6. Piping installation
Installer reference guide / Mono tank integrated type
59
Minimum active water volume
The minimum active water volume of the system is the amount of water which is always pumped around, even when all
valves in the system are closed. The use of a buffer tank can increase the active volume and therefore the operation time
between compressor start and stop.
Active Volume (space heating)
ClimateHub Indoor unit
Outdoor Unit
Buffer
Radiator Heating
Ideally, systems should be designed for around 10 to 15 minutes of operation, in order to meet with our declared
efficiencies.
This time frame is based on a maximum of 4 On/Off cycles per hour.
The required minimum active water volume can be calculated via the below stated formula:
V
min
: Minimum active volume
[dm3]
t
min
: Minimum allowed operation time is 10 min or 600 sec per cycle)
[s, sec]
Φ
min
: minimum compressor output
[kW = kJ/s]
C
water
:specific heat of water (4,2)
[kJ/kg*K]
Δ
T: Temperature increase (5-10 K)
[K]
V
min =
t
min X
Φ
min
C
water X
Δ
T
CAUTION
• Water volume of total system (except tank integrated hydro unit) for reliable defrost cycles is minimum
30 Liter (AE050/080******), 50 Liter (AE120/140/160******).
• This volume is not to be mistaken for the minimum active water volume, as that serves a different
purpose against short cycling of the compressor.
NOTE
When circulation in each space heating/cooling loop is controlled by remotely controlled valves, it is
important that the minimum water volume is guaranteed, even when all of the valves are closed.
