WO2010102640A1

WO2010102640A1 - Hybrid thermal energy systems and applications thereof

Info

Publication number: WO2010102640A1
Application number: PCT/EP2009/001676
Authority: WO
Inventors: Elias Nomikos; Nikos Manioudakis; Dimitris Tolias
Original assignee: Sol Energy Hellas S.A.
Priority date: 2009-03-09
Filing date: 2009-03-09
Publication date: 2010-09-16

Abstract

The present invention provides a hybrid thermal energy system for heating and/ or cooling applications comprising solar collection means for transferring heat energy to a heat transfer fluid, thermal upgrading means for increasing the thermal energy within the system such as a heat pump and thermal storage means.

Description

HYBRID THERMAL ENERGY SYSTEMS AND APPLICATIONS THEREOF

TECHNICAL FIELD OF THE INVENTION

The present invention relates to improved thermal energy systems and more particularly to hybrid thermal energy systems such as solar assisted heat pump systems and the applications thereof for heating and/or cooling systems and hot water production in domestic, commercial or industrial buildings.

BACKGROUND OF THE INVENTION Solar assisted heat pumps (S.A.H.P.) are known to be able to provide a useful source of thermal energy due to a significant reduction in carbon dioxide emissions.

A typical solar assisted heat pump system comprises at least one collector for absorbing solar energy and an energy converter in the form of a heat pump to upgrade the energy to be used in for example space heating and hot water applications. The success of solar assisted heat pump systems is dependent upon installation costs and operating efficiency. A solar assisted system is merely dependent upon the climatic conditions and the day to day weather changes. Thus, a solar assisted system cannot operate in a steady state mode and the system has to be optimised for all weather conditions, so as to be a reliable and efficient system for all year round use.

Moreover, the use of a heat pump poses an additional complication, since the efficiency of the collectors generally decreases with increasing collection temperatures. In contrast the coefficient of performance (COP) of a heat pump is generally inversely proportional to the temperature lift provided by the heat pump. A lower collection temperature requires a greater temperature lift by the heat pump and so there is a constant balance that needs to be struck to maintain suitable operating efficiency.

A similar situation exists in the cooling mode when the heat pump has to lower the temperature in a low temperature level by transferring energy to a high temperature level. The cooled heat transfer fluid can then be used for cooling applications. Excess heat in the high temperature level can be radiated via the collectors e.g. during the night when the ambient temperature is lower than the system temperature in order to ensure a high coefficient of performance of the heat pump. In addition, it is often the case that, when the greatest amount of energy is available from the sun and atmosphere, the energy consumption for heating applications is at a minimum and therefore, it should be paid attention how to store the heat for maintaining the absorbed energy in a form which is suitable for use as required without incurring an unacceptably high loss together with a decrease in temperature. Various systems are already known for heating buildings and preparing domestic hot water, which employ solar collectors, wherein said systems are designed as devices that provide the heating of domestic hot water, directly or using heat exchangers usable for heating, or cooperate with the collector section of a water heat pump by sharing the heat carrying medium of the collector section - ground traps of low potential heat. For most heat pumps, however, the application of a shared medium for the collector and the solar device is not feasible, as the collectors have to be filled with an antifrost mixture compatible with the required properties of the heat pump type. Circulation in the primary circuit is usually stabilized at a temperature of about 0° C, but the low-pressure part of the compressor circuit after expansion works at a temperature of about -25° C. In order to share the circuits on the other side, it is necessary to use mixer valves, an electronic control system and backup sources that can reduce the energy benefits and the efficiency of such systems.

Although each of the known systems represents an attempt to overcome the problems associated with the hybrid thermal energy systems, there still exists a need for an improved efficient system that can be easily installed with low cost of manufacturing, less complex and reduced power consumption.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide an improved hybrid thermal energy system for heating and/or cooling applications, which overcomes the deficiencies of the prior art and avoids high manufacturing costs. It is another object of the present invention to provide an efficient hybrid thermal energy system such as a solar assisted heat pump, which is less complex and can be easily installed.

