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Posted by nicksanspam on July 4, 2004, 12:13 am
 
ASHRAE-standard 55-2004 ("Thermal environmental conditions for human
occupancy") defines two "comfort zones," winter (with a clo = 1 clothing
thermal resistance) and summer (clo = 0.5.) Its BASIC program estimates
the Predicted Mean Vote (PMV: +3 hot, +2 warm, +1 slightly warm, 0 neutral,
-1 slightly cool, -2 cool, and -3 cold) and the Predicted Percentage
Dissatisfied (PPD) based on clothing, activity, metabolic rate, external
work, air temp, mean radiant temp, air velocity, and RH...

50 CLO = 1'clothing insulation (clo)
60 MET=1.1'metabolic rate (met)
70 WME=0'external work (met)
80 TA.6'air temp (C)
90 TR.6'mean radiant temp (C)
100 VEL=.1'air velocity (m/s)
120 RH'relative humidity (%) make one of RH or PA non-zero...
130 PA=0'water vapor pressure
140 DEF FNPS(T)=EXP(16.6536-4030.183/(TA+235))'sat vapor pressure, kPa
150 IF PA=0 THEN PA=RH*10*FNPS(TA)'water vapor pressure, Pa
160 ICL=.155*CLO'clothing resistance (m^2K/W)
170 M=MET*58.15'metabolic rate (W/m^2)
180 W=WME*58.15'external work in (W/m^2)
190 MW=M-W'internal heat production
200 IF ICL<.078 THEN FCL=1+1.29*ICL ELSE FCL=1.05+.645*ICL'clothing factor
210 HCF.1*SQR(VEL)'forced convection conductance
220 TAA=TA+273'air temp (K)
230 TRA=TR+273'mean radiant temp (K)
250 TCLA=TAA+(35.5-TA)/(3.5*(6.45*ICL+.1))'est clothing temp
260 P1=ICL*FCL:P2=P1*3.96:P3=P1*100:P4=P1*TAA'intermediate values
300 P508.7-.028*MW+P2*(TRA/100)^4
310 XN=TCLA/100
320 XF=XN
330 N=0'number of iterations
340 EPS=.00015'stop iteration when met
350 XF=(XF+XN)/2'natural convection conductance
360 HCN=2.38*ABS(100*XF-TAA)^.25
370 IF HCF>HCN THEN HC=HCF ELSE HC=HCN
380 XN=(P5+P4*HC-P2*XF^4)/(100+P3*HC)
390 N=N+1
400 IF N>150 GOTO 550
410 IF ABS(XN-XF)>EPS GOTO 350
420 TCL0*XN-273'clothing surface temp (C)
440 HL1=.00305*(5733-6.99*MW-PA)'heat loss diff through skin
450 IF MW>58.15 THEN HL2=.42*(MW-58.15) ELSE HL2=0'heat loss by sweating
460 HL3=.000017*M*(5867-PA)'latent respiration heat loss
470 HL4=.0014*M*(34-TA)'dry respiration heat loss
480 HL5=3.96*FCL*(XN^4-(TRA/100)^4)'heat loss by radiation
490 HL6L*HC*(TCL-TA)'heat loss by convection
510 TS=.303*EXP(-.036*M)+.028'thermal sensation transfer coefficient
520 PMV=TS*(MW-HL1-HL2-HL3-HL4-HL5-HL6)'predicted mean vote
530 PPD0-95*EXP(-.03353*PMV^4-.2179*PMV^2)'predicted % dissatisfied
540 GOTO 580
550 PMV999!:PPD0
580 PRINT TA,RH,CLO,PMV,PPD

T (C)   RH   clo   PMV            PPD

19.6    86   1     -.4778556      9.769089
23.9    66   1      .4732535      9.676994
25.7    15   1      .5239881      10.74283
21.2    20   1     -.4779105      9.770202
23.6    67   .5    -.4747404      9.706658
26.8    56   .5     .5145492      10.53611
27.9    13   .5     .5003051      10.23146
24.7    16   .5    -.4883473      9.982468

The first 4 lines are the winter comfort zone corners.
The second 4 lines are the summer comfort zone corners.

Nick


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  • comfort
  • nicksanspam
  • 07-04-2004
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