INGENIEUR
OA-AHU Condition Design On coil Condition |
27 º C |
100 % RH |
Design Off coil Condition |
13.5 º C |
100 % RH |
Condensate from OA-AHU |
|
1.481 / hr |
FCU Condition Design On coil Condition |
23 º C |
60 % RH |
Design Off coil Condition |
23 º C |
60 % RH |
Condensate from OA-AHU |
|
0.368 / hr |
Total Condensate |
1.849 m 3 / hr |
Condensate recycle to cooling tower from OA-AHU |
1.481 m 3 / hr |
Condensate recovery |
80 % |
Table 3 : Calculation of 80 % recovery from AHU condensate |
Figure 9 : Average Annual HVAC Efficiency in kW / Ton
Menara KEN TTDI ’ s air-conditioning is designed to have a system efficiency ( DSE ) for a central chilled water plant of 0.65 kW / RT for peak building cooling load ( more than 500 RT ). The efficiency dropped slightly due to lower usage cooling load in the building as some of the tenants still work from home . Nevertheless , the total system efficiency for Menara KEN TTDI has reached the benchmark of the BCA Green Mark Super Low Energy ( SLE ) certification requirement .
Since the designed cooling capacity is 800 Refrigerant Tons ( RT ), a combination of Variable Speed Driven ( VSD ) 500 RT chillers and a Thermal Energy Storage system is employed to yield an optimum chillers ’ plant efficiency of 0.55 kW / RT .
This is equivalent to a coefficient of performance ( COP = Cooling Capacity , kW / Electrical Input , kW ) of 6.4 . Besides specifying for energy-efficient chillers , variable speed drive inverters are stipulated for all cooling tower fans , chilled water pumps and condenser water pumps to optimise the chillers ’ plant running efficiency .
Variable speed drive is an essential component for the chiller plants as a slight 20 % reduction in speed ( i . e . flow rate ) can potentially reap up to 50 % savings in energy consumption . The simulated peak cooling load is 780 RT over the air-conditioning area of 27,952 m 2 which gives a cooling load density of 98 W / m 2 . With a gross floor area ( GFA ) of 41,389 m 2 , efforts to minimise
28 VOL 91 JULY-SEPTEMBER 2022