In accordance with the above objects of the present invention, a hybrid thermal energy system for heating and/ or cooling applications is provided comprising solar collection means in fluid communication with a solar circuit for transferring heat energy to a heat transfer fluid, thermal upgrading means for increasing the thermal energy within the system such as a solar assisted heat pump and a thermal energy production circuit provided with thermal storage means, the solar collection means, thermal upgrading means and thermal storage means being connected to allow the transfer of heat throughout the system via the heat transfer fluid, and control means arranged to receive input data for controlling the flow of the heat transfer fluid throughout the system. Further preferred embodiments of the present invention are defined in dependent claims 2 to 10.

Other objects and advantages of the present invention will become apparent to those skilled in the art in view of the following detailed description in conjunction with the accompanying drawings, wherein like reference numbers refer to similar parts throughout the drawings, and wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a solar assisted heat pump according to the present invention.

Fig. 2 shows a solar assisted heat pump with a fan -coil assembly in the solar circuit according to the present invention.

Fig. 3 shows a solar assisted heat pump with a fan -coil assembly in the solar circuit and three- way valve according to the present invention.

Fig. 4 shows a solar assisted heat pump with a fan -coil assembly in the refrigeration circuit according to the present invention.

Fig. 5 shows a solar assisted heat pump with a fan -coil assembly in the refrigeration circuit with a three-way valve according to the present invention. Fig. 6 shows a solar assisted heat pump with a fan -coil assembly in parallel to the refrigeration circuit according to the present invention. Fig. 7 shows a solar assisted heat pump with cooling heat exchanger according to the present invention. Fig. 8 shows a solar assisted heat pump with cooling heat exchanger in the refrigeration circuit according to the present invention.

Fig. 9 shows a solar assisted heat pump with two the refrigeration circuits according to the present invention.

Fig. 10 shows a solar assisted heat pump with two refrigeration circuits and cooling heat exchangers according to the present invention.

Fig. 11 shows a cross-sectional view of a solar collector with a fan assembly according to the present invention.

Fig. 12 shows a cross-sectional view of an alternative solar collector with a coil - back assembly according to the present invention. Fig. 13 shows a solar assisted heat pump with a fan -coil assembly in parallel to the refrigeration circuit with thermal storage means according to the present invention.

Fig. 14 shows a schematic hot water production system according to the present invention.

Fig. 15 shows a schematic heating, cooling and hot water production system according to the present invention. Fig. 16 shows an alternative schematic system for heating, cooling by air handling and hot water production according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

A conventional heat pump uses a refrigeration system to extract heat from the surrounding environment to heat a fluid. The heat pump system is based on a refrigeration cycle, and comprises an evaporator to absorb heat, a condenser to release heat, a compressor, an expansion valve and the circuits charged with heat transfer fluid such as refrigerant.

The heat transfer fluid or refrigerant can be any refrigerant used in traditional air conditioning and/or heat pump systems. Exemplary refrigerants include carbon dioxide, hydrofiuorocarbons, and hydrochlorofluorocarbons. Other examples of refrigerants include chlorodifiuoromethane (sold as R-22), chloropentafluoroethane (sold as R- 502), dichlorodifluoromethane (sold as R- 12), trichlorofluoromethane (sold as R- 11), trichlorotrifluoroethane (sold as R-113), tetrafluoroethane (sold as R- 134a), and dichlorotrifluoroethane (sold as R- 123). In a most preferred embodiment, the refrigerant is carbon dioxide.

In conventional heat pumps an operational problem may occur when rejection takes place in a cold environment (e.g. during the winter) when either the process stops, thus no heating production, or the compressor must consume a lot more energy to be able to reject the cooling energy (defrost etc). This problem can be avoided with the assistance of solar collection means.

