "..." <offonoffoffon...@gmail.com> wrote:
> > 6. Aquaflector-http://www.aquaflector.com/technology.htmlvery
I fully agree that overall this system is nowhere near the level of
precision or concentration required. I think the principles used are
quite clever and simple. Using water to create a precise level and a
large volume being controlled by a small flow. I cant see how we can
use that technology but it gives one possibilities to think on.
Yes you are correct that cloud cover (which can last for a day or more
easily), eclipses, do play havoc on light sensors. Perhaps this is
another benefit of a thermal system? If there is insuffient sun to
confuse a light sensor there is probably insufficient sun to
concentrate to heat water?
Thermal sensors, yes thermal mass could well cause lags and over
correcting and oscillating/ hunting- like any control system. Perhaps
a free air temp measurement would be better from the less thermal mass
issue. Like any system it would take some developing. If there was an
easy solution it would already have been done. Parameters like,
delays, sensitivity etc would definately have to be played with. But
maybe not much? Yes I agree that a micro- controller system is
definately a better way to go. I guess the question is could we
adequately get by with out one? We may be able to, so why bother with
one if we dont need one.
Having said all that, as you correctly point out any sensing system
has drawbacks. A computer calculated system may well work out to be
the most workable? I am just proposing options and alternatives as I
understand them. I am learning, but by no means profess to be an
authority. From the information I can find, most systems dont seem to
use them. I'm sure they are getting better though.
Having said what you consider to be drawback with the above concepts
what are your ideas on what might be most suitable?
Torque of motors. Yes I agree that the motor I used as an example is
most likely going to be too small for this application. I chose the
biggest on that particular site. I more intended it to be an example
of the type possible. There will be many questions related to motor
capacity size. How many we intend to use to share the load, how well
counter balanced the system is, total mechanical control system
friction and inertia etc etc. We are more at the workable concept
stage, than the particular specifications stage.
Accuracy/ precision/ tolerances- This all boils down to 2 factors-
1. Control precision of pinion rotation.
We control these by using gearing on our motors and stepper motors. Ie
a highly geared motor only outputs a little for a lot of motor input.
It then comes down to how fast the motor spins and how quickly we can
stop it. There is also the potential issue of gear backlash.
A stepper moves in indvidual rotational steps of typically say 1.8
degs/ 200 steps per revolution. So we can stop them very quickly to
move them very small amounts. Of course we can also have a combination
of the 2 ie a geared stepper.
Again it all comes down to what is the minimum we need to make this
work well. We can certainly go the biggest and best, but we are trying
to keeps things as simple, inexpensive and reliable as possible.
2. Gear mesh backlash between the rack and pinion. We have to
calculate allowing for an amount of backlash as a fact of practical
reality. We will obviously design our system with features to keep
backlash to a minimum. For example keeping some pressure on the gears
to force them into mesh. The normal trick is to have our motor mounted
on a pivoting base above the rack. The weight of the motor, perhaps
additional weight or spring pressure putting some pressure holding the
pinion tighter in mesh.
Reality is that the gear pitch, usually quoted in No of teeth per
inch/ pitch. If we allow for backlash the distance of our pitch as our
design worse case scenerio we are OK. If we ever had this much we
would have serious problems with our system, like missing gear teeth
etc. The rack I used as an an example had a pitch of 24. Ie 1/24th of
an inch- which is around 1mm for those that can speak metric or
between 1/16 and a 1/32" ie not much. In our example using our 1 metre
links this equates to around 0.057 deg/ 3.44 mins/ <0.001 radian
(1/1000th of a radian) of reflector rotation. We should also add any
other potential points of wear. In the arrangement I suggest we have a
pivot point where our individual 1m link attach to our common rail.
Also our any gear backlash in our geared motor. So a total of 3
potential slop areas if we use a geared motor. If we calculate our
maximum potential slop is greater than our required accuracy tolerance
we can easily increase our lever length. Ie if we uesd a 2 metre lever
instead on a 1 metre our accuracy would be twice. Ie we would get
<0.0005 radian reflector rotational slop for wear equivalent of 1
pitch of our rack. The most detrimental wear factor would be in the
reflector rotational pivots. I cant see any way around this, and all
other CLFR systems have this as well. Indeed compared with using
geared motors attached directly to relectors we would be capable of
far greater precision. Essentially only limited to the length of the
levers we use. A lever of course is a solid form of mulitplication not
like gearing. All our potential wear is reduced by a factor equivalent
to the ratio of mirror to pivot to lever length. Lever length is an
easy inexpensive way to get the accuracy we want. From what I can see
a far more difficult issue on how to get reflector accuracy are the
factors above the reflector pivot. Like twist in reflectors, sag,
accuracy of pivot alignment from support frame inaccuracies,
distortion from temp changes, wind, foundation subsidence, target
movement etc etc.
From what I have read I dont think this seems to be a showstopper
issue with existing projects. They seem to work so maybe these issues
arent as crucial as we think. But atleast as many alternatives are
being considered as possible.
Cheers.
On Apr 25, 2:59 am, "..." <offonoffoffon...@gmail.com> wrote:
> > 6. Aquaflector-http://www.aquaflector.com/technology.htmlvery
> > simple
> > system. Possibly not so robust but quite clever and may have something
> > to offer?
>
> The site says "makes a great heater". This system probably only gets a few
> suns of concentration. what a difference precision makes. probably he
> doesn't know about nonimaging concentrators, which could achieve equal or
> better concentration than that without tracking at all.
>
> 7. Computer calculated- from geographic position, date, etc. Does not
>
> > actually know where sun is only where it should be. Least desirable in
> > my humble opinion.
>
> Immunity to sensor error is a pretty big advantage. How does a light
> sensing tracking system deal with 15 min of cloud cover? Thermal mass on
> temp sensors causes constant overcorrection and oscillations (related to the
> time constant of the thermal mass heating).
>
> I think a micro-controller will be necessary in any tracking system for this
> project.
>
> Do you think the rated torque load of the geared motor you link to is
> sufficient to drive the linked assembly you propose?
>
> https://sdp-si.com/eStore/PartDetail.asp?Opener=Group&PartID=57804&Gr...
> > system. Possibly not so robust but quite clever and may have something
> > to offer?
>
> The site says "makes a great heater". This system probably only gets a few
> suns of concentration. what a difference precision makes. probably he
> doesn't know about nonimaging concentrators, which could achieve equal or
> better concentration than that without tracking at all.
>
> 7. Computer calculated- from geographic position, date, etc. Does not
>
> > actually know where sun is only where it should be. Least desirable in
> > my humble opinion.
>
> Immunity to sensor error is a pretty big advantage. How does a light
> sensing tracking system deal with 15 min of cloud cover? Thermal mass on
> temp sensors causes constant overcorrection and oscillations (related to the
> time constant of the thermal mass heating).
>
> I think a micro-controller will be necessary in any tracking system for this
> project.
>
> Do you think the rated torque load of the geared motor you link to is
> sufficient to drive the linked assembly you propose?
>
>
> For the rack and pinion actuator, what are the issues with tolerances? how
> precise could a rack and pinion system be?
>
> I'll look into following this up with some estimations on how degree of
> accuracy will effect the utility/efficiency of the system.
>
> -elliot
>
> --
> To post to this group, send email to solar-...@googlegroups.com
> For more options, visit this group athttp://groups.google.com/group/solar-turbine?hl=en
> Seehttp://openfarmtech.org/index.php?title=Solar_Power_Generator_Distill...
> For the rack and pinion actuator, what are the issues with tolerances? how
> precise could a rack and pinion system be?
>
> I'll look into following this up with some estimations on how degree of
> accuracy will effect the utility/efficiency of the system.
>
> -elliot
>
> --
> To post to this group, send email to solar-...@googlegroups.com
> For more options, visit this group athttp://groups.google.com/group/solar-turbine?hl=en
Ozheliguy
Apr 26, 2010, 12:23:31 PM4/26/10
to Solar Turbine
Hi,
just some more thoughts on 'closed loop' feed back control systems.
Oscillatating/ hunting was mentioned as potential problem with non
micro computer control circuit systems. This could be correct but not
necessarily.
However a system is controlled this issue is overcome with 2
'mechanisms'.
1. Speed of actuation and,
2. Accuracy/ sensitivity.
So our question is can we control these factors without a micro
computer controller or do we need one? Well agreed it is certainly
easy with them. I think it may be just as easy without one.
