Appendix F: Perez Anisotropic Model Coefficients for Luminous Efficacy and Zenith Luminance Model

TABLE F.1

Efficacy and Zenith Luminance Coefficients for Each Sky Condition Bin

Global Luminous Efficacy Direct Luminous Efficacy

E bin	a1	b1	c1	d1	a1	b1	c1	d1
1	96.63	-0.47	11.50	-9.16	37.20	-4.55	-2.98	117.12
2	107.45	0.79	1.79	-1.19	98.99	-3.46	-1.21	12.38
3	98.73	0.70	4.40	-6.95	109.83	-4.90	-1.71	-8.81
4	92.72	0.56	8.36	-8.31	110.34	-5.84	-1.99	-4.56
5	86.73	0.98	7.10	-10.94	106.36	-3.97	-1.75	-6.16
6	88.34	1.39	6.06	-7.60	107.19	-1.25	-1.51	-26.73
7	78.63	1.47	4.93	-11.37	105.75	0.77	-1.26	-34.44
8	99.65	1.86	-4.46	-3.15	101.18	1.58	-1.10	-8.29
		Diffuse Luminous Efficacy			Zenith Luminance Value
E bin	a1	b1	c1	d1	a1	b1	c1	d1
1	97.24	-0.46	12.00	-8.91	40.86	26.77	-29.59	-45.75
2	107.22	1.15	0.59	-3.95	26.58	17.73	58.46	-21.25
3	104.97	2.96	-5.53	-8.77	19.34	2.28	100.00	0.25
4	102.39	5.59	-13.95	-13.90	13.25	-1.39	124.79	15.66
5	100.71	5.94	-22.75	-23.74	14.47	-5.09	160.09	9.13
6	106.42	3.83	-36.15	-28.83	19.76	-3.88	154.61	-19.21
7	141.88	1.90	-53.24	-14.03	28.39	-9.67	151.58	-69.39
8	152.23	0.35	-45.27	-7.98	42.91	-10.62	130.80	-164.08
Source:	Perez, R., P. Ineichen	, R. Seals, J. Michalsky,	and R. Stewart. (1990).	Modeling daylight avail

ability and irradiance components from direct and global irradiance. Solar Energy, Vol. 44, No, 5, pp. 271-289. With permission from Elsevier.

TABLE F.2

Sky Condition Bin and High-Low Boundaries for Bin

£ Bin	£ Low	£ High
1	1.000	1.065
2	1.065	1.230
3	1.230	1.500
4	1.500	1.950
5	1.950	2.800
6	2.800	4.500
7	4.500	6.200
8	6.200

Source: Perez et al. The Development and Verification of the Perez Radiation Model. Contractor Report Sand88- 7030 National Laboratories. http://prod. sandia. gov/ techlib/access-control. cgi/1988/887030.pdf.

£ is the ratio of diffuse/global irradiance.

TABLE F.3

Regression Equations for ai… di Perez Luminance Model Coefficients as Function of Sky Condition BIN Number (= x = 1 to 8)

Подпись: Global

Подпись:

ai bi ci di

Data from http://prod. sandia. gov/techlib/access-control. cgi/1988/887030.pdf accessed 27 Oct 2012.

FIGURE 2.2 Thermal (top right) and solid-state photoelectric detector pyranometers including a silicon photovoltaic reference cell (bottom left).

FIGURE 2.4 Left to right: Shaded, ventilated thermal pyranometer for diffuse sky irradi – ance; unshaded thermal pyranometer for total hemispherical irradiance; same model shaded thermal pyranometer and thermal pyrheliometer (below pyranometers) mounted on a solar tracker.

FIGURE 2.5 Rotating shadow-band radiometer. Rotating band is below silicon photodiode photoelectric pyranometer (just above horizon line).

Wavelength nanometers

FIGURE 2.6 Representative distributions of power as a function of wavelength for solar energy at the top of the atmosphere (extraterrestrial), solar beam radiation, diffuse sky radiation, and total radiation on a horizontal surface for clear sky conditions. Bars show regions of energy utilization by conversion systems. Note especially the difference between the global and diffuse horizontal spectra.

FIGURE 2.10 Typical absolute cavity pyrheliometer for reference DNI measurements.

FIGURE 6.1 Global hemispherical pyranometers (left, silicon photodiode; right, thermopile) measuring plane of array irradiance for photovoltaic performance testing.