A high efficiency collector can very easily raise water temperatures to higher than 20-25⁰C even in a cold environment during the day. The minimum ambient temperature of heat extraction - from the heat pump evaporator - is in the range of O⁰C. Thus if the process is assisted by a solar collector, then the heat transfer is obviously enhanced. This enhanced heat transfer scheme results to higher efficiencies even during the winter - or during the night because the collector is in fact a "cooling energy radiator" and can work with the environment's temperature - and the production of heating is constant. Figure 1 shows the core system of the present invention which is the refrigeration cycle, as in any heat pump system. The solar assisted heat pump system according to one embodiment of the invention comprises a heat pump having a compressor (1), an evaporator (2), an expansion device (3), a condenser (4) and the circuit (C) charged with the heat transfer fluid.

The thermal energy or hot water is produced directly by its condenser (4) (refrigerant to water heat exchanger). However, the rejection of cooling energy does not take place by using a fan - coil assembly e.g. an evaporator, as used in conventional air cooled heat pumps, but via a second refrigerant to water heat exchanger as used in conventional water cooled heat pumps. The evaporator (2) of the system of the present invention is connected directly to a solar collection means (5), such as a solar collector or a solar field, wherein said solar collection means (5) produces the necessary heating energy to provide for the evaporator (2) and thus allows for the cooling energy to be rejected.

The compressor (1) provides the motive force for moving the heat transfer fluid contained within the circuit (C) between the heat transfer coils of the evaporator (2) and condenser (4) and compresses the refrigerant to a liquid state which is at a high pressure and a high enthalpy. The compressor can be any type of motor driven refrigerant compression device. The condenser (4) is in fluid communication with the compressor (2) and receives incoming liquefied refrigerant under pressure and induces a phase change in the refrigerant from a liquid phase to a gas phase. In the condenser (4) the refrigerant releases heat to the thermal energy circuit (A) provided with thermal storage means to store the heat, so as to be available when needed. The refrigerant passes through the expansion device (3) after it exits the heat exchanger (4). The expansion device (4) expands and reduces the pressure of the refrigerant. The expansion device (3) can be capillary tube or Automatic Expansion Valve ("AEV") or Thermostatic Expansion Valve ("TEV") or Electric or Electronic Expansion Valves ("EXV") or other known type of expansion device. After expansion, the refrigerant flows into the evaporator (2) and exits at a higher enthalpy and higher pressure than in a conventional refrigeration cycle. In the evaporator (2), the refrigerant absorbs heat from the solar circuit (B) thereby heating the refrigerant and then re-enters the compressor (1), completing the cycle. The solar assisted heat pump system further comprises a thermostat controller.

The flow of the pump is controlled thermostatically so as not to allow the overheating of the evaporator (2) and consequently the refrigerant (suction temperature and pressure) which could lead to very high pressure and temperature at the outlet of the compressor (1) and could eventually destroy it. The flow is also regulated so as to supply a constant temperature to the inlet of the evaporator (2) which also ensures steady conditions for the refrigeration cycle and also a relatively constant Coefficient of Performance (COP) of the heat pump. The higher suction temperature by the compressor (1), which translates to work already provided by the solar collector (5), so that the compressor's output will be added to the solar collector's output and consequently the total output of the system will be higher than in a conventional heat pump. In order to take the energy from the solar collector (5) a circulator pump (7) is located in the solar circuit (B) to supply the necessary flow of the thermal fluid between the evaporator (2) and the collector (5). The power input to the circulator pump (7) in relation to the power derived from the collector has a ratio of approximately 1 :30, so the effect of the circulator pump in the overall COP is very small if not negligible. Therefore, in order to produce an X amount of heating energy one would need a compressor (1) that consumes Y amount of energy and the COP of that heat pump would be X: Y. For the solar assisted heat pump (S.A.H.P.) to produce the same amount of energy X one would need a smaller compressor because the work of the collector is added to the one of the compressor. Consequently Y=Y1+Y2 where Yl is the power of the new smaller compressor and Y2 is the power of the circulator pump. Thus, the COP of the SAHP is X : (Y1+Y2). However Y2 is very small, so in fact the COP of the SAHP is X : Yl where Yl is smaller than Y and so the COP of the SAHP is higher of a conventional heat pump.