Speed- speed required of actuation of mirror rotation is quite low. We
can 'trade' speed for precision/ accuracy and force required. We can
use lever lengths and gearing to allow us to use reletively small and
inexpensive motors. Our speed being low will give us the extra benefit
of a lesser tendancy to oscillate or hunt. A rough calculation of our
system speed actuation maximum requirement. Max sun elevation around
90 degs from dawn to midday- say 6 hours. If our elevation is as much
as 90 ish degs this would be at low latitudes, ie tropical. Tropical
daylight hours are reasonably constant at around 12 hours a day year
round. So, working on our max of 90 degs in 6 hours = 15 degs/ hour or
0.25 deg/ minute. As we know our mirrors only need to move half of
this ie 0.125/ min (1/8th deg/ min). Using a 1 mtr levers this is less
than 1/8”/ 2.5 mm movement per minute. This slow rate can be achieved
with gearing both internally in the motor and also with gear ratio of
the rack and pinion. So through gearing we can trade a small force and
high ’ish’ motor output speed into a much larger force and slower
speed- just what we want.
Realistically probably better to have a bit of speed in reserve to say
catch up quickly, after our system gets a bit lost for a while, with
the sun that has hidden behind clouds for some time. This is also
controlled in some systems with a built in delay. I think we can quite
easily control these factors without a micro computer controller
circuit. A delay mechanism is certainly easy to control with a micro
computer, ie 555's etc but because of the low speeds we are talking
about I doubt we need this.
Sensitivity- The point where no feedback error signal occurs,
(referred to as the null point), is what we are striving to maintain.
However if this is too precise/ small the system will always overshoot
and have to re correct back the opposite way again- referred to as
‘oscillating’ or ‘hunting ‘. Again with a very slow actuation speed
overshoot is reduced or hopefully eliminated altogether. The system
has time to react before it travels past the target point. Ie one
feedback loop error signal turns off before the opposite one turns
on.
Again I think our sensitivity can be adjusted without micro computer
controllers. Using the example of heat sensing controlling moving our
heat sensors further from the target will reduce the system
sensitivity.
My thinking is perhaps to try the simple inexpensive methods first. If
it is too difficult to make it work acceptably then add more
complexity/ technology. I think to experiment with this sort of
system could be a quick and inexpensive process to determine if it's
workable. If it doesn’t look like it will ‘fly’ we progress to plan A,
B, C etc, spending more money with micro controller computers,
commercial probe systems or whatever. This is all part of the
development process. If it was easy anyone could do it and it would
been done already. It hasn’t been achieved yet.
I am reasonably comfortable the way to move the mirrors is reasonably
straight forward and economically achievable. The way to control that
movement is the main question, but we have enough good possibilities
to start experimenting with.
Cheers.
On Apr 25, 2:59 am, "..." <offonoffoffon...@gmail.com> wrote:
> > 6. Aquaflector-http://www.aquaflector.com/technology.htmlvery
just some more thoughts on 'closed loop' feed back control systems.
Oscillatating/ hunting was mentioned as potential problem with non
micro computer control circuit systems. This could be correct but not
necessarily.
However a system is controlled this issue is overcome with 2
'mechanisms'.
1. Speed of actuation and,
2. Accuracy/ sensitivity.
So our question is can we control these factors without a micro
computer controller or do we need one? Well agreed it is certainly
easy with them. I think it may be just as easy without one.
Speed- speed required of actuation of mirror rotation is quite low. We
can 'trade' speed for precision/ accuracy and force required. We can
use lever lengths and gearing to allow us to use reletively small and
inexpensive motors. Our speed being low will give us the extra benefit
of a lesser tendancy to oscillate or hunt. A rough calculation of our
system speed actuation maximum requirement. Max sun elevation around
90 degs from dawn to midday- say 6 hours. If our elevation is as much
as 90 ish degs this would be at low latitudes, ie tropical. Tropical
daylight hours are reasonably constant at around 12 hours a day year
round. So, working on our max of 90 degs in 6 hours = 15 degs/ hour or
0.25 deg/ minute. As we know our mirrors only need to move half of
this ie 0.125/ min (1/8th deg/ min). Using a 1 mtr levers this is less
than 1/8”/ 2.5 mm movement per minute. This slow rate can be achieved
with gearing both internally in the motor and also with gear ratio of
the rack and pinion. So through gearing we can trade a small force and
high ’ish’ motor output speed into a much larger force and slower
speed- just what we want.
Realistically probably better to have a bit of speed in reserve to say
catch up quickly, after our system gets a bit lost for a while, with
the sun that has hidden behind clouds for some time. This is also
controlled in some systems with a built in delay. I think we can quite
easily control these factors without a micro computer controller
circuit. A delay mechanism is certainly easy to control with a micro
computer, ie 555's etc but because of the low speeds we are talking
about I doubt we need this.
Sensitivity- The point where no feedback error signal occurs,
(referred to as the null point), is what we are striving to maintain.
However if this is too precise/ small the system will always overshoot
and have to re correct back the opposite way again- referred to as
‘oscillating’ or ‘hunting ‘. Again with a very slow actuation speed
overshoot is reduced or hopefully eliminated altogether. The system
has time to react before it travels past the target point. Ie one
feedback loop error signal turns off before the opposite one turns
on.
Again I think our sensitivity can be adjusted without micro computer
controllers. Using the example of heat sensing controlling moving our
heat sensors further from the target will reduce the system
sensitivity.
My thinking is perhaps to try the simple inexpensive methods first. If
it is too difficult to make it work acceptably then add more
complexity/ technology. I think to experiment with this sort of
system could be a quick and inexpensive process to determine if it's
workable. If it doesn’t look like it will ‘fly’ we progress to plan A,
B, C etc, spending more money with micro controller computers,
commercial probe systems or whatever. This is all part of the
development process. If it was easy anyone could do it and it would
been done already. It hasn’t been achieved yet.
I am reasonably comfortable the way to move the mirrors is reasonably
straight forward and economically achievable. The way to control that
movement is the main question, but we have enough good possibilities
to start experimenting with.
Cheers.
On Apr 25, 2:59 am, "..." <offonoffoffon...@gmail.com> wrote:
> > 6. Aquaflector-http://www.aquaflector.com/technology.htmlvery
> > simple
> > system. Possibly not so robust but quite clever and may have something
> > to offer?
>
> The site says "makes a great heater". This system probably only gets a few
> suns of concentration. what a difference precision makes. probably he
> doesn't know about nonimaging concentrators, which could achieve equal or
> better concentration than that without tracking at all.
>
> 7. Computer calculated- from geographic position, date, etc. Does not
>
> > actually know where sun is only where it should be. Least desirable in
> > my humble opinion.
>
> Immunity to sensor error is a pretty big advantage. How does a light
> sensing tracking system deal with 15 min of cloud cover? Thermal mass on
> temp sensors causes constant overcorrection and oscillations (related to the
> time constant of the thermal mass heating).
>
> I think a micro-controller will be necessary in any tracking system for this
> project.
>
> Do you think the rated torque load of the geared motor you link to is
> sufficient to drive the linked assembly you propose?
>
> https://sdp-si.com/eStore/PartDetail.asp?Opener=Group&PartID=57804&Gr...
> > system. Possibly not so robust but quite clever and may have something
> > to offer?
>
> The site says "makes a great heater". This system probably only gets a few
> suns of concentration. what a difference precision makes. probably he
> doesn't know about nonimaging concentrators, which could achieve equal or
> better concentration than that without tracking at all.
>
> 7. Computer calculated- from geographic position, date, etc. Does not
>
> > actually know where sun is only where it should be. Least desirable in
> > my humble opinion.
>
> Immunity to sensor error is a pretty big advantage. How does a light
> sensing tracking system deal with 15 min of cloud cover? Thermal mass on
> temp sensors causes constant overcorrection and oscillations (related to the
> time constant of the thermal mass heating).
>
> I think a micro-controller will be necessary in any tracking system for this
> project.
>
> Do you think the rated torque load of the geared motor you link to is
> sufficient to drive the linked assembly you propose?
>
>
> For the rack and pinion actuator, what are the issues with tolerances? how
> precise could a rack and pinion system be?
>
> I'll look into following this up with some estimations on how degree of
> accuracy will effect the utility/efficiency of the system.
>
> -elliot
>
> --
> To post to this group, send email to solar-...@googlegroups.com
> For more options, visit this group athttp://groups.google.com/group/solar-turbine?hl=en
> Seehttp://openfarmtech.org/index.php?title=Solar_Power_Generator_Distill...
> For the rack and pinion actuator, what are the issues with tolerances? how
> precise could a rack and pinion system be?
>
> I'll look into following this up with some estimations on how degree of
> accuracy will effect the utility/efficiency of the system.
>
> -elliot
>
> --
> To post to this group, send email to solar-...@googlegroups.com
> For more options, visit this group athttp://groups.google.com/group/solar-turbine?hl=en
Marcin Jakubowski
Apr 26, 2010, 1:23:22 PM4/26/10
to solar-...@googlegroups.com
Milton,
What simple and inexpensive tests would you propose on the simpler methods of tracking, and what would be the desirable proofs-of-concept that we can learn from these methods?
Marcin--
--------------------------------------------------
Marcin Jakubowski, Ph.D.
