NL1041201B1

NL1041201B1 - Renewable energy system.

Info

Publication number: NL1041201B1
Application number: NL1041201A
Authority: NL
Inventors: Wilhelmus Antonius Cornelis Bloks Theodorus
Original assignee: Wilhelmus Antonius Cornelis Bloks Theodorus; Paul Theodorus Johannus Andreas Bloks
Priority date: 2015-02-20
Filing date: 2015-02-20
Publication date: 2016-10-12

Abstract

A system for providing renewable energy, compnsmg a solar thermal collector, a distribution circuit for transporting the heat transport medium from the solar thermal collector to a heat storage and returning the return heat transport medium from the heat storage to the solar thermal collector, a heat exchanger and one or more circulating pumps. A heat pump is arranged for using waste heat of the returned heat transport medium and a mixer is arranged for mixing heat transport medium which has been cocled down by the heat pump, with the returned heat transport medium. The mixer is further arranged for diverting the mixed heat transport medium towards the heat pump. The system further cernprises a by-pass, arranged fora diversion of the heat transport medium which has left the solar thermal collector, towards the solar thermal collector before the heat transport medium enters the heat storage.

Description

RENEWABLE ENERGY SYSTEM

TECHNICAL FIELD

The present invention relates generally to renewable energy systems using solar heat and, more particularly, to a renewable energy system having a heat storage apparatus which stores high-temperature heat energy, obtained from solar energy, in a heat storage so that the stored energy can be used as a stable energy source.

BACKGROUND

Energy systems depending on the presence of sun light deliver most energy during day time. After sun set, however, the demand for energy in especially households remains or is even higher than during daytime when there is already a higher outside temperature and in the case of people having a daytime job, consequently less demand for energy. To solve this discrepancy between the moment of energy supply and energy demand, several heat storage systems have been proposed. One example is described in USA patent application US2012085093A1, which discloses a hybrid renewable energy system having an underground heat storage apparatus. A solar collector is provided on or around a building structure and collects solar heat to heat a heat medium. A transfer pipe transfers the heat medium, heated by the solar collector, into the underground. The heat storage apparatus stores heat received from the heat medium and heats, using the stored heat, both cold water supplied from the building structure through a supply pipe and air supplied from an inlet duct. A return pipe returns the heat medium from the heat storage apparatus to the solar collector. An inlet pipe supplies hot water produced by the heat storage apparatus to the building structure. A connection duct supplies air heated by the heat storage apparatus into the building structure to heat the room of the building structure.

Heat pipes are known form patent applications such as described in UK patent application GB2103350A, which discloses a solar collector comprises a radiationabsorbing plate and at least one metal tube for containing a heat transfer medium, the plate being in thermal contact with the tube and being enclosed within a radiation transparent glass envelope sealed in vacuum-tight fashion, through a metal collar, to said tube; wherein the collar is of a generally truncated conical shape, the smaller diameter end being seated around the periphery of the metal tube, and the larger diameter end being sealed to the glass envelope, and wherein the thickness of the collar reduces at the larger diameter end portion to terminate in a knife edge and the glass is sealed to the inside of said portion.

Assemblies which enables the combination of multiple heat pipes are also known. One example is described in UK patent application GB2449766A, which discloses a solar collector which comprises at least one elongate tube for absorbing solar radiation and transferring heat to a fluid, and an end fitting providing a fluid connection. The end fitting is connectable to a corresponding end fitting of an adjacent elongate member to permit the passage of fluid between the end fittings without requiring a separate manifold. The end fittings have a seal for engaging the passageways of adjacent end fittings, where the end fitting may be provided with a circumferential groove or recess for receiving an O-ring seal. Preferably, the solar collector is of the direct flow type and comprises a solar absorbing tube containing the elongate tube, which further contains a concentrically positioned inner pipe, to form two concentric internal flow passage ways, for the flow of a fluid to be heated. Preferably, an annular outer passageway communicates with an end fitting cold fluid inlet conduit and the inner passageway communicates with an end fitting hot fluid outlet conduit. A central wall may divide the end fitting into the cold fluid inlet conduit and the hot fluid outlet conduit. In use, the end fittings are interconnected to provide fluid flow paths without the need for a manifold, where any number of solar collector tubes may be connected in this way. A disadvantage of the current art solutions is that the source of the heat storage is either disruptive to the environment, such as in the case of underground heat storage, and/or requires a relatively large amount of additional electrical energy to power the various pumps, such as heat pump and circulation pumps. This reduces the Coefficient Of Performance considerably.

