Performance Investigation and Structure Optimization of a Flat Dual-Function Solar Collector

Table 3

Water heating efficiency of the collector in different days.

Date	(°C)	Tinital (°C)	Tfinal (°C)	(°C)	(MJ/m^2 day)	(%)	(%)
03/31	18.5	13.0	55.2	42.2	24.3	58.2	4.37
04/01	26.5	28.5	58.1	29.7	18.0	55.2	5.37
04/07	22.2	17.2	51.9	34.7	19.2	60.8	4.88
04/26	24.2	17.1	57.7	40.6	22.8	59.7	4.46
05/09	26.4	22.6	43.0	20.4	11.3	60.6	6.90
05/10	27.4	23.0	58.8	35.8	20.9	57.5	4.79
05/11	28.4	28.4	58.6	30.2	17.7	57.3	5.31
05/16	30.3	32.6	60.3	27.7	16.6	56.0	5.61
05/21	21.8	17.8	54.7	36.9	21.2	58.3	4.71
06/02	27.4	28.0	52.3	24.4	14.5	56.4	6.10
06/08	32.6	25.7	57.3	31.7	17.3	61.4	5.15
06/12	31.9	26.4	55.5	29.1	16.3	60.0	5.44