Technical data

www.dimplex.de 01.2012 | Project planning manual for heat pumps for heating and domestic hot water preparation | 67
Domestic hot water preparation with heat pumps 6.2.1
Combination of multiple domestic hot water
cylinders
If water consumption is very high or if heat pumps with an output
of more than approx. 28 kW are implemented for domestic hot
water operation, the heat exchanger area required to ensure that
adequate domestic hot water temperatures are maintained can
be created by connecting the heat exchangers of several domes-
tic hot water cylinders in parallel or in series. (Refer to German
Technical and Scientific Association for Gas and Water - work
sheet W551)
Fig. 6.5: Connecting domestic hot water cylinders in parallel
Connecting more than one domestic hot water cylinder in parallel
is particularly suitable where large quantities of water are tapped.
This is only possible when identically constructed domestic hot
water cylinders are used. When connecting the heat exchangers
with the domestic hot water circuit, the pipes from the tee joint
onwards leading to each cylinder should have the same pipe di-
ameter and the same length. This ensures that the heating water
volume flow is divided between the two systems with the same
drop in pressure. (see Fig. 6.5 on page 67)
Fig. 6.6: Connecting domestic hot water cylinders in series
It should be taken into consideration during series integration of
domestic hot water cylinders that the heating water must first
pass through the cylinder from which the domestic hot water is
drawn. (see Fig. 6.6 on page 67)
6.2 Air-to-water heat pump module LI 2M for utilisation of waste heat
6.2.1 Intended purpose
The heat pump module LI 2M allows the use of waste heat from
unpolluted air. In the simplest case the plug-in device draws the
warm air directly via the integrated radial fan and cools it down.
The refrigerating circuit "pumps" the extracted heat to a usable
temperature level and discharges it again via a heat exchanger.
The heating water circuit, to be connected externally, directs the
usable waste heat to the heating system or a water cylinder with
integrated heat exchanger.
The highest efficiency is reached when the heat pump module is
operated at a low temperature level to, e.g., heat a preheating
stage for domestic hot water preparation.
The heat pump is designed exclusively for heating heating water
and domestic hot water!
The heat pump is suitable for mono-energy operation via the
heat exchanger down to an external temperature of 0 °C.
ATTENTION!
Due to the lower operating limit the heat pump module can cool the
installation location down to 0 °C. Frost protection must be ensured.
Proper defrosting of the evaporator is guaranteed by maintaining
a heating water return temperature of more than 18 °C or 20 °C
(see Appendix Operating Range) during continuous operation.
The following is not permitted:
 Operating the pump with solvent-based or explosive ex-
haust air
 connecting extractor hoods to the ventilation system
 utilising exhaust air containing grease residues
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