Originally posted by jacob perkins
You might find this interesting,but I find it confusing and apt to give me a headache.However,I will try respond.
First,I will just state some facts that you seem to have missed.You stated something about liquid and vapor levels being constant.I dont know what you meant,but I can say with certainty that liquid and vapors are not constant but a dynamic in the system.The only constants I can think of are the weight of the refrigerant charge and the volume of all the interconnected componants.
let me tell you a little story...and since the purpose of mechanical refrigeration is cooling,our story begins in the evaporator:
At start up the heat load on the evaporator is high.Our evaporator will require alot of liquid refrigerant from the condenser ,to boil and absorb heat from the air passing over the coil.Our saturation temperture and superheat will be high,and our vapor will be very dense.This heavy suction vapor will require more work from our compressor.With an increased amp draw the compressor will send this vapor on to the condenser,where pressure will be increased to send more liquid back to where it is needed--the highly loaded evaporator.We will have less liquid in our condenser at this time,because conditions of the evaporator.
Now later that very same day...when the room temperture has dropped,the heat load on the evaporator is less.With lower evaporator heat load,our suction pressure,superheat,and vapor density levels have dropped.
The vapor enters the compressor,and very little electromechanical work is required to send it on to the condenser.This light vapor causes a lower highside pressure and more liquid being stored in the condenser circuit,and less being sent to the evaporator.
The moral of the story is this:The evaporator heat load and the liquid requirementof the evaporator are factors influencing the density of suction vapors.And suction vapors will influence the work of the compressor,highside pressure,and level of liquid storage in the condenser.
Or in other words,the way it was taught to me:
"the evaporator is the Boss and all other componants do what it says via its bully messenger,the vapor density.
And...it's saturday nite!