3. STRUCTURE OF SCREW CHILLER
17
ENGLISH
Screw chiller heat exchanger is composed of evaporator and condenser, and has 2 shells which can be conveniently
separated. To maximize the heat exchanging capability, the tube arrangement is optimized, and to prevent the de-
crease of COP, refrigerant distributor is installed for the even distribution of liquid refrigerant in the entire tubes. And
an efficiency increasing subsidiary cooler is installed for over-cooling of condensed liquid refrigerant.
At the upper part of the heat exchanger, relief valve is installed in cases for abnormal situations.
Heat exchanger
Expansion unit
Safety valve
Refrigerant outlet
B
ody
Refrigerant distributor
Refrigerant inlet
tube
Refrigerant inlet
Collision
prevention plate
Refrigerant inlet
tube
Safety valve
Inlet
B
ody
Inlet
Figure 8. Evaporator
Figure 9. Condenser
Figure 10. Butterfly valve
Figure 11. Orifice
Expansion unit consists of butterfly valve and orifice. At 100% load situation, the pressure loss at the orifice is
smaller than the refrigerant pressure loss in the condenser, thus the super-cooled refrigerant passes through the ori-
fice. At this stage the maximum amount of refrigerant is flowing into the evaporator. As the load reduces gradually,
the circulating amount of refrigerant also reduces and accordingly the refrigerant level in the condenser is getting
low. When the amount of liquid refrigerant reduces, the gas amount in the orifice is getting larger, raising the resist-
ance thus controlling the flow rate.
Summary of Contents for LCWW
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