STIEBEL ELTRON Heat pumps, Техническое руководство

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Heat pump principle
the most important contribution to
the heat pump function is made by
the refrigerant (in the following also
referred to as "process medium"). this
evaporates at the lowest temperatures.
if you route outside air or water to a
heat exchanger (evaporator), in which
the process medium circulates, then
that refrigerant extracts the required
evaporation heat from the heat source
and changes from a liquid into a
gaseous state. During this process,
the heat source cools down by a few
degrees. A compressor draws the
process medium in and compresses
it. the increase in pressure also raises
the temperature; in other words,
the process medium is "pumped"
to a higher temperature level. that
requires electrical energy. As the
compressor is of the suction gas-
cooled design, the energy (motor
heat) is not lost, but reaches the
downstream condenser together with
the compressed process medium.
Here, the process medium transfers
its absorbed energy to the circulating
system of the hot water heating
system by being returned into the
liquid state again. An expansion valve
reduces the still prevalent pressure
and the circular process starts again.
Heat pump coefficient of performance
the coefficient of performance
ε
HP
is equal to the quotient of heating
output Q
HP
and electrical power
consumption P
HP
in accordance with
the following equation
it provides a factor, by which yield
exceeds expenditure. the coefficient
of performance is subject to the
temperature of the heat source
and that of the heat consumer. the
higher the heat source temperature
and the lower the heat consumer
temperature, the higher the coefficient
of performance. it relates, as current
value, always to a specific operating
condition.
How doES a HEat pUmp work?
ε
HP
=
Q
HP
P
HP
Main layout of a heat pump refrigeration circuit
Compressor
inlet line
Gaseous process medium
low pressure
Pressure line
Gaseous process medium
high pressure
liquid line
liquid process medium
high pressure
injection line
liquid process medium
low pressure
expansion valve
Flow
return
evaporator
Heating
energy
environmental
energy