System Analysis
Figure A. System schematic of the centralized chiller system for the DATC building
The DATC building houses a large hall for multi-purpose functions and its air-conditioning system is
a centralized chi
...
System Analysis
Figure A. System schematic of the centralized chiller system for the DATC building
The DATC building houses a large hall for multi-purpose functions and its air-conditioning system is
a centralized chiller system. Chilled water exits the chiller at 1oC, but the effects of pumping and
ambient heating increase the water temperature to 4 oC as it enters the Air Handling Unit (AHU) of
the DATC. The chilled water cools the air coming from the hall and then returns to the chiller
system.
In the AHU of the DATC building, chilled water enters at 4 oC and exits at 10 oC at a flow rate of 10
litres per minute. Air from the building is to be cooled from its initial temperature of 38 oC.
The chiller system operates based on the vapour compression refrigeration cycle with a single stage
compression and a water-cooled condenser. The isentropic efficiency of the compressor is assumed
at 90%. The evaporator design is based on the shell-and-tube multipass heat exchanger. The
refrigerant enters and exits through the shell at its saturation temperature, while the chilled water
flows through the tube and exits the evaporator at 1oC.
For this air-conditioning system:
2. Assuming that the heat loss to the surrounding during the heat exchange process in the AHU
is 10% from the emitted heat transfer rate, plot the changes in air exit temperature if the air
flow rate into the AHU ranges from 1000 to 5000 litres per minute. Then, identify the suitable
operating range for the airflow into the AHU to meet the standard comfort temperature
requirement. [CO2]
[Show More]