Essentials
Continued from page 59
The BS box is the controlling
mechanism of refrigerant flow
depending on the room requirements.
It can be seen from the picture that during heating the
refrigerant returning from the indoor unit is in liquid form. The
flow direction depends on the cooling:heating ratio. The size of
this pipe is smaller than the other two pipes.
The suction line is refrigerant at low pressure and always
flows to the condenser compressor.
The discharge line is refrigerant at high pressure and always
flows from the condenser.
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It is generally known as a ‘three pipe system’. The outdoor
unit can have an air-cooled or water-cooled condenser. In the
liquid line is a high-pressure refrigerant gas at a moderate
temperature. The refrigerant can flow towards or away from
the condenser.
Figure 2: Typical BS box.
The BS box is the controlling mechanism of refrigerant flow
depending on the room requirements.
References:
• ASHRAE
• Daikin RACA
RACA Journal I June 2019
61