DISCLOSURE OF INVENTION

It is an object of the present invention to provide an environmental friendly, renewable energy system which enables an improved efficiency. It is a further object of the invention to provide a renewable energy system which capable of supplying the full demand of a household with respect to heating up a house and tap water, without or at least with considerable less need for additional conventional heat sources such as electrical heaters, or the burning of fossil fuels and gas.

The object is realized by a system for providing renewable energy, comprising: a solar thermal collector comprising one or more solar collectors provided on a building structure or in a vicinity of the building structure, the solar thermal collector arranged for collecting solar radiation to heat a heat transport medium; a first distribution circuit for transporting the heat transport medium from the solar thermal collector to a heat storage and returning the return heat transport medium from the heat storage to the solar thermal collector; a first heat exchanger for transferring the heat of the heated transport medium to a heat storage medium in the heat storage; one or more circulating pumps for enabling the transporting if the heat transport medium in the first distribution circuit, wherein the system further comprises that: a heat pump is arranged for using waste heat of the returned heat transport medium, a mixer is arranged for mixing heat transport medium which has been cooled down by the heat pump, with the returned heat transport medium; the mixer is further arranged for diverting the mixed heat transport medium towards the heat pump. the system further comprises a by-pass, arranged for a diversion of the heat transport medium which has left the solar thermal collector, towards the solar thermal collector before the heat transport medium enters the heat storage, said diverted heat transport medium comprising the returned heat transport medium; the by-pass is arranged for executing the diversion under the condition that the heat transport medium transported from the solar thermal collector is equal to or lower than the temperature of the heat storage medium in the heat storage

Further embodiments may comprise the following:

The system further comprises a T-piece arranged for allowing flow of the heat transport medium which has been cooled down by the heat pump towards the mixer device, and arranged for allowing the returned heat transport medium to the solar thermal collector. A second distribution circuit is arranged for distributing tap water, said second distribution circuit comprising a second heat exchanger for transferring heat from the heat storage medium to the second distribution circuit. A third distribution circuit is arranged for distributing process water of a central heating system, said third distribution circuit comprising a third heat exchanger for transferring heat from the heat storage medium to the third distribution circuit, or a direct connection to the heat storage, whereby the heat storage medium is arranged for being used as process medium for the third distribution circuit.

The first, second and/or third heat exchanger comprises a heat exchanger of the group comprising: a plate heat exchanger; a spiral heat exchanger; a phase change heat exchanger; a waste heat recovery unit.

The heat pump is arranged for using a refrigerant such as R410a or R134a.

The heat storage apparatus comprises a tank which is at least partly filled with a Phase Change Material.

The system further comprises a buffer tank arranged for storing thermal energy from the system if the availability of thermal energy in the heat storage is greater than the demand for thermal energy or if the temperature of the returned heat transport medium exceeds a threshold, and arranged for supplying thermal energy to the heat storage when the demand for thermal energy is greater than the availability of thermal energy or if the temperature of the returned heat transport medium is below a threshold.

The buffer tank is at least partly filled with the Phase Change Material.

The Phase Change Material has a phase change temperature in the range of 20-25 oC.

The Phase Change Material is encapsulated in one or more separate plastic containers such as round or rounded containers having a diameter in the range of 25-35 mm.

The system further comprises a thermodynamic apparatus, arranged for producing electricity from heat produced by the system.

The heat produced by the system comprises any one of the group comprising: heat of the first, the second or the third distribution circuit; heat of the heat transport medium; heat of the heat storage medium; heat of the process medium; heat of the heat storage; heat of waste tap water of the second distribution circuit.

The energy used for operating the heat pump and/or the one or more circulating pumps is provided by a renewable energy system which produces electricity.

The system comprises one or more additional heat storage devices arranged for the purpose of any of the group comprising: increased heat storage capacity; faster heating of the heat storage medium; connection the second and/or third distribution circuit.

The system comprises a control unit, arranged for controlling the system, said control unit comprising self-learning software, which processes input parameters of the group comprising: meteorological data; temperature, volumetric flow, and/or pressure values as measured by sensors arranged in the system; temperature, pressure, and/or humidity values as measured by sensors in or surrounding a building which is heated by the system; data relating to a weather forecast, such as expected Ultra Violet values.

