Solar Collector angle
Daniel Shen
manually adjust the angle
of the solar collector three times a year? (This might not be
feasible for a super heavy collector.)
Just a thought off the top of my head.
Dan
On Mar 21, 2007, at 2:04 PM, solar-buddies group wrote:
>
> solar buddies
> http://groups.google.com/group/solar-buddies?hl=en
>
> solar-...@googlegroups.com
>
> Today's topics:
>
> * Clear Air Attenuation - 5 messages, 2 authors
> http://groups.google.com/group/solar-buddies/browse_thread/thread/
> 65032f910eb90211?hl=en
> * Is it optimum to only preheat DHW with solar? - 2 messages, 2
> authors
> http://groups.google.com/group/solar-buddies/browse_thread/thread/
> b3e99dd4af5f29e2?hl=en
> * View this page "solarwaterheater" - 1 messages, 1 author
> http://groups.google.com/group/solar-buddies/browse_thread/thread/
> 1740cea1129846db?hl=en
> * Energy Rates - 7 messages, 3 authors
> http://groups.google.com/group/solar-buddies/browse_thread/thread/
> 8480e2d196552dd5?hl=en
> * graph.php (PNG Image, 900x480 pixels) - 1 messages, 1 author
> http://groups.google.com/group/solar-buddies/browse_thread/thread/
> 8c2b115970c76214?hl=en
> * New job for John - 3 messages, 2 authors
> http://groups.google.com/group/solar-buddies/browse_thread/thread/
> 6dbf77548d4007e1?hl=en
> * mods to John Allen's Solar Thermal system - 2 messages, 1 author
> http://groups.google.com/group/solar-buddies/browse_thread/thread/
> cf1c385919ae171f?hl=en
> * Plastic pipe bending experiment - 4 messages, 3 authors
> http://groups.google.com/group/solar-buddies/browse_thread/thread/
> 84b51131d95ac450?hl=en
>
> ======================================================================
> ========
> TOPIC: Clear Air Attenuation
> http://groups.google.com/group/solar-buddies/browse_thread/thread/
> 65032f910eb90211?hl=en
> ======================================================================
> ========
>
> == 1 of 5 ==
> Date: Tues, Mar 20 2007 1:38 am
> From: "Joe Rich"
>
>
> No, not a simple one, but if someone has the space, I have an idea for
> a cheap drive - use rear differential from cars / trucks.
> I have been thinking of this for awhile - should be able to drive
> quite a large panel with relatively simple motors. Just a thought.
>
> Joe
>
>
> On Mar 19, 6:17 pm, "Tony Luck" <tony.l...@gmail.com> wrote:
>> On 3/19/07, Joe Rich <RichMan...@gmail.com> wrote:
>>
>>> The result of their estimate for clear air atmospheric
>>> attenuation for
>>> our latitude at local noon on December 21 is 742 watts/m^2, or -2.6
>>> dB; for June 21 it is 962 watts/m^2, or - 1.4 dB (having designed
>>> link
>>> budgets for satellites, I think in dB).
>>
>>> When one takes into account the cosine of the normal of the
>>> collector
>>> and the sun angle, the losses throughout the day of a fixed
>>> collector
>>> become quite high.
>>
>> A Google search for "insolation san francisco" turned up some daily
>> insolation tables for a few years. Ignoring the bad values near the
>> solstices (as presumably cloudy days) I saw around 183 around the
>> winter solstice, and 636 around the summer solstice. So yes, the
>> low sun angle during the winter is measurably very bad for solar
>> harvesting.
>>
>> I've seen repeated assertions on the internet that a tracking
>> collector
>> isn't cost effective (none with data to back this up ... but I
>> have difficulty
>> envisioning a cheap, sturdy, sun-tracking panel that is easy to mount
>> to a typical house).
>>
>> -Tony
>
>
>
>
>
> == 2 of 5 ==
> Date: Mon, Mar 19 2007 9:17 pm
> From: "John Allen"
>
>
>> December 21 is 742 watts/m^2
>
> OK, I cheat. I aim my collector to be perpendicular to noon sun, to
> the
> shadow covers more area than my collector. That would explain how I
> can
> achieve 500 watts/m^2 at about 50% efficiency in February. I really
> should
> calculate, or measure, the shadow.
>
> A big factor that is not much talked about is that w/o any seasonal
> positioning, your orientation can, at best, be ideal at one moment
> per year
> and is way out of whack 6 months from that moment.
>
> The rule of thumb to aim at latitude plus 15 is based on a lot of
> assumptions that may not be true for a particular installation.
>
>> optimizing the budget, both in regards to signal strength and
>> finances.
>
> I'm with you on this attitude.
>
> ja
>
> On 3/19/07, Joe Rich <RichM...@gmail.com> wrote:
>>
>>
>> I have a book, which I have had for a very long time, by Kreider and
>> Kreith "Solar Heating and Cooling". I am implementing some of the
>> equations in this book in a visual basic program - I find if I do
>> this
>> modeling, I have a much better understanding of what is actually
>> happening.
>>
>> The result of their estimate for clear air atmospheric attenuation
>> for
>> our latitude at local noon on December 21 is 742 watts/m^2, or -2.6
>> dB; for June 21 it is 962 watts/m^2, or - 1.4 dB (having designed
>> link
>> budgets for satellites, I think in dB).
>>
>> When one takes into account the cosine of the normal of the collector
>> and the sun angle, the losses throughout the day of a fixed collector
>> become quite high.
>>
>> The winter attenuation is a little suprising to me at first glance,
>> probably because of my ignorance of the subject. Does this sound
>> correct?
>>
>> Maybe I should be thinking of a cup half full instead of a cup half
>> empty. However, my training on satellite comm links makes me
>> think of
>> $/dB in optimizing the budget, both in regards to signal strength and
>> finances.