Open Source Ecology
http://openfarmtech.org/weblog
http://www.replab.org
opensourceecology at gmail dot com
Skype: marcin_ose
--------------------------------------------------
Nobody said that building the world's first open source village would be easy.
-- Anonymous, 2009
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-- Robert A. Heinlein
NOTICE: All discussion in this communication is in the public domain, unless otherwise noted. If you are sharing proprietary, confidential, or otherwise privileged information, you must make that explicit. Otherwise, this discussion may be copied, republished, and otherwise used in the public domain - respectfully and with proper attribution. Furthermore, please consider that we are not interested in discussion as much as action. Therefore, we are particularly interested in discussion of ideas that both parties can commit to by acting on them.
What simple and inexpensive tests would you propose on the simpler methods of tracking, and what would be the desirable proofs-of-concept that we can learn from these methods?
Marcin
--------------------------------------------------
Marcin Jakubowski, Ph.D.
Open Source Ecology
http://openfarmtech.org/weblog
http://www.replab.org
opensourceecology at gmail dot com
Skype: marcin_ose
--------------------------------------------------
Nobody said that building the world's first open source village would be easy.
-- Anonymous, 2009
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-- Robert A. Heinlein
NOTICE: All discussion in this communication is in the public domain, unless otherwise noted. If you are sharing proprietary, confidential, or otherwise privileged information, you must make that explicit. Otherwise, this discussion may be copied, republished, and otherwise used in the public domain - respectfully and with proper attribution. Furthermore, please consider that we are not interested in discussion as much as action. Therefore, we are particularly interested in discussion of ideas that both parties can commit to by acting on them.
Ozheliguy
Apr 26, 2010, 2:49:31 PM4/26/10
to Solar Turbine
Hi all,
2 x $10 temp switches may be enough to control our system? We would
soon find out when we try. It is all a question of a temp switch
heating, closing and driving the mirrors away to a point where the
switch cools and opens, but before the other gets hot and closes. This
maybe possible with our mirrors moving quite slowly. Just theorising
here. We want to keep the costs as low as possible maybe this is a way
to do it? If we prove that the concept works, we learn what we can and
cant get away with using. Or possibly a couple of small solar panels
operating relays to drive our control motor/s? I dont know how much we
can pick these up for but I would think quite cheaply and readily. The
example I posted recently was from small solar powered 'path' garden
lights. Although solar cells are like any light/ sun tracking system
require extra complexity with some mechanism to halve the mirror
movement to that of the sun. Ie aiming mirror or something.
I am interested to hear other ideas and suggestions from everyone else
out there.
Cheers.
On Apr 26, 2:23 pm, Marcin Jakubowski <joseph.dolit...@gmail.com>
wrote:
> >http://openfarmtech.org/index.php?title=Solar_Power_Generator_Distill...
>
> - Show quoted text -
2 x $10 temp switches may be enough to control our system? We would
soon find out when we try. It is all a question of a temp switch
heating, closing and driving the mirrors away to a point where the
switch cools and opens, but before the other gets hot and closes. This
maybe possible with our mirrors moving quite slowly. Just theorising
here. We want to keep the costs as low as possible maybe this is a way
to do it? If we prove that the concept works, we learn what we can and
cant get away with using. Or possibly a couple of small solar panels
operating relays to drive our control motor/s? I dont know how much we
can pick these up for but I would think quite cheaply and readily. The
example I posted recently was from small solar powered 'path' garden
lights. Although solar cells are like any light/ sun tracking system
require extra complexity with some mechanism to halve the mirror
movement to that of the sun. Ie aiming mirror or something.
I am interested to hear other ideas and suggestions from everyone else
out there.
Cheers.
On Apr 26, 2:23 pm, Marcin Jakubowski <joseph.dolit...@gmail.com>
wrote:
>
> --
> --------------------------------------------------
> Marcin Jakubowski, Ph.D.
> Open Source Ecologyhttp://openfarmtech.org/webloghttp://www.replab.org
> --
> --------------------------------------------------
> Marcin Jakubowski, Ph.D.
> opensourceecology at gmail dot com
> Skype: marcin_ose
> --------------------------------------------------
>
> Nobody said that building the world's first open source village would be
> easy.
>
> -- Anonymous, 2009
>
> A human being should be able to change a diaper, plan an invasion, butcher a
> hog, conn a ship, design a building, write a sonnet, balance accounts, build
> a wall, set a bone, comfort the dying, take orders, give orders, cooperate,
> act alone, solve equations, analyze a new problem, pitch manure, program a
> computer, cook a tasty meal, fight efficiently, die gallantly.
> Specialization is for insects.
>
> -- Robert A. Heinlein
>
> NOTICE: All discussion in this communication is in the public domain, unless
> otherwise noted. If you are sharing proprietary, confidential, or otherwise
> privileged information, you must make that explicit. Otherwise, this
> discussion may be copied, republished, and otherwise used in the public
> domain - respectfully and with proper attribution. Furthermore, please
> consider that we are not interested in discussion as much as action.
> Therefore, we are particularly interested in discussion of ideas that both
> parties can commit to by acting on them.
>
> --
> To post to this group, send email to solar-...@googlegroups.com
> For more options, visit this group athttp://groups.google.com/group/solar-turbine?hl=en
> Seehttp://openfarmtech.org/index.php?title=Solar_Power_Generator_Distill...- Hide quoted text -
> Skype: marcin_ose
> --------------------------------------------------
>
> Nobody said that building the world's first open source village would be
> easy.
>
> -- Anonymous, 2009
>
> A human being should be able to change a diaper, plan an invasion, butcher a
> hog, conn a ship, design a building, write a sonnet, balance accounts, build
> a wall, set a bone, comfort the dying, take orders, give orders, cooperate,
> act alone, solve equations, analyze a new problem, pitch manure, program a
> computer, cook a tasty meal, fight efficiently, die gallantly.
> Specialization is for insects.
>
> -- Robert A. Heinlein
>
> NOTICE: All discussion in this communication is in the public domain, unless
> otherwise noted. If you are sharing proprietary, confidential, or otherwise
> privileged information, you must make that explicit. Otherwise, this
> discussion may be copied, republished, and otherwise used in the public
> domain - respectfully and with proper attribution. Furthermore, please
> consider that we are not interested in discussion as much as action.
> Therefore, we are particularly interested in discussion of ideas that both
> parties can commit to by acting on them.
>
> --
> To post to this group, send email to solar-...@googlegroups.com
> For more options, visit this group athttp://groups.google.com/group/solar-turbine?hl=en
>
> - Show quoted text -
...
Apr 26, 2010, 4:00:00 PM4/26/10
to solar-...@googlegroups.com
I think marcin was asking for the specifics of a test which would demonstrate a hint of the validity or fallacy of these proposed ideas.
One needs more than that. Like a motor to control the reflectors, the circuitry (analog, simple digital or microcontroller), reflectors and the reflector actuating system.
I think elaborating an inexpensive proof-of concept is an excellent idea. we can be very specific about what parts we need, what they would cost, and what the experiment would prove.
>Torque of motors. Yes I agree that the motor I used as an example is
>most likely going to be too small for this application. I chose the
>biggest on that particular site. I more intended it to be an example
>of the type possible.
2 x $10 temp switches may be enough to control our system?
One needs more than that. Like a motor to control the reflectors, the circuitry (analog, simple digital or microcontroller), reflectors and the reflector actuating system.
I think elaborating an inexpensive proof-of concept is an excellent idea. we can be very specific about what parts we need, what they would cost, and what the experiment would prove.
>Torque of motors. Yes I agree that the motor I used as an example is
>most likely going to be too small for this application. I chose the
>biggest on that particular site. I more intended it to be an example
>of the type possible.
I just brought that up because you offered a quote on it, but if that motor is not what we need, then why suspect that the price of that motor is at all related to what we would need to spend?
Ozheliguy
Apr 26, 2010, 5:27:22 PM4/26/10
to Solar Turbine
Yeh OK,
I was thinking in my own mind that certain issues are not exactly
proved in detail, but conceptually highly possible and therefore
probably the way to proceed- like motors, rack and pinions, common
link and individual levers. I have a fair idea what I think should
work, although the exact model suitable, and therefore price still
needs to determined precisely. However to proceed to that point we
need to agree what concept/s are worth pursuing. Then we can find out
exactly a range of motor models and prices that are most likely to fit
our needs. I don’t know a great deal about these motors. All I know is
that they're what seems to be generally used and therefore shouldn’t
be too much of an issue. You seem to have some ideas here what might
be suitable here- open to suggestions. When we get that far it is
probably better to look at the real physical system with individual
levers, common link, rack, mirrors, counterweights and physically see
what sort of loads are actually involved. We can use spring scales or
whatever as we know what max speeds are required.
