OPTION I:
OPTION II:
OPTION III:
OPTION IV:
OPTION V:
Baseline system with dehumidification coil only (CC)
Rotary passive desiccant air-to-air heat exchanger coupled with
dehumidification coil. (EW+CC)
Rotary passive desiccant air-to-air heat exchanger coupled with
dehumidification coil and sensible air to air heat exchanger. (EW+CC+SW)
Active desiccant dehumidification wheel (with condenser heat reactivation)
coupled with DX Cooling coil. (CC+ADESW)
Rotary passive desiccant air-to-air heat exchanger coupled with
dehumidification coil and passive desiccant dehumidification wheel.
(EW+CC+PDHC)
Table 1
On studying the hourly data of outside air, one
can see that RH control definitely is a problem in
moderate weather which is present almost 2500
hrs a year for city like Atlanta in the US.
The various DOAS technologies evaluated in
this article are shown in Table 1.
Option I: Schedule of DOAS System
with Cooling Coil
OPTION I: Baseline system with dehumidification
coil only (CC)
This option gives high efficiency heat recovery and
reduces the total installed tonnage of the HVAC
system. Since the recovery reduces the both latent
and sensible load of the outside air (the recoveries
can be as high as 85%) and the dehumidification
iv) Better performance of the chiller in terms
coil reduces the dew point to almost 45OF, this
of IKW/TR due to higher CHW temperature.
approach is most widely used and is highly cost
effective and paybacks are often negative.
OPTION II: Rotary Passive Desiccant Heat
The benefits of this option are:
Exchanger With Coil. (EW+CC)
i) Installed tonnage
reduction,
Option II: Schedule of DOAS with Enthalpy Wheel and Cooling Coil
ii) L o w e r
power
consumption of
the installed HVAC
system,
iii) Higher apparatus
dew point (ADP) of
sensible cooling
devices hence lower
row deeps (lower
pressure drop) and
higher chilled water
(CHW) temperature of
the main Chiller, and
35