The present disclosure claims the priority of LU501801 filed on 5 April 2022, the disclosure of which is herein incorporated by reference.

The present invention relates to a heating/cooling module for interconnecting a heating/cooling system with at least one and preferably exactly one heating/cooling unit.

Where words are separated by a slash ( 7” ), the word before the slash usually relates to a heating scenario, whereas the word behind the slash relates to a cooling scenario. In a heating scenario, the heating/cooling system and unit is used for heating. In a cooling scenario, the heating/cooling system and unit is used for cooling. The slash can be replaced by an “and/or” or an “or”.

Thus, the term “heating/cooling” shall be understood in the sense that the heating/cooling system or the heating/cooling unit can be operated to heat only or to cool only. Thus, it is either a heating system or a cooling system and, correspondingly, either a heating unit or a cooling unit.

An important part on the way to meet the requirements and measures to reduce energy consumption and an important part of sustainable development (climate agreements, the European Green Deal; 7 ^th , 1 1 ^th , and 13 ^th Sustainable Development Goals of the United Nations) are changes in the building sector. In order to increase the energy efficiency of buildings, the European Union has enacted legislation i.e. Directive on Energy Performance of buildings 2010/31/ EU (EPBD), that promoted the energyefficient renovation of older buildings, connections of buildings to district heating systems (DH), and the construction of new near-zero energy buildings (n-ZEB), among others. This should importantly reduce energy consumption for space heating and cooling, which in the EU accounts for about 30 % of the total final energy consumption. On 15 ^th December 2021 , the European Commission published a proposal for a recast of the Energy Performance of Buildings Directive, in the framework of the Fit for 55 % Package. The package aims lead EU for a 55 % reduction in carbon emissions by Following the partial revision of the 2012 Energy Efficiency Directive (2012/27/EC) in 2018, through the amending Directive 2018/2002/EU, the European Commission launched on 14 ^th July 2021 a proposal for recasting the EU Directive on Energy Efficiency. The new proposal introduces a higher target for reducing primary energy consumption for 39 % and final energy consumption for 36 % by 2030 (being at present defined by 32.5 % for both primary and final consumption). The new directive also proposes to nearly double the member state annual energy savings obligations in end use.

Since around two thirds of the buildings in the EU were built at a time before thermal standards were introduced, and most of these buildings will still be in use in 2050, it would be desirable to find efficient, simple and cost-effective solutions for their energy-efficient renovation.

One of the common heating setups in residential buildings in the EU member states is central heating with boilers and hot water radiators operating in high-temperature mode, for example above 45 °C. Related systems thereto are described in EP 04 09 739 A1 , DE 298 21 457 U1 , EP1 653 184A1 , EP 0 928 939A2, JP 2002/162050 A.

Another common setup of energy consumption is related to the connection of a building to district heating (DH). DH systems are also being upgraded to increase energy efficiency by lowering the supply temperature. Current fourth-generation DH systems operate with supply temperatures between 50 and 60 °C. However, the future 5 ^th generation of DH systems will operate at even lower temperature levels, which are at least 10 K lower than previous generations of DH systems and what existing radiators in related buildings are usually constructed for.

To replace the old and less efficient heating setups, the European Commission has proposed the use of renewable energy sources, heat pumps, waste heat recovery, and the use of DH systems of newer generations. All the above proposals use a low temperature regime, where the temperature is much lower than in the current boiler central hydronic heating systems. For example, the working fluid in currently used third DH generation is pressurized hot water below 100 °C in combination with 70 °C temperature heating units, while in more efficient fourth DH generation, the working fluid is water below 70 °C in combination with 50 °C heating units. In the fifth generation of DH systems, waste heat, renewable heat sources, or heat pumps represent the major heat source. Another heat source can be represented by the return pipeline in DH system being at the temperature level between 20 to 40 °C. In order to achieve the same comfort level and higher energy efficiency, the internal hydronic heating system needs to be replaced or adapted according to the new heat source. This represents a large additional cost and a major intervention in the building.

The adjustment of heating units for low temperature regime can be made by increasing the area or using a different type of the heating unit, or by utilizing the thermal mass of buildings while operating in a longer time interval of the heating mode. Specifically, low-temperature DH systems require an additional heat source on the user side, for example a thermal booster, to raise the DH working fluid temperature if needed. These can be electric and gas boilers, heat pumps based on the vapour compression cycle or sorption cycle, waste heat, and solar energy. Such a booster is large and must have a high thermal power as it raises the working fluid temperature for the entire building. Its use is particularly ineffective when the temperature is to be raised locally.

It is therefore an object of the present invention to provide a cost and energy-efficient solution which can be used in conjunction with the available heating systems and heating units as are readily available in current buildings. It is another object of the present invention to provide a cost and energy-efficient solution which can be used in new buildings or when buying a new heating system. Similarly, an efficient way of cooling old and/or modern buildings is desired.

At least one of the objects is satisfied by a heating/cooling module in accordance with any one of the independent claims. Preferred embodiments of the present invention are described in the dependent claims. At least in some aspects, the present invention relates to a heating/cooling module for interconnecting a heating/cooling system with at least one and preferably exactly one heating/cooling unit. The heating/cooling module comprises: a solid-state energy conversion device having a first side which is configured to receive a fluid flow that is preheated/precooled by the heating/cooling system, to heat/cool the fluid flow to a higher/lower temperature while it flows through the first side of the solid-state energy conversion device, and to use the fluid flow with the higher/lower temperature for providing heat/cold to the heating/cooling unit, and the solid-state energy conversion device has a second side which is configured to absorb/reject heat from/to the fluid flow after being used for providing heat/cold to the heating/cooling unit. The second side can cool/heat the fluid flow from the heating/cooling unit to a lower/higher temperature.

Preferably, the fluid flow through the first side of the solid-state energy conversion device is a fluid flow in a hydraulically closed fluid circuit, and the fluid flow through the second side of the solid-state energy conversion device is a fluid flow in a hydraulically closed fluid circuit. The fluid circuits can be interconnected, for example in the heating/cooling unit and/or in the heating/cooling system, when the heating/cooling module interconnects the heating/cooling system with the at least one and preferably exactly one heating/cooling unit. The fluid flows are usually implemented by use of a liquid, such as water.

The heating/cooling module can be arranged in a housing.

At least in some embodiments, the heating/cooling system or the heating/cooling unit can be configured to provide heating and cooling. Thus, the system and/or unit can have a mode of operation in which the system or unit can provide cooling and another mode of operation in which the system or unit can provide heating.

At least in some embodiments, related to a heating scenario, the heating/cooling module is a heating module and the heating/cooling unit is a heating unit, and the first side of the solid-state energy conversion device is configured to receive a fluid flow that is preheated by the heating system, to heat the fluid flow to a higher temperature while it flows through the first side of the solid-state energy conversion device, and to use the fluid flow with the higher temperature for providing heat to the heating unit, and the second side of the solid-state energy conversion device is configured to absorb heat from the fluid flow after being used for providing heat to the heating unit.

At least in some embodiments related to a cooling scenario, the heating/cooling module is a cooling module and the heating/cooling unit is a cooling unit. The first side of the solid-state energy conversion device can then be configured to receive a fluid flow that is precooled by the cooling system, to cool the fluid flow to a lower temperature while it flows through the first side of the solid-state energy conversion device, and to use the fluid flow with the lower temperature for providing cold to the cooling unit, and the solid-state energy conversion device has a second side which is configured to reject heat to the fluid flow after being used for providing cold to the cooling unit.