I have been reasonably specific of the type of mechanism I suggest in
my recent posts. I think we need some input from the rest of the team
to decide which ways to proceed. I haven’t designed a complete system
in specific detail- yet. But I have suggested a number of concepts I
think might be worth pursuing.
So at that point we would have the means of moving the mirrors but
still need to develop the method of controlling that movement. We
would have several options. We would start at the simpler, cheaper but
unproven devices. Then if they aren’t going to be able to be made to
work, we spend more on more expensive proven systems.
Time Line of Project Progression
1. Decide as a group what concepts we wish to pursue,
2. Find out more details of those concepts, ie range of motor models
and prices,
3. Build either the real, or mock up reflector array, with mirrors,
rotation mechanical mechanisms etc
4. Decide on required specific motor/s to drive the mechanism- (At
this point we will have an array with mirrors and a powered rotational
system). ,
5. Start `experimenting’ with a control system for our powered mirror
rotation system. Start with the less complex cheaper possibilities
like our $10 temp switches
http://in.rsdelivers.com/product/honeywell/2455rc-90820388/bi-metallic-thermostat-160degc-open-temp/4940867.aspx
to run our motors one way or the other. We know it can be done and we
know there are a number of possible options to achieve it. The worst
case scenario is that we have to spend some more money to buy someone
else’s proven technology like http://www.acrosolarlasers.com/acrosolarcatalog8.html
for $650.
Cheers.
> Seehttp://openfarmtech.org/index.php?title=Solar_Power_Generator_Distill...
I was thinking in my own mind that certain issues are not exactly
proved in detail, but conceptually highly possible and therefore
probably the way to proceed- like motors, rack and pinions, common
link and individual levers. I have a fair idea what I think should
work, although the exact model suitable, and therefore price still
needs to determined precisely. However to proceed to that point we
need to agree what concept/s are worth pursuing. Then we can find out
exactly a range of motor models and prices that are most likely to fit
our needs. I don’t know a great deal about these motors. All I know is
that they're what seems to be generally used and therefore shouldn’t
be too much of an issue. You seem to have some ideas here what might
be suitable here- open to suggestions. When we get that far it is
probably better to look at the real physical system with individual
levers, common link, rack, mirrors, counterweights and physically see
what sort of loads are actually involved. We can use spring scales or
whatever as we know what max speeds are required.
I have been reasonably specific of the type of mechanism I suggest in
my recent posts. I think we need some input from the rest of the team
to decide which ways to proceed. I haven’t designed a complete system
in specific detail- yet. But I have suggested a number of concepts I
think might be worth pursuing.
So at that point we would have the means of moving the mirrors but
still need to develop the method of controlling that movement. We
would have several options. We would start at the simpler, cheaper but
unproven devices. Then if they aren’t going to be able to be made to
work, we spend more on more expensive proven systems.
Time Line of Project Progression
1. Decide as a group what concepts we wish to pursue,
2. Find out more details of those concepts, ie range of motor models
and prices,
3. Build either the real, or mock up reflector array, with mirrors,
rotation mechanical mechanisms etc
4. Decide on required specific motor/s to drive the mechanism- (At
this point we will have an array with mirrors and a powered rotational
system). ,
5. Start `experimenting’ with a control system for our powered mirror
rotation system. Start with the less complex cheaper possibilities
like our $10 temp switches
http://in.rsdelivers.com/product/honeywell/2455rc-90820388/bi-metallic-thermostat-160degc-open-temp/4940867.aspx
to run our motors one way or the other. We know it can be done and we
know there are a number of possible options to achieve it. The worst
case scenario is that we have to spend some more money to buy someone
else’s proven technology like http://www.acrosolarlasers.com/acrosolarcatalog8.html
for $650.
Cheers.
...
Apr 26, 2010, 9:27:47 PM4/26/10
to solar-...@googlegroups.com
I don’t know a great deal about these motors. All I know is
that they're what seems to be generally used and therefore shouldn’t
be too much of an issue. You seem to have some ideas here what might
be suitable here- open to suggestions.
I think we could say the motor should be strong enough to hold its own against say 15 mph winds. then double that number. If it can push against that, I assume it can push through other smaller forces. from that we can get a specific torque that is probably a safe level. I'll look more into it later.
What happened to the hydraulic idea. I don't think trying to use steam from the system directly is a good design, but using non-corrosive propane or something we can pump back by thermal means* would be better than trying to produce and store electricity to power the system.
*(hydraulic pressure is generated by slight warming, and then the spent (expanded) vapor is re-condensed into the storage container at night with chilled water)
Is a hydraulic system driven by an uncertain pressure workable? Does it require more sensors? electricity will still be necessary for the control electronics, but not for the force of the actuator.
Time Line of Project Progression
1. Decide as a group what concepts we wish to pursue,
2. Find out more details of those concepts, ie range of motor models
and prices,
3. Build either the real, or mock up reflector array, with mirrors,
rotation mechanical mechanisms etc
4. Decide on required specific motor/s to drive the mechanism- (At
this point we will have an array with mirrors and a powered rotational
system). ,
5. Start `experimenting’ with a control system for our powered mirror
rotation system. Start with the less complex cheaper possibilities
like our $10 temp switches
I like the thermal sensor idea. black aluminum or something would have a very fast response time (low thermal mass and high conductivity) and the control system could be damped by analog means to minimize overshoot and oscillations.
either electric or hydraulic w/ hydraulic prefered.
-elliot
Marcin Jakubowski
Apr 26, 2010, 10:45:33 PM4/26/10
to solar-...@googlegroups.com
I think that we need some serious tracking electronics, starting with some kind of a light sensor, not a thermal sensor.
It appears that a thermal sensor is good for one slat or one reflecting device, but if you have 16 slats, how can you tell which of the slats is aligned if the thermal sensor is located at the receiver, and the receiver is getting the combined input of many slats? Which slat do you tell to move?
It seems that the only foolproof solution is a photosensor on each slat. I would start with the circuits available from a proven source such as redrok.com - http://www.redrok.com/electron.htm#led3x , or, look at Arduino-based solar trackers - http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1224541956/9
With the arduino, we can program in basic tracking logic, and then fine-tune with sensors of some sort.
Marcin
It appears that a thermal sensor is good for one slat or one reflecting device, but if you have 16 slats, how can you tell which of the slats is aligned if the thermal sensor is located at the receiver, and the receiver is getting the combined input of many slats? Which slat do you tell to move?
It seems that the only foolproof solution is a photosensor on each slat. I would start with the circuits available from a proven source such as redrok.com - http://www.redrok.com/electron.htm#led3x , or, look at Arduino-based solar trackers - http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1224541956/9
With the arduino, we can program in basic tracking logic, and then fine-tune with sensors of some sort.
Marcin
--
--------------------------------------------------
Marcin Jakubowski, Ph.D.
Open Source Ecology
http://openfarmtech.org/weblog
http://www.replab.org
opensourceecology at gmail dot com
Skype: marcin_ose
--------------------------------------------------
Nobody said that building the world's first open source village would be easy.
-- Anonymous, 2009
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-- Robert A. Heinlein
NOTICE: All discussion in this communication is in the public domain, unless otherwise noted. If you are sharing proprietary, confidential, or otherwise privileged information, you must make that explicit. Otherwise, this discussion may be copied, republished, and otherwise used in the public domain - respectfully and with proper attribution. Furthermore, please consider that we are not interested in discussion as much as action. Therefore, we are particularly interested in discussion of ideas that both parties can commit to by acting on them.
--------------------------------------------------
Marcin Jakubowski, Ph.D.
Open Source Ecology
http://openfarmtech.org/weblog
http://www.replab.org
opensourceecology at gmail dot com
Skype: marcin_ose
--------------------------------------------------
Nobody said that building the world's first open source village would be easy.
-- Anonymous, 2009
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-- Robert A. Heinlein
NOTICE: All discussion in this communication is in the public domain, unless otherwise noted. If you are sharing proprietary, confidential, or otherwise privileged information, you must make that explicit. Otherwise, this discussion may be copied, republished, and otherwise used in the public domain - respectfully and with proper attribution. Furthermore, please consider that we are not interested in discussion as much as action. Therefore, we are particularly interested in discussion of ideas that both parties can commit to by acting on them.
Ozheliguy
Apr 27, 2010, 8:06:13 AM4/27/10
to Solar Turbine
Morning all,
Yes sounds fair. Please feel free to try and calculate motor
requirements. I think it will be difficult to calculate with much real
world accuracy with so many unkown variables.
Yeh certainly haven't forgotten about hydraulics. Have since also
considered a rotary hydraulic motor driving. Yes agree steam/ hot
water is probably not ideal. But so far as hydraulics goes the issues
are, as I see them;-
1. To buy a commercial rotary motor and electric driven pump is I
think going to be to expensive? Started to ask questions about this
but lost momentum waiting for replies etc. This is probably easier for
someone living in a bigish developed country city going to visit so
auto accessory/ engineering/ agricultural suppliers and asking what
they might have and how much etc face to face. Doing this by internet
and email only gets us so far. Unfortunately I dont have that luxuary.