>>
>> Joe
>>
>>
>>>
>>
>
>
> --
> John A Allen
>
>
>
>
> == 3 of 5 ==
> Date: Tues, Mar 20 2007 5:53 pm
> From: "Joe Rich"
>
>
> It seems to me for heating, one wants to size the system for winter
> and, if the arrays are fixed, point them for optimum collection in
> winter. Then, as the sun rises in declination, the decreased
> attenuation (along with the increase in ambient temperature) will
> compensate for the cosine of the angle between the sun rays and the
> normal to the collector.
>
> Maybe I will do some simulation when I get my software finally
> completed. All the functions are essentually done and debugged, just
> need to build the top level function to do the simulation, and port it
> to VBA in excel instead of VB.
>
> Joe
>
> On Mar 19, 9:17 pm, "John Allen" <johnaal...@gmail.com> wrote:
>>> December 21 is 742 watts/m^2
>>
>> OK, I cheat. I aim my collector to be perpendicular to noon sun,
>> to the
>> shadow covers more area than my collector. That would explain how
>> I can
>> achieve 500 watts/m^2 at about 50% efficiency in February. I
>> really should
>> calculate, or measure, the shadow.
>>
>> A big factor that is not much talked about is that w/o any seasonal
>> positioning, your orientation can, at best, be ideal at one moment
>> per year
>> and is way out of whack 6 months from that moment.
>>
>> The rule of thumb to aim at latitude plus 15 is based on a lot of
>> assumptions that may not be true for a particular installation.
>>
>>> optimizing the budget, both in regards to signal strength and
>>> finances.
>>
>> I'm with you on this attitude.
>>
>> ja
>>
>> On 3/19/07, Joe Rich <RichMan...@gmail.com> wrote:
>>
>>
>>
>>
>>
>>
>>
>>> I have a book, which I have had for a very long time, by Kreider and
>>> Kreith "Solar Heating and Cooling". I am implementing some of the
>>> equations in this book in a visual basic program - I find if I do
>>> this
>>> modeling, I have a much better understanding of what is actually
>>> happening.
>>
>>> The result of their estimate for clear air atmospheric
>>> attenuation for
>>> our latitude at local noon on December 21 is 742 watts/m^2, or -2.6
>>> dB; for June 21 it is 962 watts/m^2, or - 1.4 dB (having designed
>>> link
>>> budgets for satellites, I think in dB).
>>
>>> When one takes into account the cosine of the normal of the
>>> collector
>>> and the sun angle, the losses throughout the day of a fixed
>>> collector
>>> become quite high.
>>
>>> The winter attenuation is a little suprising to me at first glance,
>>> probably because of my ignorance of the subject. Does this sound
>>> correct?
>>
>>> Maybe I should be thinking of a cup half full instead of a cup half
>>> empty. However, my training on satellite comm links makes me
>>> think of
>>> $/dB in optimizing the budget, both in regards to signal strength
>>> and
>>> finances.
>>
>>> Joe
>>
>> --
>> John A Allen- Hide quoted text -
>>
>> - Show quoted text -
>
>
>
>
>
> == 4 of 5 ==
> Date: Tues, Mar 20 2007 6:00 pm
> From: "Joe Rich"
>
>
> Tony
>
> More thoughts on trackers - since I am new to this field, some of this
> is probably common knowledge.
>
> I am used to AZ/EL tracking for satellites. However, I also am
> familiar with telescope tracking for right ascension (RA) and
> declination (DECL). I know that the C-Band dishes use some form of
> the RA/DECL tracking, as they only track in one direction, which is
> essentially RA.
>
> I would believe that one could fairly easily modify a C-Band tracking
> system to track the sun. One could periodically have to correct for
> the change in solar declination due to the seasons, but this could be
> fairly infrequent and done manually. I beleive a C-Band tracking
> system should support a fairly big collector, as some of the antennas
> were on the order of 10 to 15 feet diameter. Also, there are a fair
> number of these systems not being used anymore as most people have
> switched over to the Dish systems.
>
> I am not sure about the control of these systems - how do they know
> what the RA is? But this has to be fairly simple and could probably
> be implemented with a simple controller and a "few lines of code".
>
> Joe
>
> On Mar 19, 6:17 pm, "Tony Luck" <tony.l...@gmail.com> wrote:
>> On 3/19/07, Joe Rich <RichMan...@gmail.com> wrote:
>>
>>> The result of their estimate for clear air atmospheric
>>> attenuation for
>>> our latitude at local noon on December 21 is 742 watts/m^2, or -2.6
>>> dB; for June 21 it is 962 watts/m^2, or - 1.4 dB (having designed
>>> link
>>> budgets for satellites, I think in dB).
>>
>>> When one takes into account the cosine of the normal of the
>>> collector
>>> and the sun angle, the losses throughout the day of a fixed
>>> collector
>>> become quite high.
>>
>> A Google search for "insolation san francisco" turned up some daily
>> insolation tables for a few years. Ignoring the bad values near the
>> solstices (as presumably cloudy days) I saw around 183 around the
>> winter solstice, and 636 around the summer solstice. So yes, the
>> low sun angle during the winter is measurably very bad for solar
>> harvesting.
>>
>> I've seen repeated assertions on the internet that a tracking
>> collector
>> isn't cost effective (none with data to back this up ... but I
>> have difficulty
>> envisioning a cheap, sturdy, sun-tracking panel that is easy to mount
>> to a typical house).
>>
>> -Tony
>
>
>
>
>
> == 5 of 5 ==
> Date: Tues, Mar 20 2007 11:40 am
> From: "John Allen"
>
>
>> for heating, one wants to size the system for winter
> and, if the arrays are fixed, point them for optimum collection in
> winter.
>
> I agree and in fact that is standard practice. However, that
> assumes you
> have nothing useful to do with the much bigger flux of energy that is
> available in the summer. The very thought of letting all that capital
> equipment idle for half of the day during half of the year, makes the
> skinflint in me cringe. It may be the best solution unless someone
> can solve
> the 'summer surplus' problem/opportunity.
