Aisin AXGP224E1, Technical Manual, Page: 107 / 126

11
6.1 Cooling mode
The refrigerant (R410A) processed by the GHP flows through electronic expansion valve and
enters the lower part of the AWS unit heat exchanger at low pressure. The gas evaporates in the
plate heat exchanger by taking heat from the counter current water flow. It goes back to the GHP
as overheated steam. The outdoor unit fans create an air flow through the heat exchanger and
thus the refrigerant can condense.
At the same time, the water coming from the buffer tank is cooled and pumped again into the
primary circuit by the AWS built in pump. Flow switch, pressure switch and anti freeze thermo
sensor overlook the water temperature never to drop inside the heat exchanger. In fact, water may
freeze and the heat exchanger can be damaged.
6.2 Heating mode
The refrigerant (R410A) processed by the GHP enters the upper part of the AWS unit heat
exchanger as high pressure overheated steam. The gas condenses in the plate heat exchanger by
ceasing heat to the co current water flow. It goes back to the GHP as high pressure liquid, through
the bypass pipe. The two outdoor unit expansion valves divide the return flow, reducing its
pressure. The GHP manages the evaporation through the heat exchanger and the heat recovery.
At the same time, the water coming from the buffer tank is heated and pumped again into the
primary circuit by the AWS built in pump.
4
6
TO GHP 1
FROM GHP 1
3
5
2
9
F
7
1
8
AWS REFRIGERANT CIRCUIT AND HYDRAULIC CIRCUIT
COOLILNG MODE
4
6
5
3
2
1
TO GHP 2
FROM GHP 2
10
10
6 Refrigerant circuit and hydraulic circuit
1) Expansion valve driver
2) Check valve
3) Electronic expansion valve
4) Water inlet temperature probe
5) Water outlet temperature probe
6) Plate heat exchanger
0) 7) Water pressure difference switch
8) Air vent valve
9) Flow switch
10) Pump (not included in the version E1J)
11) Expansion valve pressure sensor