2. My long self made hydraulic linear actuator. Could be quite easy
and cheap to make from standard size hydraulic seals, stainless or
steel pipe etc. This would negate the need for a rack and pinion set
up. But as you say probably a better option would be to use a small
electric pump and say standard hydraulic fluid and resevior module.
Again a visit to an RV or commercial accessory place is best. However
I sensed some reluctance to take this project on. Some responses
seemed daunted by the prospect of building a steam engine and this was
seen as more of the same.
3. Hydraulic thermal expeansion system, I agree I like the concept.
Perhaps we should look into it more. Sounds like you have some ideas.
I dont see uncertain pressures being an issue. They can either be
regulated down to a constant or almost constant. Or we live with
differing rates of actuation it could still work adequately.
Cheers.
> Seehttp://openfarmtech.org/index.php?title=Solar_Power_Generator_Distill...
Yes sounds fair. Please feel free to try and calculate motor
requirements. I think it will be difficult to calculate with much real
world accuracy with so many unkown variables.
Yeh certainly haven't forgotten about hydraulics. Have since also
considered a rotary hydraulic motor driving. Yes agree steam/ hot
water is probably not ideal. But so far as hydraulics goes the issues
are, as I see them;-
1. To buy a commercial rotary motor and electric driven pump is I
think going to be to expensive? Started to ask questions about this
but lost momentum waiting for replies etc. This is probably easier for
someone living in a bigish developed country city going to visit so
auto accessory/ engineering/ agricultural suppliers and asking what
they might have and how much etc face to face. Doing this by internet
and email only gets us so far. Unfortunately I dont have that luxuary.
2. My long self made hydraulic linear actuator. Could be quite easy
and cheap to make from standard size hydraulic seals, stainless or
steel pipe etc. This would negate the need for a rack and pinion set
up. But as you say probably a better option would be to use a small
electric pump and say standard hydraulic fluid and resevior module.
Again a visit to an RV or commercial accessory place is best. However
I sensed some reluctance to take this project on. Some responses
seemed daunted by the prospect of building a steam engine and this was
seen as more of the same.
3. Hydraulic thermal expeansion system, I agree I like the concept.
Perhaps we should look into it more. Sounds like you have some ideas.
I dont see uncertain pressures being an issue. They can either be
regulated down to a constant or almost constant. Or we live with
differing rates of actuation it could still work adequately.
Cheers.
Ozheliguy
Apr 27, 2010, 8:31:02 AM4/27/10
to Solar Turbine
Hi all,
I can see you are thinking of sensing and controlling each mirror
individually. I know this was the original idea. However my thinking
is that it doesnt seem necessary. The sun moves through the same arc
as do all the mirrors need to to follow it. Each mirror could be
individually initially setup for it's aiming. Call this say the
mirrors 'pre track angle'. This will save considerably in complexity
and therefore expense and reliablity.
To me it seems the same whether we are trying to sense heat or light
at the target if the mirrors are all linked together. Trying to use
light sensors obviously works well as most other systems seem to use
it. But we have to overcome issues like stray reflections etc. Not
insurmountable. My idea of a thermal sensor system is based on the
premise it would be detecting heat concentrated by 16 mirrors. This is
quite a distinctive signature and not likely to be confused with any
normal ambient temperature.
Sure Redrok trackers I'm sure are fine. I also like the idea of
Arduino, not that I know anything about it. I'm sure you do and know
of it's capabilities. If that's what is preferred fine lead on.
Cheers.
On Apr 26, 11:45 pm, Marcin Jakubowski <joseph.dolit...@gmail.com>
wrote:
> Arduino-based solar trackers -http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1224541956/9
> >http://openfarmtech.org/index.php?title=Solar_Power_Generator_Distill...
I can see you are thinking of sensing and controlling each mirror
individually. I know this was the original idea. However my thinking
is that it doesnt seem necessary. The sun moves through the same arc
as do all the mirrors need to to follow it. Each mirror could be
individually initially setup for it's aiming. Call this say the
mirrors 'pre track angle'. This will save considerably in complexity
and therefore expense and reliablity.
To me it seems the same whether we are trying to sense heat or light
at the target if the mirrors are all linked together. Trying to use
light sensors obviously works well as most other systems seem to use
it. But we have to overcome issues like stray reflections etc. Not
insurmountable. My idea of a thermal sensor system is based on the
premise it would be detecting heat concentrated by 16 mirrors. This is
quite a distinctive signature and not likely to be confused with any
normal ambient temperature.
Sure Redrok trackers I'm sure are fine. I also like the idea of
Arduino, not that I know anything about it. I'm sure you do and know
of it's capabilities. If that's what is preferred fine lead on.
Cheers.
On Apr 26, 11:45 pm, Marcin Jakubowski <joseph.dolit...@gmail.com>
wrote:
> I think that we need some serious tracking electronics, starting with some
> kind of a light sensor, not a thermal sensor.
>
> It appears that a thermal sensor is good for one slat or one reflecting
> device, but if you have 16 slats, how can you tell which of the slats is
> aligned if the thermal sensor is located at the receiver, and the receiver
> is getting the combined input of many slats? Which slat do you tell to move?
>
> It seems that the only foolproof solution is a photosensor on each slat. I
> would start with the circuits available from a proven source such as
> redrok.com -http://www.redrok.com/electron.htm#led3x, or, look at
> kind of a light sensor, not a thermal sensor.
>
> It appears that a thermal sensor is good for one slat or one reflecting
> device, but if you have 16 slats, how can you tell which of the slats is
> aligned if the thermal sensor is located at the receiver, and the receiver
> is getting the combined input of many slats? Which slat do you tell to move?
>
> It seems that the only foolproof solution is a photosensor on each slat. I
> would start with the circuits available from a proven source such as
> Arduino-based solar trackers -http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1224541956/9
>
> --
> --------------------------------------------------
> Marcin Jakubowski, Ph.D.
> Open Source Ecologyhttp://openfarmtech.org/webloghttp://www.replab.org
> --
> --------------------------------------------------
> Marcin Jakubowski, Ph.D.
> opensourceecology at gmail dot com
> Skype: marcin_ose
> --------------------------------------------------
>
> Nobody said that building the world's first open source village would be
> easy.
>
> -- Anonymous, 2009
>
> A human being should be able to change a diaper, plan an invasion, butcher a
> hog, conn a ship, design a building, write a sonnet, balance accounts, build
> a wall, set a bone, comfort the dying, take orders, give orders, cooperate,
> act alone, solve equations, analyze a new problem, pitch manure, program a
> computer, cook a tasty meal, fight efficiently, die gallantly.
> Specialization is for insects.
>
> -- Robert A. Heinlein
>
> NOTICE: All discussion in this communication is in the public domain, unless
> otherwise noted. If you are sharing proprietary, confidential, or otherwise
> privileged information, you must make that explicit. Otherwise, this
> discussion may be copied, republished, and otherwise used in the public
> domain - respectfully and with proper attribution. Furthermore, please
> consider that we are not interested in discussion as much as action.
> Therefore, we are particularly interested in discussion of ideas that both
> parties can commit to by acting on them.
>
> --
> To post to this group, send email to solar-...@googlegroups.com
> Skype: marcin_ose
> --------------------------------------------------
>
> Nobody said that building the world's first open source village would be
> easy.
>
> -- Anonymous, 2009
>
> A human being should be able to change a diaper, plan an invasion, butcher a
> hog, conn a ship, design a building, write a sonnet, balance accounts, build
> a wall, set a bone, comfort the dying, take orders, give orders, cooperate,
> act alone, solve equations, analyze a new problem, pitch manure, program a
> computer, cook a tasty meal, fight efficiently, die gallantly.
> Specialization is for insects.
>
> -- Robert A. Heinlein
>
> NOTICE: All discussion in this communication is in the public domain, unless
> otherwise noted. If you are sharing proprietary, confidential, or otherwise
> privileged information, you must make that explicit. Otherwise, this
> discussion may be copied, republished, and otherwise used in the public
> domain - respectfully and with proper attribution. Furthermore, please
> consider that we are not interested in discussion as much as action.
> Therefore, we are particularly interested in discussion of ideas that both
> parties can commit to by acting on them.
>
> --
> To post to this group, send email to solar-...@googlegroups.com
> For more options, visit this group athttp://groups.google.com/group/solar-turbine?hl=en
> Seehttp://openfarmtech.org/index.php?title=Solar_Power_Generator_Distill...- Hide quoted text -
>
> - Show quoted text -
> Seehttp://openfarmtech.org/index.php?title=Solar_Power_Generator_Distill...- Hide quoted text -
>
> - Show quoted text -
...
