Study on the Optimizing Operation of Exhaust Air Heat Recovery and Solar Energy Combined Thermal Compensation System for Ground-Coupled Heat Pump

Table 3

Range of hourly total solar irradiance R_R corresponding to K_t in XH-2 similar days group.

Kt range	Serial number of cleanness index range	Possible weather conditions	Total solar irradiance range RR (w/m^2)	The maximal hourly total solar irradiance range RR in; DS-1 (w/m^2)	Data sources
0~0.15	KT1	Overcast but may transform to rain and; Haze (severe or heavy pollution)	20.5~81.3	24.87	Dest 1.14
0.15~0.28	KT 2	Overcast and will not transform to rain	81.3~162.5	115.6	Dest 1.13
0.28~0.5	KT 3	Weather transform between cloudy and overcast	162.5~421.0	407	2012.1.15
				290	2013.1.12
				191	2013.1.13
				375	2013.1.14
				338	2013.1.15
				169.94	Dest 1.12
				319.34	Dest 1.15
				345.95	Dest 1.16
				304.5
0.5~0.74	KT 4	Weather transform between cloudy and sunny, haze (medium or mild pollution)	421.0~806.8	610	2012.1.12
				715	2012.1.13
				804	2012.1.14
				787	2014.1.12
				642	2014.1.13
				627	2014.1.14
				723	2014.1.15
				701.1
0.74~1	KT 5	Sunny and sunny with hazy	806.8~1176.3	809	2012.1.14