Alternatively, if the same compressor is used and not a smaller one, then the power output of the S.A.H.P would also be higher and thus, its COP would be higher than of a conventional heat pump.

However, the following drawbacks have been noticed, namely that the solar collector can operate only during the day and second since the solar collector's power output is in direct analogy to the solar radiation and ambient temperature - among other parameters - under certain conditions the heating energy supplied by the collector will not be sufficient and so the heat pump will not be able to reject the cooling energy totally.

It has been surprisingly found that the required heat transfer according to the present invention is achieved by employing a fan - coil assembly in the system. The fan - coil assembly (8, 9) is added in parallel to the solar collector (5) as shown in Figure 2. The fluid medium of the solar circuit (B) is water. Two two-way electro valves (10) are located within the solar circuit to control the flow rate of the fluid. In case that there is insufficient heating power production from the collector then the fan (9) will operate by taking part of the flow or the total flow provided by the pump. The fan — coil assembly (8, 9) can operate as in any normal heat pump but it is placed in the solar circuit (B) instead of being positioned in the refrigeration circuit (C). This offers the advantage that since the working fluid is a water - glycol mixture, its thermal conductivity and thermal capacity are much higher than those of the refrigerant, so the fan - coil assembly can be smaller. Also it is easier to control a water mixture circuit, as for example there is no phase change taking place, and so the conditions in the evaporator (8) — temperature and flow — of the primary circuit can practically remain steady almost continuously. An alternative system according to the present invention comprises instead of two two-way electro valves, one three way valve (11) installed as shown in Figure 3. The valves can be either on - off or progressive.

Another important feature in order to maximize the power output of the S.A.H.P. is to control the flow of pump (6) of the thermal energy production circuit in relation to two factors:

1. The required output temperature of the condenser (4)

2. The required energy output of the condenser (4)

In case the SAHP should always supply a constant temperature, then the flow of the pump (6) of the thermal energy production circuit (A) will be regulated accordingly. When there is a high energy production from the solar collector (5) and subsequently from the SAHP, then in order to keep the same output temperature the pump (6) must supply a higher flow and vice versa.

Another alternative embodiment of the present invention in order to keep the S.A.H.P. operating day and night is to arrange the fan - coil assembly (8, 9) in the refrigerant circuit (C) in series with the evaporator (2), as shown in Figure 4. If the fan - coil assembly (8, 9) is connected in series to the solar evaporator (2), the refrigeration cycle becomes slightly unstable, since the refrigerant cannot be controlled completely due to the phase change and the constantly changing environmental conditions. However, the rejection can be easier since the refrigerant goes directly in to the fan-coil assembly at a lower temperature than the temperature of the water mixture and thus the heat transfer is enhanced.

When there is enough heat production by the solar collector then the fan (9) can stop working, so that there is no power consumption for the fan. However the refrigerant still goes through the coil and by doing so there is a first heat transfer from the environment, provided that the environment temperature is higher than that of the refrigerant, and the solar evaporator (8) adds the remaining energy to complete the cycle. In case the environment temperature is lower than the temperature of the refrigerant we can stop the refrigerant going through the coil (8) by installing a bypass which can be actuated two two- way electro valves (10) as shown in Fig. 4 or by a three way electro valve (11) as shown in Figure 5. According to another embodiment of the present invention, the fan - coil assembly (8, 9) is located in parallel to the solar circuit (B) as shown in Figure 6, wherein after the condenser (4) of the SAHP the refrigerant is separated into two branches. In the first branch there is a first expansion valve (3) or capillary tube and then the expanded fluid goes to the solar evaporator (2). The second branch has a second expansion valve (3) or capillary tube and the fluid is lead to the fan-coil assembly (8, 9). When sufficient amount of energy is provided by the solar absorber, then total volume of the fluid will pass by the solar evaporator (2). However, when the solar evaporator (2) cannot provide the total energy required, then part or the total amount of the fluid passes through the fan - coil assembly. By using two check valves after each evaporator we can control the flow and through which evaporator the fluid will pass. The two evaporators can work totally independent from each other, by themselves or together dependent.