The control unit is further arranged for downloading and/or uploading the gathered input data.

BRIEF DESCRIPTION OF THE DRAWINGS

The figures show views of embodiments in accordance with the present invention. FIGURE 1 shows a diagram of an embodiment of the invented renewable energy system.

DETAILED DESCRIPTION

The invention is now described by the following aspects and embodiments, with reference to the figures. FIGURE 1 shows a diagram of the elements of the first distribution circuit of the invented renewable energy system 100. The thick limes represent the pipes for transporting a heat transport medium. A preferred heat transport medium is a distilled water/glycol mixture, preferably with a mix of 58-60% water and 40-42% glycol. Hereinafter, for the purpose of readability, the heat transport medium is therefore referred to as “glycol”, unless named otherwise. The open triangles point towards the direction of the glycol. The smaller arrows with plain points are used for the purpose of further explanation. Functional devices are represented as functional blocks using thinner lines.

The working principle of the present invention is as follows.

Solar thermal collector 200 heats up glycol passing the heat pipe tips. The solar thermal collector comprises at least one elongate tube 201 for absorbing solar radiation and transferring heat to a fluid, and an end fitting providing a fluid connection. The end fitting is connectable to a corresponding end fitting of an adjacent elongate member 204 to permit the passage of glycol which enters as relative cold glycol through pipe 510 through the inlet 203 and leaves as heated glycol from outlet 202 towards pipe 501. Cold glycol is pumped though the system back to the solar collector by circulating pump 605. The heated glycol is transported through pipe 501 to heat storage 300, which is preferably a double-walled and isolated tank filled with a heat storage medium such as water to which an additional heat storage medium such as Phase Change Material may be added. When the heated glycol enters heat storage 300, it has a temperature T1 at point 302. Through piping system 301, which runs through heat storage 300, the heat of the heated glycol is transferred to relative colder heat storage medium in the heat storage 300. As the glycol runs through the piping system 301, the glycol transfers heat to the heat storage medium in heat storage 300 and the glycol cools down to temperature T3 at point 304.

The heat storage medium may comprise water. Additionally a second heat storage medium may be added to heat storage 300. One preferred heat storage medium comprises Phase Changing Material (PCM). The PCM may be added to heat storage 300 as such or encapsulated in plastic balls. Preferable the plastic balls are of a size in the range of 25-35 mm and change phase in a temperature range of 20-25 °C. More preferably the plastic balls have diameter of 30 mm and the change phase temperature is 22 °C.

In order to prevent the plastic balls 314 to melt, a basket 315 is provided which separates the balls 314 from the piping system 301. The temperature in the piping system 301 may rise far above 130 oC under certain conditions, such as a very sunny day.

To ensure that the temperature T2 at point 303 (which is at a point right after 302) is at a desirable temperature, even when solar thermal collector 200 does not provide sufficient heating of glycol through pipe 501, a heat pump 600 is configured for supplying additional heat through pipe 506 to a heat exchanger (not shown) coupled to heat storage 300. This is further explained as follows. The temperatures mentioned are examples.

The temperatures T1, T2 and T3 may also be measured at 311, 312 and 313 respectively.

Typically, the desired temperature of the heat storage medium, as measured in the upper half of the heat storage, is 62-65 °C. In order to reach this temperature, heat pump 600 adds heat to the heat storage only when necessary and until the temperature of the heat storage medium is at the desired level of 62-65 °C. In this way relatively high temperature heat storage is available for heating up tap water (such as drinking water or bathing water) in a separate piping system of a second distribution circuit for providing the tap water (not shown).

This high temperature heat storage also provides the possibility to add a third distribution circuit arranged for a central heating system to the renewable energy system, wherein process medium (such as water) of the radiators of the central heating system is heated to a desirable operating temperature of approximately 60-85°C. The process medium of the central heating system may be separated from the heat storage medium of the renewable energy system, and heated through a piping system embedded in the upper half of heat storage 300. Alternatively the fluid part of the heat storage medium comprised in the heat storage 300 may be used as process medium for the central heating system.

Preferably separated piping systems of the second and/or third distribution circuits are configured as a spiral running through the heat storage medium in the heat storage 300.