Apr 27, 2010, 11:45:08 AM4/27/10
to solar-...@googlegroups.com
Marcin:
A unified array is much preferable to controlling mirrors individually. In my opinion, we should pursue individually controlled mirrors only if play in the unifying assembly (rack and pinion or whatever) turns out to be greater than the allowable imprecision of the system.
hydraulics:
is there an advantage of using an electric motor to pressurize hydraulic fluid rather than just using a motor to drive the system directly?
to me, hydraulics are preferable only if they can be thermally driven (delta Pressure is from vapor pressure at chilled water temp to pressure at one or two suns concentration).
-elliot
--
To post to this group, send email to solar-...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/solar-turbine?hl=en
See http://openfarmtech.org/index.php?title=Solar_Power_Generator_Distillation_Transcript
A unified array is much preferable to controlling mirrors individually. In my opinion, we should pursue individually controlled mirrors only if play in the unifying assembly (rack and pinion or whatever) turns out to be greater than the allowable imprecision of the system.
hydraulics:
is there an advantage of using an electric motor to pressurize hydraulic fluid rather than just using a motor to drive the system directly?
to me, hydraulics are preferable only if they can be thermally driven (delta Pressure is from vapor pressure at chilled water temp to pressure at one or two suns concentration).
-elliot
--
To post to this group, send email to solar-...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/solar-turbine?hl=en
Ozheliguy
Apr 27, 2010, 1:23:16 PM4/27/10
to Solar Turbine
Adantages of using an electric motor to pressurise hydraulics rather
than straight mechanical output.
Energy efficiency- no,
Simplyfication of mechanical linkages- possibly,
Force multiplication- no, not an issue in this case,
Cost- I wouldn't think so,
Precission- no gears but probably no real difference,
Reliability- less mechanical wear, but can also leak, generally more
reliable than gear/ motor/ micro switches/ clutches combinations
Not a simple or conclusive answer, sorry.
> Seehttp://openfarmtech.org/index.php?title=Solar_Power_Generator_Distill...
than straight mechanical output.
Energy efficiency- no,
Simplyfication of mechanical linkages- possibly,
Force multiplication- no, not an issue in this case,
Cost- I wouldn't think so,
Precission- no gears but probably no real difference,
Reliability- less mechanical wear, but can also leak, generally more
reliable than gear/ motor/ micro switches/ clutches combinations
Not a simple or conclusive answer, sorry.
Ozheliguy
Apr 27, 2010, 2:18:39 PM4/27/10
to Solar Turbine
Hi all,
yes had a look a your Arduino link. It does indeed look very good. I'm
also sure that it is going to be better to get some of the experts in
this area that are out there to advise on this. I also noticed the
infared temp sensors http://www.solarbotics.com/sensors/ ($50 ea) .
Maybe these might be good? Non contact, one pointing either side of
the collector target, or an equal and appropriate distance from, with
your clever circuitry sensing differences driving our motor/s to keep
the sensor temps even? I also noticed someone else using solar cells
as tracking sensors.
cheers.
On Apr 26, 11:45 pm, Marcin Jakubowski <joseph.dolit...@gmail.com>
wrote:
> Arduino-based solar trackers -http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1224541956/9
> >http://openfarmtech.org/index.php?title=Solar_Power_Generator_Distill...
yes had a look a your Arduino link. It does indeed look very good. I'm
also sure that it is going to be better to get some of the experts in
this area that are out there to advise on this. I also noticed the
infared temp sensors http://www.solarbotics.com/sensors/ ($50 ea) .
Maybe these might be good? Non contact, one pointing either side of
the collector target, or an equal and appropriate distance from, with
your clever circuitry sensing differences driving our motor/s to keep
the sensor temps even? I also noticed someone else using solar cells
as tracking sensors.
cheers.
On Apr 26, 11:45 pm, Marcin Jakubowski <joseph.dolit...@gmail.com>
wrote:
> I think that we need some serious tracking electronics, starting with some
> kind of a light sensor, not a thermal sensor.
>
> It appears that a thermal sensor is good for one slat or one reflecting
> device, but if you have 16 slats, how can you tell which of the slats is
> aligned if the thermal sensor is located at the receiver, and the receiver
> is getting the combined input of many slats? Which slat do you tell to move?
>
> It seems that the only foolproof solution is a photosensor on each slat. I
> would start with the circuits available from a proven source such as
> redrok.com -http://www.redrok.com/electron.htm#led3x, or, look at
> kind of a light sensor, not a thermal sensor.
>
> It appears that a thermal sensor is good for one slat or one reflecting
> device, but if you have 16 slats, how can you tell which of the slats is
> aligned if the thermal sensor is located at the receiver, and the receiver
> is getting the combined input of many slats? Which slat do you tell to move?
>
> It seems that the only foolproof solution is a photosensor on each slat. I
> would start with the circuits available from a proven source such as
> Arduino-based solar trackers -http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1224541956/9
>
> --
> --------------------------------------------------
> Marcin Jakubowski, Ph.D.
> Open Source Ecologyhttp://openfarmtech.org/webloghttp://www.replab.org
> --
> --------------------------------------------------
> Marcin Jakubowski, Ph.D.
> opensourceecology at gmail dot com
> Skype: marcin_ose
> --------------------------------------------------
>
> Nobody said that building the world's first open source village would be
> easy.
>
> -- Anonymous, 2009
>
> A human being should be able to change a diaper, plan an invasion, butcher a
> hog, conn a ship, design a building, write a sonnet, balance accounts, build
> a wall, set a bone, comfort the dying, take orders, give orders, cooperate,
> act alone, solve equations, analyze a new problem, pitch manure, program a
> computer, cook a tasty meal, fight efficiently, die gallantly.
> Specialization is for insects.
>
> -- Robert A. Heinlein
>
> NOTICE: All discussion in this communication is in the public domain, unless
> otherwise noted. If you are sharing proprietary, confidential, or otherwise
> privileged information, you must make that explicit. Otherwise, this
> discussion may be copied, republished, and otherwise used in the public
> domain - respectfully and with proper attribution. Furthermore, please
> consider that we are not interested in discussion as much as action.
> Therefore, we are particularly interested in discussion of ideas that both
> parties can commit to by acting on them.
>
> --
> To post to this group, send email to solar-...@googlegroups.com
> Skype: marcin_ose
> --------------------------------------------------
>
> Nobody said that building the world's first open source village would be
> easy.
>
> -- Anonymous, 2009
>
> A human being should be able to change a diaper, plan an invasion, butcher a
> hog, conn a ship, design a building, write a sonnet, balance accounts, build
> a wall, set a bone, comfort the dying, take orders, give orders, cooperate,
> act alone, solve equations, analyze a new problem, pitch manure, program a
> computer, cook a tasty meal, fight efficiently, die gallantly.
> Specialization is for insects.
>
> -- Robert A. Heinlein
>
> NOTICE: All discussion in this communication is in the public domain, unless
> otherwise noted. If you are sharing proprietary, confidential, or otherwise
> privileged information, you must make that explicit. Otherwise, this
> discussion may be copied, republished, and otherwise used in the public
> domain - respectfully and with proper attribution. Furthermore, please
> consider that we are not interested in discussion as much as action.
> Therefore, we are particularly interested in discussion of ideas that both
> parties can commit to by acting on them.
>
> --
> To post to this group, send email to solar-...@googlegroups.com
> For more options, visit this group athttp://groups.google.com/group/solar-turbine?hl=en
> Seehttp://openfarmtech.org/index.php?title=Solar_Power_Generator_Distill...- Hide quoted text -
>
> - Show quoted text -
> Seehttp://openfarmtech.org/index.php?title=Solar_Power_Generator_Distill...- Hide quoted text -
>
> - Show quoted text -
Marcin Jakubowski
Apr 27, 2010, 3:26:05 PM4/27/10
to solar-...@googlegroups.com
On Tue, Apr 27, 2010 at 7:31 AM, Ozheliguy <miltf...@gmail.com> wrote:
Hi all,
I can see you are thinking of sensing and controlling each mirror
individually. I know this was the original idea. However my thinking
is that it doesnt seem necessary. The sun moves through the same arc
as do all the mirrors need to to follow it. Each mirror could be
individually initially setup for it's aiming. Call this say the
mirrors 'pre track angle'. This will save considerably in complexity
and therefore expense and reliablity.
Are all the angles that the slats have to turn the same, or are they different for each mirror?
Marcin
...
Apr 27, 2010, 3:37:42 PM4/27/10
to solar-...@googlegroups.com
Are all the angles that the slats have to turn the same, or are they different for each mirror?
Ozheliguy
Apr 27, 2010, 4:44:03 PM4/27/10
to Solar Turbine
Yes,
All the mirrors rotational arcs are the same magnitude. Ie half of sun
elevation. Refer to my diagrams loaded on this site.
