Heat Pump - Hot Gas Reheat - Deumidification
Heat Pump - Hot Gas Reheat - Deumidification
(OP)
Hello,
Is it possible, with a heat pump, to do a Hot Gas Reheat, by diverting some of the Hot Gas from the Condensor to a reheat Coil. The goal is to respond to a call for dehumification without further cooling.
Please see attached diagram.
Equipment:
Heat Pump : (New-To Be supplied)3 Ton, 2 stage.
Controller : (Existing) Honeywell Vision Pro IAQ with dehumidifcation call capability.
Air Handler: (Existing) Custom built including plenum fan with VF Drive. The air flow can be varied.
Questions :
Can it be done ? or
Will this cause the heat pump to malfunction ?
Apart from the reheat coil, and 3-way valve, what other components would be required ?
Is there a manufacturer who manufactures such a Heat pump, ready for this of use.
What is the best way to execute such a design ?
Is it possible, with a heat pump, to do a Hot Gas Reheat, by diverting some of the Hot Gas from the Condensor to a reheat Coil. The goal is to respond to a call for dehumification without further cooling.
Please see attached diagram.
Equipment:
Heat Pump : (New-To Be supplied)3 Ton, 2 stage.
Controller : (Existing) Honeywell Vision Pro IAQ with dehumidifcation call capability.
Air Handler: (Existing) Custom built including plenum fan with VF Drive. The air flow can be varied.
Questions :
Can it be done ? or
Will this cause the heat pump to malfunction ?
Apart from the reheat coil, and 3-way valve, what other components would be required ?
Is there a manufacturer who manufactures such a Heat pump, ready for this of use.
What is the best way to execute such a design ?





RE: Heat Pump - Hot Gas Reheat - Deumidification
RE: Heat Pump - Hot Gas Reheat - Deumidification
One option though would be to use a heat pipe around the AHU coil.
http:/
review their dehumidifier heat pipes.
RE: Heat Pump - Hot Gas Reheat - Deumidification
Walkes..Thx I already looked at heat pipes, they are very compelling, but I don't have the space in this case.
Thank you all for your insight !
RE: Heat Pump - Hot Gas Reheat - Deumidification
RE: Heat Pump - Hot Gas Reheat - Deumidification
What do you mean by 'Many codes /standards prohibit non cycle rh for comfort cooling. ' in this situation?
Back of the envelope calcs :
In dehumidification mode, run only first stage compressor. Therefor : 67% x 3 Tons = 24 000 btu(approx) of cooling.
At that capacity, run the blower at 800 cfm.
The reheat required would be that needed to maintain discharge air at 75 F. Therefor assuming a discharge air at the evaporator is 50F, The required reheat would be : 1.08 x 800cfm x (75F-50F)=21600 Btus...approx = to the cooling capacity.
(Difference could be explained by latent cooling perhaps)
I would therefor use a 6 KW electric coil c/w an SCR , with a temp sensor in the supply air stream to ensure the required reheat.
Is this better than a Hot gas reheat ? And is this good, or generally acceptable practice ?
Sincerest regards