NEMA Type 12 Cabinet Coolers - Technical Information

NEMA Type 12 Cabinet Panel Coolers - Frigid-X - Sizing Specifications:

MODEL NO.	VERSION	BTU/Hr. cooling* (WATTS)
61008A	NEMA Type 12 Continuous Operation	580 (170)
61015A	NEMA Type 12 Continuous Operation	1100 (322)
61025A	NEMA Type 12 Continuous Operation	1800 (527)
61030A	NEMA Type 12 Continuous Operation	2100 (615)
61040A	NEMA Type 12 Continuous Operation	2900 (849)

63008A	NEMA Type 12 on-off control	580 (170)
63015A	NEMA Type 12 on-off control	1100 (322)
63025A	NEMA Type 12 on-off control	1800 (527)
63030A	NEMA Type 12 on-off control	2100 (615)
63040A	NEMA Type 12 on-off control	2900 (849)

*Cooling effect based on 95 degrees temperature inside cabinet, 100 PSIG (6.9 BAR) compressor inlet pressure, and 70ºF (21ºC) inlet temperature.
BTU/hr. figures rounded to nearest 100 BTU/hr (1 WATT).

All Continuous Operation models include the cooling unit, filter with auto drain and cold air distribution kit.

All On-Off control units include the cooling unit, filter with auto drain, cold air distribution kit, solenoid valve and thermostat.

NEMA Type 12 Cabinet Panel Coolers - Frigid-X™ - Selection:

Cabinet Panel Coolers come with a 5 micron filter with an automatic drain for the compressed air supply to insure clean, dry air and an air distribution kit to circulate the cold air inside the enclosure for even cooling.

Cabinet Panel Coolers are available with or without thermostat control.

When constant cooling and a constant positive purge is required we recommend the continuous operating version without the thermostat and solenoid valve. The cooling effect can be controlled by adding a regulator in line to reduce pressure for reduced cooling when it is not required and to conserve energy.

Systems utilizing a thermostat and solenoid valve saves air by activating the air conditioner only when the internal temperature reaches a critical level. The adjustable thermostat is factory set at 95°F but can be readjusted on site.

Thermostat and solenoid valve systems are recommended where the heat load can fluctuate (such as for frequency drives) and where a continual purge is not required. The thermostat and solenoid "package" can also be added at a later date to a continuous system.

Calculating Heat Load In Your Electrical/Electronic Panel Enclosure:

Total heat load consists of the heat transfer from outside your panel and from the heat dissipated inside the control unit.

Useful terms, and conversions:

1 BTU/hr = 0.293 watts
1 BTU/hr - 0.000393 horsepower
1 Watt = 3.415 BTU/hr
1 horsepower = 2544 BTU/hr
1 Watt = 0.00134 horsepower
1 Square Foot = 0.0929 square meters
1 Square Meter = 10.76 square foot

Typical fan capacity:

4" fan: 100 CFM (2832 LPM)
6" fan: 220 CFM (6230 LPM)
8" fan: 340 CFM (9628 LPM)
10" fan 550 CFM (15574 LPM)

BTU/hr. cooling effect from fan 1.08 x (temp. inside panel in ºF - temp. outside panel in degrees F) x CFM
Watts cooling effect from fan: 0.16 x (temp. inside panel in ºC - temp. outside panel in degrees C) x LPM

Calculating BTU/hr. or Watts:

Determine the heat generated inside the enclosure. Approximations may be necessary. For example, if you know the power generated inside the unit, assume 10% of the energy is dissipated as heat.

For heat transfer from the outside, calculate the area exposed to the atmosphere except for the top of the control panel.

Choose the internal temperature you wish to have, and choose the temperature difference between it an the maximum external temperature expected.

From the conversion table that follows, determine the BTU/hr. per square foot (or watts per square meter) for the temperature difference.

Multiply the panel surface area times the BTU/hr. per square foot (or watts per square meter) to get the external heat transfer in BTU/hr or in watts.

Sum the internal and external heat loads calculated.

If you do not know the power used in the enclosure but you can measure temperatures, then measure the temperature difference between the outside at current temperature, and the present internal cabinet temperature.

Note size and number of any external fans. Provide this information to Nex Flow™ to assist in sizing the appropriate cooling system.

Temperature Difference in ºF	BTU/hr./sq. ft.	Temperature Difference in ºC	Watts/sq.m
5	1.5	3	5.2
10	3.3	6	11.3
15	5.1	9	17.6
20	7.1	12	24.4
25	9.1	15	31.4
30	11.3	18	39.5
35	13.8	21	47.7
40	16.2	24	55.6

Example:

The control panel has two frequency drives totaling 10 horsepower and one module rated at 100 watts. The maximum outside temperature expected is 105ºF or 40.5ºC. The area of the control panel exposed sides, except for the top is 42 square feet or 3.9 square meters. We want the internal temperature to be 95ºF or 35ºC.

Total internal power is 10 hp x 746 watts/hp - 7460 plus 100 watts = 7560 watts.
Assume 10% forms heat = an internal heat load of 756 watts.

Total internal power is 10 hp x 2544 BTU/hp = 25440 BTU/hr plus 100 watts x 3.415 BTU/hr/watt = 25782 BTU/hr.

Assume 10% forms heat = an internal heat load of 2578 BTU/hr.

External heat load: The temperature difference between the desired temperature and the outside is 10ºF or 5.5ºC. Using the conversions (and interpolating where necessary) we multiply the area by the conversion factor:

42 sq. ft x 3.3 - 139 BTU/hr or 3.9 sq. m x 10.3 = 40 watts

Total Heat Load: 756 + 40 - 796 watts or 2578 + 139 - 2717 BTU/hr.

You would use a Model 61040 for constant operation or a Model 63040 for one-off control. (Rated at 2900 BTU/hr or 849 watts).

Downloads

	Panel Coolers
	Maintenance & Installation