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Aquarea air / water heat pump – design handbook 07 / 2014
Project Design
Heat pump selection
General criteria | What capacity is needed?
5.7 Heat pump selection
5.7.1 General criteria
5.7.2 What capacity
is needed?
The selection of a suitable heat pump is made via the required heating
capacity. In addition, the following decisions must be taken:
• Should a Bi-Bloc system or a Monobloc system be used?
• Should the heat pump be used just for heating or also for cooling?
• Should the heat pump be powered by a single phase or three phase
supply (three phase units have higher coefficients of performance)?
The main requirements on air / water heat pumps are determined using
the calculated heating load to EN 12831 and outside design temperature.
Furthermore, also the hot water heating and possible outages from the
power company must be accounted for. Also the length of pipe between
the outdoor unit and hydromodule (Bi-Bloc) as well as between the
Monobloc unit and building must be considered because long pipe runs
lead to loss of some heating capacity. Not only the capacity of the heat
pump but also their supply water temperature at design outside tempera-
ture is important for correct selection of the heat pump.
Aquarea heat pumps have an additional electric heater which can pro-
vide extra heat supply in the event of very low outside temperatures.
All the above points must be considered together for the calculation
of required heat pump capacity:
1.
Heating load (see section “Establishing the heating load and outside
design temperature”)
2.
Outside design temperature (see section “Establishing the heating
load and outside design temperature”)
3.
Hot water tank charging (required time for water heating with the heat
pump)
4.
The power company's restrictions (if applicable, e.g. once per day
for 2 hours)
5.
Pipe correction factor (see section “Planning Heat Source - Air”
for consideration of losses through long pipe lengths)
