ASHRAE-Standard-55 - Page 042

Extracted Content

BDSIG = TB - TempBodyNeutral; WARMB = (BDSIG > 0) * BDSIG; SkinBloodFlow = (SkinBloodFlowNeutral + CDIL * WARMC)/(1 + CSTR

     - COLDS);

SkinBloodFlow = Math.max(0.5, Math.min(90.0, SkinBloodFlow)); REGSW = CSW * WARMB * Math.exp(WARMS/10.7); REGSW = Math.min(REGSW, 500.0); var ERSW = 0.68 * REGSW; //Evaporative resistance of air layer var REA = 1.0/(LR * FACL * CHC); 

//Evaporative resistance of clothing (icl=.45) var RECL = RCL/(LR * ICL); var EMAX = (FindSaturatedVaporPressureTorr(TempSkin) VaporPressure)/(REA + RECL); var PRSW = ERSW/EMAX; var PWET = 0.06 + 0.94 * PRSW; var EDIF = PWET * EMAX - ERSW; var ESK = ERSW + EDIF; if (PWET > WCRIT) {

PWET = WCRIT; PRSW = WCRIT/0.94; ERSW = PRSW * EMAX; EDIF = 0.06 * (1.0 - PRSW) * EMAX; ESK = ERSW + EDIF;

} if (EMAX < 0) { EDIF = 0; ERSW = 0; PWET = WCRIT; PRSW = WCRIT; ESK = EMAX;

} ESK = ERSW + EDIF; MSHIV = 19.4 * COLDS * COLDC; M = RM + MSHIV; ALFA = 0.0417737 + 0.7451833/(SkinBloodFlow + 0.585417); } //End iteration

var HSK = DRY + ESK; //Total heat loss from skin var RN = M - WME; //Net metabolic heat production var ECOMF = 0.42 * (RN - (1 * METFACTOR)); if (ECOMF < 0.0) ECOMF = 0.0; //From Fanger EMAX = EMAX * WCRIT; var W = PWET; var PSSK = FindSaturatedVaporPressureTorr(TempSkin); var CHRS = CHR; //Definition of ASHRAE std. environment, denoted “S” CHCS = 3.0 * Math.pow(PressureInAtmospheres, 0.53);

if (!CALCULATE_CE && MET > 0.85) {

CHCS = Math.max(CHCS, heatTransferConvMet); }

if (CHCS < 3.0) CHCS = 3.0; var CTCS = CHCS + CHRS; var RCLOS = 1.52/((MET - WME/METFACTOR) + 0.6944) - 0.1835; var RCLS = 0.155 * RCLOS; var FACLS = 1.0 + KCLO * RCLOS; var FCLS = 1.0/(1.0 + 0.155 * FACLS * CTCS * RCLOS); var IMS = 0.45;

40 ANSI/ASHRAE Standard 55-2023