Industrial Water-Cooled Chillers -- Evaporator Side question.

[Subystud]

Hello,

Heard something interesting from a chiller rep in that the evaporator-side piping is interchangeable -- heat transfer would still be the same. This is NOT true for the condenser side, this does have a specific piping configuration.

So it got me thinking the following:
From a physical standpoint, the evaporator is a 2 phase system. It’s a boiling refrigerant. Phase changes occur at constant temperature, so the evaporator should be isothermal. If the evaporator is isothermal, then the heat removed should just be a function of residence time in the evaporator tube bundles, which is independent of which side the fluid to be cooled enters the evaporator side.

Now, if residence time in the evaporator is the main factor for removing sensible heat from the Chilled Water then what happens when the Chilled Water flow is backed off? Does the Chilled Water now have a lower leaving temperature from “residing” in the tube bundles longer? Does the chiller compressor back off at this point? This I am unsure about. If the flow is reduced 25%, would the leaving temperature be 100%/75% = 1.333 * delta T? Thus a delta T of 10F at 100% flow would now be 13.33F at the 25% reduced flowrate?

What about the condenser side? Typically, the inlet/outlet is stacked, and the cooling tower water always enters the bottom of the condenser bundle. What's the significance of this?

Thanks.

 

[EnergyProfessional]

what does "evaporator-side piping is interchangeable" mean?

and both condenser and evaporator have phase change, just in reverse. Evaporator evaporates, condenser, condenses.