>
> ja
>
> On 3/20/07, Joe Rich <RichM...@gmail.com> wrote:
>>
>>
>> It seems to me for heating, one wants to size the system for winter
>> and, if the arrays are fixed, point them for optimum collection in
>> winter. Then, as the sun rises in declination, the decreased
>> attenuation (along with the increase in ambient temperature) will
>> compensate for the cosine of the angle between the sun rays and the
>> normal to the collector.
>>
>> Maybe I will do some simulation when I get my software finally
>> completed. All the functions are essentually done and debugged, just
>> need to build the top level function to do the simulation, and
>> port it
>> to VBA in excel instead of VB.
>>
>> Joe
>>
>> On Mar 19, 9:17 pm, "John Allen" <johnaal...@gmail.com> wrote:
>>>> December 21 is 742 watts/m^2
>>>
>>> OK, I cheat. I aim my collector to be perpendicular to noon sun,
>>> to the
>>> shadow covers more area than my collector. That would explain how
>>> I can
>>> achieve 500 watts/m^2 at about 50% efficiency in February. I really
>> should
>>> calculate, or measure, the shadow.
>>>
>>> A big factor that is not much talked about is that w/o any seasonal
>>> positioning, your orientation can, at best, be ideal at one
>>> moment per
>> year
>>> and is way out of whack 6 months from that moment.
>>>
>>> The rule of thumb to aim at latitude plus 15 is based on a lot of
>>> assumptions that may not be true for a particular installation.
>>>
>>>> optimizing the budget, both in regards to signal strength and
>>>> finances.
>>>
>>> I'm with you on this attitude.
>>>
>>> ja
>>>
>>> On 3/19/07, Joe Rich <RichMan...@gmail.com> wrote:
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>> I have a book, which I have had for a very long time, by Kreider
>>>> and
>>>> Kreith "Solar Heating and Cooling". I am implementing some of the
>>>> equations in this book in a visual basic program - I find if I
>>>> do this
>>>> modeling, I have a much better understanding of what is actually
>>>> happening.
>>>
>>>> The result of their estimate for clear air atmospheric
>>>> attenuation for
>>>> our latitude at local noon on December 21 is 742 watts/m^2, or -2.6
>>>> dB; for June 21 it is 962 watts/m^2, or - 1.4 dB (having
>>>> designed link
>>>> budgets for satellites, I think in dB).
>>>
>>>> When one takes into account the cosine of the normal of the
>>>> collector
>>>> and the sun angle, the losses throughout the day of a fixed
>>>> collector
>>>> become quite high.
>>>
>>>> The winter attenuation is a little suprising to me at first glance,
>>>> probably because of my ignorance of the subject. Does this sound
>>>> correct?
>>>
>>>> Maybe I should be thinking of a cup half full instead of a cup half
>>>> empty. However, my training on satellite comm links makes me
>>>> think of
>>>> $/dB in optimizing the budget, both in regards to signal
>>>> strength and
>>>> finances.
>>>
>>>> Joe
>>>
>>> --
>>> John A Allen- Hide quoted text -
>>>
>>> - Show quoted text -
>>
>>
>>>
>>
>
>
> --
> John A Allen
>
>
>
>
>
> ======================================================================
> ========
> TOPIC: Is it optimum to only preheat DHW with solar?
> http://groups.google.com/group/solar-buddies/browse_thread/thread/
> b3e99dd4af5f29e2?hl=en
> ======================================================================
> ========
>
> == 1 of 2 ==
> Date: Tues, Mar 20 2007 1:40 am
> From: "Joe Rich"
>
>
> John - might ask metacrylics if they have experience with this type of
> application. I am sure they have seen almost everything.
>
> Joe
>
> On Mar 19, 6:26 pm, "Tony Luck" <tony.l...@gmail.com> wrote:
>> On 3/16/07, John Allen <johnaal...@gmail.com> wrote:
>>
>>> I'm now dreaming of switching from my
>>> 55 gallon drums to large plywood boxes lined with Metacrylics "A
>>> layered,
>>> watertight blanket of elastomeric acrylics, encapsulating a tough
>>> stitch
>>> bonded polyester fabric. The result is a system which handles
>>> roof, deck,
>>> and building movement regardless of extreme temperature,
>>> thermoshock,
>>> earthquakes, hurricanes or floods."
>>
>> I'd also been wondering about a "big box" storage tank ... my
>> thoughts
>> on materials were on resin-fiberglass ... but the metacrylics
>> sounds like
>> it might be easier to work with. I wonder how gracefully these
>> materials
>> age in the environment we are planning to subject them to (the
>> storage
>> tank doesn't sound any more hostile than the roof for which these
>> were
>> designed ... perhaps less so as there is no UV-light to contend
>> with). But
>> it would be good to have some guess at the expected lifetime (both to
>> evaluate the cost effectiveness, and for planning replacement before
>> failure ... a leak is going to result in a very wet basement).
>>
>> -Tony
>
>
>
>
>
> == 2 of 2 ==
> Date: Mon, Mar 19 2007 9:27 pm
> From: "John Allen"
>
>
> Good idea. I'll do that.
>
> ja
>
> On 3/19/07, Joe Rich <RichM...@gmail.com> wrote:
>>
>>
>> John - might ask metacrylics if they have experience with this
>> type of
>> application. I am sure they have seen almost everything.
>>
>> Joe
>>
>> On Mar 19, 6:26 pm, "Tony Luck" <tony.l...@gmail.com> wrote:
>>> On 3/16/07, John Allen <johnaal...@gmail.com> wrote:
>>>
>>>> I'm now dreaming of switching from my
>>>> 55 gallon drums to large plywood boxes lined with Metacrylics "A
>> layered,
>>>> watertight blanket of elastomeric acrylics, encapsulating a tough
>> stitch
>>>> bonded polyester fabric. The result is a system which handles roof,
>> deck,
>>>> and building movement regardless of extreme temperature,
>>>> thermoshock,
>>>> earthquakes, hurricanes or floods."