The heating/cooling unit can be one of the following: segment or column radiator, a panel radiator, a panel-convector radiator, a smooth- or finned-tube radiator, any type of convector radiator including fan coils, floor or ceiling heating/cooling system, air conditioning system, heat recovery system, etc.

In a particular case, the heating/cooling module heats sanitary hot water. In this particular case, the heating/cooling unit serves for storage of the sanitary hot water.

The heating/cooling system can be configured to operate in the low (for a heating system) or high (for a cooling system) temperature regime. The temperature regime can be the temperature regime of a district heating/cooling system or a low/high temperature heat pump system or waste heat or renewable energy sources low/high temperature heating/cooling system. The heating/cooling system can be a district heating/cooling system.

The heating/cooling system can be an internal heating/cooling system.

The heating/cooling fluid of an internal heating/cooling system can be provided by a district heating/cooling system, from a low temperature heat pump, from waste heat or from renewable energy sources. The solid-state energy conversion device can comprise, in particular in a solid-state energy conversion module assembly, between the first side and the second side, at least one material or compound that exhibit different phenomena in solid-state physics. These phenomena in which temperature gradients or temperature changes are formed within the material/compound as a response to external stimuli (i.e. forces, fields, energy fluxes, etc), can be used through the thermodynamic cycle for heating and/or cooling via a heat pump principle. Such phenomena can be obtained by a magnetocaloric, electrocaloric, elastocaloric, barocaloric, multicaloric, thermionic, Peltier, magneto-Peltier, spin-Peltier, spin-dependent Peltier, and anomalous Ettingshausen effect.

Embodiments of the present invention can be used in new buildings or in conjunction with newly bought heating/cooling systems. Considering that extreme outside temperatures occur on a limited number of days in a year, the heating/cooling system can be intentionally designed with minimum heating/cooling capacity that suffices for the main part of the year and it can be supplemented with the heating/cooling module for the rare periods when the need for heating/cooling is greater.

A component of the heating/cooling module is the solid-state energy conversion device. The solid-state energy conversion device can comprise or consists of at least one material or compound, preferably arranged between the first side and the second side, to provide temperature gradients or temperature changes within the material or compound as a response to external stimuli, such as forces, fields, energy fluxes, etc. The temperature gradients or temperature changes can be used in thermodynamic cycles for heating and/or cooling via heat pump principle. Underlying physical effects can be magnetocaloric, electrocaloric, elastocaloric, barocaloric, multicaloric, thermionic, Peltier, magneto-Peltier, spin-Peltier, spin-dependent Peltier, and anomalous Ettingshausen effect.

The at least one material or compound can be arranged in a solid-state energy conversion module assembly that is arranged between the first side and the second side of the solid-state energy conversion device. The first side and the second side each provide at least one fluid channel for the respective fluid flow through the sides. The module assembly can have a modular structure. The solid-state energy conversion device can be or comprise a thermoelectric device and/or a heat pump, for example a Peltier device, a thermionic heat pump device, a spin caloritronic heat pump device, a magneto-thermoelectric heat pump device, a magnetocaloric heat pump device, an electrocaloric heat pump device, a mechanocaloric heat pump device, a multicaloric heat pump device, or a combination thereof.

Such a device can comprise the mentioned solid-state energy conversion module assembly and provide or include the material or compound.

At least in some embodiments, the solid-state energy conversion device can comprise one or more Peltier modules. The Peltier modules can be arranged side by side and all can face upwards. The first fluid flow is/can be arranged along the top surface of Peltier modules and the second fluid flow is/can be arranged along the bottom surface of Peltier modules.

In the example with Peltier modules, each of the Peltier modules comprises several Peltier elements. In a Peltier element, heat is transported from the cold to the hot side by the thermoelectric effect or Peltier effect, which arises when a direct electric current flows through two oppositely doped (N and P-doped) semiconducting materials with different Peltier coefficients. Peltier elements in a Peltier module are preferably electrically connected in series and thermally in parallel. Therefore, one surface, for example the top surface, heats up and the other surface, for example the bottom surface, cools down. If the direction of electric current is switched, the hot and cold surfaces of a Peltier module also change.

The heating/cooling module, which can be arranged between the heating/cooling system and the heating/cooling unit can increase (in the case of heating) or decrease (in the case of cooling) the temperature of the fluid flow as preheated or precooled by the heating/cooling system and provide heat/cold from/to the fluid flow with the higher/lower temperature to the heating/cooling unit. In this way, a common heating/cooling unit, which was originally intended to be used in conjunction with a heating/cooling system operating in the high/low temperature regime, for example a heating system that provided a fluid flow at a temperature above 50 °C, can be used now in conjunction with a heating system that provides a fluid flow in the low temperature regime, for example temperatures around 20 °C to 40 °C.

It is preferred that one heating/cooling module is connected to one heating/cooling unit. In other words, preferably, each heating/cooling unit is equipped with its own heating/cooling module.

The solid-state energy conversion device can have one or more solid-state energy conversion module assemblies. Thus, the solid-state energy conversion device can have a modular structure.

In some embodiments, the solid-state energy conversion device can be a thermoelectric device which can have one or more Peltier modules arranged between the first side and the second side. The first side can be regarded as hot side of the solid-state energy conversion device, while the second side can be regarded as the cold side in the case of heating. It is the opposite in the case of cooling.

In the heating scenario, the fluid flow through the second side can be used to heat the fluid flow through the first side. Thereby, fluid flow flowing from the heating unit can transfer heat to the second side of the thermoelectric device. Therefore, the fluid flow flowing from the heating system to the heating unit is additionally heated in the first side of the thermoelectric device. In this way, an energy efficient heating of the fluid flow to the higher temperature can be obtained.

The solid-state energy conversion device can be configured to receive the preheated (in the heating scenario) or precooled (in the cooling scenario) fluid flow from the heating/cooling system, to heat/cool this fluid flow and to provide the fluid flow with the higher/lower temperature to the heating/cooling unit. Furthermore, the solid-state energy conversion device can be configured to receive the fluid flow back from the heating/cooling unit, to cool/heat this fluid flow, and to provide the fluid flow with the lower/higher temperature back to the heating/cooling system. Therefore, the fluid flow as provided by the heating/cooling system can run through the solid-state energy conversion device and the heating/cooling unit. Moreover, the fluid flow can be provided back to the solid-state energy conversion device and the heating/cooling system from the heating/cooling unit. Thus, at least in some embodiments, a single loop of fluid flow can be used to heat/cool the heating/cooling unit.

At least in some embodiments, the first side comprises a channel or multichannel, in particular only one channel or only one multichannel, which is configured such that the fluid flow flows only through the channel or multichannel as one direction pass and/or the second side comprises a channel or multichannel which is configured such that the fluid flow flows only through the channel or multichannel as one direction pass. Preferably, the fluid flow through the first side is directed in the opposite flow direction as the fluid flow through the second side. The channel or multichannel can therefore be a one direction pass. The first side of the solid-state energy conversion device is therefore configured such that the fluid flow through the first side only flows once through the first side and/or the second side of the solid- state energy conversion device is configured such that the fluid flow through the second side only flows once through the second side. Thus, the fluid flow through each side is not guided two times or more through the respective side, but only once. The solid-state energy conversion device can thereby be operated with small temperature differences between the two sides so that a large coefficient of performance (COP) can be obtained.

