Technical data
www.dimplex.de 01.2012 | Project planning manual for heat pumps for heating and domestic hot water preparation | 5
What are the benefits of a heat pump?
What are the benefits of a heat pump?
The fact that a large percentage of our energy supply is produced
from fossil fuels poses serious consequences for our environ-
ment. Large quantities of pollutants, such as sulphur dioxide and
nitrogen oxide, are released during combustion.
Domestic space heating with fossil fuels contributes significantly
to pollutant emissions because extensive emission control meas-
ures, such as those used in modern power plants, cannot be car-
ried out. Since our oil and gas reserves are limited, basing such
a large percentage of our energy supply on fossil fuel sources
also presents a serious problem.
The way electrical energy is generated will change in the future
to favour more renewable or newly developed generation meth-
ods. You, too, can be a part of this development because elec-
tricity - as the energy of the future - is the operating energy of
heat pumps.
What does a heat pump do?
A heat pump is a type of “transport device” that raises the tem-
perature level of the heat that is freely available in the environ-
ment.
How does a heat pump convert low-temperature
heat into high-temperature heat?
It extracts stored solar heat from the environment – ground,
water (e.g. ground water) and air (e.g. outside air) – and transfers
this, along with the operating energy, in the form of heat to the
heating and domestic hot water circuit.
Heat cannot transfer from a cold body to a warm body on its own.
Rather, it flows from a body with a higher temperature to a body
with a lower temperature (Second Law of Thermodynamics). For
this reason, the heat pump must raise the temperature of the
thermal energy extracted from the environment using high-grade
energy - e.g. electricity for the drive motor - to a level suitable for
heating and domestic hot water preparation.
The heat pump actually works like a refrigerator. It uses the same
technology, but with the opposite effect. Heat pumps extract heat
from a cold environment which can then be used for heating and
DHW preparation.
Glossary
Defrosting
Regular routine for removing frost and ice from evaporators on
air-to-water heat pumps by applying heat. Air-to-water heat
pumps with reversal of the direction of circulation feature the
rapid and energy efficient defrosting properties required.
Bivalent-parallel operation
The bivalent operating mode (today this is normally bivalent-par-
allel operation) functions with two heat generators (two sources
of energy), i.e. the heat pump covers the heating requirements
up to a determined temperature limit, and is then backed up by a
second energy source in parallel.
Bivalent/renewable operating mode
The bivalent renewable operating mode makes it possible to in-
corporate renewable heat sources such as wood or thermal solar
energy. Should renewable energy sources be available, then the
heat pump is blocked and the current heating, domestic hot
water or swimming pool requirements are met by the renewable
cylinder.
Carnot factor
The ideal reference cycle for all thermodynamic cycles is the so-
called Carnot cycle. This (theoretical) model cycle gives maxi-
mum efficiency and - in comparison to a heat pump - the theoret-
ically greatest possible COP. The Carnot factor is based solely
on the temperature difference between the warm side and the
cold side.
D-A-CH seal of approval
Certificate for heat pumps in Germany, Austria and Switzerland
which fulfil specific technical requirements, have a 2-year war-
ranty, ensure the availability of spare parts for 10 years and
whose manufacturers offer a comprehensive customer service
network. The seal of approval also certifies that a line of heat
pumps has been manufactured as a series.
EnEV
The Ordinance for Energy-Saving Thermal Insulation and En-
ergy-Saving Building Installation Technology (EnEV) [German:
Verordnung über energiesparenden Wärmeschutz und ener-
giesparende Anlagentechnik bei Gebäuden (Energieeinspar-
verordnung EnEV)] has been in force since February 1, 2002. It
supersedes the Thermal Insulation and Heating System Ordi-
nance. In addition to specifying standards for new buildings, this
ordinance also sets deadlines for exchanging outdated heating
systems.
Utility company shut-off times
Local utility companies offer special tariffs for heat pumps, pro-
vided that the power supply can be shut off by the utility company
at certain times of the day. The power supply can, for example,
be interrupted for 3 x 2 hours within a 24-hour period. This
means that the daily heat output (quantity of heat produced daily)
must be produced within the period of time in which electrical en-
ergy is available.
Expansion valve
Heat pump component between the liquefier and the evaporator
for reducing the condensation pressure to match the respective
evaporation pressure determined by the evaporation tempera-
ture. The expansion valve also controls the quantity of refrigerant
to be injected in relation to the respective evaporator output.
Limit temperature / bivalence point
The outside temperature at which the 2nd heat generator is addi-
tionally connected in mono energy (electric heating element) and
bivalent-parallel operation (e.g. boiler) as required, and both
modes of operation jointly provide the house with heat.