Quote Originally Posted by Segei View Post
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?
Yes seen mass flow devices on ammonia!
These flow meters are normally coupled to computers and give real time readings, they also totalise (add up the total flow, like a water meter)
If a single plant (common refrigeration system)
then liquid flow is common, compressor suction pressure and temperature are common. You can calculate your nett refrigeration effect.
How you record the data can determine if instantaneous performance is calculated or long term averages.
If you have a LT pot and a HT pot, then you need 2 flow meters and 2 sets of temp/pressure equipment.
Let the compressor unload. we are measuring all, not a problem.
System losses, total change in enthalpy gives refrigeration effect, but not all the change is related to chiling the product/area.
Such as pressure drop down suction line and heat ingress to the suction line, to what level you go to is determided by the mighty Dollar, Euro, Pound, Yen etc. ( I sorted stated this already)
On a practical note the bigger the plant, the more worth while.
The original writer did not give size or application, only wanted to know how to do it.
He state that the comps were recips, so will have some for of wear and thus reduced performance.
The more actual correct info you have the more accurate your result.
I am certainaly not detracting the skill of a good engineer, I would rather have one of these than a computer. The combination complements each other.