>>>
>>> I'd also been wondering about a "big box" storage tank ... my
>>> thoughts
>>> on materials were on resin-fiberglass ... but the metacrylics sounds
>> like
>>> it might be easier to work with. I wonder how gracefully these
>> materials
>>> age in the environment we are planning to subject them to (the
>>> storage
>>> tank doesn't sound any more hostile than the roof for which these
>>> were
>>> designed ... perhaps less so as there is no UV-light to contend
>>> with).
>> But
>>> it would be good to have some guess at the expected lifetime
>>> (both to
>>> evaluate the cost effectiveness, and for planning replacement before
>>> failure ... a leak is going to result in a very wet basement).
>>>
>>> -Tony
>>
>>
>>>
>>
>
>
> --
> John A Allen
>
>
>
>
>
> ======================================================================
> ========
> TOPIC: View this page "solarwaterheater"
> http://groups.google.com/group/solar-buddies/browse_thread/thread/
> 1740cea1129846db?hl=en
> ======================================================================
> ========
>
> == 1 of 1 ==
> Date: Mon, Mar 19 2007 8:52 pm
> From: "John Allen"
>
>
>> Is anyone doing this?
>
> For PV, yes. I think they call it Building Integrated PV. I believe
> new
> construction is a better opportunity, but there is also a lot of old
> buildings that are not going to be torn down anytime soon. There is an
> interesting territory in between, where you do a remodel that is
> focused on
> reducing the energy needs. Unfortunately, you are likely to need
> some other
> aspect of the remodel to make it worth doing. My ZEH remodel is on
> the back
> burner for lack of sufficient auxilarly motivation.
>
>> Yes, I would like to further understand the ROI of these systems.
>
> Anybody want to help me build a spreadsheet model for ROI on Solar
> Thermal?
>
> ja
>
> On 3/19/07, Joe Rich <RichM...@gmail.com> wrote:
>>
>>
>> Yes, I would like to further understand the ROI of these systems.
>> Given the energy information from both SVP and PGE, I could see where
>> the payoff could be greatly different where one lives.
>>
>> I am also thinking of ways of reducing the costs. It seems that for
>> new installations if the units were built directly into the roof,
>> this
>> could lower costs. In other words, the roof insulation and surface
>> could also be the solar panel insulation and back surface, and the
>> glass pane could replace shingles. Is anyone doing this?
>>
>> Joe
>>
>> On Mar 18, 8:56 pm, "John Allen" <johnaal...@gmail.com> wrote:
>>> I agree. In this case the retail price of both pumps is about the
>>> same.
>>> There are less expensive (AC) pumps that would do the job though.
>>> Along
>> that
>>> line of thinking, solar systems are not without maintenance.
>>> Glycol is
>> not
>>> forever, neither are pumps. All things considered, I do not believe
>> there is
>>> a commercially installed solar DHW system that makes much sense on a
>> pure
>>> financial basis. The DIY payoff is not a lot better unless you
>>> can write
>> off
>>> your time as R&R, or education, or saving the world.
>>>
>>> BTW, I hope to buy the DC pumps at wholesale. Of course I have to
>>> buy
>> many
>>> of them. Anybody interested in at least 50% discount on the $300
>>> retail
>>> price?
>>>
>>> if you reply to this, please drop sdcc-1. I only added that list
>>> because
>> I
>>> did not want to be perceived there as not responding to the good
>> question
>>> from Joe.
>>>
>>> ja
>>>
>>> On 3/18/07, Joe Rich <richman...@gmail.com > wrote:
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>> John, it would also be interesting to know if this pump will
>>>> ever pay
>> for
>>>> itself, if one had to pay going prices for it.
>>>
>>>> Joe
>>>
>>>> On 3/18/07, John Allen <johnaal...@gmail.com> wrote:
>>>
>>>>>> I'm also hoping to build one for my house...
>>>
>>>>> SUPER!. Dan, It was your idea that we document and share what
>>>>> works
>> so
>>>>> you and others could also build one. Today I installed a DC pump
>> connected
>>>>> directly to an old 29 watt panel, putting out only 18 watts. It
>> worked just
>>>>> as well as my 80 watt AC pump controlled by a Differential
>> Temperature
>>>>> Controller!! I was worried about it pumping beyond the perfect
>>>>> point
>> to stop
>>>>> but it did not. It also ramped down smoothly. The old system would
>> oscillate
>>>>> between full on and full off in the beginning and end of each
>>>>> day of
>> sun. I
>>>>> did not finish the install untill 11:30 this morning so I
>>>>> missed the
>> ramp
>>>>> up. Will report on that tomorrow - on "solar-buddies" <
>>>>> solar-...@googlegroups.com>, only.
>>>
>>>>> John Allen
>>>
>>>>> On 3/17/07, Daniel < d...@eyeqsantacruz.com> wrote:
>>>
>>>>>> Wow, that documentation/summary was pretty good!
>>>>>> I'm also hoping to build one for my house...
>>>
>>>>>> Dan
>>>
>>>>> --
>>>>> John A Allen
>>>
>>> --
>>> John A Allen- Hide quoted text -
>>>
>>> - Show quoted text -
>>
>>
>>>
>>
>
>
> --
> John A Allen
>
>
>
>
>
> ======================================================================
> ========
> TOPIC: Energy Rates
> http://groups.google.com/group/solar-buddies/browse_thread/thread/
> 8480e2d196552dd5?hl=en
> ======================================================================
> ========
>
> == 1 of 7 ==
> Date: Mon, Mar 19 2007 8:55 pm
> From: "John Allen"
>
>
>> mere $0.36434 per kWh.
>
> Thank you very much for the clarification.
>
> I have heard a rumor the the .36 is headed for .4? within a year.
>
> Tony, what kind of ROI calcs do you have for your PV system?
>
> ja
>
> On 3/19/07, Tony Luck <tony...@gmail.com> wrote:
>>
>>
>> On 3/19/07, John Allen <johna...@gmail.com> wrote:
>>> Wow, Does anyone know when PGE top tier went up to $.45 ???