The heat pump uses waste heat of the glycol which has passed the heat storage 300. Typically the glycol having a temperature T1=62 °C at point 302 is cooled down to 55 °C at point 304 after transferring heat to the heat storage medium. The heat pump 600 preferably comprises an evaporator 601, a condenser 602 and a compressor 603. The heat pump 600 uses the lower temperature of the heat storage medium in the lower half of the heat storage for the operation of the condenser 602. The evaporator 601 uses the return glycol through pipe 502 which is cooled down by mixing glycol which is cooled down by the evaporator. For example 20% of the return glycol is used for the evaporator 601, whereas in this case 80% of the cold glycol as delivered by the evaporator 601 is used in order to deliver glycol at a desired temperature for the evaporator 601. The following is a typical example.

Return glycol in pipe 502 has a temperature of 55 °C. In three-way valve 405 (part of the mixer) the return glycol is partially (20%) redirected towards the evaporator 601. Cold glycol (12 °C) is supplied by the evaporator to the solar thermal collector 200 through pipe 505, T-piece 407 and pipe 508. T-piece 406 allows this cold glycol in pipe 508 to be diverted towards evaporator 601, successively through pipe 509, three-way valve 405, pipe 503, three-way valve 404 (part of the mixer) and pipe 504. Three-way valve 405 mixes the glycol entering from pipe 509 (cold glycol), as indicated with arrow 509a with the glycol entering from pipe 502 (warm glycol), as indicated with arrow 509b, in a ratio wherein cold glycol is 80% and warm glycol is 20%. In terms of flow this means that warm glycol has a volumetric flow rate of 5 L/min, whereas cold glycol has a flow rate of 20 L/min. In order to achieve the desired mixing ratio of cold glycol and warm glycol, glycol is diverted in T-piece 406 from 0-100% (diversion is indicated with arrow 508a) of the glycol from pipe 508 towards pipe 509. The level of diversion depends on differences in pressure in pipe 510 and pipe 509. A lower pressure in pipe 509 results in more volumetric flow in pipe 509. Three-way valve 404 (by-pass device and part of the mixer) is arranged for redirecting the glycol coming from the three-way valve 405 towards the heat pump 402, if sufficient temperature difference is available between the glycol leaving the evaporator 601 and glycol entering the evaporator 601. The combination of three-way valve 405 and three-way valve 404 functions therefore as mixer. When activation of the heat pump is not necessary, three-way valve 404 directs the glycol of pipe 503 to pipe 507. From pipe 507 the glycol is then further directed via T-piece 407 to pipe 508.

The condenser 602 of the heat pump 600 is part of a closed circuit filled with a heat transport medium comprising a refrigerant such as R410A or R134A. Heat is transferred from the heat storage medium in heat storage 300 to the heat transport medium via a heat exchanger (not shown). The heat transport medium flows through pipe 506 to the heat storage 300 and returns through pipe 511 tot the condenser 602. The heat transport medium is pumped around by circulating pump 604. The circulating pump 604 may be arranged for being regulated from preferably 20% to 100% of its capacity. Typically 100% comprises a volumetric flow rate of 25 L/min.

In order to increase energy efficiency as much as possible and/or to prevent cooling down of the storage medium, by-passes are provided.

One proposed by-pass comprises three-way valve 408 which diverts the flow of glycol towards T-piece 411 as soon as it is measured that the temperature of the heat transport medium is lower than the temperature of the heat storage medium in heat storage 300.

Another by-pass is provided at T-Piece 412, which allows the flow of pipe 506 to be diverted through pipe 520 towards three-way valve 413. Three-way valve 413 directs the heat transport medium coming from the condenser 602 of heat pump 600 immediately to the inlet of the condenser 602 in the case that the heat transport medium in pipe 506 has a lower temperature than the heat storage medium in heat storage 300.

The system may further comprise a buffer tank 320 arranged for storing thermal energy from the system when for example the availability of thermal energy in the heat storage 300 is greater than the demand for thermal energy or if the glycol in pipe 502 is above a certain threshold (which may be measured at point 313 or 304). The buffer tank 320 is further arranged for supplying thermal energy to the heat storage 300, when for example the demand for thermal energy is greater than the availability of thermal energy or when the temperature of glycol in pipe 502 is below a certain threshold. This adds to a balanced system which is less dependent of sunny weather and fluctuating demands for thermal energy. The buffer tank 320 is part of a by-pass system wherein heat is stored in the buffer tank as defined by the logic of the control unit of the system. This logic determines if the buffer tank should be stored with energy or not, in dependence of the current amount of heat stored in the buffer tank 320, the current heat stored in heat storage 300, the current demand of thermal energy and/or the expected demand of thermal energy. The expected demand of thermal energy may be defined by the logic of the control unit based on pre-set algorithms or self-learning algorithms.

