114
Aquarea air / water heat pump – design handbook 07 / 2014
Example 10
Heat pump cascade with hydraulic isolation of the heating circuits by means of buffer tank
Closed-loop control of cascade operation by means of an external controller,
taking into account operating time, redundancy and peak load.
CLOSE
OPEN
N
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
CLOSE
OPEN
CLOSE
OPEN
N
COOL
HEAT
N
L
N
M
M
CLOSE
OPEN
N
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
CLOSE
OPEN
CLOSE
OPEN
N
COOL
HEAT
N
L
N
2
4
4
5
6
3
3
Schematic illustration – relevant standards
and guidelines must be observed!
2
Room thermostat
3
Outside temperature sensor
(integrated in the outdoor unit)
4
Control for heating circuit
mixer (building side)
5
Overriding control of the cascade operation mode
6
Buf
fer tank
