Calculate RTU kW?
Calculate RTU kW?
(OP)
Hi folks,
I was hoping someone could help me a little. Namely, what considerations should be made when calculating the kW total of a rooftop unit? I have been using the following equation: I*V*1.73/1000=kW
I have been using that formula for the compressor(s) and each fan. If a fan HP is known, I use the following instead: HP*0.746=kW
Is this fair? Are RTU compressors typically cycled, or run simultaneously? Any information would be helpful. Thank you kindly.
I was hoping someone could help me a little. Namely, what considerations should be made when calculating the kW total of a rooftop unit? I have been using the following equation: I*V*1.73/1000=kW
I have been using that formula for the compressor(s) and each fan. If a fan HP is known, I use the following instead: HP*0.746=kW
Is this fair? Are RTU compressors typically cycled, or run simultaneously? Any information would be helpful. Thank you kindly.





RE: Calculate RTU kW?
RE: Calculate RTU kW?
Thanks for the response. I have attached an example nameplate.
From the data on the nameplate--and the equations I listed above--I have calculated a total of 21.0 kW for the two compressors, two outdoor fans, the supply fan, and the combustion air blower. It is a 15-ton unit. The nameplate shows an output capactiy between 40-55 kW.
Would you say my calculations are incorrect? Again, any and all help is greatly appreciated.
RE: Calculate RTU kW?
RE: Calculate RTU kW?
RE: Calculate RTU kW?
Not to sound blunt, but could the PF be calculated from the information given in my previous attachment? As far as I know, PF = real power / apparent power