WATER HEATING SYSTEM AND METHOD

Abstract

A water heating system comprising: - a circuit (2) through which a working fluid circulates; said circuit (2) comprising a means (20) for heating the working fluid; - a first line (31) for supplying water for sanitary use; - a second line (32) for supplying water intended for heating at least one area of ​​a building; - first heat exchange means (5) for exchanging heat between the circuit (2) and the first supply line (31); - second heat exchange means (4) for exchanging heat between the circuit (2) and the second supply line (32). The heating means (20) is a piston pump (21). [FIG. 1]

Description

Title of the invention: SYSTEM AND METHOD FOR HEATING WATER

[0001] The present invention relates to a system and method for heating hot water to be used both for heating at least one environment of a building and for sanitary water used in a building.

[0002] It is therefore a water heating system for civil use.

[0003] Building heating systems are known. In this case, hot water at send to the convectors and hot water to be used as sanitary water can be obtained by means of a boiler that burns fuel. Alternatively, a heat pump can be used in which the classic elements of a reverse refrigeration cycle are used: compressor acting on a fluid that is at least partially gaseous, condenser, evaporator, expansion valve. The COP (Coefficient of Performance) of a heat pump of this type is generally less than 7. The COP is an efficiency index of a heat pump and corresponds to the ratio between the energy delivered (for example, the heat transferred to the environment to be heated) and the electrical energy consumed.

[0004] In this context, the objective of the present invention is to provide a heating system and method that achieves high performance, while simultaneously optimizing energy consumption. Another objective is to enable easy maintenance. An additional objective is to provide a solution that is silent.

[0005] The specified objectives are substantially achieved by a heating system and method described below. According to a first aspect, the invention relates to a water heating system comprising: - a circuit in which a working fluid circulates; said circuit comprising a means for heating the working fluid and being devoid of an evaporator, - a first water supply line for sanitary use, - a second water supply line intended for heating at least one environment of a building, - first heat exchange means for exchanging heat between the circuit and the first supply line, - second heat exchange means for exchanging heat between the circuit and the second supply line.

[0006] The system is characterized in that the heating means consists of a piston pump.

[0007] In other words, the circuit in which the working fluid circulates is devoid of an evaporator and the heating means consists solely of a piston pump for heating the working fluid circulating in said circuit. Consequently, the heating of the working fluid does not require air or liquid from the external environment. This means that the heating of the system does not depend on the external temperature.

[0008] According to another characteristic, the circuit comprises an electric motor for driving the piston pump, said electric motor comprising / being an asynchronous magnetic electric motor.

[0009] In a preferred embodiment, the working fluid is selected from the group consisting of R1233ZD(E), R1234ZE and R295.

[0010] Advantageously, the working fluid is R1233ZD(E) which has a global warming potential (GWP) of 5, i.e. a low greenhouse effect. According to a specific embodiment, the first heat exchange means comprise: - a loop which is closed on itself, in which a heat transfer fluid circulates, - a first heat exchanger which puts the working fluid circulating in the circuit and the heat transfer fluid circulating in said loop into thermal communication, - a heat exchanger tank in thermal communication with said first supply line.

[0011] Advantageously, said first water supply line for sanitary use comprises a coil which passes inside the tank.

[0012] In this embodiment, the system advantageously comprises an additional heat exchanger for exchanging heat between the circuit and the first supply line.

[0013] Preferably, the system comprises an expansion valve interposed between said first heat exchanger and said additional heat exchanger.

[0014] The invention also relates to a method of heating water involving the previously disclosed system.

[0015] The method comprises the following steps: - circulate the working fluid in the circuit, - heat the working fluid circulating in said circuit, - transmitting the heat from the working fluid to the water for sanitary use; said water for sanitary use circulating in the first supply line, - transmitting the heat from the working fluid to the water for heating at least one environment of a building; said heating water circulating in the second supply line.

[0016] Advantageously, the working fluid has a pressure of between 6 and 8 bars and preferably always remains in the liquid phase in the circuit.

[0017] Other characteristics and advantages of the present invention emerge from the description given for information purposes and therefore non-limiting of a preferred but non-exclusive embodiment of a heating system and method, illustrated schematically in [Fig.l].

[0018] In the accompanying figures of the drawings, reference numeral 1 denotes a water heating system.