The solar assisted heat pump system of the present invention can also be used to provide cooling as in any other heat pump. This can be done either by installing a heat exchanger (12) in series and before the solar collector (5) in the solar circuit as shown in Figure 7. When the pump (7) is connected to the heat exchanger (12), the heat pump can provide cooling and the remaining cooling energy will be rejected by the solar collector or by the fan — coil assembly (8, 9).

Another alternative system to provide cooling is to install a heat exchanger (12) in the refrigeration circuit (C) before the solar evaporator (2). This way lower temperature can be extracted. This alternative system is shown in Figure 8.

It is obvious that the greater the power output, the more solar collectors are required, the greater the volume of water that is required in the circuit larger heat exchangers, larger circulating pumps etc. In order to overcome this obstacle we have to consider the following fact in any refrigeration cycle. The heating power output is approximately 20-30% higher than the cooling power to be rejected. So in order to get an amount of A KW of heating power, then A-20% KW must be rejected, so the solar collectors (5) must have an output of A-20% KW. However, if two refrigeration circuits are connected in series in such a way that the evaporator of the circuit producing the heating energy, it is connected as the evaporator of the second circuit, this means that since the heating energy required to take the rejection of the first circuit is A-20%, then the cooling energy that has to be rejected from the compressor of the second circuit will be also 20% less and equal to (A-20%)-20%. In short, the power required from the solar collectors is approximately 40% less than the heating power output of the condenser of the first circuit.

Furthermore, since the required temperature produced from the second circuit will be very low in the range of 30oC, a smaller compressor will be required in order to produce the required amount of energy for the rejection of the first circuit (C). This way we could theoretically connect a very large number of refrigeration circuits (C, C) so that on the one side we would get an X amount of power and on the other side have a single collector. This alternative S.A.H.P is shown in Figure 9.

The SAHP system with at least two refrigeration circuits (C, C) can also provide cooling from either the first (C) or the second (C) refrigeration circuit or both with the addition of heat exchangers (12) in the circuits in series located before their evaporators (2), as shown in Figure 10.

In all alternative systems of the present invention all components of the solar assisted heat pump system are integrated and placed in a single unit or casing. In the same casing the two circulator pumps (6, 7) can also be included, but not the solar collector or collectors. The control is performed by a single control box placed either on the unit or away from it by a wire.

Still another alternative system is to remove the fan (9) from either the refrigeration circuit (C) or the solar circuit (B) and connect it directly with the solar collector. In cases wherein the solar radiation is low, the fan will blow the air through the collector towards the absorber of the collector, thereby enhancing the heat transfer from the environment, which is at low temperature. Such a solar collector is shown in Figure 11.

Moreover, in all the SAHP systems of the present invention a buffer tank can be installed in the solar circuit in order to smoothen the temperature feed towards the solar evaporator (2).

According to another embodiment of the present invention, the evaporator (2) of the refrigerant circuit is replaced by a tank with an internal heat exchanger. The heating energy from the solar collection means will be transferred via the internal heat exchanger to the refrigerant causing it to evaporate and the vapors of the tank will be transferred consequently to the compressor for the cycle to complete. Several internal heat exchangers can be installed in the tank, in order to be able to provide energy from alternative sources, other than just from solar collectors.

Moreover, according to another embodiment of the present invention, wherein in order to be able to maximize the energy yield of the solar collection means, when the operation of the S.A.H.P. and thus of the solar collection means is at very low temperatures (0° -20⁰C), the energy yield is enhanced directly from the environment (ambient air) by using a solar collector with a coil — back assembly as shown in Figure 12. In a coil -back solar collector, the back plate of the solar collector has been replaced with another coil such as a conventional refrigerant coil of the type used in refrigerators. Hence, the cold fluid coming from the evaporator (2) of the S.A.H.P. system is first passing through the first heating coil (primary heating coil) at the back of the solar collector, thus gaining energy directly from the environment. Subsequently, the fluid is lead via an internal pipe connection to the solar collector's absorber and the secondary heating coil. Said secondary heating coil is formed as in conventional flat plat collector hydroskeleton welded to an absorbing surface, thereby absorbing the necessary solar energy. The coil - back, since it is under the solar collector absorber, takes also energy from it. In short, this coil - back solar collector absorbs much more energy than a conventional solar collector due to the enhanced interaction with the environment.

Still another embodiment of the present invention is depicted in Figure 13 which shows a more flexible variation of the SAHP. The pump (7) in the solar circuit (B) of the solar evaporator (2) pumps the cold fluid, such as water, towards the solar collector (5). When there is a high production of thermal energy from the solar collector (5), instead of providing the total amount of the energy to the solar evaporator (2), (a condition that could eventually even damage the compressor (I)), part of the energy is diverted via a bypass circuit to a thermal storage tank (13) by turning on the two-way electro valve (10). When the second two-way electro valve (10) located in the solar circuit (B) before the entrance of the solar evaporator (2) is turned off, the total amount of the thermal energy is diverted to the storage thermal tank (13). When the first electro valve (10) is turned off and thus, there is no communication with the storage tank, the total amount of the energy is sent to the SAHP. The storage tank (13) is equipped with two internal heat exchangers (14). The solar collector is connected directly to one of the internal heat exchangers, whereas the second is connected to the condenser of the solar assisted heat pump. This variation of the SAHP can exploit even better the high availability of solar energy bypassing the refrigeration circuit (C). In the mean time it allows the system to operate in cases with lower availability in solar energy with a lot higher efficiency than just a solar collector and finally when the collector is unable to produce usable temperatures the SAHP can produce all the necessary energy at a very high COP. The present invention can be applied in hot water production assembly wherein the SAHP can be connected to any thermal storage means such as tank existing or new, since the connections refer to a simple hydraulic joining between the unit and the tank (see Figure 14).

The system of Figure 14 heats up a hot water tank. The water of the tank is circulated by a pump via the condenser of the system. The hot water that is produced can be used as sanitary hot water.

Tap water is supplied to the tank and hot water from the tank is supplied to the installation's network. This way the tank acts also as a buffer tank thus smoothening the temperature and since the water temperature in the tank is stratified; hot water at the top and the cold at the bottom of the tank, the SAHP system of the present invention operates at higher COP because the heat transfer always takes place using the cold water.

Another installation wherein the SAHP system of the present invention produces energy for space heating and production of sanitary hot water and provides cooling energy for space cooling is shown in Figure 15. The system heats up a thermal storage means, such as hot water buffer tank. This tank supplies with hot water a heating system of an installation as well as the sanitary hot water tank. A pump circulates the hot water from the buffer to a plate heat exchanger and another pump circulates the sanitary water from the tank to the secondary circuit of the heat exchanger. This way the sanitary circuit is separated from the heating system circuit. At the same time the system produces cold water and, through another buffer tank, it can supply a cooling system of an installation.

A variation of SAHP system of the present invention where two extra refrigeration circuits to air heat exchanger coils are connected in series with the condenser and evaporator heat exchangers providing cooling and heating to an air handling unit as shown in Figure 16. At the same time the SAHP provides for space heating and sanitary hot water. The solar collectors can be connected either directly to the evaporator or via a buffer tank. The SAHP is enclosed in an air handling unit. It includes air heating and cooling elements as well as water heating and cooling elements (plate heat exchangers). The SAHP can produce hot water for the heating system of the installation as well as the sanitary hot water through a plate heat exchanger.

At the same time it supplies energy to the heating element of the air handling unit, which can be used to heat up the air before it enters a building. The system uses an air dehumidification element (cooling element) and a solar buffer to gain heat. This operation performs with an increased COP acting as a total heat recovery to the air handling unit.

While the present invention has been described with respect to the particular embodiments, it will be apparent to those skilled in the art that various changes and modifications in design and construction may be made in the invention without departing from the spirit and scope thereof, as defined in the appended claims.

Claims

1. A hybrid thermal energy system for heating and/ or cooling applications comprising solar collection means (5) in fluid communication with a solar circuit (B) for transferring heat energy to a heat transfer fluid, thermal upgrading means for increasing the thermal energy within the system such as a solar assisted heat pump and a thermal energy production circuit (A) provided with thermal storage means, the solar collection means, thermal upgrading means and thermal storage means (13) being connected to allow the transfer of heat throughout the system via the heat transfer fluid, and control means arranged to receive input data for controlling the flow of the heat transfer fluid throughout the system.

2. The hybrid thermal energy system according to claim 1, wherein the thermal upgrading means is a solar assisted heat pump comprising a compressor (1), a condenser (4), an expansion device(3), an evaporator (2), and a refrigeration circuit (C) charged with a heat transfer fluid, such as a refrigerant.

3. The hybrid thermal energy system according to claim 2, wherein it further comprises a fan - coil assembly (8, 9).

4. The hybrid thermal energy system according to claim 3, wherein said fan - coil assembly (8, 9) is located in the solar circuit (B) and in fluid communication with the solar collector (5).

5. The hybrid thermal energy system according to claim 3, wherein said fan - coil assembly (8, 9) is located in the refrigeration circuit (C) and in fluid communication with the evaporator (2) and the expansion device (3) of the refrigerant circuit in series or in parallel.

6. The hybrid thermal energy system according to any preceding claim, wherein said solar collection means (5) comprises a fan directly connected with the solar collector in such a way that the fan can blow air through the solar collector towards the absorber of the solar collector thereby enhancing the heat transfer from the environment.

7. The hybrid thermal energy system according to any preceding claim, wherein said solar collection means (5) comprises a first heating coil or coil- back and a second heating coil, wherein the cold fluid, coming from the evaporator (2) of the solar assisted heat pump system, first passes through the first heating coil at the back of the solar collector and subsequently, the fluid is lead via an internal pipe connection to the secondary heating coil and the solar collector's absorber.

8. The hybrid thermal energy system according to any preceding claim, wherein said system comprises two refrigeration circuits connected in series.

9. The hybrid thermal energy system according to any preceding claim, wherein said system further comprises an additional heat exchanger (12) in order to provide cooling, said heat exchanger (12) being installed either in the refrigeration circuit (C) before the solar evaporator (2) or in the solar circuit (B) before the solar collector (5).

10. The hybrid thermal energy system according to any preceding claim, wherein a circulator pump (7) is provided in the solar circuit (B) and a circulator pump (6) is provided in the thermal energy production circuit (A) and the flow of the fluid is controlled by a valve (10, 11).

11. The hybrid thermal energy system according to any preceding claim, wherein all the components of the solar assisted pump system form a single integral unit, placed in a single casing.

12. The hybrid thermal energy system according to any preceding claim, wherein said system is controlled by a single control box placed either on the unit or away from it by a wire.

13. The hybrid thermal energy system according to any preceding claim, wherein said system is used for hot water production and/or heating, cooling and hot water production and/or heating, cooling by air handling and hot water production.