Therefore, at least in some embodiments, the first side of the solid-state energy conversion device can comprise a single flow channel or multichannel which only extends once through the first side in order to ensure that the fluid flow only flows once through the first side. Correspondingly, the second side of the solid-state energy conversion device can comprise a single flow channel which only extends once through the second side to ensure that the fluid flow only flows once through the second side. For example, there is no flow channel which includes two separate portions that run through the respective side along different or opposite flow directions. A flow channel can be realized by use of a pipe or a porous structure provided in the side of the solid-state energy conversion device.

At least in some embodiments, the heating/cooling module can be intended for boosting a temperature level between an, in particular hydronic, heating/cooling system and at least one, or preferably exactly one heating/cooling unit, the heating/cooling module can comprise: a solid-state energy conversion device, having a first side which is configured to receive a fluid flow that is preheated/precooled by the heating/cooling system, to heat/cool the single fluid flow to a higher / lower temperature while it flows in a given direction through the first side of the solid-state energy conversion device, and to use the fluid flow with the higher/lower temperature for providing heat/cold to the heating/cooling unit, and the solid-state energy conversion device having a second side which is configured to receive the single fluid flow flowing in counter direction with regard to a given direction of single fluid flow through the first side, and the single fluid flow flowing after being used for providing heat/cold to the heating/cooling unit, to cool/heat the fluid flow to a lower/higher temperature and to reuse the fluid flow with the lower or higher temperature for preheating/precooling again by the heating/cooling system.

In all embodiments described herein, the fluid can be a liquid, such as water.

At least in some embodiment, the heating/cooling module can be intended for boosting a temperature level between in particular a hydronic heating/cooling system and at least one, or preferably exactly one heating/cooling unit, the heating/cooling module comprises: a solid-state energy conversion device, having a first side which is configured to receive a liquid flow that is preheated/precooled by the heating/cooling system, to heat/cool the single liquid flow to a higher / lower temperature while it flows in a given direction through the first side of the solid-state energy conversion device, and to use the liquid flow with the higher/lower temperature for providing heat/cold to the heating/cooling unit, and the solid-state energy conversion device having a second side which is configured to receive the single liquid flow flowing in counter direction with regard to a given direction of single liquid flow through the first side, and the single fluid flow flowing after being used for providing heat/cold to the heating/cooling unit, to cool/heat the liquid flow to a lower/higher temperature and to reuse the liquid flow with the lower or higher temperature for preheating/precooling again by the heating/cooling system. Thus, through each side of the solid-state energy conversion device, there is only a single fluid flow. In particular, there is no backflow of the fluid flow on each side of the solid-state energy conversion device so that the fluid is not guided twice through the respective side of the solid-state energy conversion device.

In some embodiments, the fluid flow through each side of the solid-state energy conversion device can be implemented by use of a flow channel arranged on each side. In some embodiments, there is only a single flow channel, which can be a multichannel, arranged on each side of the solid-state energy conversion device. A flow channel can be realized by use of a pipe, for example a copper pipe, or by a porous structure provided in the side of the solid-state energy conversion device. Having a single flow channel on each side of the solid-state energy conversion device allows operating the module with small temperature differences between the two sides of the solid-state energy conversion device, while a large COP can be achieved.

The heating/cooling module may comprise a first heat exchanger having a first fluid passage providing an inlet for receiving a fluid flow from the heating/cooling system and an outlet for providing the fluid flow back to the heating/cooling system after it has flown through the first fluid passage, wherein the heat exchanger comprises a second fluid passage which is configured to output a fluid flow that is preheated or precooled, in particular, indirectly, by the heat from heating/cooling system and to receive the fluid flow with the lower/higher temperature, wherein the first fluid passage and the second fluid passage are arranged such that heat is transferrable between the fluid flow in the second fluid passage and the fluid flow in the first fluid passage.

The fluid flows through the heating/cooling module and the first heat exchanger can be closed fluid circuits, in particular when the heating/cooling module is connected to the heating/cooling system and the heating/cooling unit. Thus, the fluid flows can run in closed loops that completely extend for example in piping or tubing. Preferably, when the heating/cooling module is arranged between the heating/cooling system and the heating/cooling unit, the second fluid passage of the first heat exchanger forms a closed loop for the fluid flow together with the fluid channels in the heating/cooling module and the heating/cooling unit.

The heating/cooling module can comprise a fluid pump to drive the fluid flow through the solid-state energy conversion device, and, in particular, through the second fluid passage. The fluid pump can further serve to drive the fluid flow through the heating/cooling unit.

The heating/cooling module, and in particular the solid-state energy conversion device, may be configured to receive the fluid flow with the higher temperature (in case of a heating system) or with the lower temperature (in case of a cooling system), to provide the fluid flow with the higher/lower temperature to the heating/cooling unit, to receive the fluid flow back from the heating/cooling unit and to provide the fluid flow with the lower/higher temperature back to the first heat exchanger. A loop of fluid flow can thus be arranged between the heating/cooling module and the heating/cooling unit.

At least in some embodiments, related to the heating scenario, the heating/cooling module comprises a second heat exchanger having a third fluid passage which is configured to receive the fluid flow with the higher temperature and to output the fluid flow after being used for providing heat, in particular, indirectly, to the heating/cooling unit. The second heat exchanger has a fourth fluid passage which provides an outlet for providing a fluid flow to the heating/cooling unit and an inlet for receiving the fluid flow back from the heating/cooling unit, and the third fluid passage and the fourth fluid passage are arranged such that heat is transferrable from the fluid flow with the higher temperature in the third fluid passage to the fluid flow in the fourth fluid passage. The second heat exchanger allows decoupling a fluid flow in the heating/cooling module from a fluid flow in the heating/cooling unit. The fluid flows can be realized in two loops, with an energy exchange occurring between the loops in the second heat exchanger.

The fluid flows through the heating/cooling module, the first heat exchanger and the second heat exchanger can be closed fluid circuits, in particular when the heating/cooling module is connected to the heating/cooling system and the heating/cooling unit. Thus, the loops can be closed loops that completely extend for example in pipes or tubes. Hence, there is no passage through open space that is not confined by a flow channel.

Preferably, the second fluid passage of the first heat exchanger and the third fluid passage of the second heat exchanger are arranged in a closed loop together with the fluid channels of the two sides of the heating/cooling module.

At least in some embodiments, related to a cooling scenario, the heating/cooling module may comprise a second heat exchanger having a third fluid passage which is configured to receive the fluid flow with the lower temperature and to output the fluid flow after being used for providing, in particular, indirectly, cold to the heating/cooling unit. The second heat exchanger has a fourth fluid passage which provides an outlet for providing a fluid flow to the heating/cooling unit and an inlet for receiving the fluid flow back from the heating/cooling unit. Heat can be transferred from the fourth passage to the third, so that the fluid in the fourth passage cools down and flows back to the cooling unit. The second heat exchanger can allow decoupling a fluid flow in the heating/cooling module from a fluid flow in the heating/cooling unit. The fluid flows can be realized in two loops, with an energy exchange occurring between the loops in the second heat exchanger.

At least in some embodiments, the heating/cooling module comprises a fluid pump to drive the fluid flow through the heating/cooling module and/or the heating/cooling unit.

At least in some aspects, the invention relates to a heating/cooling module for interconnecting a heating/cooling system with at least one and preferably exactly one heating/cooling unit. The heating/cooling module comprises: a first heat exchanger having a first fluid passage with an inlet for receiving a fluid flow from the heating/cooling system and an outlet for providing the fluid flow with a higher temperature (in case of a heating scenario) or a lower temperature (in case of a cooling scenario) to an inlet of the heating/cooling unit, a solid-state energy conversion device having a first side which is configured to receive a fluid flow from an outlet of a second fluid passage of the first heat exchanger, to cool (in case of a heating scenario) or to heat (in case of a cooling scenario) the fluid flow to a lower/higher temperature while it flows through the first side of the solid-state energy conversion device, and to provide the fluid flow with the lower/higher temperature to an inlet of a third fluid passage of a second heat exchanger.

