Calculating Heat Absorbed due to Sunlight.
I will be using a value of 150 watts/m2, of infrared radiation (heat). For practical purposes, this value needs to be gathered by performing a site visit. The most common dimensions for a 20-foot container are 6.1m long, 2.44m wide, and 2.59m high, for a volume of 39 m3. Assuming that 3 sides are being heated by the sun, and that the container is an ideal conductor, we have a surface area of:
(6.1m x 2.44m) + (6.1m x 2.59m) + (2.44m x 2.59m) = 37m2
37m2 x 150 watts/m2 = 5.5kW = 18,800Btu/hr = 1.6 Tons of cooling
Calculating Heat Generated by Servers
This one is straightforward, and the heat dissipation can be obtained from the manufacturer specs. For example, an HP DL380G8 releases 1725 BTU/hr on a 460Watt power supply.
Calculating Heat Generated by the UPSMost modern UPS operate with 90% efficiency meaning that one can assume. I usually calculate heat loading by measuring the input current using a clamp meter and assuming that 10% is given off as heat. (I won't go into apparent power) Example:
10A x 230V = 2300 Watts being consumed by the UPS.
Therefore heat given off = 230Watts = 800Btu/hr
18,800Btu/hr + 1725 BTU/hr + 800Btu/hr = 21,325Btu/hr
Selecting Cooling Equipment
For the above setup, the closest comfort cooling unit would be a 24K Btu unit.
Temperature and Humidity MonitoringI tend to use RoomAlert.
Easy Ethernet 'Plug & Play' setup for immediate IT & facilities physical environment monitoring. Includes built-in Digital Temperature sensor, Device ManageR software &
Includes external Digital Temperature Sensor. Includes ports for 2 digital sensors, 1 switch sensor or dry contact & port for Light Tower or Relay. Offers advanced alerting by email, email-to-SMS, SNMP, webpage update and more.