|
Approximate Pressure Control Settings
|
Application
|
Temp
Range
(ºF)
|
Evaporator
TD
(ºF)
|
REFRIGERANT |
|
R-22 |
R-134a |
R404A |
R-507 |
|
Out |
In |
Out |
In |
Out |
In |
Out |
In |
|
Beverage Cooler |
25 to 38 |
15 |
41 |
66 |
17 |
33 |
53 |
82 |
56 |
86 |
|
Floral Cooler |
|
Produce Cooler |
|
Smoked Meat Cooler |
32 to 35
|
15 |
38 |
62 |
15 |
30 |
49 |
77 |
52 |
81 |
|
Service Deli |
|
Seafood |
|
Multi-Deck Fresh Meat |
26 to 29 |
15 |
32 |
54 |
11 |
25 |
42 |
68 |
45 |
72 |
|
Frozen Glass Door |
-10 to 0 |
10 |
9 |
24 |
-- |
-- |
15 |
33 |
16 |
35 |
|
Frozen Walk-in |
|
Frozen Ice Cream |
-30 to -20 |
10 |
0 |
10 |
-- |
-- |
4 |
16 |
4 |
18 |
| Frozen Food - Open Type |
|
Evacuation Pressures |
|
in.Hg
Vacuum |
P.S.I.A. |
Microns |
mm Hg |
Boiling Point of Water
(°F) |
| 0.00 |
14.696 |
759,966 |
760 |
212 |
| 4.92 |
12.279 |
653,000 |
653 |
205 |
| 9.23 |
10.162 |
525,525 |
526 |
194 |
| 15.94 |
6.866 |
355,090 |
355 |
176 |
| 20.72 |
4.519 |
233,680 |
234 |
158 |
| 24.04 |
2.888 |
149,352 |
149 |
140 |
| 25.00 |
2.383 |
123,217 |
123 |
132 |
| 26.13 |
1.788 |
92,455 |
92 |
122 |
| 27.75 |
1.066 |
55,118 |
55 |
104 |
| 28.67 |
0.614 |
31,750 |
32 |
86 |
| 28.92 |
0.491 |
25,400 |
25 |
80 |
| 29.02 |
0.442 |
22,860 |
23 |
76 |
| 29.12 |
0.393 |
20,320 |
20 |
72 |
| 29.22 |
0.344 |
17,780 |
18 |
69 |
| 29.32 |
0.295 |
15,240 |
15 |
64 |
| 29.42 |
0.246 |
12,700 |
13 |
59 |
| 20.52 |
0.196 |
10,160 |
10 |
58 |
| 29.62 |
0.147 |
7,620 |
8 |
45 |
| 29.74 |
0.088 |
4,571 |
5 |
32 |
| 29.82 |
0.049 |
2,540 |
3 |
21 |
| 29.87 |
0.0245 |
1,270 |
1 |
6 |
| 29.91 |
0.0049 |
254 |
0.25 |
-24 |
| 29.915 |
0.00245 |
127 |
0.13 |
-35 |
| 29.919 |
0.00049 |
25.4 |
0.025 |
-60 |
| 29.9195 |
0.00024 |
12.7 |
0.013 |
-70 |
| 29.9199 |
0.000049 |
2.54 |
0.003 |
-90 |
| 29.9200 |
0.000000 |
0.00 |
0.000 |
--- |
|
Formulas & Conversions |
| 1 gallon water |
= |
8.346 lb (@68ºF) |
1 sq. ft. EDR |
= |
240 Btu |
| QS |
= |
m x c x ∆t |
QL |
= |
m x hf |
| 1 pound |
= |
7000 grains |
1 ton refrigeration |
= |
12,000 Btu/hr. |
| 1 boiler HP |
= |
33,479 Btu/hr. |
1 ton refrigeration |
= |
3.515 kW |
|
Pressure |
Electrical |
| 1 atmosphere |
= |
14.696 psi |
1 watt |
= |
3.412 Btu/hr |
| 1 lb. |
= |
27.72 in. w.c. |
1 Btu/hr. |
= |
0.2931 watt |
| 1 oz. |
= |
1.73 in. w.c. |
1 horsepower |
= |
2545 Btu/hr. |
| psia |
= |
in. Hg/2.036 |
1 horsepower |
= |
746 watts |
| in. Hg |
= |
psia x 2.036 |
Voltage = Amperage x Resistance |
| mm Hg |
= |
psia x 51.715 |
Watts = (Amperage)2 x Resistance |
| in Hg. vacuum |
= |
29.921 - in. Hg |
Watts = Voltage x Amperage |
| microns |
= |
51,715 x psia |
COP = EER x 0.293 |
| 1 ft (head) |
= |
0.433 psi |
EER = Output(BTU)/Input(WATTS) |
|
Nominal Airflow |
|
Cooling = 400 CFM per ton |
| Heating = 12 CFM per 1000 BTU input |
|
CFMnew = CFMold x (RPMnew/RPMold) |
| RPM = (120 x Hz)/ Number of poles |
| BTUh (sensible) = CFM x 1.08 x Temperature Rise |
| BTUh (latent) = 0.68 x Q x ∆g |
| Water quantity (gpm) required for heating and cooling = q/500∆twater |
|