R-values of reflective insulation materials
nicks...@ece.villanova.edu
multi-airspace reflective insulation materials" by Andre O. Desjarlais
and David W. Yarbrough, from ASTM STP 1116--Insulation Materials, Testing
and Applications, Ronald S. Graves and Donald C. Wysocki, editors, 2nd volume,
October 1991, pp 24-43:
20 DATA 2.5,5.09,7.5,1.4959,-0.608,6.359e-2,6.5572e-3,2.7129e-4
30 DATA 3.5,4.68,7.82,-1.3771,.2989,5.93e-3,1.2676e-3,8.7056e-2
40 DATA 2.5,4.35,7.2,-2.2234,0.6784,-3.028e-2,1.6481e-3,2.3528e-2
50 DATA 0,0,0,0,0,0,0,0
60 DATA 2.5,3.49,6.8,-.862,.2912,-3.863e-4,.16645,-1.397e-2
70 DATA 2.5,4.14,6.9,-.3,.0381,2.409e-2,1.5679e-2,-3.4369e-2
80 FOR I=0 TO 5
90 READ GR0(I),GR1(I),GR2(I),A(I),B(I),C(I),A2(I),A3(I)
100 NEXT I
110 DIR=0'heatflow direction
120 IF DIR=-1 THEN DIR$="down"
130 IF DIR=0 THEN DIR$="horiz"
140 IF DIR=1 THEN DIR$="up"
150 DIAG=0'0 for up or down, 1 for diagonal heatflow
160 IF DIAG=0 THEN DIAG$="no" ELSE DIAG$="yes"
170 I=2*DIR+DIAG+2'index (0-5, skipping 3)
180 T1=30'surface 1 temp (F)
190 T2=70'surface 2 temp (F)
200 DT=ABS(T2-T1)'temp diff
210 TBAR=(T1+T2)/2'mean temp
220 HR=.00686*((TBAR+460)/100)^3'radiation conductance (Btu/h-F-ft^2)
230 E1=.05'surface 1 emittance
240 E2=.05'surface 2 emittance
250 E=1/(1/E1+1/E2-1)'effective emittance
260 L=3.5'airspace width (inches)
270 LGR=LOG(DT*L^3)/LOG(10)+3.4146-.004359*TBAR+3.6441E-06*TBAR^2'log10 Grashof
280 IF LGR<LOG(GR0(I))/LOG(10) THEN LNU=0: GOTO 320
290 IF LGR>=LOG(GR1(I))/LOG(10) THEN LNU=A(I)+B(I)*LGR+C(I)*LGR^2:GOTO 320'eq 5
300 LNU=A2(I)*(LGR-LOG(GR0(I))/LOG(10))^2
310 LNU=LNU+A3(I)*(LGR-LOG(GR0(I))/LOG(10))^3'equation 6
320 NU=10^LNU'Nusselt number
330 K=.0003053*TBAR+.1575'air conductivity (Btu-in/F-ft^2-F)
340 HC=K*NU/L'convection conductance
350 R=1/(E*HR+HC)'US R-value (ft^2-F-h/Btu)
360 PRINT "gap (in):",L
370 PRINT "dir:",DIR$,"diag:",DIAG$
380 PRINT "T1 (F):",T1,"T2 (F):",T2
390 PRINT "Tmean (F):",TBAR,"dT (F):",DT
400 PRINT "E1:",E1,"E2:",E2
410 PRINT "Eeff:",E
420 PRINT "R-value:",R
gap (in): 3.5
dir: horiz diag: no
T1 (F): 30 T2 (F): 70
Tmean (F): 50 dT (F): 40
E1: .05 E2: .05
Eeff: 2.564103E-02
R-value: 2.461726
Nick
Red Green
JoeSpareBedroom
ransley
> "Red Green" <postmas...@127.0.0.1> wrote in message
>
> news:Xns9A8EE6A61...@216.168.3.70...
>
>
>
>
>
> > nicksans...@ece.villanova.edu wrote in
>
> - Show quoted text -
Can anyone understand what he posted, will it actualy help
themselves ! No..its nickys numbers, again.
Solar Mike
What version of basic is this, looks like GWBasic or TurboBasic, something I
last used about 15 - 20 years ago. Can you still get it. Have been running
VB.Net last 8 years, and VB6 before that.
If someone could point me in the direction of where to get a suitable
windows version to run this, would be cool to try running the code.
Cheers
Mike (NZ)
JoeSpareBedroom
news:4816...@clear.net.nz...
It would be even cooler to go read a book.
nicks...@ece.villanova.edu
>What version of basic is this, looks like GWBasic...
Yup. IIRC, gwbasic.exe is still available free from a web site and runs from
a DOS prompt. BWbasic is almost identical and runs with Ubuntu linux. The new
ASHRAE comfort spec also contains a gwbasic program.
It's not easy to estimate the US R-value of a reflective insulation system.
It varies from about 1 to 10, depending on emissivities, airspace thickness,
mean temperature, temperature difference, and the direction of heatflow.
The complex table in the ASHRAE HOF rarely matches real situations, but
this program can help with that.
Nick
Solar Mike
<nicks...@ece.villanova.edu> wrote
> Yup. IIRC, gwbasic.exe is still available free from a web site and runs
> from
> a DOS prompt. BWbasic is almost identical and runs with Ubuntu linux. The
> new
> ASHRAE comfort spec also contains a gwbasic program.
>
> It's not easy to estimate the US R-value of a reflective insulation
> system.
> It varies from about 1 to 10, depending on emissivities, airspace
> thickness,
> mean temperature, temperature difference, and the direction of heatflow.
> The complex table in the ASHRAE HOF rarely matches real situations, but
> this program can help with that.