The solid-state energy conversion device has a second side which is configured to receive the fluid flow from an outlet of the third fluid passage of the second heat exchanger and to heat (in case of a heating scenario) or to cool (in case of a cooling scenario) the fluid flow to a higher/lower temperature while it flows through the second side, and to provide the fluid flow with the higher/lower temperature to an inlet of the second fluid passage of the first heat exchanger.

The second heat exchanger further comprises a fourth fluid passage with an inlet for receiving a fluid flow from the heating/cooling unit and with an outlet for providing the fluid flow back to the heating/cooling system.

In case of a heating scenario, the first side of the solid-state energy conversion device serves to cool the fluid flow through the first side, in particular by use of a solid-state energy conversion module assembly arranged between the first side and the second side. The first side can therefore be regarded as cold side. The second side of the solid-state energy conversion device serves to heat the fluid flow through the second side, so that the second side can be regarded as hot side.

In case of a cooling scenario, the first side of the solid-state energy conversion module serves to heat the fluid flow through the first side, in particular by use of a solid-state energy conversion module assembly arranged between the first side and the second side. The first side can therefore be regarded as hot side. The second side of the solid-state energy conversion device serves to cool the fluid flow through the second side, so that the second side can be regarded as cold side.

The heating/cooling module, which can be arranged between the heating/cooling system and the heating/cooling unit can increase (in case of a heating scenario) or decrease (in case of a cooling scenario) the temperature of the fluid flow as preheated or precooled by the heating/cooling system and provide heat/cold from the fluid flow with the higher/lower temperature to the heating/cooling unit. In particular, the first heat exchanger can heat/cool the fluid flow coming from the heating/cooling system up to a higher/lower temperature, so that a fluid flow with the higher/lower temperature can be provided to the heating/cooling unit. Therefore, a common heating/cooling unit, which was originally intended to be used in conjunction with a heating/cooling system operating in the high temperature regime (in case of a heating system, for example a heating system that provided a fluid flow at a temperature of above 50 °C) or in a low temperature regime (in case of a cooling system, for example a cooling system that provided a fluid flow at a temperature of below 10 °C), can be used now in conjunction with a modern heating/cooling systems. For example, a modern heating system provides a fluid flow in a low temperature regime, for example temperatures around 30 °C to 40 °C. For example, a modern cooling system provides a fluid flow in a high temperature regime, for example temperatures around 10 °C to 15 °C.

The first fluid passage and the second fluid passage may be arranged in the first heat exchanger to transfer heat (in a heating scenario) or cold (in a cooling scenario) from the second fluid passage to the first fluid passage. The third fluid passage and the fourth fluid passage may be arranged in the second heat exchanger to transfer heat from/to the fourth fluid passage to/from the third fluid passage. An efficient heating/cooling of the fluid flow that is provided to the heating/cooling unit can therefore be achieved.

The heating/cooling module may further comprise a pump for circulating the fluid flow through a closed loop comprising the second fluid passage and the third fluid passage and a fluid passage through the first side and a fluid passage through the second side.

The solid-state energy conversion device can comprise a solid-state energy conversion module assembly arranged between the first side and the second side of the solid-state energy conversion device. The assembly can include one or more solid-state energy conversion modules, which can be or are preferably coupled fluidly in a series and preferably electrically in parallel with respect to each other. In particular, the solid-state energy conversion modules can be arranged one after another, so that a fluid passage for the fluid flow, which runs through the first side of the solid-state energy conversion device, runs past the solid-state energy conversion modules consecutively. Alternatively or additionally, a corresponding fluid passage for the fluid flow, which extends through the second side of the solid-state energy conversion device, can run past the solid-state energy conversion modules consecutively.

The solid-state energy conversion modules can be used to heat or cool one side and to cool or heat the other side of the module, while transport of heat is possible between the two sides. An efficient energy transfer is therefore possible between the two sides while one side is cooled (heated) and the other is heated (cooled).

At least in some embodiments, a number of solid-state energy conversion modules is between a minimum of 1 and a maximum of 1000.

The solid-state energy conversion modules can for example be one of the following: Peltier modules, caloric heat pump modules, thermionic heat pump modules, spincaloritronic heat pump modules, magneto-thermoelectric heat pump modules.

At least in some embodiments, the heating/cooling module can comprise a power supply and/or a controller for the solid-state energy conversion device. A power supply can provide electric power to the solid-state energy conversion device, and a controller can control operation of the solid-state energy conversion device. The power supply also can provide electric power to valves and pumps. The controller can also control the valves and pumps. Each of the power supply and the controller can be arranged in separate housings or both in a single housing.

At least in some aspects, the invention also relates to a heating/cooling arrangement comprising a heating/cooling module in accordance with the present invention, a heating/cooling system, and a heating/cooling unit, wherein the heating/cooling module fluidly interconnects the heating/cooling system and the heating/cooling unit.

The heating/cooling system may operate at a lower (in case of a heating scenario) or a higher (in case of a cooling scenario) fluid temperature than the heating/cooling unit. Thus, the heating/cooling system can operate in a low (in case of a heating scenario) or in a high (in case of a cooling scenario) temperature regime, while the heating/cooling unit operates in a high (in case of a heating scenario) or a low (in case of a cooling scenario) temperature regime. The system is particularly useful for interconnecting a heating/cooling unit as commonly used in older buildings with a modern low temperature heating/cooling system.

Heating/cooling units and other components of a central heating/cooling system in current or older buildings are usually adapted to the heating or cooling source and the operating temperature regime. As older systems are based on high temperature regimes for heating and low temperature regimes for cooling, the components might be changed to maintain the same comfort level in the rooms when switching to a decarbonised and more energy efficient low temperature heating system or high temperature cooling system. Examples for low temperature heating systems are low temperature DH, low temperature heat pump, waste heat or heat from renewable energy sources. Examples for high temperature cooling are cooling by use of natural sources, cooling with or assisted by renewable energy sources, or any other cooling by adapting the heat source temperature to be high.

A heating/cooling module in accordance with embodiments of the present invention provides an energy efficient means that enables maintaining heating units when transitioning to a low temperature heat source. Similarly, a heating/cooling module in accordance with embodiments of the present invention provides an energy efficient means that enables maintaining cooling units when transitioning to a high temperature cold source. It can even be possible to decrease or minimize the size of heating/cooling units in old building stock. Buildings can therefore be renovated toward higher energy efficiency, where one often has to deal with limited space and limited options e.g. for complete replacement of internal hydronic heating/cooling system. Thus, the proposed heating/cooling module enables a simple renovation process while increasing energy efficiency.

At least in some embodiments, the solid-state energy conversion device of a heating/cooling module can include one or more solid-state energy conversion modules, for example in form of an integrated thermoelectric Peltier heating/cooling support unit. The heating/cooling module can be used for modification of a segment or column radiator, a panel radiator, a panel-convector radiator, a smooth- or finned- tube radiator, any type of convector radiator including fan coils, a floor or ceiling heating/cooling system, an air conditioning system, a heat recovery system, etc., designed for use in a heating scenario in a high temperature regime, in a way that enables them to work in a low temperature regime. Correspondingly, a cooling unit designed for use in conjunction with a cooling system operating in a low temperature regime can now be used in conjunction with a cooling system operating in a high temperature regime.

Heating/cooling units can for example be any type of radiators, such as a segment or column radiator, a panel radiator, a panel-convector radiator, a smooth- or finned- tube radiators, fan coils, and air-heaters of air-conditioning systems or heat (cold) recovery systems.

In some embodiments, the heating/cooling module heats sanitary hot water. The heating/cooling unit can then also serve for storage of the sanitary hot water.

At least some embodiments of the heating/cooling module in accordance with the present invention provide a means for the transition to low temperature central heating system or to a high temperature cooling system in a building stock, since they provide a solution for increasing (in a heating scenario) or decreasing (in a cooling scenario) the supply temperature of a fluid provided to a heating/cooling unit, while they can be operated in a simple, silent, vibration-free, environmentally friendly (non-harmful solid-state refrigerants), and energy efficient way.

At least some embodiments of the present invention can provide a simple and cost- effective solution for localized increase of the temperature level in internal hydronic heating systems. Correspondingly, a simple and cost-effective solution for localized decrease of the temperature level in internal hydronic cooling systems can be provided.

The following examples relate to heating and/or cooling systems: renovation of building stock, where the space restrictions and construction of the building do not enable large modifications or do not enable large modifications of internal hydronic heating/cooling system to be adapted for low/high temperature regime; possibility of using existing heating/cooling units without requirements for their full replacement; compared to vapor compression heat pumps, embodiments of the present invention may enable fully silent operation, with better control, no harmful refrigerants, no vibrations and is localized (for example as an end-heating/cooling unit of a hydronic heating/cooling system); compared to an integrated electric heater, embodiments of the present invention may enable substantially more energy efficient operation and can be local (for example as an end-heating unit of a hydronic heating system); design of a new building stock, in which the available heat/cold sources at the boundary of the building do not provide sufficiently high/low temperature for internal heating/cooling or heating of sanitary hot water.

At least in some embodiments, the heating/cooling module serves as interface between hydronic heating/cooling distribution system, or district heating/cooling, or heating substation, and at least one final heater/cooler, e.g. radiator, fan coil, HVAC system, sanitary hot water, etc.

At least in some embodiments, the heating/cooling module can be configured to provide heating and/or cooling, for example to heat domestic hot water.

At least in some embodiments, the heating/cooling module does not comprise any waste or sanitary water collector, such as a shower pan or a bath tub, and it does not use such waste water for heating.

At least in some embodiments, all fluid flows, in particular the fluid flows through the heating/cooling module, are in at least one hydraulically closed circuit. Therefore, at least in some embodiments, there is no fluid flow through open space. Thus, the fluid flows are guided by tubes or pipes, which form at least one closed circuit. At least in some embodiments, no cleaning fluid is used for the fluid flows. At least in some embodiments, all fluid flow is based on a liquid flowing in one or more closed circuits. Therefore, air or another gas is usually not used as a fluid. At least in some embodiments, no fluid flow through the heating/cooling module uses waste water or humid air. Therefore, a fouling of the heat transfer area, which can be caused by waste water or humid air, can be avoided. The fouling can cause a decrease in the heat transfer efficiency, potential pressure drop, which may lead to problematic control, and may require maintenance. The claimed heating/cooling module and arrangement do preferably not comprise a water tank, such as an underground water tank.

At least in some embodiments, the fluid flow rate on one side of the heating/cooling module, in particular on one side of the solid-state energy conversion device, and the fluid flow rate on the other side of the heating/cooling module, in particular on the other side of the solid-state energy conversion device, can be separately controlled, in particular at any conditions. The fluid flow rates can be controlled with different valves and/or pumps, for example in order to provide an optimal fluid flow and energy efficient heat transfer under different operating conditions of the heating/cooling module.

Therefore, at least in some embodiments, the efficiency of the one or more solid- state energy conversion devices of the heating/cooling module can be controlled and kept high, since the return flow of the circuit from the internal heating/cooling system can pass the cold/hot side along one or more and preferably a plurality of solid-state energy conversion devices and since the supply flow of the circuit passes the hot/cold side along the one or more and preferably the plurality of the solid-state energy conversion devices. Therefore, by having the counter-fluid flow, one flow direction of the fluid of the circuit is in direction along the hot side of the one or more solid-state energy conversion devices. Another opposite flow direction of the fluid flow, in particular of the same circuit, can be along the cold side of the one or more solid state energy conversion devices. As a consequence, the temperature difference of each of the solid-state energy conversion devices can be kept low which can highly increase the coefficient of performance.

At least in some embodiments, the heating/cooling module and in particular the solid- state energy conversion device, is configured to operate continuously, in particular for a longer amount of time, such as for at least one or more hours or one or more days.

At least in some embodiments, the cooling module is configured to transfer dissipated heat only to the liquid in the corresponding fluid flow, but never to the air. At least in some embodiments, the cooling does not concern radiant/floor cooling.

At least in some embodiments, the counter fluid flows through a solid-state energy conversion device of the heating/cooling module allow small temperature differences between the hot and cold sides of each solid-state energy conversion device of the heating/cooling module, allowing the operation of the heating/cooling module at high energy efficiency.

At least in some embodiments, a temperature span can be obtained between the inlet and outlet of the heating/cooling module along the path of the fluid flow, by using multiple solid-state energy conversion devices along to the fluid path, and by maintaining small temperature differences between the hot and cold sides of each solid-state energy conversion device. Therefore, the solid-state energy conversion devices and, consequently, the heating/cooling module can operate with a high energy efficiency.

At least in some embodiment, the heating/cooling module can serve as the interface between a low temperature heat source (e.g. low temperature district heating, from heat production unit of the low temperature central hydronic heating), and a heating/cooling unit, such as a hydronic heating/cooling device. Therefore, the heating/cooling module is usually not integrated into the system as this is usually the case for a conventional integration of a heat pump. In the case of heating, the heating/cooling module preferably only serves to increase the temperature of the fluid (in the case of cooling to the decrease of the temperature) in order to provide a desired temperature level for a hydronic radiator or fan-coil heating/cooling, or HVAC, or heating the sanitary hot water.

Exemplary embodiments of the present invention are described in the following with reference to the accompanying drawings in which: Fig. 1 shows schematically a heating scenario of a heating/cooling module in accordance with an embodiment of the present invention which is arranged between a heating/cooling system and a heating/cooling unit;

Fig. 2 shows schematically a heating scenario of a heating/cooling module in accordance with another embodiment of the present invention which is arranged between a heating/cooling system and a heating/cooling unit;

Fig. 3 shows schematically a heating scenario of a heating/cooling module in accordance with yet another embodiment of the present invention which is arranged between a heating/cooling system and a heating/cooling unit;

Fig. 4 shows schematically a heating scenario of a heating/cooling module in accordance with still another embodiment of the present invention which is arranged between a heating/cooling system and a heating/cooling unit;

Fig.5 is a diagram of a heat flux rate from an individual exemplary radiator at nominal flow rate versus different supply temperatures (along the x-axis) and return temperatures (along the y-axis) for a heating scenario;

Fig.6 is a diagram for a heating scenario with solid-state energy conversion modules. The example shows temperature in “Celsius over a series of Peltier modules, which operate with an example of temperature difference of 5 K between the hot and cold side, the temperature levels of the Peltier modules and the temperature of the fluid flowing across the hot and cold side of the Peltier modules;

Fig. 7 is a diagram for a heating scenario with solid-state energy conversion modules. The example shows temperature in “Celsius over a series of Peltier modules, which operate with an example of temperature difference of 10 K between the hot and cold side, the temperature levels of the Peltier modules and the temperature of the fluid flowing across the hot and cold side of the Peltier modules;

Fig. 8 is a diagram for a heating scenario with solid-state energy conversion modules. The example shows temperature in “Celsius over a series of Peltier modules, which operate with an example of temperature difference of 20 K between the hot and cold side, the temperature levels of the Peltier modules and the temperature of the fluid flowing across the hot and cold side of the Peltier modules;

Fig. 9 is a diagram for a heating scenario with solid-state energy conversion modules. The example shows the coefficient of performance (COP) over the temperature difference in Kelvin for the temperature difference between the hot and cold side of Peltier modules and an equivalent electric heater, both being connected to a heating/cooling unit. We have considered three different second law efficiencies (i.e. exergy efficiencies) of a Peltier module (from 5 to 10 %), and the temperature of the heat sink being 70 °C.

