GENERAL DESCRIPTION
27
Cascade Cooling (2 HP – 3.5 HP systems)
After passing the bypass tee, the liquid refrigerant flows through the thermostatic expansion valve (item
111) where it changes to a low pressure, two phase refrigerant. The two phase refrigerant is cold due to
the flashing of refrigerant. It enters the cascade condenser (item 113) where the heat from system 2
boils the rest of the R-404A refrigerant into a vapor. The cascade condenser serves as the evaporator
for system 1. If dehumidification is called for, some of the R-404A refrigerant is diverted to the humidity
loop prior to entering the thermostatic expansion valve (see Humidity Loop section).
Superheated R-404A vapor exits the cascade condenser and moves through the system 1 suction line. A
suction service valve (item 115) is located near the compressor.
Cascade Cooling (6 HP – 20 HP systems)
After passing the bypass tee, the liquid refrigerant flows through the maximum liquid line solenoid (item
110) and into the maximum thermostatic expansion valve (item 111) where it changes to a low pressure,
two phase refrigerant. In parallel with maximum valves, liquid refrigerant flows through a minimum
liquid line solenoid (item 119) and into the minimum thermostatic expansion valve (item 120) where it
also changes to a low pressure, two phase refrigerant. The two phase refrigerant is cold due to the
flashing of refrigerant. The two phase refrigerant enters the cascade condenser (item 113) where the
heat from System 2 boils the rest of the R-404A refrigerant into a vapor. The cascade condenser serves
as the evaporator for System 1. If dehumidification is called for, some of the R-404A refrigerant is
diverted to the humidity loop (see Humidity Loop section).
Superheated R-404A vapor exits the cascade condenser and moves through the System 1 suction line. A
suction service valve (item 115) is located near the compressor.
Humidity Loop (Optional Equipment)
When dehumidification or dry bulb cooling is called for while in humidity mode, the unit will operate in
single stage mode and not as a cascade unit. High pressure liquid refrigerant from the condenser, is
diverted into two separate paths.
The first path is to the liquid-line solenoid (item H149) and into the capillary tube (item H150) where it
changes to a low pressure, two phase refrigerant. The two phase refrigerant is cold due to the flashing
of refrigerant. The two phase refrigerant enters the evaporator coil (item H113) and leaves as a
superheated vapor. Superheated R-404A vapor exits the evaporator coil and moves through the System
1 suction line.
To Next Page
Loading...