>>
>> That $0.45 rate is from the time-of-use (E-6) tariff and only applies
>> to 1pm to 7pm summertime (May-October) usage. Unless my solar
>> panels break, I should not only never hit the +300% baseline level
>> in that period, I should be collecting $$$ from PG&E during that
>> time period each day as my net usage will be negative. Sadly I
>> don't think that they'll credit me at $0.45/kWh (even if I give them
>> +300% of the baseline usage) ... but they will pay at the peak-time
>> baseline rate of $0.20865 which is a two-for-one deal against the
>> off-peak rate.
>>
>> The normal residential rate is the E-1 tariff which maxes out at a
>> mere $0.36434 per kWh.
>>
>> -Tony
>>
>>>
>>
>
>
> --
> John A Allen
>
>
>
>
> == 2 of 7 ==
> Date: Mon, Mar 19 2007 10:52 pm
> From: "Tony Luck"
>
>
>> Tony, what kind of ROI calcs do you have for your PV system?
>
> Akeena provided a bunch of numbers in their bid ... the bottom line
> was payback of the installation cost at about the 11-12 year mark. I
> can dig up the folder and find some more of the details on how they
> got to that number (I've been meaning to do so for a while, I want to
> put more stuff on my solar web page, comparing the predicted with the
> actual performance).
>
> -Tony
>
>
>
>
> == 3 of 7 ==
> Date: Tues, Mar 20 2007 6:25 am
> From: "John Allen"
>
>
> Tony,
>
> Where is your solar web page?
>
> No rush, but I would lke to see the numbers and more especially the
> formula(s) for ROI.
>
> Perhaps the most fundamental is the ratio between total initial
> cost and
> yearly energy savings. After that there are a lot of details that are
> different for different people, like tax rate, cost of capital, and
> predicted energy inflation.
>
> ja
>
> On 3/19/07, Tony Luck <tony...@gmail.com> wrote:
>>
>>
>>> Tony, what kind of ROI calcs do you have for your PV system?
>>
>> Akeena provided a bunch of numbers in their bid ... the bottom line
>> was payback of the installation cost at about the 11-12 year mark. I
>> can dig up the folder and find some more of the details on how they
>> got to that number (I've been meaning to do so for a while, I want to
>> put more stuff on my solar web page, comparing the predicted with the
>> actual performance).
>>
>> -Tony
>>
>>>
>>
>
>
> --
> John A Allen
>
>
>
>
> == 4 of 7 ==
> Date: Tues, Mar 20 2007 8:33 am
> From: "Mary Medeiros"
>
>
> John,
>
> Unfortunately, we don't have any data on how many SVP customers use
> air conditioning.
>
> Mary
>
>>>> "John Allen" <johna...@gmail.com> 3/19/2007 10:40 AM >>>
> Wow, Does anyone know when PGE top tier went up to $.45 ???
>
> Maybe I should shift a bit and go after solar thermal air
> conditioning...
> I do not use air conditioning but of course many people do, even
> around
> here. Mary can you ball park how many SVP residential customers use
> air
> conditioning? Small Businesses?
>
> ja
>
> On 3/19/07, Tony Luck <tony...@gmail.com> wrote:
>>
>>
>> PG&E tariffs are here:
>>
>> http://www.pge.com/tariffs/ERS.SHTML
>>
>> But they are quite complex (worse, I think, than cell phone plans).
>> First the "baseline" usage is dependent on where you live, even
>> within
>> the south bay there may be multiple different baseline values.
>>
>> Then the cost of power is on a progressive scale based on
>> average daily usage in a billing period.
>>
>> So a simple question like: "How much does it cost to run
>> a particular electrical device" cannot be answered even
>> approximately without knowing:
>> 1) Where do you live?
>> 2) How much power do you use per month?
>> and possibly also (if you have time-of-use metering)
>> 3) When will you use it?
>>
>> My cost per kWh could vary by a factor of 5 (from $0.09 for
>> baseline off-peak usage to $0.45 for >300%baseline
>> peak usage).
>>
>> -Tony
>>
>>>
>>
>
>
> --
> John A Allen
>
>
>
>
>
>
> == 5 of 7 ==
> Date: Tues, Mar 20 2007 1:18 pm
> From: "Tony Luck"
>
>
> On 3/20/07, John Allen <johna...@gmail.com> wrote:
>> Tony,
>>
>> Where is your solar web page?
>
> http://solar.sippelhouse.com but right now it just has graphs showing
> power and energy produced today (which are pretty sad today with 100%
> cloud cover ... but at least the panels are getting the dust rinsed
> off by
> the rain), a last 60-days graph, and a link to a page with some basic
> system information.
>
>> No rush, but I would lke to see the numbers and more especially the
>> formula(s) for ROI.
>
> I'll dig out the predictions from the Akeena sales pitch together with
> the assumptions on which they were based.
>
>> Perhaps the most fundamental is the ratio between total initial
>> cost and
>> yearly energy savings. After that there are a lot of details that are
>> different for different people, like tax rate, cost of capital, and
>> predicted energy inflation.
>
> I'm planning on adding some predicted vs. actual numbers.
>
> -Tony
>
>
>
>
> == 6 of 7 ==
> Date: Tues, Mar 20 2007 1:33 pm
> From: "John Allen"
>
>
> Thanks, I believe I looked at that early in our relationship but
> not since.
> It is a very useful site. Did you build it? What does sippel refer to?
>
> Nn http://solar.sippelhouse.com/daylen.png, can you tell me why
> there is
> sharp transition on the sun rise and set times twice a year? Is
> that the
> damnable daylight savings time? Imagine all the programming time
> that has
> gone into factoring that out of things.
> http://solar.sippelhouse.com/daylen.png
>
> ja
>
> On 3/20/07, Tony Luck <tony...@gmail.com> wrote:
>>
>>
>> On 3/20/07, John Allen <johna...@gmail.com> wrote:
>>> Tony,
>>>
>>> Where is your solar web page?