[0019] The system 1 comprises a circuit 2 in which a working fluid circulates.

[0020] The working fluid may be a HFO (hydrofluoroolefin) based fluid such as R1366Mzz or R1233 ZD, or ammonia based or inhibited calcium carbonate or others. It is advantageously R1233ZD(E).

[0021] In practice, the working fluid in circuit 2 always remains in the liquid phase and advantageously between 6 and 8 bars.

[0022] The circuit 2 comprises a means 20 for heating the working fluid.

[0023] Circuit 2 comprises a first line 31 for supplying water for use sanitary. The first supply line 31 typically receives mains water as an inlet (typically at 3 bars and 15°C). Such an inlet corresponds to reference 310.

[0024] The system 1 comprises a second line 32 for supplying heating water to at least one environment of a building. This is water intended to pass through elements adapted to diffuse heat in an environment of the building (for example convectors 7). The second supply line 32 is closed on itself and therefore defines a recirculation line. The first and second lines 31, 32 are separate and distinct.

[0025] The numeral adjectives "first" and "second" are used previously only to distinguish the supply lines, they do not indicate an order or priority (the same applies to the rest of the text).

[0026] The system 1 comprises first heat exchange means 5 for exchanging heat between the circuit 2 and the first supply line 31.

[0027] The first heat exchange means 5 comprise a loop 50 closed on itself in which a heat transfer fluid circulates (the closed loop 50 is therefore a circuit). Such a heat transfer fluid in the loop 50 always remains in the liquid state.

[0028] The first heat exchange means 5 comprise a first heat exchanger 52 which places the working fluid circulating in the circuit 2 and the heat transfer fluid circulating in said loop 50 in thermal communication. In one embodiment particular embodiment, the working fluid enters the first exchanger 52 at a temperature between 110°C and 130°C and leaves it at a temperature between 30°C and 50°C. The heat transfer fluid circulating in the loop 50 in this embodiment leaves the first exchanger 52 at a temperature above 80°C (for example between 80° and 90°C).

[0029] The first heat exchange means 5 comprise a heat exchanger tank 53 in thermal communication with said first supply line 31. For example, such a tank 53 has a capacity of between 10 and 30 liters, typically 15 liters. The tank 53 also comprises an expansion tank 530. Suitably, the system 1 comprises a pump 501 (typically centrifugal) for recirculating the heat transfer fluid in the loop 50. The pump 501 is located downstream of the first exchanger 52 and upstream of the tank 53.

[0030] In particular, the first line 31 for the supply of water for sanitary use comprises a coil 311 which passes inside the tank 53. The heat transfer fluid is present in the tank 53 and bathes the outside of the coil 311. Suitably, in the operating mode described above, the sanitary water leaving the tank 53 is at a temperature between 55°C and 65°C. Suitably, a temperature probe 531 at the tank 53 measures the temperature of the heat transfer fluid.

[0031] Advantageously, the system comprises an additional heat exchanger 54 through which said working fluid and said water for sanitary use pass. Suitably, the additional heat exchanger 54 fulfills the function of preheating the sanitary water (before it enters the tank 53 or rather the coil 311 present in the tank 53). The exchanger 54 is located after the tank 53 in the direction of flow of the sanitary water. The first exchanger 52 and the additional exchanger 54 are separated from each other.

[0032] Suitably, the circuit 2 comprises an expansion valve 23 interposed between said heat exchanger 52 and said additional heat exchanger 54. The expansion valve 23 is located at the inlet of the additional heat exchanger 54. Suitably, the expansion valve 23 can receive an input signal depending on the pressure downstream of the additional heat exchanger 54.

[0033] As illustrated in [Fig.l], the first heat exchanger 52, the second heat exchanger 55 and said additional exchanger 54 are arranged in series along the circuit 2. The first exchanger 52 is downstream of the second exchanger 55 and upstream of the additional exchanger 54.

[0034] The system 1 comprises second heat exchange means 4 between the circuit 2 and the second supply line 32. The second heat exchange means 4 comprise / are for example a second heat exchanger 55, typically a plate exchanger. They define an area in which the circuit 2 and the second supply line 32 are in thermal contact. The second exchanger 55 therefore affects both the circuit 2 and the second supply line 32. For example, the working fluid could enter the second heat exchange means 4 at a temperature between 150 and 130°C and leave at a temperature between 130°C and 110°C. Suitably, the heating water for at least one environment of a building leaves the exchanger at a temperature between 80 and 90°C.

