into a collection pan below each unit from which, together with
condensate from the other five units, is drained by gravity to the
collector, placed next to the condensate assisted pre-cooling (CAP)
AHU at the lowest floor (Fig. 1). The condensate, including that from
the main cooling coil of the CAP AHU, is first supplied to the precooling
coil of the CAP AHU and then flows directly into the cooling
tower basin, thus reducing the amount of required potable water
and improving cooling tower water chemistry. The cold condensate
is constantly sent to the energy recovery pre-cooling coil via a
small pump.
The first step in this study is to collect annual weather data for
several cities in south-east Asia region [5]. The average monthly
dry bulb temperature and relative humidity data for representative
cities are shown in Figs. 2 and 3, respectively. As seen, the
highest and most consistent latent load throughout the year occurs
in Singapore, which has been chosen as a representative city for the
purpose of this study.
The next step is to determine the absolute humidity values for
the on/off-coil dry bulb temperature and relative humidity. For both
cases without and with heat pipe the assumed leaving conditions
are 16 ◦C dry bulb temperature with a 99% and 60% relative humidity,
respectively. The psychrometric state points, associated with
the average annual conditions, are shown in Figs. 4 and 5.
Finally, the amount of condensate produced from the dehumidification
process is calculated using mass balance equation: