Technical data

6 | Project planning manual for heat pumps for heating and domestic hot water preparation | 01.2012 www.dimplex.de
Glossary
Seasonal performance factor
The seasonal performance factor is defined as the ratio of the
quantity of electrical energy supplied in one year to the amount of
thermal energy extracted by the heat pump system. It is based
on a particular heating system taking the respective design of
that system into consideration (temperature level and tempera-
ture difference) and is not the same as the coefficient of perform-
ance.
Annual effort figure
The annual effort figure is exactly the opposite of the perform-
ance factor. The annual effort figure indicates what input (e.g.
electrical energy) is required to achieve a defined benefit (e.g.
heating energy). The annual effort figure also includes the en-
ergy for the auxiliary drives. VDI Guideline 4650 is used to calcu-
late the annual effort figure.
Refrigeration capacity
Heat flow which is extracted from the environment by the evapo-
rator of a heat pump. The heat output of the compressor is calcu-
lated from the electrical power consumption and refrigerating ca-
pacity applied.
Refrigerant
The working medium used in a refrigerating machine or heat
pump is called a refrigerant. It can be characterised as a fluid
which is used for transferring heat in a refrigerating system. Re-
frigerants absorb heat at a low temperature and pressure and
emit heat at a higher temperature and pressure. Refrigerants
which are non-poisonous and non-inflammable are designated
as safety refrigerants.
COP
The ratio between the absorbed electrical energy and the heat
output emitted by the heat pump is expressed by the coefficient
of performance (COP). This is measured under standardised
boundary conditions in a laboratory according to EN 255 /
EN 14511 (e.g. for air A2/W35, A2= air intake temperature
+2 °C, W35= heating water flow temperature 35 °C). A COP of
3.2, for example, means that 3.2 times the consumed electrical
energy is available as usable heat output.
Ig p,h diagram
Graphic representation of the thermodynamic properties of a
working medium (enthalpy, pressure, temperature).
Mono energy operation
In principle, the mono energy mode of operation is a bivalent-par-
allel mode of operation utilising only one source of energy, nor-
mally electricity. The heat pump supplies a large part of the re-
quired heat output. An electric heating element supplements the
heat pump on those few days during the year with extremely low
outside temperatures.
Air-to-water heat pumps are normally dimensioned for a limit
temperature (also known as the bivalence point) of approx.
-5 °C.
Monovalent operation
In this operating mode, the annual heat consumption of the build-
ing is completely covered (100%). This type of application should
be preferred wherever possible.
Brine-to-water and water-to-water heat pumps are normally op-
erated in monovalent mode.
Buffer tank
The installation of a heating water buffer tank is basically recom-
mended to lengthen the runtimes of the heat pump during peri-
ods of reduced heating demand.
A buffer tank is absolutely essential for air-to-water heat pumps
to guarantee a minimum runtime of 10 minutes during defrosting
(regular routine for removing frost and ice from the evaporator).
Sound
A distinction is made between two types of sound, airborne
sound and solid-borne noise. Airborne sound is sound which
spreads through the air. Solid-borne noise spreads through solid
materials or fluids and is also partially emitted as airborne sound.
The audible sound range is between 16 and 16,000 Hz.
Sound pressure level
The sound pressure level, measured in the surroundings, is not
a machine-specific quantity, but a quantity dependent on the test
distance and the test location.
Sound power level
The sound power level is a machine-specific and comparable pa-
rameter for the acoustic output emitted by a heat pump. Both the
sound emission level to be expected at particular distances and
the acoustic environment can be estimated. The standard treats
the sound power level as a characteristic noise value.
Brine / brine fluid
Frost-proof mixture consisting of water and a glycol-based anti-
freeze concentrate for use in ground heat collectors and bore-
hole heat exchangers.
Evaporator
Heat exchanger of a heat pump in which a heat flow is extracted
by evaporation of a working medium of the heat source (air,
ground water, ground) at a low temperature and with a low pres-
sure.
Compressor
Machine for the mechanical conveyance and compression of
gases. The pressure and temperature of the refrigerant are
raised considerably by means of compression.
Liquefier
Heat exchanger of a heat pump in which the heat flow is emitted
by liquefaction of a working medium.
Heat consumption calculation
Accurate dimensioning is essential for heat pump systems be-
cause overdimensioned systems increase energy costs and
have a negative effect on efficiency.
The heat consumption is calculated on the basis of national
standards:
The specific heat consumption (W/m
2
) is multiplied by the living
space area to be heated. The result is the total heat consumption
including both the transmission heat consumption and the venti-
lation heat consumption.