Description; General; Refrigerant Circuit (Heat Pump Operating Principle - Dimplex BWP 30 HS Installation And Operating Instructions Manual

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Description

2.1 General

The domestic hot water heat pump is a ready-to-use heating de-
vice whose main components are a domestic hot water cylinder,
the components of the refrigerant, air and water circuits and the
control, regulation and monitoring devices required for automatic
operation.
With the help of electrical energy, the domestic hot water heat
pump uses the heat stored in the drawn-in air for domestic hot
water preparation. The internal heat exchanger can be con-
nected to additional heat generators such as boilers and solar
energy systems. The devices are equipped with an electric
flange heater (1.5 kW) as standard.
The temperature of the drawn-in air (the heat source) serves as
the reference value for the energy consumption, the domestic hot
water preparation heat-up time and domestic hot water tempera-
ture.
For this reason, an air duct system (DN 160, max. length 10 m)
can be connected to the standard spigot of the domestic hot
water heat pump for targeted waste heat recovery. For the heat
pump to be operated effectively, air short-circuits between the
drawn-in air and the blown-out air must always be avoided. This
can, for example, be achieved through the use of a flexible air
hose on the intake and outlet side.
Falling outlet air temperatures reduce the heat pump's heat out-
put and increase the heat-up time. In order for the heat pump to
be operated economically, the air intake temperature should not
fall below 15 °C.
The flange heater fulfils four functions:
 Supplementary heating
The heat-up time is approximately halved by switching on
the flange heater in addition to the heat pump.
 Frost protection
With the BWP 30HS version, the flange heater switches on
automatically and heats the water (nominally) up to the do-
mestic hot water setpoint temperature if the air intake tem-
perature falls below 8 ±1.5 °C.
With the BWP 30HSD version, the flange heater switches on
automatically, and heat pump operation is deactivated,
when this temperature falls below -8 °C ± 1.5 °C. When the
temperature is below 8 °C, the flange heater is switched on
if the setpoint temperature has not been reached after a pe-
riod of 8 hours. This function is inactive if the domestic water
is heated by a 2nd heat generator via the internal heat ex-
changer.
 Emergency heating
In the event of a heat pump fault, the domestic hot water
supply is maintained by the flange heater.
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 Thermal disinfection
Using the operator panel keypad, domestic hot water tem-
peratures above 60 °C (up to 65 °C) can be programmed via
the "thermal disinfection" menu. These temperatures are
achieved through the flange heater above 60 °C. For higher
temperatures to be reached, the adjusting screw (Cap. 2.3
on pag. 4) on the temperature controller casing must be
turned to the right-hand stop.
NOTE
When the domestic hot water temperature reaches > 60 °C, the heat
pump switches off and the domestic hot water preparation is heated
solely by the flange heater. The factory setting for the heating element
controller is 65 °C.
2.2 Refrigerant circuit (heat pump
operating principle)
The refrigerant circuit is a closed system in which the R134a re-
frigerant is the energy source. The finned heat exchanger ex-
tracts heat from the drawn-in air at a low evaporation tempera-
ture, and transfers it to the refrigerant. The vaporous refrigerant
is drawn in by a compressor, where it is compressed to a higher
pressure and temperature level before being transported to the
liquefier, where the heat absorbed in the evaporator and part of
the compressing energy is transferred to the water. Subse-
quently, the high condensation pressure is lowered to the evapo-
ration pressure via a throttle mechanism (expansion valve), and
the refrigerant can again extract heat from the drawn-in air in the
evaporator.
451903.66.11 · FD 9401
BWP 30HS - BWP 30HSD
EN-3