The flow of glycol in pipe 502 coming from the heat storage 300 may be diverted through three-way valve 409 and pipe 517 towards buffer tank 320. From buffer tank 320 the glycol is lead back in pipe 502 through pipe 518 and three-way valve 410. In the buffer tank 320 the heat is transferred from the glycol to a heat storage medium in buffer tank 320. The buffer tank 320 may be filled with PCM as heat storage medium, preferably encapsulated in plastic balls 321 having a diameter of 30-35 mm. More preferably these balls are 30 mm in diameter. The PCM balls may be submerged in water or another fluid in order to transfer the heat of the glycol running through the buffer tank to the PCM balls. As the buffer tank 320 uses waste heat of the return flow of the glycol, the buffer tank is typically a low temperature buffer. The dimension of the buffer tank may be kept relatively small because the PCM increases the capacity of heat storage considerably. An increase with a factor six is achievable, which means that a buffer tank of 100 L completely filled with PCM has the same heat storage capacity as a 600 L tank filled with just water.

Additionally, extra heat storage devices may be connected to the first distribution circuit. The heat storage devices may be configured to increase the heat storage capacity in general. The additional heat storage may also comprise a smaller heat storage, with a smaller volume of heat storage medium arranged for being heated faster.

The additional heat storage may also comprise a different heat storage medium, with different characteristics. The additional heat storage may also be dedicated for heating the second or third distribution circuit.

The energy for operating the compressor 603 of heat pump 402, the circulating pump 604 and/or the circulating pump 605 is optionally provided by an additional renewable energy system or other thermodynamic apparatus which provides electricity, such as a photo-voltaic solar power system or a wind energy system. As back up, the pumps 604,600,605 may be powered by mains supply.

As input for the algorithms of the logic running in the control, various data may be used. On the one hand one or more sensors may be integrated in the system. For example the temperature at points at the upper half of the heat storage medium (e.g. points 302 and 311), half way the heat storage medium (e.g. points 303 and 312) and at the lower half of the heat storage medium (e.g. points 304 and 313) maybe measured by installed temperature sensors, connected to the control. Other input data may comprise temperature sensed by external sensors around the house or on the roof, internal sensors in one or more rooms in the house, temperature sensors in the solar thermal collector, other parts of the system and other distribution circuits connected to the system.

Besides temperature sensors, other sensors may be applied such as pressure sensors for measuring pressure such as the air pressure within the house, or for measuring the pressure of the heat transport medium, the heat storage medium in the system or the various pumps that are used in the system etcetera.

The control unit may be connected to the internet and gather data such as weather reports and forecasts. The control unit may also be arranged to upload its data to a central database connected to the system. Other systems may be connected to this database and thus form a network of information sources and information users.

With this connected network the system may be enabled for example to assess its own performance in comparison with similar systems in the same climate conditions.

By using all these input data the control unit may be arranged to be self-learning, and improve its COP and general performance. It may also improve its ability to provide sufficient heat at any time of the day when the inhabitants need hot water. Eventually the system is balanced optimally with the proposed logic and control, able to provide sufficient energy to e.g. a household to be independent of delivery of natural gas.

The control unit may be accessed and the system status may be displayed using e.g. an App on a mobile phone, which is connected to the system through Internet or directly by Wi-Fi. In the case of a Wi-Fi connection, a Wi-Fi communication module may be connected to the control.

The term "substantially" herein, such as in "substantially ..." etc., will be understood by the person skilled in the art. In embodiments the adjective substantially may be removed. Where applicable, the term "substantially" may also include embodiments with "entirely", "completely", "all", etc. Where applicable, the term "substantially" may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, including 100%. The term "comprise" includes also embodiments wherein the term "comprises" means "consists of.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The term "and/or" includes any and all combinations of one or more of the associated listed items. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The article "the" preceding an element does not exclude the presence of a plurality of such elements. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

