Contact US
Cabinet Coolers
Catalog RequestDetermine Correct Model for
Your Use

Sizing Guide - How to Calculate Heat Load for your Enclosure
To determine the correct model for your application, it is first necessary to determine the total heat load to which the control panel is subjected. This total heat load is the combination of two factors — heat dissipated within the enclosure and heat transfer from outside into the enclosure.

To Calculate Btu/hr.:

1. First, determine the approximate Watts of heat generated within the enclosure.  Watts x 3.41 = Btu/hr.

2. Then, calculate outside heat transfer as follows:
    a. Determine the area in square feet exposed to the air, ignoring the top of the cabinet.
    b. Determine the temperature differential between maximum surrounding temperature and desired internal temperature. Then, using the Temperature Conversion Table (below), determine the Btu/hr./ft.2 for that differential. Multiplying the cabinet surface area times Btu/hr./ft.2 provides external heat transfer in Btu/hr.

3. Add internal and external heat loads for total heat load.

Temperature Conversion Table
Temperature
Differential ° F
Btu/hr/ft.2
5 1.5
10 3.3
15 5.1
20 7.1
25 9.1
30 11.3
35 13.8
40 16.2

Example:
    Internal heat dissipation: 471 Watts or 1,606 Btu/hr.
    Cabinet area: 40 ft.2
    Maximum outside temperature: 110°F
    Desired internal temperature: 95°F

The conversion table (above) shows that a 15°F temperature differential inputs 5.1 Btu/hr./ft.2

40 ft.2 x 5.1 Btu/hr./ft.2 = 204 Btu/hr. external heat load.

Therefore, 204 Btu/hr. external heat load plus 1,606 Btu/hr. internal heat load = 1,810 Btu/hr. total heat load or Btu/hr. refrigeration required to maintain desired temperature.

In this example, the correct choice is a 2,000 Btu/hr. Cabinet Cooler System. Choose a Cabinet Cooler model by determining the NEMA rating of the enclosure (type of environment), and with or without thermostat control.


Need Help Sizing EXAIR Cabinet Coolers?
Fill out our online Cabinet Cooler Sizing Guide and we'll contact you with our recommendation right away - OR - For answers NOW, call our Application Engineering Department at 1-800-903-9247 (outside the U.S. and Canada call 513 671-3322).


To Calculate Kcal/hr.:
1. First, determine the approximate Watts of heat generated within the enclosure. Watts x .86 = Kcal/hr.

2. Then, calculate outside heat transfer as follows:
    a. Determine the area in square meters exposed to the air, ignoring the top of the cabinet.
    b. Determine the temperature differential between maximum surrounding temperature and desired internal temperature. Then, using the Metric Temperature Conversion Table (below), determine the Kcal/hr./m2 for that differential. Multiplying the cabinet surface area times Kcal/hr./m2 provides external heat transfer in Kcal/hr.

3. Add internal and external heat loads for total heat load.

Temperature Conversion Table (METRIC)
Temperature
Differential ° C
Kcal/hr/m2
3 4.5
6 9.7
9 15.1
12 21.0
15 27.0
18 34.0
21 41.0

Example:
    Internal heat dissipation: 471 Watts or 405 Kcal/hr.
    Cabinet area: 3.7m2
    Maximum outside temperature: 44°C
    Desired internal temperature: 35°C

The conversion table (above) shows that a 9°C temperature differential inputs 15.1 Kcal/hr./m2 .

3.7m2 x 15.1 Kcal/hr./m2 =56 Kcal/hr. external heat load.

Therefore, 56 Kcal/hr. external heat load plus 405 Kcal/hr. internal heat load = 461 Kcal/hr. total heat load or Kcal/hr. refrigeration required to maintain desired temperature.

In this example, the correct choice is a 504 Kcal/hr. Cabinet Cooler System. Choose a Cabinet Cooler model by determining the NEMA rating of the enclosure (type of environment), and with or without thermostat control.


Applications Applications CAD Library CAD Library FAQs FAQs
PDF Library PDF Library Presentations Presentations Videos Videos
QUICK ORDER:
CART INFORMATION:
APPLICATION SEARCH:
 
 
 
 
 
Bookmark and Share
 
  Follow Us
  RSS Wordpress Twitter Facebook