<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META content="text/html; charset=unicode" http-equiv=Content-Type>
<META name=GENERATOR content="MSHTML 9.00.8112.16443"></HEAD>
<BODY style="PADDING-LEFT: 10px; PADDING-RIGHT: 10px; PADDING-TOP: 15px"
id=MailContainerBody leftMargin=0 topMargin=0 CanvasTabStop="true"
name="Compose message area">
<DIV>> NREL says an average year in NYC has 1096 CDDs with a 65 F base... so
a house with no internal heat gains or solar gain and (say) 400 Btu/h-F of
thermal conductance needs 24h/dayx1096F/dayx400Btu/h-F = 10.52 million Btu (note
the units) per year of cooling...<BR><BR>Oops. That should be
24h/dayx1096F-dayx400Btu/h-F = 10.52 million Btu. A degree-day is a
temperature-time product.<BR><BR>> or 10.52M/26 = 405 kWh worth $72.84 at
0.18/kWh with a 26 SEER<BR><BR><A
title="http://www.greenbuildingadvisor.com/blogs/dept/musings/window-mounted-air-conditioners-save-energy?utm_source=email&utm_medium=eletter&utm_term=cooling-options&utm_content=20120530-wall-mounted-air-conditioner&utm_campaign=green-building-advisor-eletter
CTRL + Click to follow link"
href="http://www.greenbuildingadvisor.com/blogs/dept/musings/window-mounted-air-conditioners-save-energy?utm_source=email&utm_medium=eletter&utm_term=cooling-options&utm_content=20120530-wall-mounted-air-conditioner&utm_campaign=green-building-advisor-eletter">http://www.greenbuildingadvisor.com/blogs/dept/musings/window-mounted-air-conditioners-save-energy?utm_source=email&utm_medium=eletter&utm_term=cooling-options&utm_content=20120530-wall-mounted-air-conditioner&utm_campaign=green-building-advisor-eletter</A> says<BR><BR>>For
typical residential air conditioners, EER equals about 0.875
SEER.<BR><BR>Comparing apples to apples, the 10 EER window AC would have a
10/0.875 = 11.4 SEER (maybe more, if the fan doesn't run all the time), so it
would use 10.52M/11.4 = 923 kWh worth $166.10, with a simple payback of
($2100-$210)/($166.10-$72.84) = 20.3 years, compared to a $2100 SEER 26 split
system, without the use of room occupancy sensors.<BR><BR>>How would this
change for a house with 8 rooms each occupied 2 hours per day, with doors and
lots of wall insulation between rooms and 30-minute occupancy
sensors?<BR><BR>With no common walls or time delay, a 10-SEER window system
would be like an inexpensive 80-SEER central AC system...</DIV>
<DIV><BR>> NREL says an average July day is 76.8 F in NYC, with a 68.2
min and a 0.0123 humidity ratio, which is fairly comfortable. Smart night
ventilation on comfortable nights can help.<BR><BR>How much, if a small box
turns off the window AC and opens a 2-watt outdoor damper or runs a $69 2470 90
watt fan on comfortable nights, using the ASHRAE comfort standard?<BR><BR><A
title="http://www.amazon.com/Lasko-Electrically-Reversible-Window-2155A/dp/B00002N5Z9/ref=sr_1_1?s=appliances&ie=UTF8&qid=1339144279&sr=1-1
CTRL + Click to follow link"
href="http://www.amazon.com/Lasko-Electrically-Reversible-Window-2155A/dp/B00002N5Z9/ref=sr_1_1?s=appliances&ie=UTF8&qid=1339144279&sr=1-1">http://www.amazon.com/Lasko-Electrically-Reversible-Window-2155A/dp/B00002N5Z9/ref=sr_1_1?s=appliances&ie=UTF8&qid=1339144279&sr=1-1</A></DIV>
