Exemplary solar heat collectors are described in U.S. Pat. No. 4,144,875--Bruno et al.; U.S. Pat. No. 4,119,083--Heyen et al.; U.S. Pat. No. 4,115,225--Ortabasi; and U.S. Pat. No. 4,091,793--Herman et al. However, as far as is known, the prior art does not disclose utilization of a solar energy collector structure as disclosed by the present inventors providing improved thermal efficiency at all angles of incidence and particularly at angles of incidence greater than 60.degree. as defined herein either alone or in the combinations claimed herein.