>>
>> http://solar.sippelhouse.com but right now it just has graphs
>> showing
>> power and energy produced today (which are pretty sad today with 100%
>> cloud cover ... but at least the panels are getting the dust
>> rinsed off by
>> the rain), a last 60-days graph, and a link to a page with some basic
>> system information.
>>
>>> No rush, but I would lke to see the numbers and more especially the
>>> formula(s) for ROI.
>>
>> I'll dig out the predictions from the Akeena sales pitch together
>> with
>> the assumptions on which they were based.
>>
>>> Perhaps the most fundamental is the ratio between total initial
>>> cost and
>>> yearly energy savings. After that there are a lot of details that
>>> are
>>> different for different people, like tax rate, cost of capital, and
>>> predicted energy inflation.
>>
>> I'm planning on adding some predicted vs. actual numbers.
>>
>> -Tony
>>
>>>
>>
>
>
> --
> John A Allen
>
>
>
>
> == 7 of 7 ==
> Date: Tues, Mar 20 2007 2:23 pm
> From: "Tony Luck"
>
>
> On 3/20/07, John Allen <johna...@gmail.com> wrote:
>> Thanks, I believe I looked at that early in our relationship but
>> not since.
>> It is a very useful site. Did you build it?
>
> I wrote the logging software, and used "gnuplot" to make the graphs.
> The inverters produce other data (such as heat-sink temperature, and
> some mysterious MPPT data) that I may add later if I find an
> interesting
> way to display it (especially if in summer I find that excessive
> inverter
> temperature is affecting the yield of AC-watts).
>
>> What does sippel refer to?
>
> We are the third owners of our 1909 craftsman house. The first owner
> (from 1909 to 1979) was Effie Church-Sippel ... hence we refer to our
> house as "The Sippel House" as it might have been known in its early
> years ... but for the minor historical detail that she started out as
> "Effie Church", and only added the Sippel to her name when she
> married ... but "The Sippel House" sounds a lot cooler than "The
> Church House".
>
>> http://solar.sippelhouse.com/daylen.png , can you tell
>> me why there is sharp transition on the sun rise and set times
>> twice a year?
>
> Either there is a giant black-hole in our solar system that
> periodically
> stops or boosts the rotation of the earth ...
>
>> Is that the damnable daylight savings time?
> Ah, yes ... that seems a lot more likely :-)
>
>> Imagine all the programming time
>> that has gone into factoring that out of things.
>
> In this case it was programming time to put that *in*. The
> software that generates sunrise/sunset times for me does
> so in UTC, but I usually think in local time.
>
> -Tony
>
>
>
>
>
> ======================================================================
> ========
> TOPIC: graph.php (PNG Image, 900x480 pixels)
> http://groups.google.com/group/solar-buddies/browse_thread/thread/
> 8c2b115970c76214?hl=en
> ======================================================================
> ========
>
> == 1 of 1 ==
> Date: Mon, Mar 19 2007 9:07 pm
> From: "John Allen"
>
>
> Voltage is on the right and runs from about 12 to 15. It is
> measured close
> to the battery.
>
> Yes current is in and out of the battery. It ignores some
> production which
> goes directly to the load. My base load is steady at .5 amps
> (mostly the
> wireless router), but there is a very variable load created by
> plugging my
> laptop to the bus, and when I do that during sunny hours, those
> electrons
> are not counted.
>
> Lots of room for improvement but the ROI on that would be very low.
> I've
> learned to deduce items that are not presented clearly. Definitely
> not for
> public consumption. Ditto for my thermal data system. This is an
> opportunity...
>
> I have yet to see any solar thermal system, other than mine, that
> provides
> ANY data on how much work it is doing. I'm a little suspicious
> about why
> that is.
>
> ja
>
>
> On 3/19/07, Joe Rich <RichM...@gmail.com> wrote:
>>
>>
>> I am a little confused by the chart. as I do not know where the
>> voltage measurement is being taken I am suprised to see negative
>> voltages during night hours. Also the current goes negative, which I
>> can understand (discharging from batteries?).
>>
>> But good stuff -
>>
>> Joe
>>
>> On Mar 18, 9:24 pm, "John Allen" <johnaal...@gmail.com> wrote:
>>> Now that I am using the small PV panel for the Solar thermal
>>> system, it
>>> appears we are storing about 3 amp hours (36 watt hours) less
>>> into the
>>> batteries. however we are saving about 5*80 400 watt hours of PGE
>>> juice.
>>> That was one of our bigger electrical loads.
>>>
>>> http://svallens.com/emeterlogger/graph.php?
>>> start=1174105166&end=11742...
>>>
>>> --
>>> John A Allen
>>
>>
>>>
>>
>
>
> --
> John A Allen
>
>
>
>
>
> ======================================================================
> ========
> TOPIC: New job for John
> http://groups.google.com/group/solar-buddies/browse_thread/thread/
> 6dbf77548d4007e1?hl=en
> ======================================================================
> ========
>
> == 1 of 3 ==
> Date: Mon, Mar 19 2007 9:28 pm
> From: "John Allen"
>
>
> Today I accepted a job at Sustainable
> Spaces<http://www.sustainablespaces.com/>.
> I'll start off doing residential building performance testing.
> These folks
> started off installing pV but discovered there was a better ROI in
> improving
> more basic things like air leaks, insulation and HVAC equipment.
> They also
> sell solar equipment but only after fixing any egregious problems that
> exist.
>
> --
> John A Allen
>
>
>
>
> == 2 of 3 ==
> Date: Tues, Mar 20 2007 5:47 pm
> From: "Joe Rich"
>
>
> Way to go, John. Damn work ethic.
>
> On Mar 19, 9:28 pm, "John Allen" <johnaal...@gmail.com> wrote:
>> Today I accepted a job at Sustainable
>> Spaces<http://www.sustainablespaces.com/>.
>> I'll start off doing residential building performance testing.
>> These folks
>> started off installing pV but discovered there was a better ROI in
>> improving
>> more basic things like air leaks, insulation and HVAC equipment.
>> They also
>> sell solar equipment but only after fixing any egregious problems
>> that
>> exist.
