2.3.2. Cooling tower design
SACH-k2 uses water cooling for the condenser of ECS. A highperformance
water cooling tower was used in the present
study. The design follows the research results of Hu and
Huang (2005). Cellulous pads (0.45 m 0.45 m 0.6 m) were
used to construct the cooling tower matrix. The air fan consumes
380Wat full speed with flowrate 1.08e1.25m3 s1. The
water circulation pump consumes 45 W at flowrate
32e38 L min1 and 3.8e5.4 mH2O head. The schematic of
water cooling tower is shown in Fig. 7. The real hardware is
shown in Fig. 8.
2.3.3. Power consumption control system of ECS cooling
tower
SACH-k2 uses water cooling for condenser of ECS as described
above. Fan and pump will consume electrical energy during
operation (Fig. 7). ECS must be operated at a condenser temperature
Tc below the critical temperature Tc
to keep the
ejector working under double-choking condition (Huang et al.,
1999). Usually, the operating point of Tc is always below the
critical temperature Tc
. This means that Tc can be raised to
Tc
without decreasing cooling effect of ECS. In the other
words, the fan or pump speed can be reduced to increase the
cooling water temperature as well as the condenser temperature
to save energy.
The condensing pressure will increase with decreasing fan
speed as well as input power without changing the cooling
effect of ECS (entrainment ratio of ejector) until the
condensing pressure larger than the critical condensing
pressure. An feedback control system using amicro-processor
is designed which will reduce the fan speed but still keeping
the ejector working at double-choking condition. An inverter
is connected to the fan motor so that it can be triggered by the