An Algorithm to Determine the Optimum Tilt Angle of a Solar Panel from Global Horizontal Solar Radiation

Table 7

The average β of the optimum tilt angle values computed using the diffuse solar radiation models, relative to the latitude values used above. A linear regression with 95% confidence interval provided the coefficients 𝑎₁ and 𝑎₂ and the correlation coefficients ranging from 0.944 to 0.993, reported in the last column.

β (𝑙1)	β (𝑙2)	β (𝑙3)	β (𝑙4)	β (𝑙5)	β (𝑙6)	Coefficients		Correlation 𝑟
						𝑎1	𝑎2
54.07	56.08	62.07	62.80	67.72	—	31.33	0.68	0.953
46.45	48.25	54.30	53.93	59.17	70.90	16.25	0.86	0.944
35.97	38.13	44.32	44.62	48.70	59.87	6.80	0.84	0.957
23.37	27.70	31.57	33.55	38.03	48.15	−6.07	0.87	0.975
13.65	18.80	22.50	24.03	30.17	37.92	−14.95	0.87	0.978
9.05	14.70	18.42	20.95	24.73	33.77	−19.27	0.87	0.985
11.03	16.78	20.62	23.62	26.08	34.67	−15.65	0.83	0.988
19.25	24.70	28.72	31.27	33.70	40.22	−4.23	0.75	0.989
31.15	36.40	39.95	43.22	45.53	52.75	6.42	0.77	0.993
43.20	47.37	52.37	53.93	59.90	65.70	15.84	0.83	0.983
51.90	54.13	60.20	63.10	68.07	—	23.61	0.84	0.977
55.60	58.15	65.15	67.20	69.75	—	30.56	0.76	0.968