Fig. 10 shows schematically a cooling scenario of a heating/cooling module in accordance with a further embodiment of the present invention which is arranged between a heating/cooling system and a heating/cooling unit;

Fig. 11 shows schematically an example where a heating module is used for heating of sanitary hot water in sanitary water heating unit;

Fig. 12 shows schematically another example where a heating module is used for heating of sanitary hot water in sanitary water heating unit;

Fig. 13 shows schematically an example of a solid-state energy conversion device, which comprises Peltier modules.

The heating/cooling module 11 shown in Fig. 1 connects a heating/cooling system 13 with one heating/cooling unit 15. The heating/cooling system 13, for example, can be a district heating/cooling system, a low temperature heat pump system, waste heat source, or renewable energy source. Other examples are given throughout the description.

The heating/cooling system 13 in the examples of Figs. 1 to 9 is a heating system 13 that serves for heating purposes. Correspondingly, the heating/cooling module 11 is a heating module 11 . Fig. 10 described further below addresses a cooling scenario, such that the heating/cooling system and the heating/cooling module described with regard to Fig. 10 is a cooling system and a cooling module, respectively.

The heating/cooling module 1 1 comprises a solid-state energy conversion device 17. With regard to the exemplary description of the figures, the solid-state energy conversion device 17 has a first side 19 which is configured to receive a fluid flow 23 that is preheated by the heating system 13, to heat the fluid flow 23 to a higher temperature while it flows through the first side 19 of the solid-state energy conversion device 17, and to use the fluid flow with the higher temperature 25 for providing heat to the heating unit 15.

The solid-state energy conversion device 17 has a second side 21 , which is configured to receive the fluid flow 27 after being used for providing heat to the heating unit 15, to cool the fluid flow 27 to a lower temperature and to reuse the fluid flow 29 with the lower temperature for preheating again by the heating system 13.

A solid-state energy conversion module assembly 18 can be arranged between the first side 19 and the second side 21 . The assembly 18 can include one or more modules. The solid-state energy conversion modules can for example be one of the following: Peltier modules, caloric heat pump modules, thermionic heat pump modules, spin-caloritronic heat pump modules, magneto-thermoelectric heat pump modules. For the example presented below, we mainly refer to Peltier modules.

In the embodiment of Fig. 1 , the heating module 11 and the heating unit 15 are connected to the heating system 13 such that there is a single loop of fluid flow. The heating module 1 1 comprises an inlet 31 for connecting an outlet of the heating system 13 to receive the fluid flow 23, at for example a temperature of 35°C, from the heating system 13. A valve 33, which can be an element of the heating module 1 1 or the heating system 13, can be arranged to be able to close the fluid flow, for example in case of an emergency or repair.

The fluid flow 23 passes through the first side 19 of the heating module 13. The first side 19 comprises a fluid passage for the fluid flow through the first side 19. In the heating module 1 1 , the fluid flow is heated to the higher temperature, for example to 55°C. The fluid flow 25 with the higher temperature is provided to the heating unit 15. An outlet 35 of the heating module 11 is connected to an inlet of the heating unit 15. The fluid flow 25 can be directly provided to the heating unit 15. The fluid flow circulates in the heating unit 15 and exits at an outlet which is connected to a further inlet 37 of the heating module 11 . The fluid flow 27 re-enters the heating module 11 at a temperature of about 45°C, for example. The fluid flow 27 passes through a fluid passage, which extends through the second side 21 , where the fluid flow is cooled to a lower temperature, for example 25°C. The fluid flow 29 with the lower temperature is provided back to the heating system 13 via an outlet 39 of the heating module 11 which is connected to an inlet of the heating system 13. The further valves 33, 41 , 43, 45 are arranged between inlets and outlets of the heating module 11 , heating system 13, and heating unit 15, respectively, as shown in Fig. 1 , and they serve to open or close the fluid loop as necessary.

The solid-state energy conversion device 17, comprising solid-state energy conversion module assembly 18, is configured to receive the preheated fluid flow 23 directly from the heating system 13, to provide the fluid flow 25 with the higher temperature directly to the heating unit 15, to receive the fluid flow back from the heating unit 15 where it has been cooled and to provide the fluid flow 29 with the lower temperature directly back to the heating system 13.

In some embodiments, the first side 19 comprises only a channel or multichannel which is configured such that the fluid flow 23 flows only through the channel or multichannel as one direction pass. The second side 21 comprises only a channel or multichannel which is configured such that the fluid flow 27 flows only through the channel or multichannel as one direction pass. Preferably, the fluid flow 23 through the first side 19 is directed in the opposite flow direction as the fluid flow 27 through the second side 21 .

Therefore, the first side 19 can be configured such that the fluid flow 23 through the first side 19 only flows once through the first side 19, and the second side 21 can be configured such that the fluid flow 27 through the second side 21 only flows once through the second side. The fluid flow 23 through the first side 19 can be directed in the opposite flow direction as the fluid flow 27 through the second side 21 . The valves 33, 41 , 43, and 45 can be arranged on a housing 47 of the heating module 11 . The housing 47 can house the solid-state energy conversion device 17. A power supply 49 can provide electric power to the solid-state energy conversion device 17, and a controller 51 can control operation of the solid-state energy conversion device 17. The power supply 49 also can provide electric power to valves and pumps. The controller 51 can also control the valves and pumps. Each of the power supply 49 and the controller 51 can be arranged in a separate housing or in the housing 47.

The heating module of Fig. 2 differs from the heating module of Fig. 1 in that the heating module 11 of Fig. 2 comprises a first heat exchanger 53, which allows decoupling the fluid flow of the heating system 13 from the fluid flow in the heating module 11 and the heating unit 15.

The heat exchanger 53 comprises a first fluid passage 54, which provides an inlet 31 for receiving a fluid flow 57 from the heating system 13 and an outlet 39 for providing the fluid flow 59 back to the heating system 13 after it has flown through the first fluid passage 54. Moreover, the first heat exchanger 53 has a second fluid passage 55 which is configured to output the fluid flow 23 that is preheated by the heat from heating system 13, for example to 30°C, and to receive the fluid flow 29 with the lower temperature, for example at 20°C. The first fluid passage 54 and the second fluid passage 55 are arranged such that heat is transferred from the fluid flow in the first fluid passage 54 to the fluid flow in the second fluid passage 55. Thus, the fluid flow 23 that is preheated by the heating system 13 is not directly provided by the heating system 13, but heated in the heat exchanger 53 via the fluid flow from the heating system 13.

