Addition Air-Conditioning Required ?

[peterwork]

Do we need extra airconditioning in the existing equipment room due to our additional 2 nos 3kVA UPS.

Equipment room size is 8m (L) X 6m (W)

Existing Loading:
- Control power supply (8 nos. UPS each 2kVA)
- Signal equipment power supply (10 nos. UPS each 2kVA)

Existing Air-conditioner: 2 Nos, each 1.5 HP

New Loading: 2 nos 3kVA UPS

Thanks.

 

[IRstuff]

A/C is usually tons or BTUH

TTFN

FAQ731-376

 

[VerneE]

In my experience, each Hp of cooling unit condenser motor yields about 1.1 ton of cooling capacity, so two 3 Hp units could supply 3.3 tons of cooling (one ton cooling is 12,000 Btu/hr).

The existing units total 36 kVA power and if losses are about 20% to the space as heat gain (rather inefficient units) then existing cooling requirements for those units are about 2 tons. If this room is in an air conditioned office area (no heat loads from walls or roof) then the two new units will add about 4,000 Btu/hr additional cooling, and that should be picked up by the existing units.

If the room walls and roof are exterior, someone needs to calculate the heat gain from those based on wall & roof construction to see if additional cooling capacity needs to be added.