Technical data

72 | Project planning manual for heat pumps for heating and domestic hot water preparation | 01.2012 www.dimplex.de
6.4 Domestic hot water preparation with heat pumps
6.4 Domestic ventilation units for domestic hot water preparation
New types of materials and construction materials have made it
possible to significantly reduce heating energy consumption. Op-
timum thermal insulation combined with a good seal on the outer
shell of the building ensures that almost no heat is lost to the out-
side air. On the other hand, extremely well sealed windows pre-
vent the necessary exchange of air in both old buildings and new
buildings. This effect leads to contamination of the indoor air.
Water vapour and pollutants accumulate in the air and must be
actively discharged.
How to ventilate correctly?
Probably the simplest way to ventilate a room is to refresh the air
by opening a window. Ventilation at regular intervals by briefly
opening the windows is recommended to maintain an acceptable
living environment. To do this several times daily in all rooms is
tiresome, time-consuming and on account of today's typical work
and living habits totally infeasible.
Automatic room ventilation with heat recovery ensures that the
air that needs to be exchanged from both a hygienic and con-
structional standpoint is exchanged in an energy-conscious and
economically feasible manner.
Advantages of domestic ventilation units
 Fresh, clean air without indoor air pollutants and excessive
humidity
 Automatic management of the required number of daily ven-
tilation procedures without requiring active assistance
 Reduced ventilation losses through
heat recovery
 Integrated filter for insects, dust and fine particle pollutants
 Shielding from external noise and increased
security with closed windows
 Positive evaluation according to the German Federal Energy
Efficiency Ordinance (EnEV)
The use of a mechanical domestic ventilation unit with heat re-
covery is essential in many cases. The preferred type of waste
heat recovery should be clarified before making a decision re-
garding which type of ventilation system to install.
It makes sense to use the exhaust air from the de-aeration and
ventilation of living quarters as an energy source for preparing
domestic hot water, because buildings require both ventilation
and domestic hot water all year round. A second heat generator
should be integrated whenever domestic hot water consumption
is high.
Dimplex offers a selection of different exhaust air systems with
domestic hot water heat pumps
Table 6.4: Ventilation units with domestic hot water heat pumps
NOTE
Further information on the design of ventilation units and our current
product portfolio is available on our website under Ventilation technol-
ogy.
6.5 Comparison of the convenience and the costs of different types of
domestic hot water heating systems
6.5.1 Decentralized domestic hot water supply (e.g. continuous-flow heaters)
Advantages in comparison to heat pumps for
heating purposes:
a) Smaller investment
b) Minimal space requirement
c) Increased heat pump availability for space heating
(particularly in the case of monovalent operation and during
shut-off times)
d) Low water losses
e) No downtime losses or circulation losses
Disadvantages in comparison to heat pumps for
heating purposes:
a) Higher operating costs
b) Loss of comfort because the domestic hot water tempera-
tures are dependent on the tap speed
(in the case of hydraulic devices)
Order
reference
Cylinder
capacity
l
Air vol-
ume flow
m³ / h
Application
LWP 200 200 140
Residential units up to approx.
110 m²
LWP 300W 290 230
Residential units up to approx.
160 m²