Quote Originally Posted by mad fridgie View Post
You can get a flow meter for just about any material.
To calculate COP of a system you need to know your load (the bit you are cooling) In rooms this is quite difficult (practically hugh variables) By knowing the actual mass flow of the refrigerant and the conditions it is at, you can calculate refrigeration effect, if you then remove system losses either by detail measurement or theoretical calcs you will end u with nett refrigeration effect. (how detailed to determine accuracy)
Damage to compressor parts valves, rings etc, effect volumetric efficiency, which inturn effects actual mass flow, thus makes changes to power draw (COP)
Did you see any ammonia refrigeration plant with flow meters?
Theoretically we can do everything but practically.... Typically ammonia refrigeration has a few evaporative temperatures. You need flow meter for every temperature. To compare apple and apple suction pressures and discharge pressure should be kept constant. Efficiency of the compressors should not be changed(no unloading for screw compressors). I didn't get about system losses. What do you mean?