Development of Optimal Tilt Angle Models of a Photovoltaic Module for Maximum Power Production: Ethiopia

Table 6

Statistical errors of the developed equation using isotropic and anisotropic.

Time	Isotropic models
	RMSE	MBE	MAE	MAPE	R^2	RMSE	MBE	MAE	MAPE	R^2
	Equ (15)					Equ (16)
Winter	0.855	0.170	0.657	2.00	0.9994	0.926	0.731	0.859	2.77	0.9991
Spring	0.107	0.068	0.073	2.07	0.9991	0.205	0.145	0.173	6.04	0.9953
Autumn	0.354	0.068	0.319	1.73	0.9996	0.475	0.161	0.423	2.70	0.9991
Annual	0.204	0.172	0.172	1.24	0.9998	0.368	0.290	0.310	2.47	0.9991
	Equ (17)					Equ (18)
Winter	0.821	0.653	0.758	2.31	0.9994	0.368	0.279	0.308	0.87	0.9999
Spring	0.572	0.473	0.489	8.02	0.8836	0.132	0.123	0.123	3.41	0.9988
Autumn	0.628	0.168	0.517	3.56	0.9984	0.252	0.044	0.194	0.94	0.9998
Annual	0.370	0.258	0.298	2.35	0.9991	0.170	0.136	0.154	1.05	0.9999