The heating module 11 of Fig. 2 can comprise a fluid pump 61 to drive the fluid flow through the heating module 11 and through the heating unit 15. Although not shown in Fig. 1 , such a fluid pump could also be integrated into the fluid system of the heating module 17 of Fig. 1.

The heating module of Fig. 3 differs from the heating module of Fig. 2 in that the heating module of Fig. 3 further comprises a second heat exchanger 63, which allows decoupling the fluid flow of the heating module 17 from the fluid flow of the heating unit 15.

The solid-state energy conversion device 17, comprising solid-state energy conversion module assembly 18, is configured to receive the fluid flow 23 and to heat it. The solid-state energy conversion device 17 is further configured to provide the fluid flow 25 with the higher temperature to the second heat exchanger 63 which has a third fluid passage 65 which is configured to receive the fluid flow 25 with the higher temperature and to output the fluid flow 27 after being used for providing heat to the heating unit.

The second heat exchanger 63 has a fourth fluid passage 67, which is connected to outlet 35 for providing a fluid flow 69 to the heating unit 15, for example at 55 °C, and to inlet 37 for receiving the fluid flow 71 back from the heating unit after it has run through the heating unit 15 and, thus, cooled down, for example to 45 °C.

The third fluid passage 65 and the fourth fluid passage 67 are arranged such that heat is transferred from the fluid flow 25 with the higher temperature in the third fluid passage 65 to the fluid flow in the fourth fluid passage 67.

A fluid pump 73 can be arranged in the heating module 11 to drive the fluid flow through the heating module 11 , and in particular through the fourth fluid passage 67, and through the heating unit 15.

The heating module 101 shown in Fig. 4 interconnects a heating system 103, e.g. a DH system, a low temperature heat system, a low temperature heat pump system, waste heat source, or renewable energy source with a heating unit 105. The heating module 101 comprises a first heat exchanger 107 having a first fluid passage 109 with an inlet 111 for receiving a fluid flow 113 from the heating system 103 and an outlet 115 for providing the fluid flow 117 with a higher temperature to an inlet of the heating unit 105.

A solid-state energy conversion device 121 , comprising solid-state energy conversion module assembly 122, of the heating module 101 has a first side 123 which is configured to receive a fluid flow 127 from an outlet 131 of a second fluid passage 129 of the first heat exchanger 107, for example having temperature 50 °C, to cool the fluid flow to a lower temperature, for example to 20 °C, while it flows through the first side 123 of the solid-state energy conversion device 121 , and to provide the fluid flow 135 with the cooler temperature to an inlet 137 of a third fluid passage 139 of a second heat exchanger 141 .

The solid-state energy conversion device 121 has a second side 125, which is configured to receive the fluid flow 143 from an outlet 145 of the third fluid passage 139 of the second heat exchanger 141 and to heat the fluid flow to a higher temperature, for example 60 °C, while it flows through the second side 125, in particular through a fluid passage extending through the second side. The fluid flow 147 with the higher temperature is provided to an inlet 133 of the second fluid passage 129 of the first heat exchanger 107.

The second heat exchanger 141 comprises a fourth fluid passage 149 with an inlet 151 for receiving a fluid flow 155, for example at 35 °C, from the heating unit 105 and with an outlet 153 for providing the fluid flow 157 back to the heating system, for example at 25 °C.

The heating module 101 of Fig. 4 heats the incoming fluid flow 113, which is for heating example at 35 °C, while it passes through the first heat exchanger 107, to the fluid flow 117 with a higher temperature, for example 45 °C, which is provided to the heating unit 105. The fluid flow 155 from the heating unit 105, which is for example at 35 °C, is cooled down to 25 °C in the heating example and provided back to the heating system 103, see fluid flow 157.

The heating modules described above with regard to Figs. 1 to 4 enable the use of modern low temperature heating systems in conjunction with conventional heating units that are designed to operate in a higher temperature regime. Further advantages and benefits are described in the following.

For example, the thermal performance of a heating module connected or embodied to an e.g. individual radiator unit can be evaluated separately. First, the heat flux transferred from the radiator to ambient depends on nominal flow rate, supply and return temperature. For example, a radiator in Fig. 5 transfers 418 W of nominal heat flux at a nominal flow rate, a supply temperature of 55 °C, and a return temperature of 48 °C. If the supply temperature is decreased while maintaining the same fluid flow rate, the heat flux decreases accordingly. Reducing supply temperature from 55 to 45 °C results in 36 % lower heat flux or 67 % lower heat flux when decreasing from 55 to 35 °C.

Embodiments of the heating module can be used to raise the temperature of each individual radiator to a higher temperature to maintain the required comfort level in the room without radiator replacement.

Figs. 6, 7, and 8 show three exemplary cases, where multiple Peltier modules are used in a solid-state energy conversion module assembly. The Peltier modules are only an example. They are connected hydraulically in series. They are preferably connected electrically in parallel in preferred embodiments of the heating module. The supply and return temperatures from a heating system are 35 °C and 25 °C, while Peltier modules can raise the temperature to 55 °C before entering the radiator. This enables the radiator to transfer nominal heat flux.

The Peltier modules for example operate with 5 K (Fig. 6), 10 K (Fig. 7) and 20 K (Fig. 8) temperature difference between the hot and cold sides of the Peltier modules. Each graph shows the temperatures of the hot and the cold sides of Peltier modules and temperatures of fluid flowing across the hot and the cold sides. Fluid that flows across the hot and cold side of Peltier modules heats up to the temperature of individual Peltier module. An ideal heat transfer is considered in this evaluation. The temperature change between two neighbouring Peltier modules is set to half of the total temperature difference between the hot and cold side, which results in different number of required Peltier modules (i.e. 8 modules at 5 K, 4 modules at 10 K and 2 modules at 20 K). In each case, fluid inlet to the hot side of the Peltier modules assembly from the heating system heats up from 35 to 55 °C, while the outlet from the radiator that enters the cold side of Peltier modules assembly depends on the temperature difference of the case. Fig. 9 shows a COP, the maximum coefficient of performance, of two different devices that can be used to increase temperature level of working fluid before entering the radiator. One device is an electric heater, which heats the working fluid via resistance heating. The COP of an electric heater is therefore assumed to be equal to 1 . On the other hand, the COP is higher for a second device, which can be an embodiment of a heating module in accordance with the present invention. COP for heating mode of the latter device is calculated as a sum of absorbed heat of a Peltier modules assembly and input electric power to the Peltier modules assembly, divided by the input electric power to the Peltier modules assembly. Multiple Peltier modules operating with smaller temperature difference enable more energy efficient way of heating the fluid. We have considered three different second law efficiencies (i.e. exergy efficiencies) of a Peltier module (from 5 to 10 %), and the temperature of the heat sink being 70 °C. The COP was estimated for different temperature differences between the hot and cold side of Peltier modules inside the Peltier modules assembly. If the temperature difference between the hot and cold side is 12 K, COP is 4.3, whereas if the temperature difference is 36 K, COP is 1 .75.

The heating/cooling module 11 of Fig. 10 differs from the one of Fig. 1 in that the heating/cooling module 11 is used for cooling, and thus it is a cooling module. Correspondingly, the heating/cooling system 13 is a cooling system.

The solid-state energy conversion device 17, comprising solid-state energy conversion module assembly 18, shown in Fig. 10 has a first side 19 which is configured to receive a fluid flow 23 that is precooled by the cooling system 13, for example to about 12 °C. The solid-state energy conversion device 17 and in particular the first side 19 is further configured to cool the fluid flow 23 to a lower temperature (here to 7 °C) while it flows through the first side 19 of the solid-state energy conversion device 17, and to use the fluid flow with the lower temperature 25 for providing cold to the cooling unit 15.

