Limit temperature / bivalence point
Outdoor temperature where the secondary heating
appliance cuts in under bivalent operation.
Monovalent mode
In this mode, the heat pump is the sole heating
appliance in the building all year round. Monova-
lent mode is primarily used in combination with
brine/water and water/water heat pumps.
Noise
Noise is transmitted in media such as air or water.
Essentially there are two types of noise, airborne
sound and solid-borne sound. Airborne sound is
transmitted entirely via the air. Solid-borne sound
is transmitted in solid materials or liquids and is
only partially radiated as airborne sound. The
audible range of sound lies between 20 and
20,000 Hz.
Refrigerant
The working medium used in a refrigerant plant,
e.g. heat pump, is referred to as the refrigerant.
The refrigerant is a liquid which is used for thermal
transfer in a refrigeration plant and which is able to
absorb heat by changing its state at low tempera-
tures and low pressures. A further change of state
at higher temperatures and higher pressure serves
to dissipate this heat.
Refrigerating capacity
Heat flux extracted from the environment by the
evaporator (air, water or soil).
Regulations and guidelines
The erection, installation and commissioning of
heat pumps has to be undertaken by qualified spe-
cialist engineers. In doing so, various standards
and directives are to be observed.
Seal inspection
System operators are obliged to ensure the pre-
vention of refrigerant leakage in accordance with
the directive on substances that deplete the ozone
layer (EC 2037/2000) and the Regulation on Cer-
tain Fluorinated Greenhouse Gases (EC
842/2006). In addition, a minimum of one annual
service and inspection must be carried out, as well
as a sealing test for refrigerating plants with a
refrigerant filling weight over 3 kg.
Seasonal performance factor
The seasonal performance factor relates to the
ratio of heat content delivered by the heat pump
system to the supplied electrical energy in one
year. It may not be compared to the performance
number. The seasonal performance factor
expresses the reciprocal of the annual power input
factor.
Single energy-source mode
The heat pump covers a large proportion of the
required thermal output. On a few days per year an
electrical heating coil supplements the heat pump
under extremely low outdoor temperatures. Dimen-
sioning of the heat pump for air/water heat pumps
is generally based on a limit temperature (also
known as balance point) of approx. -5 °C.
Sound pressure level
The sound pressure level is a comparable charac-
teristic quantity for the radiated acoustic output of a
machine, for example, a heat pump. The noise
emission level at certain distances and acoustic
environments can be measured. The standard is
based on a sound pressure level given as a nom-
inal noise level.
Split AC unit
Design where one part of the device is positioned
outdoors and the other inside the building. Both
units are connected to each other by a refrigerant
pipe.
Storage tank
The installation of a hot-water storage tank is gen-
erally recommended in order to extend the running
time of the heat pump under low heat require-
ments. A storage tank is required for air/water heat
pumps in order to bridge off-periods.
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