Controllable Hot Gas Reheat

Carolina Heat Pipe’s Hot Gas Reheat system provides controllable hot gas reheat to increase the latent cooing capacity and resulting dehumidification of direct expansion (packaged) air conditioning systems.

The system is activated from a call for dehumidification by a humidistat into our custom controller that allows hot gas from the compressor to flow into a separate (condensing) hot gas reheat coil mounted downstream of the evaporator coil. For many packaged units, the reheat is temperature controlled by a single solenoid valve with on/off control to provide reheat from the compressor and thereby improving the dehumidification.

When the hot gas reheat system is activated, the dry bulb temperature of the supply air is increased slightly, lowering the relative humidity. Doing so will result in the unit running longer to satisfy the cooling load in the space and thereby removing more moisture. If the space temperature cannot be maintained during this dehumidification process, then the hot gas reheat system should be deactivated to allow for maximum cooling by the unit.

Carolina Heat Pipe (CHP) provides a custom control module positioned between existing thermostat and the package unit that establishes a cooling first, dehumidification second, operating mode. This ensures the space cooling load always has top priority over dehumidification.

CHP also offers full modulating control for Hot Gas Reheat if desired. Subcool + Hot Gas Reheat is another design solution available from CHP. See Subcool Reheat of Refrigerant.

Please note most packaged air conditioning units, including heat pumps, are designed to be temperature controlled. The hot gas reheat system should only be activated in the cooling mode, NOT the heating mode.

Projects using Controllable Hot Gas Reheat…
• Pompano Beach
• Buford High School
• Catholic Diocese of Charleston

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