[0035] Suitably, the working fluid and the heating water of at least one environment of a building circulate countercurrently in the second heat exchange means 4.

[0036] A temperature probe 321 is placed along the second line 32.

[0037] The system 1 comprises a water recirculation pump 322 along the second line 32. The water recirculation pump 322 is typically a centrifugal pump. It allows the water to be recirculated along the second line between the second heat exchange means and the convectors 7.

[0038] The heating means 20 is a piston pump 21. Typically, it is a high-pressure piston pump 21. The system 1 can be considered as a heat pump in the sense that it has a COP greater than 7, preferably greater than 10. The COP (Coefficient of Performance) is an index of efficiency of a heat pump and is given by the ratio between the energy delivered and the electrical energy consumed. However, unlike a standard heat pump, the system of the invention does not include an evaporator.

[0039] The pump 21 thus causes the working fluid to heat. This occurs due to the compressive action on the incompressible working fluid. Such compression forces the working fluid along the conduits of the pump 21, causing an increase in kinetic energy and frictional heating.

[0040] Suitably, the circuit 2 comprises only said piston pump 21 for heating the working fluid circulating therein.

[0041] The piston pump 21 is a volumetric pump of known type, if considered in itself. The piston pump could be an axial piston pump, but also a piston pump of another type. For example, it comprises pistons housed in corresponding pumping chambers. The pumping chambers are conveniently integrated in a body which can be rotatable. The rotation of this body and therefore of the pumping chambers causes the rotation of the pistons and thus determines an alternating back and forth movement of the pistons in the corresponding pumping chambers. In fact, the pistons have one end pressed by means elastic against a plate inclined relative to the axis of rotation of the pumping chambers.

[0042] The system 1 comprises an electric motor 22 for driving the piston pump 21. The electric motor 22 preferably comprises / is an asynchronous magnetic electric motor 22. This contributes to the quietness of the system 1. Suitably, the motor 22 comprises an inverter. The operation of the motor 22 is also regulated according to the feedback provided by the temperature sensors 321 placed along the second line 32.

[0043] The additional exchanger 54 is interposed between the first exchanger 52 and the piston pump 21.

[0044] The system 1 may comprise a filter 61, an inspection hole 62, a liquid reservoir 63. They are conveniently arranged downstream of the first exchanger 52 and upstream of the additional heat exchanger 54.

[0045] The system 1 suitably comprises a soundproof housing housing the piston pump 21.

[0046] The system 1 also comprises a control unit for controlling the overall operation and regulation of the temperatures and pressure required to maintain the working fluid circulating in the circuit 2 in the liquid phase.

[0047] An object of the present invention is also a method of heating water.

[0048] The method is advantageously implemented by a system 1 having one or several of the characteristics described above.

[0049] The method comprises the following steps: - circulating a working fluid in a circuit 2; suitably, such a working fluid always remains liquid when recirculating within the circuit 2 (it could therefore also be called a working liquid); - heat the working fluid circulating in circuit 2.

[0050] The heating phase of the working fluid passing through the circuit 2 occurs when the working fluid passes through the piston pump 21 placed along the circuit 2. Consequently, the piston pump 21 heats the working fluid. Suitably, at least at the pump 21 (but preferably throughout), the working fluid is liquid. The piston pump 21 acts on said working fluid so that the pressure of the working fluid is between 6 and 8 bar, for example when R1233ZD(E) is used. In some embodiments, the piston pump 21 acts on said working fluid, causing an increase in pressure of at least 10 bar and / or an increase in temperature of at least 90°C. Downstream of the piston pump 21, temperatures of the working fluid are obtained, which are higher than 110°C or 120°C. Pump 21, in addition to causing the heating of the working fluid, is also solely responsible for its movement..

