Multiple Condensers Critically Charged

[Inniswhe]

I have an ice rink application with both a evap condenser mounted on the roof and a frame/plate water cooled condenser for heat recovery piped in parallel.

I was planning on using a surge type high pressure receiver to provide ample storage for the potential liquid backup in the evap condenser when it is not in use.

There is a motorized valve on the line leading to the evaporative condenser to minimize unwanted condensing effect when the water condenser is capturing the condenser heat.

The plan is to feed the flooded frame and plate evaporator is with a motorized control valve and level control.

Does anyone have any experience with this sort of parallel condensers with a simplified system that would eliminate the high pressure receiver and use a high pressure float valve to feed the evaporator suction accumulator. It would be a critically charged system with an oversized suction accumulator on the evaporator that could hold the extra charge to permit the evap. condenser to hold up liquid if this occurs without starving the evaporator.

The condensing temp. is normally 95-100F during heat recovery. The outside ambient can get down to 0F.

[charlie n]

Looks like somebody is trying to copy my designs. Use a high side float valve on each condenser and size the liquid separator to hold the winter charge of the Evap condenser. You also need a pressure regulator in parallel with the motorized valve in the discharge pipe.

[Inniswhe]

Charlie N, I didn't realize you used that design in your work. I wasn't trying to copy it anything specifically just thought it was a good idea so its good to hear it is a proven approach.

I assume the PRV is to deal with heat reclaim shortfalls when a little excess heat needs to be relieved and then the motorized valve takes over when the heat reclaim is off ??

[charlie n]

No problem it's hardly an exclusive design.
You hit it with the PRV. In the winter when your heated fluid isn't warm enough, the motorized valve will be closed. The PRV will prevent the compressors from starting up against a closed discharge pipe. I usually select it for full compressor capacity at about 1 bar pressure drop then set it to open at the design condension pressure for heat recovery. Don't forget to connect the pressure control for the evap. condenser downstream of the motor valve/PRV assembly.