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WSV6 VERTICAL SERIES - IOM
28 WSV6 Vertical Series – IOM
APPLICATION CONTINUED
HOT GAS REHEAT DEHUMIDIFICATION
OVERVIEW
Because ventilation air is introduced into buildings, indoor air quality (IAQ) and relative humidity (RH) are important issues to
address in selecting heating and cooling equipment. With the Hydrotech WSV6 hot gas reheat dehumidification option, the
return air from space is conditioned by a dedicated air-to-refrigerant coil and then reheated by a reheat coil to control space
temperature and reduce space relative humidity. Reduced relative humidity levels also provide an improvement in indoor air
quality.
ON/OFF HOT GAS REHEAT
The Hydrotech WSV6 hot gas reheat dehumidification has DDC control so the unit is BMS (BACnet MSTP) ready. See
IOM8083D01 for more information on DDC Controller. Besides DDC controller, hot gas reheat dehumidification consists of a
reheat coil (mounting of the air leaving side of the indoor air coil), a reheat valve and a bleed off valve. With this hot gas reheat
dehumidification option, the return air from the space is conditioned by the air-to-refrigerant indoor air coil, then reheated by
the reheat coil to control not only the space temperature, but to also reduce the relative humidity of the space. The hot gas
reheat dehumidification functions only during the cooling cycle.
DEHUMIDIFICATION
When the space sensible temperature has been met (thermostat is satisfied) and the space relative humidity is still higher than
set point (de-humidistat has not satisfied), the unit will operate in the dehumidification mode. The reheat valve energizes,
allowing the high-pressure refrigerant gas to flow from the compressor through the reversing valve. The high pressure and hot
refrigerant is diverted in two paths. One goes through the reheat valve then the reheat coil to raise the leaving air temperature.
The other goes through the coaxial coil. The 2-phase refrigerant from the reheat coil and the liquid refrigerant from the coaxial
are mixed before entering the evaporator for dehumidification. Dehumidification will stop when either de-humidistat has been
satisfied or there is demand of space sensible temperature. If there is a demand from space sensible temperature, the unit will
operate in cooling mode.