[0051] The method comprises the step of carrying out heat transfer from the working fluid present in the circuit 2 to the water for sanitary use. Typically, a flow rate of between 12 and 16 liters / minute is envisaged. The water for sanitary use circulates in the first supply line 31. Such heat transfer from the working fluid present in the circuit 2 to the water for sanitary use occurs indirectly. In fact, a heat transfer is provided between the working fluid circulating in the circuit 2 and the heat transfer fluid circulating in the closed loop 50 and a heat transfer from the heat transfer fluid circulating in the closed loop 50 and the water for sanitary use circulating in the first line 31.

[0052] The transfer of heat from the heat transfer fluid circulating in the closed loop 50 to the water for sanitary use circulating in the first line 31 occurs in a heat exchanger preferably comprising: - a reservoir 53 in which the heat transfer fluid is present; - a section of the first line 31 passing through the reservoir 53. Typically, such a section defines a coil 311. Suitably, the coil 311 is immersed in the heat transfer fluid present in the reservoir 53. The heat transfer fluid is liquid. For example, it may be of the same type as the working fluid.

[0053] The first line 31 is a loop that winds between a network water introduction zone to one or more taps that make the water available to the user (typically in the form of running water).

[0054] The method also comprises the step of transmitting the heat of the working fluid present in the circuit 2 to the water to heat at least one environment of a building. This occurs for example by second heat exchange means 4. Typically, the second heat exchange means 4 comprise a plate exchanger.

[0055] The heating water circulates in the second supply line 32. In particular, the second line 32 recirculates on itself. Consequently, the heating water receives the heat, reaches the convectors 7 to heat at least one environment of the building, and then returns to be heated again.

[0056] The present invention has important advantages.

[0057] First of all, it makes it possible to obtain considerable heating performances which are perfectly compatible with those linked to the heating of at least part of a building and to the heating of water for sanitary use. In addition, it makes maintenance easier.

[0058] It is also possible to obtain a compact and silent solution.

[0059] The invention as conceived is susceptible of numerous modifications and variations, all falling within the inventive concept which characterizes it. In addition, all The characteristics can be replaced by other technically equivalent elements. In practice, all materials used, as well as dimensions, can be any, depending on requirements.

Claims

Claims

1. Water heating system comprising: - a circuit (2) in which a working fluid circulates; said circuit (2) comprising means (20) for heating the working fluid and being devoid of an evaporator, - a first line (31) for supplying water for sanitary use, - a second line (32) for supplying water intended for heating at least one environment of a building, - first heat exchange means (5) for exchanging heat between the circuit (2) and the first supply line (31), - second heat exchange means (4) for exchanging heat between the circuit (2) and the second supply line (32), characterized in that the heating means (20) consists of a piston pump (21).

2. System according to claim 1, characterized in that it comprises an electric motor (22) for driving the piston pump (21); said electric motor (22) comprising / being an asynchronous magnetic electric motor (22).

3. System according to any one of the preceding claims, characterized in that the working fluid is R1233ZD(E).

4. System according to any one of the preceding claims, characterized in that said first heat exchange means (5) comprise: - a loop (50) which is closed on itself, in which a heat transfer fluid circulates, - a first heat exchanger (52) which places the working fluid circulating in the circuit (2) and the heat transfer fluid circulating in said loop (50) in thermal communication, - a heat exchanger tank (53) in thermal communication with said first supply line (31).

5. System according to claim 4, characterized in that said first supply line (31) of water for sanitary use comprises a coil (311) which passes inside the tank (53).

6. System according to claim 5, characterized in that it comprises an additional heat exchanger (54) for exchanging heat between the circuit (2) and the first supply line (31).

7. System according to claim 6, characterized in that it comprises an expansion valve (23) interposed between said first heat exchanger (52) and said additional heat exchanger (54).

8. System according to any one of the preceding claims, characterized in that it comprises a control unit for regulating the temperatures and pressure required to maintain the working fluid circulating in the circuit (2) in the liquid phase.

9. A method of heating water involving the system according to any one of claims 1 to 8 comprising the following steps: - circulating the working fluid in the circuit (2), - heating the working fluid circulating in said circuit (2), - transmitting the heat of the working fluid to the water for sanitary use; said water for sanitary use circulating in the first supply line (31), - transmitting the heat of the working fluid to the water for heating at least one environment of a building; said water for heating circulating in the second supply line (32).

10. Method according to claim 9, characterized in that the working fluid has a pressure of between 6 and 8 bars.

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