ASHRAE-Standard-55 - Page 029

Extracted Content

hcn = 2.38 * pow(abs(100.0 * xf – taa), 0.25); if (hcf > hcn) hc = hcf; else hc = hcn; xn = (p5 + p4 * hc – p2 * pow(xf, 4)) / (100 + p3 * hc);

++n; if (n > 150) { alert(‘Max iterations exceeded’); return 1; } } tcl = 100 * xn – 273;

//Heat loss diff. through skin hl1 = 3.05 * 0.001 * (5733 – (6.99 * mw) – pa);

//Heat loss by sweating if (mw > 58.15) hl2 = 0.42 * (mw – 58.15); else hl2 = 0;

//Latent respiration heat loss hl3 = 1.7 * 0.00001 * m * (5867 – pa);

//Dry respiration heat loss hl4 = 0.0014 * m * (34 – ta);

//Heat loss by radiation hl5 = 3.96 * fcl * (pow(xn, 4) – pow(tra / 100, 4));

//Heat loss by convection hl6 = fcl * hc * (tcl – ta); ts = 0.303 * exp(–0.036 * m) + 0.028; pmv = ts * (mw – hl1 – hl2 – hl3 – hl4 – hl5 – hl6); ppd = 100.0 – 95.0 * exp(–0.03353 * pow(pmv, 4.0) – 0.2179 * pow(pmv,

2.0));

var r = {} r.pmv = pmv; r.ppd = ppd; return r }

Validation Table

Run	Air Temp.	Col3	RH	Radiant Temp.	Col6	Air Speed	Col8	met	clo	PMV
#	** °F**	C	%	°F	C	fpm	m/s	m/s	m/s	m/s
1	67.3	19.6	86	67.3	19.6	20	0.10	1.1	1	–0.47
2	75.0	23.9	66	75.0	23.9	20	0.10	1.1	1	0.48
3	78.2	25.7	15	78.2	25.7	20	0.10	1.1	1	0.53
4	70.2	21.2	20	70.2	21.2	20	0.10	1.1	1	–0.48
5	74.5	23.6	67	74.5	23.6	20	0.10	1.1	0.5	–0.47
6	80.2	26.8	56	80.2	26.8	20	0.10	1.1	0.5	0.52
7	82.2	27.9	13	82.2	27.9	20	0.10	1.1	0.5	0.50
8	76.5	24.7	16	76.5	24.7	20	0.10	1.1	0.5	–0.49

Note: In every case listed above, the PMV result corresponds to a calculated PPD of 10%.

ANSI/ASHRAE Standard 55-2023 27