A system for supplying sustainable energy, comprising: - a solar heat collector comprising one or more solar collectors provided on a building or in the vicinity of the building, the solar heat collector adapted to collect solar radiation to store a heat transfer medium warm up; - a first distribution circuit for transporting the heat transport medium from the solar heat collector to a heat storage and returning the heat transport medium from the heat storage to the solar heat collector; - a first heat exchanger for transferring heat from the heated heat transport medium to a heat storage medium in the heat storage; - one or more circulation pumps for enabling transport of the heat transport medium, characterized in that, "N the system further comprises that: - a heat pump is arranged for using waste heat from the returned heat transport medium; mixer is adapted to mix the heat transfer medium cooled by the heat pump with the returned heat transfer medium, - the mixer is further adapted to divert the mixed heat transfer medium to the heat pump; comprises a diversion adapted to divert heat transfer medium that has left the solar heat collector to the solar heat collector before the heat transfer medium enters heat storage, said diverted heat transfer medium comprising the reduced heat transfer medium; arranged for performing the diversion under the condition that the temperature of the heat transport medium transported from the solar heat collector is equal to or lower than the temperature of the heat storage medium in the heat storage.

The system according to claim 1, characterized in that the system further comprises a T-piece adapted to allow a flow of the heat transfer medium that was cooled by the heat pump to the mixer, and adapted to allow a flow from the heat transfer medium to the solar heat collector.

The system according to any of the preceding claims, characterized in that a second distribution circuit is arranged for distributing tap water, said second distribution circuit comprises a second heat exchanger for transferring heat from the heat storage medium to the second distribution circuit.

The system according to any of the preceding claims, characterized in that a third distribution circuit is arranged for distributing process medium from a central heating system, said third distribution system comprising a third heat exchanger for transferring heat from the heat storage medium to the third distribution circuit, or comprising a direct connection to the heat storage, wherein the heat storage medium is adapted to be used as a process medium for the third distribution circuit.

The system according to any one of the preceding claims, characterized in that the first, second and / or third heat exchanger comprises a heat exchanger of the group comprising: - a plate heat exchanger; - a spiral heat exchanger; - a phase change heat exchanger; - a waste heat recovery unit.

The system according to any one of the preceding claims, characterized in that the heat pump is adapted to use a coolant such as R410a or R134a.

The system according to any of the preceding claims, characterized in that the heat storage comprises a tank that is at least partially filled with a phase change material.

The system according to any one of the preceding claims, characterized in that the system further comprises a buffer tank adapted to store heat energy from the system, if the availability of heat energy in the heat storage is greater than the demand for heat energy or if the temperature of the returned heat transfer medium exceeds a limit value, and adapted to supply heat energy to the heat storage if the demand for heat energy is greater than the availability of heat energy or if the temperature of the returned heat transfer medium is lower than a limit value.

The system according to any of the preceding claims, characterized in that the buffer tank is at least partially filled with phase-change material.

The system according to any one of the preceding claims, characterized in that the phase change material has a phase change temperature in the range of 20-25 ° C.

The system according to any of the preceding claims, characterized in that the phase change material is encapsulated in one or more separate plastic containers such as round or rounded containers with a diameter in the range of 25-35 mm.

The system according to any of the preceding claims, characterized in that the system further comprises a thermodynamic device adapted to produce electricity from heat produced by the system.

The system according to any one of the preceding claims, characterized in that the heat produced by the system comprises one of the group, comprising: - heat from the first, the second or the third distribution circuit; - heat from the heat transfer medium; heat from the heat storage medium; - heat from the process medium; - heat from the heat storage; - heat from tap water waste from the second distribution circuit.

The system according to any of the preceding claims, characterized in that the energy used for the operation of the heat pump and / or the one or more circulation pumps is provided by a sustainable energy system that produces electricity.

The system according to any one of the preceding claims, characterized in that the system comprises one or more additional heat storage devices adapted for the purpose from one of the group comprising: - increased heat storage capacity; - accelerated heating of the heat storage medium; - connection to the second and / or third distribution circuit.

The system according to any one of the preceding claims, characterized in that the system comprises a control unit adapted to control the system, said control unit comprising self-learning software, which input data comprises from the group comprising: - meteorological data; - temperature, volume flow and / or pressure values as measured by sensors installed in the system; - temperature, pressure and / or humidity values as measured by sensors in or around a building that is heated by the system; - data related to a weather forecast, such as expected Ultra Violet values.

The system according to any one of the preceding claims, characterized in that the control unit is further adapted to download or upload the collected input data.