Compression Tank Sizing:
Vt = EVs / ((Pa/Pf)-(Pa/Po))
Vt = Compression Tank Size (gal)
Vs = Total System Water Volume (gal)
Pa = Pressure In Tank Before Fluids enter (psia)
Pf = Minimum System Pressure (Fill Pressure, psia)*
* This is building static pressure over the tank +14.7 psia, atmospheric pressure + 5 psig for venting.
If tank installed on top of the building the static pressure will be about zero and Pf shall be 12 psig.
Po = Maximum System Pressure (relief Valve Pressure, psia
E = Net Water Expansion Factor (Refer to Table 1 for water and Table 2 for glycol-water)
To use Table 1 and 2 the mean temperature is required (160-200℉ for hot water, 100℉ for chilled water)
** The term of EVs is called Expansion Volume. Vt is the Tank Volume.
|
Table 1
|
|
Temperature ℉
|
Factor
|
Temperature ℉
|
Factor
|
Temperature ℉
|
Factor
|
|
100
|
0.0057
|
155
|
0.0198
|
210
|
0.0391
|
|
105
|
0.0068
|
160
|
0.0208
|
215
|
0.0415
|
|
110
|
0.0080
|
165
|
0.0225
|
220
|
0.0433
|
|
115
|
0.0092
|
170
|
0.0243
|
225
|
0.0457
|
|
120
|
0.0097
|
175
|
0.0261
|
230
|
0.0475
|
|
125
|
0.0115
|
180
|
0.0279
|
235
|
0.0505
|
|
130
|
0.126
|
185
|
0.0296
|
240
|
0.0523
|
|
135
|
0.0138
|
190
|
0.0314
|
245
|
0.0547
|
|
140
|
0.0149
|
195
|
0.0332
|
250
|
0.0571
|
|
145
|
0.0167
|
200
|
0.0350
|
255
|
0.0595
|
|
150
|
0.0178
|
205
|
0.0374
|
|
|
|
Table 2 Temperature ℉
|
|
Type
|
% By volume
|
Approx. Freeze Temp.℉
|
100
|
110
|
120
|
130
|
140
|
150
|
160
|
180
|
200
|
220
|
240
|
250
|
|
Ethylene Glycol
|
10
20
30
40
50
|
25
16
4
-13
-35
|
1.70
1.75
1.96
2.06
2.24
|
1.47
1.54
1.68
1.77
1.91
|
1.46
1.51
1.66
1.75
1.88
|
1.31
1.38
1.49
1.56
1.67
|
1.28
1.29
1.38
1.45
1.55
|
1.24
1.29
1.38
1.45
1.55
|
1.20
1.25
1.35
1.41
1.49
|
1.13
1.18
1.25
1.31
1.38
|
1
1.15
1.22
1.27
1.34
|
1.08
1.12
1.18
1.23
1.29
|
1.06
1.10
1.15
1.20
1.25
|
1.05
1.09
1.14
1.19
1.24
|
|
Propylene Glycol
|
10
20
30
40
50
|
26
18
8
-7
-28
|
1.76
2.07
2.42
2.61
2.87
|
1.53
1.70
2.08
2.25
2.47
|
1.52
1.76
2.05
2.19
2.42
|
1.37
1.58
1.83
1.96
2.15
|
1.34
1.55
1.77
1.90
2.07
|
1.29
1.47
1.68
1.81
1.97
|
1.26
1.43
1.63
1.75
1.90
|
1.18
1.34
1.50
1.62
1.75
|
1.16
1.30
1.46
1.56
1.68
|
1.12
1.28
1.40
1.50
1.61
|
1.11
1.24
1.37
1.46
1.57
|
1.10
1.23
1.35
1.45
1.55
|