The second side 21 of the solid-state energy conversion device 17 is configured to receive the fluid flow 27 after being used for providing cold to the cooling unit 15 (here with a temperature of about 13 °C), to heat the fluid flow 27 to a higher temperature (here to about 18 °C) and to reuse the fluid flow 29 with the higher temperature for precooling again by the cooling system 13.

Correspondingly, the heating modules as described with regard to Figs. 2 to 4 in conjunction with a heating system could be used as cooling modules and could be operated in conjunction with a cooling system.

As described before, embodiments of a heating module in accordance with the invention can be used to raise the temperature of a fluid provided to an individual standard or old-type radiator to a higher temperature to obtain a desired comfort level in a room without radiator replacement. Correspondingly, embodiments of the cooling module in accordance with the invention can be used to lower the temperature of a fluid provided to an individual standard or older-type cooling unit to obtain a required comfort level, in particular during hot summer days, in a room without the need for a replacement of the cooling unit.

In a particular case, the embodiments of a heating module in accordance with the invention can be used to raise the temperature of a sanitary water. In this particular case, the heating/cooling unit can represent a storage of the sanitary hot water.

The heating module can be used for heating of sanitary hot water in sanitary water heating unit, as given in the example of Fig. 11 . As for example the heating module 11 of Fig. 11 comprises a first heat exchanger 53, which allows decoupling the fluid flow of the heating system 13 from the fluid flow in the heating module 11 and the sanitary hot water heating unit 16.

The heat exchanger 53 comprises a first fluid passage 54, which provides an inlet 31 for receiving a fluid flow 57 from the heating system 13 and an outlet 39 for providing the fluid flow 59 back to the heating system 13 after it has flown through the first fluid passage 54. Moreover, the first heat exchanger 53 has a second fluid passage 55 which is configured to output the fluid flow 23 that is preheated by the heat from heating system 13, for example to 30 °C, and to receive the fluid flow 29 with the lower temperature, for example at 20 °C. The first fluid passage 54 and the second fluid passage 55 are arranged such that heat is transferred from the fluid flow in the first fluid passage 54 to the fluid flow in the second fluid passage 55. Thus, the fluid flow 23 that is preheated by the heating system 13 is not directly provided by the heating system 13, but heated in the heat exchanger 53 via the fluid flow from the heating system 13.

The heating module 11 of Fig. 11 can comprise a fluid pump 61 to drive the fluid flow through the heating module 11 and through the sanitary hot water heating unit 16. The sanitary hot water heating unit comprises sanitary cold water inlet 56 and sanitary hot water outlet 58.

Another example for heating the sanitary hot water via the heating module is shown in the Fig. 12.

The heating module of Fig. 12 differs from the heating module of Fig. 11 in that the heating module of Fig. 12 further comprises a second heat exchanger 63, which allows decoupling the fluid flow of the heating module 17 from the fluid flow of the sanitary hot water heating unit 16.

The solid-state energy conversion device 17, comprising solid-state energy conversion module assembly 18, is configured to receive the fluid flow 23 and to heat it. The solid-state energy conversion device 17 is further configured to provide the fluid flow 25 with the higher temperature to the second heat exchanger 63 which has a third fluid passage 65 which is configured to receive the fluid flow 25 with the higher temperature and to output the fluid flow 27 after being used for providing heat to the sanitary hot water heating unit.

The second heat exchanger 63 has a fourth fluid passage 67, which is connected to outlet 35 for providing a fluid flow 69 to the top part of the sanitary hot water heating unit 15, for example at 55 °C, and to inlet 37 for receiving the fluid flow 71 back from the sanitary hot water heating unit from the bottom part of the sanitary hot water heating unit 15 and, thus, cooled down, for example to 45 °C. The third fluid passage 65 and the fourth fluid passage 67 are arranged such that heat is transferred from the fluid flow 25 with the higher temperature in the third fluid passage 65 to the fluid flow in the fourth fluid passage 67.

A fluid pump 73 can be arranged in the heating module 11 to drive the fluid flow through the heating module 11 , and in particular through the fourth fluid passage 67, and for the circulation of the water from the sanitary hot water heating unit 16.

The sanitary hot water unit comprises sanitary cold water inlet 56 and sanitary hot water outlet 58.

A component of a heating/cooling module in accordance with the present invention is a solid-state energy conversion device. An example of a solid-state energy conversion device is shown schematically in Fig. 13.

At least in some embodiments, the solid-state energy conversion device can have an arrangement of one or more solid-state energy conversion modules 183. The solid- state energy conversion modules 183 can be arranged side by side and all can face upwards. A first fluid flow 179 is arranged along a top surface of solid-state energy conversion modules 183 and a second fluid flow 181 is arranged along a bottom surface of solid-state energy conversion modules.

Each of the solid-state energy conversion modules 183 comprises several solid-state energy conversion elements. In an example of Peltier element, heat is transported from cold to hot side by the thermoelectric effect or Peltier effect which arises when a direct electric current flows through two oppositely doped (N and P-doped) semiconducting materials with different Peltier coefficients. The Peltier elements in Peltier module 183 are preferably electrically connected in series and thermally in parallel. Therefore, one surface heats up and the other cools down. If the direction of electric current is switched, the hot and cold sides of a Peltier module also change.

A solution for the increase (in case of a heating scenario) or decrease (in case of a cooling scenario) of the temperature of the working fluid supplied to a heating/cooling unit using embodiments of a heating/cooling module in accordance with the present invention has been described. The heating/cooling modules are environmentally friendly, as no harmful refrigerants with global warming potential or ozone depletion potential are used, and more energy efficient than equivalent electric heaters. The operating conditions of thermoelectric devices that include Peltier modules enable operation of Peltier modules with a small temperature difference between the hot and cold side, which increases their COP as shown for example in Fig. 9. Therefore, the expected operation can be up to several times more energy efficient than by using a conventional electric heater. Other solid-state energy conversion devices can be used instead of thermoelectric devices that include Peltier modules.

List of Reference Signs

11 heating/cooling module

13 heating/cooling system

15 heating/cooling unit

16 sanitary hot water heating unit

17 solid-state energy conversion device

18 solid-state energy conversion module assembly

19 first side

21 second side

23 fluid flow

25 fluid flow

27 fluid flow

29 fluid flow

31 inlet

33 valve

35 outlet

37 inlet

39 outlet

41 valve

43 valve

45 valve

47 housing

49 power supply

51 controller

53 first heat exchanger

54 first fluid passage

55 second fluid passage

56 sanitary cold water inlet

57 fluid flow

58 sanitary hot water outlet

59 fluid flow

61 fluid pump

63 second heat exchanger

65 third fluid passage

67 fourth fluid passage

69 fluid flow

71 fluid flow

73 fluid pump

101 heating/cooling module

103 heating/cooling system

105 heating/cooling unit

107 first heat exchanger

109 first fluid passage inlet fluid flow outlet fluid flow inlet solid-state energy conversion device solid-state energy conversion module assembly first side second side fluid flow second fluid passage outlet inlet fluid flow inlet third fluid passage second heat exchanger fluid flow outlet fluid flow fourth fluid passage inlet outlet fluid flow fluid flow fluid pump power supply controller fluid flow first fluid flow second fluid flow solid-state energy conversion module first side second side