[Equest-users] Question about Solar Loads in eQUEST

[Vikram Sami]

I have a question about how eQUEST calculates solar heat gain. I have been playing around with a little test building - 50' (E-W axis)x100' (N-S axis). The glass type is 2209 from the glazing library, and Walls are R10 and roof R20 (simplified).  I have the building set up with no HVAC system or lights, and a 24/7 equipment load of .25w/sf and 400sf/person occupants. 
 
I also set up hourly reporting for the following:

1.	
	space temps
2.	
	Building Heating & Cooling loads
3.	
	Building cooling load from solar radiation through windows (this is in the building loads option)

So far so good. The matrix below is an average temperature reading for the 21st day of each month. Needless to say, I was really surprised at the lack of diurnal variation in the temperatures. 
HR	 Jan	 Feb	 Mar	 Apr	 May	 Jun	 Jul	 Aug	 Sep	 Oct	 Nov	 Dec	
1	 59	 75	 74	 94	 97	 103	 103	 106	 95	 88	 79	 52	
2	 59	 75	 74	 94	 96	 102	 103	 105	 95	 88	 79	 52	
3	 58	 75	 73	 93	 96	 102	 102	 105	 95	 87	 79	 52	
4	 58	 75	 73	 93	 96	 101	 102	 104	 94	 87	 78	 51	
5	 57	 75	 72	 93	 95	 101	 102	 104	 94	 87	 78	 51	
6	 57	 74	 72	 92	 95	 101	 101	 104	 94	 87	 78	 51	
7	 57	 74	 72	 92	 96	 101	 101	 104	 93	 87	 77	 50	
8	 56	 74	 74	 92	 97	 101	 101	 106	 94	 87	 77	 50	
9	 59	 74	 76	 94	 99	 101	 101	 107	 94	 87	 77	 50	
10	 62	 75	 78	 95	 100	 102	 102	 108	 94	 88	 78	 51	
11	 64	 75	 79	 96	 101	 103	 102	 109	 96	 89	 78	 52	
12	 64	 75	 80	 98	 102	 103	 103	 109	 97	 90	 79	 52	
13	 65	 75	 80	 98	 102	 104	 103	 109	 98	 91	 81	 53	
14	 66	 76	 80	 99	 102	 105	 104	 109	 99	 92	 82	 54	
15	 67	 77	 82	 98	 103	 105	 104	 110	 100	 93	 83	 55	
16	 68	 77	 83	 98	 104	 105	 104	 110	 101	 94	 84	 56	
17	 69	 76	 84	 98	 105	 105	 104	 110	 101	 94	 83	 56	
18	 68	 76	 84	 97	 103	 105	 103	 110	 100	 92	 82	 54	
19	 66	 75	 83	 96	 102	 105	 102	 108	 99	 91	 81	 53	
20	 65	 75	 81	 95	 102	 103	 102	 107	 98	 91	 80	 52	
21	 65	 74	 80	 94	 101	 103	 101	 107	 97	 90	 80	 52	
22	 65	 74	 80	 93	 101	 102	 101	 106	 97	 90	 79	 51	
23	 64	 74	 79	 92	 100	 101	 100	 106	 96	 89	 79	 51	
24	 64	 74	 79	 91	 99	 101	 100	 105	 96	 89	 79	 51	
 
Below are the values for building solar cooling load(March 21st) , and I was surprised to see pretty high numbers way into the night. Whats going on here? What am I missing? Is the program really calculating solar heat gain at night?
 
Any insight would be appreciated. 
March 21st	Building Sensible
 Heating Load	Building Solar Cooling Load	Building Cooling Load	
1	-8365	9893	2873	
2	-13659	9130	622	
3	-19593	0	0	
4	-25131	0	0	
5	-30065	0	0	
6	-31552	0	0	
7	-32832	0	0	
8	0	35775	19007	
9	0	52932	66006	
10	0	63286	88046	
11	0	67255	102730	
12	0	66069	100438	
13	0	64668	91534	
14	0	66645	103475	
15	0	73743	125298	
16	0	83476	141834	
17	0	90939	149947	
18	0	91079	134182	
19	0	76486	95414	
20	0	62291	59587	
21	0	55129	43966	
22	0	49127	32469	
23	0	44022	23887	
24	-1310	30091	13995	

 

 

 

Vikram Sami, LEED AP
Direct Phone 404-253-1466 | Direct Fax 404-253-1366

LORD, AECK & SARGENT ARCHITECTURE
Responsive Design · Technological Expertise · Exceptional Service
www.lordaecksargent.com 
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