About DHW Heat Pumps
About DHW heat pumps
For a number of years, DHW heat pumps have been an extremely energy-saving alternative to electroboilers. Up to 80% of the electrical energy consumed can be saved. Hot water heat pumps have a storage tank of 50 to 300 liters capacity, in which various heat exchangers can be installed. As a corrosion inhibitor, storage tanks have a magnesium anode which, as a rule, has to be checked and replaced in the annual rhythm as well as in electroboilers. Without a magnesium anode, a steel tank would rustle within a short time. There are now also domestic hot water heat pumps, which have a stainless steel tank, which is completely maintenance-free and does not require a corrosion-resistant magnesium anode. The life of a stainless steel tank (e.g., IRICON type EDEL) is unlimited.
The heat exchanger for oversupplying the energy generated by the built-in heat pump surrounds the tank outside as a tube spiral. The heated gas from the condensation circuit flows through this coil and transmits the energy to the tank interior. This prevents refrigerant (gas) pipes from coming into contact with the water. However, these tube coils have a disadvantage in that they usually only lie on the tank surface with a small area and thus lose part of the efficiency of the heat pump. This is counteracted with a good isolation, does not completely solve this problem. IRICON industrial water heat pumps have a patented heat exchanger, which surrounds the tank surface over the entire surface and ensures high efficiency.
The output of the heat pump installed above the tank is as small as necessary to ensure the highest possible savings. The used water temperature is max. at 38 ° C, the tank is usually charged to 45-55 ° C. Thus, sufficient water of higher temperature is available for daily water abstraction. In order to counter extreme cases of higher water consumption, an additional electric heater is usually installed in the tank, which switches on when more hot water is needed. However, for reasons of high energy consumption this should be limited in time.
In addition to an electric heater, further heat exchangers may also be installed in the tank, to which e.g. a heating circuit of the room heating system and / or a solar radiator circuit can be connected, in the sense of an optimized energy saving.
The surrounding air or water from the return of a floor heating system serves as the energy source of the heat pump. These are different types of a heat pump.
Air / water heat pumps
The most commonly used type of domestic hot water heat pump operates with the ambient air temperature, i. warm air is sucked in and cold air is released, the difference between the air temperatures is the energy gain. If the domestic water heat pump is installed in a room (basement), it should have a minimum of 20m², as the air in this room is mixed with cold exiting air. The exhaust air ducts should not be connected to the outside air by means of ducts, as cold air can penetrate the ducts in the cold period in the winter and can destroy the heat exchangers. It is therefore advisable to extract the supply air to the heat pump from the warm room and to supply the cold exhaust air to a storage space. Air / water Heat pumps dehumidify the room from which air is drawn. This creates condensate, which must be discharged into the sewer system.
Water / water heat pumps
What the designation says work water / water DHW water heat pumps with the medium water as an energy carrier. These heat pumps do not have a fan but a circulation pump. These heat pumps therefore operate particularly quietly, do not emit condensate and can be installed at any location. As a rule, these heat pumps operate with the return water of a floor heating system and are connected to the heating circuit by means of a water deflecting unit. This system works very efficiently with a very high efficiency, which rarely leaves the COP value of 4.0 in winter or summer.
In the warm summer months, the underfloor heating is switched off, in which case the underfloor heating system operates as a heat exchanger for the heat pump, the cold water from the heat pump being fed back to the floor circuit. This results in a lowering of the warm room temperature. A part of the domestic water heat pumps from IRICON are available as water / water heat pumps.