>>
>> --
>> John A Allen
>
>
>
>
>
> == 3 of 3 ==
> Date: Tues, Mar 20 2007 11:35 am
> From: "John Allen"
>
>
>> Damn work ethic.
>
> Worry not. When it stops being fun, I'll quit. ;-)
>
> ja
>
> On 3/20/07, Joe Rich <RichM...@gmail.com> wrote:
>>
>>
>> Way to go, John. Damn work ethic.
>>
>> On Mar 19, 9:28 pm, "John Allen" <johnaal...@gmail.com> wrote:
>>> Today I accepted a job at Sustainable
>>> Spaces<http://www.sustainablespaces.com/>.
>>> I'll start off doing residential building performance testing. These
>> folks
>>> started off installing pV but discovered there was a better ROI in
>> improving
>>> more basic things like air leaks, insulation and HVAC equipment.
>>> They
>> also
>>> sell solar equipment but only after fixing any egregious problems
>>> that
>>> exist.
>>>
>>> --
>>> John A Allen
>>
>>
>>>
>>
>
>
> --
> John A Allen
>
>
>
>
>
> ======================================================================
> ========
> TOPIC: mods to John Allen's Solar Thermal system
> http://groups.google.com/group/solar-buddies/browse_thread/thread/
> cf1c385919ae171f?hl=en
> ======================================================================
> ========
>
> == 1 of 2 ==
> Date: Tues, Mar 20 2007 6:54 am
> From: "John Allen"
>
>
> In the thread under this subject, I plan to document the changes I
> make to
> my solar thermal system and what is learned from each change. Feel
> free to
> make suggestions.
>
> Sunday Morning about 11:30 my Solar thermal system started
> operation with a
> PV powered DC pump using no control logic. It relies on the
> coincidence that
> the PV makes electricity in approximate proportion to the heat
> collected by
> the water panel.
>
> The below graph shows the first two days of operation. There was a
> spike in
> collector temp before it started because I the sun was heating the
> collector
> befor I got all the air purged and the glycol flowing.
>
> There was a spike Monday afternoon at he end of the day because the
> little
> PV panel connected to the pump got shaded about 4:00 PM. When I
> discovered
> and corrected this about 5:00. there was still enough sun to power
> the pump
> a little.
>
> http://svallens.com/templogger/graph.php?
> start=1174138136&end=1174397336&addresses=6700000105615828,F8000001096
> CA628,3600000109546328,3A000001095EF328
> ,
>
> I have been happily surprised that this use of PV as a control
> system works
> as well as it does. I expected to need to put it in series with the
> DTC to
> avoid pumping glycol when there was enough sun to power the pump
> but not
> heat the Glycol hotter than the storage. This may become a problem
> if I
> manage to get the storage temperature hotter. If so, one alternative
> solution is to provide some shade to the side of the PV so it cuts
> down the
> PV at the end of the day. Like yesterday, but done on purpose.
>
> ja
>
> --
> John A Allen
>
>
>
>
> == 2 of 2 ==
> Date: Tues, Mar 20 2007 2:46 pm
> From: "John Allen"
>
>
> Today my fears about the lack of DTC came true, a little bit.
> Today is a cold gray drizzling day with no meaningful heat in the
> collector,
> but the pump & PV combination managed to move some glycol anyhow.
> Curiously
> I recently re-connected the sensor on the bottom of the Metal
> Barrel and it
> is the only one to tmake the result obvious. This is because my
> glycol HX
> loop sits on the bottom of each barrel. So when some cold glycol
> hit that
> spot it chilled the storage water in the bottom only. That
> gradually cooled
> down the rest of the barrel.
> http://svallens.com/templogger/graph.php?
> start=1174339409&end=1174425809&addresses=6700000105615828,F8000001096
> CA628,3600000109546328,3A000001095EF328
> I'll evaluate the total BTU's wasted after the day is over and see
> how bad
> it is.
>
> As a side note, yesterday morning Eric and I stretched out the
> copper HX
> coil for tap water in the MB and looking at the data it did not
> make a lot
> of difference in the heat extraction rates this
> morning<http://svallens.com/templogger/graph.php?
> start=1174081217&end=1174426817&addresses=F8000001096CA628,&deriv=F800
> 0001096CA628>.
> This despite the fact that almost all of the copper used to sit in
> a bunch
> at the bottom of the Metal Barrel and now it is fairly well
> distributed all
> over the metal barrel. Perhaps if I factor in the fact that the
> storage temp
> was kinda puny this morning I'd be more impressed. I'll wait for a
> day when
> that is the case and compare again. BTW the right hand scale for
> "rate of
> change" is in degrees F per hour. If I see that to 30 on a day
> when storage
> is 130 F I'll be satisfied that messing with the copper tubing was
> worth the
> fuss it took.
>
> All my polyethylene tubing is also bunched up on both bottoms, and
> I doubt
> if it will help much to distribute it better.
>
> ja
>
>
>
> --
> John A Allen
>
>
>
>
>
> ======================================================================
> ========
> TOPIC: Plastic pipe bending experiment
> http://groups.google.com/group/solar-buddies/browse_thread/thread/
> 84b51131d95ac450?hl=en
> ======================================================================
> ========
>
> == 1 of 4 ==
> Date: Tues, Mar 20 2007 5:45 pm
> From: "Joe Rich"
>
>
> As you may or may not know, one can bend rigid PVC by heating it.
> This is not approved for plumbing (at least on the high pressure
> lines) but is acceptable for electrical work. The critical things to
> watch here are temperature and kinking of the tubing. With PVC it is
> possible to essentially press a small kink out while it is still hot.
>
> I have some semi-rigid black plastic 1/2 inch ID tubing which is
> fairly thin walled. I am wanting to use this as the tubing in a
> collector. The problem is making the bends so that the tubing fits
> nicely. I am wanting to make bends with a radius of about 2 1/2 ".
