This invention is a heat pump based on an existing air-to-air heat pump design with an external component consisting of a refrigerant circuit with a compressor and an evaporator/condenser, and an internal component (room unit) with a con- denser/evaporator.

Less energy is required to heat modern homes. It is therefore challenging to find good solutions that can maintain sufficient indoor heating and hot water while using renewable energy at a cost low enough to make it economically prudent. New technical requirements also demand that a minimum proportion of energy is provided by renewable energy sources.

Traditional air-to-air heat pumps are affordable, reasonably easy to install and are very efficient. However, they can only provide indoor heating. Air-to-water and water-to-water heat pumps can be used to heat both rooms and water, but these solutions are expensive to purchase and install. There are a few ventilation heat pumps with a hot water storage tanks, but these are inefficient and do not provide a sufficiently comfortable environment.

It has been discovered that a hot water storage tank can be connected to an air-to- air heat pump, with minor alterations, creating an air-to-water-to-air heat pump. The hot water storage tank must have a specific design, but the solution would be inexpensive to produce, easy to install and very efficient. Thus the demand for both room heating (or cooling), as well as hot water, would be fulfilled.

The following documents are to be briefly referenced as known technology in this field: DE 3219277 Al, DE 10058273 Al, GB 2497171 A, WO 2012100781 A2 and DE 3403337 Al. The invention provides a heat pump including the features listed in the introduction of requirement 1, which are the characteristic features of requirement 1. More specifically this entails that the external component has a connector for an extra heat exchanger element mounted to a hot water storage tank, since the extra heat exchanger element is positioned between the outlet of the compressor and a 4-way valve.

In this embodiment, the heat pump of the present invention is divided into three main components. This embodiment is illustrated in the drawing provided. A techni- cian will understand that the drawing is a principle diagram and does not necessarily depict the components on an accurate scale. It is thus only intended to display the most important features of one embodiment of the invention. Furthermore, a technician will understand that additional components beyond what is displayed in the principle diagram may be required.

The illustration shows an external component including a compressor module 1 consisting of a compressor 4, a heat exchanger element 5, a 4-way (reversing) valve 6, two expansion valves 7 and two one-way valves 8. The internal component 2 consists of a heat exchanger element 20 and a fan 21. The hot water storage tank 3 is a container with at least one intake 17 and one outlet 19, and a preferred model will also contain a mixing valve 18. Furthermore the tank will contain at least one heat exchanger element 9 and 10, or optionally several heat exchange elements 9 and 10 connected in a daisy chain as illustrated by the drawing. The latter heat exchange elements 9 and 10 are connected to the heat pump's compressor component between the compressor 4 and the 4-way valve 6, and will transmit heat to the tank 3 when the compressor 4 is in operation regardless of the position of the 4-way valve 6. The tank 3 also contains a heat exchanger element 11 that when aided by a circulator pump allows the tank to be used as a heat source for an external heat distribution system 14, such as underfloor heating or radiators.

At the bottom of the tank there is an additional heat exchanger element 12 that can transmit heat to the tank from an alternate energy source, such as a solar panel 16, when aided by a circulator pump.

The flow of the refrigerant will be clarified in the following section. Kompressormodulens 1 kompressor 4 pumper kuldemediet inn til ovre varmeveks- lerelement 9 i tanken 3, videre til neste varmevekslerelement 10 som er lavere ned i tanken 3, videre til 4-veisventilen 6 som ved varmebehov pa innedelen 2 leder kuldemediet til varmevekslerelementet 20 i innedelen 2 og sa videre til en ekspan- sjonsventil 7 og en enveisventil 8 og videre til varmevekslerelementet 5 som da fungerer som fordamper for det gar gjennom 4-veisventilen 6 enda en gang og blir ledet tilbake inn i kompressoren 4. The compressor module's 1 compressor 4 pumps the refrigerant to the upper heat exchanger element 9 in tank 3, on to the next heat exchanger element 10, which is located further down in tank 3, to the 4-way valve 6, which when heat is needed on the internal component 2 will lead the refrigerant to the heat exchanger element 20 in the inner component 2, and on to an expansion valve 7 and a one-way valve 8, then on to the heat exchanger element 5 which will then function as an evaporator before going through the 4-way valve 6 again before finally being led back into the compressor 4.

When cooling is required for the internal component 2, the refrigerant coming from the heat exchanger elements 9 and 10 in the tank 3 will be led by the 4-way valve 6 to the heat exchanger element 5 before continuing through the expansion valve 7 and the one-way valve 8, before then continuing to the heat exchanger element 20 in the internal component 2, which will then function as an evaporator.

In addition to what is indicated above, a few comments to the functional specifica- tions of the heat pump of the invention follow below.

By making minor alterations to a traditional heat pump, at least one extra heat exchanger element can be connected in a daisy chain between the compressor's outlet and the 4-way valve. This heat exchanger element will then always function as an evaporator/hot gas heat exchanger, while the heat exchangers on the other side of the 4-way valve will alternate between heating and cooling. For example, the extra heat exchanger element connected the compressor and the 4-way valve can transmit heat to a tank filled with water, and will transmit heat regardless of whether the rest of the heat pump is cooling or heating.

A traditional heat pump with a reversing valve/4-way valve will normally have two heat exchanger elements where the 4-way valve will make them alternate between being condensers (heat) and evaporators (cooling). There are also heat pumps with several internal components, but in this case all of the heat exchanger elements will either be evaporators (cooling) or condensers (heat).

The tank contains at least one heat exchanger element connected to the compres- sor module, and a preferred model will possess two heat exchanger elements connected in a daisy chain. Heated refrigeration from the compressor will first enter the upper heat exchanger element and heat the upper part of the tank. Gradually as the heat rises in the upper part of the tank, the heat output will decrease, and more and more heat will be produced in the lower part of the tank. Should the internal component require heat, a fan in the internal component will start as soon as the condenser temperature has been sufficiently raised. The remaining heat in the refrigeration will be transferred as room heating through the internal component.

When cooling is required, the internal component will cool, with heat initially being emitted in the tank. When the water in the tank is hot enough for the condenser temperature to become critically high, the remaining heat will be dumped into the compressor module. Thus, when cooling is required for the internal component, a maximum of the excess heat will always be stored in the tank, and excess heat will only be dumped when the tank has reached its maximum temperature.

The tank also contains a heat exchanger element that allows for the transfer of heat from the tank to a heat distribution system. Examples of heat distribution systems include radiators and underfloor heating systems.

At the bottom of the tank is an additional heat exchanger element that can be used to allow an alternate heat source to heat the contents of the tank, such as a solar panel.

The state of the art as described above does not indicate the extra heat exchanger element that is mounted in the cooling circuit between the outlet of the compressor and the 4-way valve.