Answer: operating cost = 22820.736 $
Energy = 32.291 KBtu/sf.
Explanation:
Total heating load is given as = 31000 * 31.25
= 968.75* 103 Btu
From the cooling capacity application;
If 1000ftsquare = 2.8 TR
Therefore 30000ftsquare = x
Where x is the total cooling load,
Therefore x = (30000 * 2.8) / 1000
x = 84TR.
Therefore, the total cooling load, x = 84TR
Using conversion factor;
i.e. converting Btu/hr to MBH
1 MBH = 1000 Btu per hour
we have 968.75* 103 Btu/hr = 968.75 MBH
let us proceed.
Estimating the “Annual operating cost” we first calculate the maximum operating cost (Avg/Annum)
For cooling load:
Max. operatn. Cost = 14 * 84 = 1176$
For heating load:
The average heating loading hours = 1000 hrs.
Conversion to Btu/yr gives = 968.75* 103 * 1000
= 968.75* 106 Btu/yr.
Conversion of 968.75* 103Btu to Kwh gives
1Btu = 0.000293
968.75* 103 Btu = 283.84 Kwh
Therefore, average cost gives;
(8.04/100) $ = 1Kwh
X = 283.84*103
X = 22820.736 $
Operating cost = 22820.736 $
Energy use in KBtu/sf is given as
E = 968.75* 103 / 30000
E = 32.291 KBtu/sf.