>
Thanks for that Nick I will google somewhere to download it from.
Was going to use 3 reflective air spaced layers behind a trickle solar panel
array system.
Mike
.p.jm@see_my_sig_for_address.com
<msc...@paradise.net.nz> wrote:
>
><nicks...@ece.villanova.edu> wrote
>> Yup. IIRC, gwbasic.exe is still available free from a web site and runs
>> from
>> a DOS prompt. BWbasic is almost identical and runs with Ubuntu linux. The
Isn't that special :-)
>> new
>> ASHRAE comfort spec also contains a gwbasic program.
Oh, those radical modern bastards ! :-)
How's your sliderule ? Still a slippin' and a slidin' ?
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Morris Dovey
> What version of basic is this, looks like GWBasic or TurboBasic, something I
> last used about 15 - 20 years ago. Can you still get it. Have been running
> VB.Net last 8 years, and VB6 before that.
> If someone could point me in the direction of where to get a suitable
> windows version to run this, would be cool to try running the code.
>
> Cheers
> Mike (NZ)
Try <http://www.geocities.com/KindlyRat/GWBASIC.html>. I think that's
where I got my copy a while back.
I think you'll need to run it in a DOS or CMD window (depending on which
version of Windows you're running).
--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/
nicks...@ece.villanova.edu
>Thanks for that Nick I will google somewhere to download it from.
>Was going to use 3 reflective air spaced layers behind a trickle
>solar panel array system.
Under what kind of glazing? Warm water vapor quickly degrades polycarbonate.
Multiple relfective airspaces require iteration to determine intermediate
surface temps, as described in ASTM STP 1116. Adding individual airspace
resistances does not work.
Nick
Don Ocean
> On Wed, 30 Apr 2008 07:42:22 +1200, "Solar Mike"
> <msc...@paradise.net.nz> wrote:
>
>> <nicks...@ece.villanova.edu> wrote
>>> Yup. IIRC, gwbasic.exe is still available free from a web site and runs
>>> from
>>> a DOS prompt. BWbasic is almost identical and runs with Ubuntu linux. The
>
> Isn't that special :-)
>
>>> new
>>> ASHRAE comfort spec also contains a gwbasic program.
>
> Oh, those radical modern bastards ! :-)
>
> How's your sliderule ? Still a slippin' and a slidin' ?
I made mine into a really fine backscratcher. ;-p
>
>
.p.jm@see_my_sig_for_address.com
wrote:
And, for those hard to reach places .....
MULTIPLY !!!!!
David Williams
-> where I got my copy a while back.
QBasic will also run all (or virtually all) programs written in
GW-BASIC and the like.
dow
Solar Mike
nicks...@ece.villanova.edu wrote
> Under what kind of glazing? Warm water vapor quickly degrades
> polycarbonate.
vapour over time and goes brittle. I wanted them to heat bend some sheets of
it with folded right angle edges; cannot readily be done because of this.
Trickle panels are:
3m high x 1m width galv iron sheets, matt black powder coated on the sun
side, water channels made by vertically running silicon beading spaced every
5cm down the metal sheet, laying 75u clear mylar on top of the silicon,
lightly pressing before it sets to form a vapour shield. The water runs
between the metal and the mylar. Each panel then sits in a wood frame with
an overall cover of 1mm flat clear thick polycarbonate with uv protection.
Time will tell how long the mylar will last. The poly glazing will block the
uv entering the box and hopefully stop the plastic header/bottom water pipes
from falling to bits..
Was going to run multiple air spaced layers of foil faced building
insulation paper (the stuff without bitumen) behind the metal panels finally
the wooden ply bottom. Figured some water vapour will escape into the box ,
so there will be vent holes.
> Multiple relfective airspaces require iteration to determine intermediate
> surface temps, as described in ASTM STP 1116. Adding individual airspace
> resistances does not work.
May make a small test panel and do some measurements with foil then non
water absorbent insulation material.
Cheers
Mike (NZ)
nicks...@ece.villanova.edu
>Trickle panels are:
>3m high x 1m width galv iron sheets, matt black powder coated on the sun
>side, water channels made by vertically running silicon beading spaced every
>5cm down the metal sheet, laying 75u clear mylar on top of the silicon,
>lightly pressing before it sets to form a vapour shield. The water runs
>between the metal and the mylar. Each panel then sits in a wood frame with
>an overall cover of 1mm flat clear thick polycarbonate with uv protection.
Gary and I thought about a polyethylene inner cover for a pond-type
collector/store, spaced away from a hot stagnated horizontal EPDM
draindown cover/collector over polyiso board surface...
>Time will tell how long the mylar will last. The poly glazing will block the
>uv entering the box and hopefully stop the plastic header/bottom water pipes
>from falling to bits..
>
>> Multiple relfective airspaces require iteration to determine intermediate
>> surface temps, as described in ASTM STP 1116. Adding individual airspace
>> resistances does not work.
I don't think the iteration is difficult. Assume initial surface temps,
then adjust one, based on the rest, then adjust another, assuming the
rest are fixed, and so on, until they don't change much.
Nick
Solar Mike
"Morris Dovey" wrote in message
> Try <http://www.geocities.com/KindlyRat/GWBASIC.html>. I think that's
> where I got my copy a while back.
>
> I think you'll need to run it in a DOS or CMD window (depending on which
> version of Windows you're running).
>
Thanks have just gone and downloaded it from the above link.
Cheers
Mike
Mike
>It's not easy to estimate the US R-value of a reflective insulation system.
>It varies from about 1 to 10
....and most of the time it can be completely ignored (assuming you
are not working on an off the planet application)
--