Formula

[Madmacs]

Good day ppl im looking for the formula that u use to work out what size blower and comp is needed for freezer and coldrooms plz

[nike123]

There is no such formula!
There are many calculations involved in such task.

[750 Valve]

Take the internal floor area in m2 x by the refrigerant type (use ASHRAE number) all divided by the number of fans you want to run on the evaporator

Example: 6 x 3m room
18m2 x 404a = 7272
7272 / 2 fans = 3636watts

This only applies for coolrooms and not freezers, for freezers you must also divide by the amount of fans on the condensing unit!

Or failing that you can work out transmission loads, infiltration, product heat load, misc loads in room, pulldown times, air changes, etc all individually.

[CJG21]

For a coldroom we would generally work out a watts/m2 rule.

For a small room e.g. 3m x 3m with personnel door we would use approx 200-230w/m2.

You times this by the m2 to get the duty.

i.e. 9m2 x 230w/m2 = 2.07kw needed.

You can down the route of all the heat load calcs through walls, throughput of produce, number of people work in the room etc but it is a long process.