Lets say they all move 45 degs. It is usually less depending on
geographic latitude and date of the year. However the individual
mirrors will start (let's call this overnight 'parking' angle) at
different angles depending on where they are in relation to the
collector they are trying to aim sun light at. So in the proposed
configuration of the collector on the sun side of the mirror array the
mirrors closer to the collector will be angled more horizontal (lets
say to the further away mirrors. But they will all move the same
amount on any given day. To give you an example at a location of Lat 7
deg S, at max summer mid day elevation of 83 deg. The closest mirror
to the collector will 'park' at 112.5 degs from horizontal and go to a
max at noon of 154 degs. The furthest mirror parks at 100.5 degs to
max 142 degs at noon. So they both move 41.5 degrees that day.
I hope this makes sense? If you need more clarification I will try to
explain it another way.
Cheers.
On Apr 27, 4:26 pm, Marcin Jakubowski <joseph.dolit...@gmail.com>
wrote:
All the mirrors rotational arcs are the same magnitude. Ie half of sun
elevation. Refer to my diagrams loaded on this site.
Lets say they all move 45 degs. It is usually less depending on
geographic latitude and date of the year. However the individual
mirrors will start (let's call this overnight 'parking' angle) at
different angles depending on where they are in relation to the
collector they are trying to aim sun light at. So in the proposed
configuration of the collector on the sun side of the mirror array the
mirrors closer to the collector will be angled more horizontal (lets
say to the further away mirrors. But they will all move the same
amount on any given day. To give you an example at a location of Lat 7
deg S, at max summer mid day elevation of 83 deg. The closest mirror
to the collector will 'park' at 112.5 degs from horizontal and go to a
max at noon of 154 degs. The furthest mirror parks at 100.5 degs to
max 142 degs at noon. So they both move 41.5 degrees that day.
I hope this makes sense? If you need more clarification I will try to
explain it another way.
Cheers.
On Apr 27, 4:26 pm, Marcin Jakubowski <joseph.dolit...@gmail.com>
wrote:
Ozheliguy
Apr 28, 2010, 2:21:20 PM4/28/10
to Solar Turbine
Infa red sensors. The more I think about them the better they sound.
From what I have read in a number of different sources photo resistors
seem to a bit unreliable, the weak point of a sun tracking system. I
can imagine it is a very hard life for a poor photo resistor,
obviously exposed to full sun day in day out unprotected. Perhaps an
infa red sensor would have an easier life and a longer life? Maybe I
am wrong with this assumption. The other benefit might be that we
could point them either side of the collector, ie in a previously
proposed 'thermal' type application. This way again we wouldn't have
to worry about stray reflections etc, or having to have a mechanism
for halving our mirror movement to the suns. It would be like the
thermal system I recently proposed except no heat directly onto bi
metalic switch contacts, ie a non 'contact' arrangement.
Cheers.
On Apr 26, 11:45 pm, Marcin Jakubowski <joseph.dolit...@gmail.com>
wrote:
> Arduino-based solar trackers -http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1224541956/9
> >http://openfarmtech.org/index.php?title=Solar_Power_Generator_Distill...
From what I have read in a number of different sources photo resistors
seem to a bit unreliable, the weak point of a sun tracking system. I
can imagine it is a very hard life for a poor photo resistor,
obviously exposed to full sun day in day out unprotected. Perhaps an
infa red sensor would have an easier life and a longer life? Maybe I
am wrong with this assumption. The other benefit might be that we
could point them either side of the collector, ie in a previously
proposed 'thermal' type application. This way again we wouldn't have
to worry about stray reflections etc, or having to have a mechanism
for halving our mirror movement to the suns. It would be like the
thermal system I recently proposed except no heat directly onto bi
metalic switch contacts, ie a non 'contact' arrangement.
Cheers.
On Apr 26, 11:45 pm, Marcin Jakubowski <joseph.dolit...@gmail.com>
wrote:
> I think that we need some serious tracking electronics, starting with some
> kind of a light sensor, not a thermal sensor.
>
> It appears that a thermal sensor is good for one slat or one reflecting
> device, but if you have 16 slats, how can you tell which of the slats is
> aligned if the thermal sensor is located at the receiver, and the receiver
> is getting the combined input of many slats? Which slat do you tell to move?
>
> It seems that the only foolproof solution is a photosensor on each slat. I
> would start with the circuits available from a proven source such as
> redrok.com -http://www.redrok.com/electron.htm#led3x, or, look at
> kind of a light sensor, not a thermal sensor.
>
> It appears that a thermal sensor is good for one slat or one reflecting
> device, but if you have 16 slats, how can you tell which of the slats is
> aligned if the thermal sensor is located at the receiver, and the receiver
> is getting the combined input of many slats? Which slat do you tell to move?
>
> It seems that the only foolproof solution is a photosensor on each slat. I
> would start with the circuits available from a proven source such as
> Arduino-based solar trackers -http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1224541956/9
>
> --
> --------------------------------------------------
> Marcin Jakubowski, Ph.D.
> Open Source Ecologyhttp://openfarmtech.org/webloghttp://www.replab.org
> --
> --------------------------------------------------
> Marcin Jakubowski, Ph.D.
> opensourceecology at gmail dot com
> Skype: marcin_ose
> --------------------------------------------------
>
> Nobody said that building the world's first open source village would be
> easy.
>
> -- Anonymous, 2009
>
> A human being should be able to change a diaper, plan an invasion, butcher a
> hog, conn a ship, design a building, write a sonnet, balance accounts, build
> a wall, set a bone, comfort the dying, take orders, give orders, cooperate,
> act alone, solve equations, analyze a new problem, pitch manure, program a
> computer, cook a tasty meal, fight efficiently, die gallantly.
> Specialization is for insects.
>
> -- Robert A. Heinlein
>
> NOTICE: All discussion in this communication is in the public domain, unless
> otherwise noted. If you are sharing proprietary, confidential, or otherwise
> privileged information, you must make that explicit. Otherwise, this
> discussion may be copied, republished, and otherwise used in the public
> domain - respectfully and with proper attribution. Furthermore, please
> consider that we are not interested in discussion as much as action.
> Therefore, we are particularly interested in discussion of ideas that both
> parties can commit to by acting on them.
>
> --
> To post to this group, send email to solar-...@googlegroups.com
> Skype: marcin_ose
> --------------------------------------------------
>
> Nobody said that building the world's first open source village would be
> easy.
>
> -- Anonymous, 2009
>
> A human being should be able to change a diaper, plan an invasion, butcher a
> hog, conn a ship, design a building, write a sonnet, balance accounts, build
> a wall, set a bone, comfort the dying, take orders, give orders, cooperate,
> act alone, solve equations, analyze a new problem, pitch manure, program a
> computer, cook a tasty meal, fight efficiently, die gallantly.
> Specialization is for insects.
>
> -- Robert A. Heinlein
>
> NOTICE: All discussion in this communication is in the public domain, unless
> otherwise noted. If you are sharing proprietary, confidential, or otherwise
> privileged information, you must make that explicit. Otherwise, this
> discussion may be copied, republished, and otherwise used in the public
> domain - respectfully and with proper attribution. Furthermore, please
> consider that we are not interested in discussion as much as action.
> Therefore, we are particularly interested in discussion of ideas that both
> parties can commit to by acting on them.
>
> --
> To post to this group, send email to solar-...@googlegroups.com
> For more options, visit this group athttp://groups.google.com/group/solar-turbine?hl=en
> Seehttp://openfarmtech.org/index.php?title=Solar_Power_Generator_Distill...- Hide quoted text -
>
> - Show quoted text -
> Seehttp://openfarmtech.org/index.php?title=Solar_Power_Generator_Distill...- Hide quoted text -
>
> - Show quoted text -
Ozheliguy
Apr 29, 2010, 8:28:23 AM4/29/10
to Solar Turbine
Sounds interesting, I'm not sure exactly what you have in mind, can
you elaborate more please?
Chilled water temperature- how do you get/ maintain this? I guess you
are talking about around 40F/4C temperatures?
Vapour pressure of what liquid?
Why do you suggest 2 suns and how do you propose to get isolate 2 from
1 or 16 suns environment?
Thermally driven hydraulics- I think I know what you are refering to
but could you elaborate a little for me please?
> Seehttp://openfarmtech.org/index.php?title=Solar_Power_Generator_Distill...
you elaborate more please?
Chilled water temperature- how do you get/ maintain this? I guess you
are talking about around 40F/4C temperatures?
Vapour pressure of what liquid?
Why do you suggest 2 suns and how do you propose to get isolate 2 from
1 or 16 suns environment?
Thermally driven hydraulics- I think I know what you are refering to
but could you elaborate a little for me please?
...