<DIV><STRONG><FONT color=#4b0700 face="Courier New"></FONT></STRONG><BR>The box
might look something like this: <A
title="http://www.youtube.com/watch?v=wexdNx_StRc
CTRL + Click to follow link"
href="http://www.youtube.com/watch?v=wexdNx_StRc">http://www.youtube.com/watch?v=wexdNx_StRc</A></DIV>
<DIV><STRONG><FONT color=#4b0700 face="Courier New"></FONT></STRONG><BR>My
Quaker friend Thom Styles could build one. Any takers? This could work well in a
massy brick house or brownstone.<BR><BR>Phila has 1101 CDD, with an average 67.2
F July min and a 0.0133 humidity ratio...<BR><BR>Nick<BR><BR>50 CLO = 1'clothing
insulation (clo)<BR>60 MET=1.1'metabolic rate (met)<BR>70 WME=0'external work
(met)<BR>80 TA=19.6'air temp (C)<BR>90 TR=19.6'mean radiant temp (C)<BR>100
VEL=.1'air velocity<BR>120 RH=86'relative humidity (%)<BR>130 PA=0'water vapor
pressure<BR>140 DEF FNPS(T)=EXP(16.6536-4030.183/(TA+235))'sat vapor pressure,
kPa<BR>150 IF PA=0 THEN PA=RH*10*FNPS(TA)'water vapor pressure, Pa<BR>160
ICL=.155*CLO'clothing resistance (m^2K/W)<BR>170 M=MET*58.15'metabolic rate
(W/m^2)<BR>180 W=WME*58.15'external work in (W/m^2)<BR>190 MW=M-W'internal heat
production<BR>200 IF ICL<.078 THEN FCL=1+1.29*ICL ELSE
FCL=1.05+.645*ICL'clothing factor<BR>210 HCF=12.1*SQR(VEL)'forced convection
conductance<BR>220 TAA=TA+273'air temp (K)<BR>230 TRA=TR+273'mean radiant temp
(K)<BR>250 TCLA=TAA+(35.5-TA)/(3.5*(6.45*ICL+.1))'est clothing temp<BR>260
P1=ICL*FCL:P2=P1*3.96:P3=P1*100:P4=P1*TAA'intermediate values<BR>300
P5=308.7-.028*MW+P2*(TRA/100)^4<BR>310 XN=TCLA/100<BR>320 XF=XN<BR>330
N=0'number of iterations<BR>340 EPS=.00015'stop iteration when met<BR>350
XF=(XF+XN)/2'natural convection conductance<BR>360
HCN=2.38*ABS(100*XF-TAA)^.25<BR>370 IF HCF>HCN THEN HC=HCF ELSE HC=HCN<BR>380
XN=(P5+P4*HC-P2*XF^4)/(100+P3*HC)<BR>390 N=N+1<BR>400 IF N>150 GOTO
550<BR>410 IF ABS(XN-XF)>EPS GOTO 350<BR>420 TCL=100*XN-273'clothing surface
temp (C)<BR>440 HL1=.00305*(5733-6.99*MW-PA)'heat loss diff through skin<BR>450
IF MW>58.15 THEN HL2=.42*(MW-58.15) ELSE HL2=0'heat loss by sweating<BR>460
HL3=.000017*M*(5867-PA)'latent respiration heat loss<BR>470
HL4=.0014*M*(34-TA)'dry respiration heat loss<BR>480
HL5=3.96*FCL*(XN^4-(TRA/100)^4)'heat loss by radiation<BR>490
HL6=FCL*HC*(TCL-TA)'heat loss by convection<BR>510
TS=.303*EXP(-.036*M)+.028'thermal sensation transfer coefficient<BR>520
PMV=TS*(MW-HL1-HL2-HL3-HL4-HL5-HL6)'predicted mean vote<BR>530
PPD=100-95*EXP(-.03353*PMV^4-.2179*PMV^2)'predicted % dissatisfied<BR>540 GOTO
580<BR>550 PMV=99999!:PPD=100<BR>580 PRINT
TA,RH,CLO,PMV,PPD<BR><BR>19.6
86
1
-.4778556
9.769089<BR>23.9
66
1
.4732535
9.676994<BR>25.7
15
1
.5239881
10.74283<BR>21.2
20
1
-.4779105
9.770202<BR>23.6
67
.5
-.4747404
9.706658<BR>26.8
56
.5
.5145492
10.53611<BR>27.9
13
.5
.5003051
10.23146<BR>24.7
16
.5
-.4883473 9.982468<BR><BR>Innova AirTech
Instruments has an excellent comfort web site...</DIV></BODY></HTML>