>
> The OD of the tubing is almost exactly 3/4 inch, which happens to be
> the width of a 1-by piece of wood. I cut a radius on a piece of 2 1/2
> inch piece of 1-by and then cut two more pieces of wood with a radius
> of 3 1/4 inch. I added these two pieces of wood on the outside of 2
> 1/2 inch radius, one on each side, to form a channel 3/4 inch on a
> side.
>
> I then heated the tubing and molded it in the channel. This works
> great AS LONG AS THE TUBING IS NOT TOO HOT, otherwise it kinks and
> deforms.
>
> Does anyone have any other suggestions?
>
> Joe
>
>
>
>
>
> == 2 of 4 ==
> Date: Tues, Mar 20 2007 11:30 am
> From: "John Allen"
>
>
>> Does anyone have any other suggestions?
>
> I suggest you test the tubing at the highest temperature you expect
> the
> collector to experience. This will be somewhere around 300 F.
>
> A PVC fitting I used on my collector turned to putty one day when my
> circulation stopped while the sun was shinning. Maybe your PVC is
> better.
>
> ja
>
> On 3/20/07, Joe Rich <RichM...@gmail.com> wrote:
>>
>>
>> As you may or may not know, one can bend rigid PVC by heating it.
>> This is not approved for plumbing (at least on the high pressure
>> lines) but is acceptable for electrical work. The critical things to
>> watch here are temperature and kinking of the tubing. With PVC it is
>> possible to essentially press a small kink out while it is still hot.
>>
>> I have some semi-rigid black plastic 1/2 inch ID tubing which is
>> fairly thin walled. I am wanting to use this as the tubing in a
>> collector. The problem is making the bends so that the tubing fits
>> nicely. I am wanting to make bends with a radius of about 2 1/2 ".
>>
>> The OD of the tubing is almost exactly 3/4 inch, which happens to be
>> the width of a 1-by piece of wood. I cut a radius on a piece of 2
>> 1/2
>> inch piece of 1-by and then cut two more pieces of wood with a radius
>> of 3 1/4 inch. I added these two pieces of wood on the outside of 2
>> 1/2 inch radius, one on each side, to form a channel 3/4 inch on a
>> side.
>>
>> I then heated the tubing and molded it in the channel. This works
>> great AS LONG AS THE TUBING IS NOT TOO HOT, otherwise it kinks and
>> deforms.
>>
>> Does anyone have any other suggestions?
>>
>> Joe
>>
>>
>>>
>>
>
>
> --
> John A Allen
>
>
>
>
> == 3 of 4 ==
> Date: Tues, Mar 20 2007 11:34 am
> From: "John Allen"
>
>
> However, maybe the tubing you have would be useful for a heat
> excchanger. I
> use Polyethylene for the low pressure glycol loop. I junked the PVC
> fitting
> I had there because I'm hoping my storage gets close to 212 F this
> summer,
> and when I tested white PVC pipe at 212 it gets very malleable,
> while the
> polyethylene does not.
>
> ja
>
> On 3/20/07, John Allen <johna...@gmail.com> wrote:
>>
>>> Does anyone have any other suggestions?
>>
>> I suggest you test the tubing at the highest temperature you
>> expect the
>> collector to experience. This will be somewhere around 300 F.
>>
>> A PVC fitting I used on my collector turned to putty one day when my
>> circulation stopped while the sun was shinning. Maybe your PVC is
>> better.
>>
>> ja
>>
>> On 3/20/07, Joe Rich <RichM...@gmail.com> wrote:
>>>
>>>
>>> As you may or may not know, one can bend rigid PVC by heating it.
>>> This is not approved for plumbing (at least on the high pressure
>>> lines) but is acceptable for electrical work. The critical
>>> things to
>>> watch here are temperature and kinking of the tubing. With PVC
>>> it is
>>> possible to essentially press a small kink out while it is still
>>> hot.
>>>
>>> I have some semi-rigid black plastic 1/2 inch ID tubing which is
>>> fairly thin walled. I am wanting to use this as the tubing in a
>>> collector. The problem is making the bends so that the tubing fits
>>> nicely. I am wanting to make bends with a radius of about 2 1/2 ".
>>>
>>> The OD of the tubing is almost exactly 3/4 inch, which happens to be
>>> the width of a 1-by piece of wood. I cut a radius on a piece of
>>> 2 1/2
>>> inch piece of 1-by and then cut two more pieces of wood with a
>>> radius
>>> of 3 1/4 inch. I added these two pieces of wood on the outside of 2
>>> 1/2 inch radius, one on each side, to form a channel 3/4 inch on a
>>> side.
>>>
>>> I then heated the tubing and molded it in the channel. This works
>>> great AS LONG AS THE TUBING IS NOT TOO HOT, otherwise it kinks and
>>> deforms.
>>>
>>> Does anyone have any other suggestions?
>>>
>>> Joe
>>>
>>>
>>>>>
>>>
>>
>>
>> --
>> John A Allen
>
>
>
>
> --
> John A Allen
>
>
>
>
> == 4 of 4 ==
> Date: Tues, Mar 20 2007 12:11 pm
> From: "Tony Luck"
>
>
> On 3/20/07, John Allen <johna...@gmail.com> wrote:
>> However, maybe the tubing you have would be useful for a heat
>> excchanger. I
>> use Polyethylene for the low pressure glycol loop. I junked the
>> PVC fitting
>> I had there because I'm hoping my storage gets close to 212 F this
>> summer,
>> and when I tested white PVC pipe at 212 it gets very malleable,
>> while the
>> polyethylene does not.
>
> 212 F in an unpressurized storage container ... that means you'll
> have steam
> squirting out of the gaps in the insulation ... surely not a good
> thing from
> a variety of perspectives:
>
> 1) Evaporation loss from your storage system
> 2) Humidity/Moisture in your basement.
>
> If you are going to get that hot in the summer, then this is an
> area where you'll want to go back to some control circuitry for
> the pump so that it will cut out before you get to this temperature
> (the lost energy wasn't being stored anyway ... just dispersed by
> the steam).
>
> -Tony
>
>
>
>
> ======================================================================
> ========
>
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