Apr 29, 2010, 2:08:51 PM4/29/10
to solar-...@googlegroups.com
After the first suggestion of this idea I realized of course that this method would be limited by carnot efficency, which is stupid to deal with if you only have 80C temp difference. But, since the piston only has to move once (ie, not an engine), there is so little energy being expended that 1% efficency doesn't make it too difficult.
for example, with a high/low pressure diff of 150 psi (using propane at 15C and 80C I'm guessing), a 2 meter long piston one cm in diameter the work done is 650 watts. over the cource of the day, collecting 60 kw in another lower tech concentrator is, actually, really difficult.
Ok, nevermind, dumb idea. (stupid orders of magnitude).
work = PdV
(150 psi * 6894 Pa/psi)*Pi*.01^2*2m = 650
The premise of this is that getting 2.5x (trough) to 6.25x (2d concentrator) is ridiculously easy with stationary non-imaging concentrators. Especially below 100C so water can be used as a refractive element, and total internal refraction is the reflector (ie, no mirrors).
for example, with a high/low pressure diff of 150 psi (using propane at 15C and 80C I'm guessing), a 2 meter long piston one cm in diameter the work done is 650 watts. over the cource of the day, collecting 60 kw in another lower tech concentrator is, actually, really difficult.
Ok, nevermind, dumb idea. (stupid orders of magnitude).
work = PdV
(150 psi * 6894 Pa/psi)*Pi*.01^2*2m = 650
The premise of this is that getting 2.5x (trough) to 6.25x (2d concentrator) is ridiculously easy with stationary non-imaging concentrators. Especially below 100C so water can be used as a refractive element, and total internal refraction is the reflector (ie, no mirrors).
Ozheliguy
Apr 29, 2010, 4:28:08 PM4/29/10
to Solar Turbine
Hi,
just starting to have a look at that site they use canola oil. Sounds
good from that point of view. I have sent them an email asking for
more information. Maybe we just buy one of their systems, or parts, if
they look OK?
Another that I've happened across.
http://www.motherearthnews.com/Do-It-Yourself/1977-11-01/Mothers-Super-Simple-Solar-Tracker.aspx
I'll keep digging.
Cheers.
> Seehttp://openfarmtech.org/index.php?title=Solar_Power_Generator_Distill...
just starting to have a look at that site they use canola oil. Sounds
good from that point of view. I have sent them an email asking for
more information. Maybe we just buy one of their systems, or parts, if
they look OK?
Another that I've happened across.
http://www.motherearthnews.com/Do-It-Yourself/1977-11-01/Mothers-Super-Simple-Solar-Tracker.aspx
I'll keep digging.
Cheers.
Ozheliguy
May 2, 2010, 10:38:50 AM5/2/10
to Solar Turbine
Hi ,
Yes of course there are many questions to be satisfied before we would
consider going down this road. Indeed it is not designed for and could
not be used for this application in it's current form. You are exactly
correct that a solar shading application doesn’t have to be accurate
to within a few degrees. Our application as we know has to be far more
accurate than within a few degrees.
I’m not exactly sure what is currently proposed for the structure
composition of the array. The material I have found on the site, I’m
not sure if it’s the latest, talks about PVC supports, metal framing
studs, 4x4” lumber. I don’t know if these things are designed for the
accuracy we require either? Timber will vary it’s dimensions with
differing atmospheric moisture levels. Metal framing studs are
questionable about their ability to maintain a consistent angle with a
torsional input over a 10 foot span. PVC- again I’m not sure if it is
structurally rigid enough to support metal framing stud, 3 mm glass
mirror and 2x2x1/8” steel angle frame. Remember that any distortion of
the array dimensions is likely to be disastrous in terms of
concentration accuracy. I couldn’t see anything about a proposed
mirror framing stud rotational mechanism, ie bearings etc.
The questions are:
1. how much could we acquire this sort of arrangement, or some
specific parts, for and,
2. how much would we have to change to make it suitable?
It may well simply be too expensive.
They do seem to have mass produced glass carriers and torque tubes
designed to work up to 4 m spans. We are looking at around 3m spans.
They are also designed with enough structural integrity for high wind
loads high up on the side of buildings.
The other interesting thing to note is that they have a functioning
thermal hydraulic system. I think we can say that concept is proved.
Again we don’t know if it is capable of the precision required.
We may be able to use some of these components successfully. This
would save the need of starting from scratch spending time reinventing
the wheel. We would definitely need our longer individual mirror
adjustable actuation levers.
If we would try to incorporate their ‘Girasol’ thermo hydraulic system
we would need at the very least a longer throw actuator to move our
longer mirror rotational levers through a sufficient arc range to give
us our required accuracy. Just looking at their system quickly I would
also not have their collector tubes moving or linked. I would have
them fixed either side of our target receiver. These are all question
we need to look into.
I know you were joking about shading the array, but with only a little
bit of imagination I can envisage the possibility of using a building
shading system like this that is also a CFLR array. They are doing
this with PV cells on their ‘shades’- listed in the brochure. Which as
we know are far less viable? Instead of the sun’s rays heating up your
house external wall it would be used to produce useful energy. Double
bonus- less heat on your house walls so cooling load requirement
decreased. Even in winter instead of heating up your outside wall the
collected energy could be hot water run through hydronic heating pipes
where most wanted. Call me a dreamer.
Cheers.
On Apr 29, 5:28 pm, Ozheliguy <miltfro...@gmail.com> wrote:
> Hi,
>
> just starting to have a look at that site they use canola oil. Sounds
> good from that point of view. I have sent them an email asking for
> more information. Maybe we just buy one of their systems, or parts, if
> they look OK?
>
> Another that I've happened across.http://www.motherearthnews.com/Do-It-Yourself/1977-11-01/Mothers-Supe...
Yes of course there are many questions to be satisfied before we would
consider going down this road. Indeed it is not designed for and could
not be used for this application in it's current form. You are exactly
correct that a solar shading application doesn’t have to be accurate
to within a few degrees. Our application as we know has to be far more
accurate than within a few degrees.
I’m not exactly sure what is currently proposed for the structure
composition of the array. The material I have found on the site, I’m
not sure if it’s the latest, talks about PVC supports, metal framing
studs, 4x4” lumber. I don’t know if these things are designed for the
accuracy we require either? Timber will vary it’s dimensions with
differing atmospheric moisture levels. Metal framing studs are
questionable about their ability to maintain a consistent angle with a
torsional input over a 10 foot span. PVC- again I’m not sure if it is
structurally rigid enough to support metal framing stud, 3 mm glass
mirror and 2x2x1/8” steel angle frame. Remember that any distortion of
the array dimensions is likely to be disastrous in terms of
concentration accuracy. I couldn’t see anything about a proposed
mirror framing stud rotational mechanism, ie bearings etc.
The questions are:
1. how much could we acquire this sort of arrangement, or some
specific parts, for and,
2. how much would we have to change to make it suitable?
It may well simply be too expensive.
They do seem to have mass produced glass carriers and torque tubes
designed to work up to 4 m spans. We are looking at around 3m spans.
They are also designed with enough structural integrity for high wind
loads high up on the side of buildings.
The other interesting thing to note is that they have a functioning
thermal hydraulic system. I think we can say that concept is proved.
Again we don’t know if it is capable of the precision required.
We may be able to use some of these components successfully. This
would save the need of starting from scratch spending time reinventing
the wheel. We would definitely need our longer individual mirror
adjustable actuation levers.
If we would try to incorporate their ‘Girasol’ thermo hydraulic system
we would need at the very least a longer throw actuator to move our
longer mirror rotational levers through a sufficient arc range to give
us our required accuracy. Just looking at their system quickly I would
also not have their collector tubes moving or linked. I would have
them fixed either side of our target receiver. These are all question
we need to look into.
I know you were joking about shading the array, but with only a little
bit of imagination I can envisage the possibility of using a building
shading system like this that is also a CFLR array. They are doing
this with PV cells on their ‘shades’- listed in the brochure. Which as
we know are far less viable? Instead of the sun’s rays heating up your
house external wall it would be used to produce useful energy. Double
bonus- less heat on your house walls so cooling load requirement
decreased. Even in winter instead of heating up your outside wall the
collected energy could be hot water run through hydronic heating pipes
where most wanted. Call me a dreamer.
Cheers.
On Apr 29, 5:28 pm, Ozheliguy <miltfro...@gmail.com> wrote:
> Hi,
>
> just starting to have a look at that site they use canola oil. Sounds
> good from that point of view. I have sent them an email asking for
> more information. Maybe we just buy one of their systems, or parts, if
> they look OK?
>
> For more options, visit this group athttp://groups.google.com/group/solar-turbine?hl=en
> Seehttp://openfarmtech.org/index.php?title=Solar_Power_Generator_Distill...- Hide quoted text -
>
> - Show quoted text -
> Seehttp://openfarmtech.org/index.php?title=Solar_Power_Generator_Distill...- Hide quoted text -
>
> - Show quoted text -
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