rule of thumb plant sizing

Hello there,

Im about to start a new job, ive been at this job since I was an apprentice.

I hear all the time of mega watts, killo watts and even hp,
The older guys I worked with would talk of systems lets say of 100kw, they could look at a drive motor and almoat determine the plant size off the kw rating of the motor.

Im now racking my brains for all the questions I could of / should of asked.

Can anyone enlighten me on the understanding of plant capacity as I say. By looking at the motor size.

If im abit wrong in what im saying please steer me in the right direction.

I know about enthlapy charts but havent had to make one out since my college days and am maybe abit ring rusty.

Any help would be appreciated

the smaller the thumb, the bigger the kit!



look at the condenser- will tell you the kw/horsepower output
:p

That is easy. If you know what COP is to expect at certain use, than you can estimate what is refrigeration capacity from compressor motor power.

For example, non-inverter air conditioner with rotary compressor in cooling has roughly COP of about 3.
If you have compressor of 1,2 kW electrical power, than you can estimate that cooling capacity of that system is about 3,6 KW

Another case is with low temperature refrigeration where COP is about 1 (or lower). You can estimate cooling capacity of 1kW for 1kW compressor electrical power.

Knowing usual COP and EER for certain application, you can estimate capacity of system by looking at compressor electrical power.

Nevertheless, rule of thumb is only guessing.
Nowadays, with power of Internet and smart-phone, there is no need for guessing!