System and method for heating water

Abstract

A system for heating water, comprising: a circuit (2) in which a working fluid circulates, said circuit (2) comprising means (20) for heating said working fluid; a first supply line (31) for supplying sanitary water; a second supply line (32) for supplying water intended for heating at least one environment of the building; first heat exchange means (5) for exchanging heat between the circuit (2) and the first supply line (31); and a second heat exchange device (4) for exchanging heat between the circuit (2) and the second supply line (32). The heating device (20) comprises / is a piston pump (21).

Description

Technical Field

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

[0002] Therefore, it is a domestic water heating system. Background Art

[0003] Building heating systems are well known. In this case, the hot water to be fed to the convection heater and the hot water to be used as sanitary water can be obtained with the help of a boiler burning fuel. In an alternative solution, a heat pump can be used, in which the classical elements of the reverse refrigeration cycle are used: compressor, condenser, evaporator, throttling member acting on an at least partially gaseous fluid. The COP (coefficient of performance) of this type of heat pump is generally less than 7. COP is an efficiency index of the heat pump and is the ratio of the energy transferred (for example, the heat transferred to the environment to be heated) to the electrical energy consumed. Summary of the invention

[0004] In this context, the technical task of the present invention is to propose a system and a heating method capable of obtaining high performance while optimizing energy consumption. Another objective is to facilitate maintenance. Yet another objective is to provide a noiseless solution.

[0005] The defined technical task and the specified aims are substantially achieved by the system and the heating method described below.

[0006] According to a first aspect, the invention relates to a system for heating water, the system comprising:

[0007] - a circuit in which a working fluid circulates, said circuit comprising means for heating said working fluid and without an evaporator;

[0008] - a first supply line for supplying sanitary water;

[0009] - a second supply line for supplying water intended for heating at least one environment of the building;

[0010] - first heat exchange means for exchanging heat between said circuit and said first supply line; and

[0011] - second heat exchange means for exchanging heat between said circuit and said second supply line.

[0012] The system is characterized in that the heating device consists of a piston pump.

[0013] In other words, the circuit in which the working fluid circulates has no evaporator and the heating means consist only of a piston pump for heating the working fluid circulating in the circuit. Therefore, 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 or outdoor temperature.

[0014] According to another feature, the circuit comprises an electric motor for driving the piston pump, the electric motor comprising / being an asynchronous magnetic motor.

[0015] In a preferred embodiment, the working fluid is selected from the group consisting of R1233ZD(E), R1234ZE and R295.

[0016] Advantageously, the working fluid is R1233ZD(E), which has a global warming potential (GWP) of 5, ie low greenhouse effect.

[0017] According to a specific embodiment, the first heat exchange device comprises:

[0018] - a self-closed path in which a heat transfer fluid circulates;

[0019] - a first heat exchanger placing the working fluid circulating in the circuit in thermal communication with the heat transfer fluid circulating in the path; and

[0020] - a heat exchange tank in thermal communication with said first supply line.

[0021] Advantageously, said first supply line for sanitary water comprises a coil of tubing running inside said tank.

[0022] In this embodiment, the system advantageously comprises an additional heat exchanger for exchanging heat between the circuit and the first supply line.

[0023] Preferably, the system comprises a throttle valve arranged between the first heat exchanger and the additional heat exchanger.

[0024] The invention also relates to a method for heating water involving the previously disclosed system.

[0025] The method comprises the following steps:

[0026] Circulating the working fluid in the circuit;

[0027] heating the working fluid circulating in the circuit;

[0028] transferring heat from the working fluid to sanitary water flowing along a first supply line; and

[0029] Heat is transferred from the working fluid to water for heating at least one environment of a building, the water for heating flowing along a second supply line.

[0030] Advantageously, the pressure of the working fluid is between 6 and 8 bars and the working fluid preferably always remains in liquid phase in the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] like Figure 1 Further features and advantages of the invention will become more apparent from the indicative and thereby non-limiting description of preferred but not exclusive embodiments of a system and a heating method, shown schematically.

[0032] In the drawings, reference numeral 1 denotes a system for heating water. DETAILED DESCRIPTION

[0033] The system 1 comprises a circuit 2 in which a working fluid circulates.

[0034] The working fluid may be a HFO fluid (hydrofluoroolefin based fluid), such as R1366Mzz or R1233ZD, or an ammonia based or inhibited calcium carbonate or other fluid. Advantageously, the working fluid is R1233ZD(E).

[0035] Suitably, the working fluid in circuit 2 is always kept in liquid phase and advantageously kept between 6 and 8 bars.

[0036] The circuit 2 comprises means 20 for heating the working fluid.

[0037] The circuit 2 comprises a first supply line 31 for supplying sanitary water. The first supply line 31 typically receives input tap water (typically at 3 bar and 15° C.). Such input water corresponds to reference 310 .

[0038] The system 1 comprises a second supply line 32 for supplying heated water to at least one environment of the building. This water is intended to flow in an element suitable for diffusing heat in the building environment, such as a convection heater 7. The second supply line 32 is closed in itself and thus defines a recirculation line. The first supply line 31 and the second supply line 32 are separate and not identical.

[0039] The numerical adjectives "first" and "second" are used in the preceding text only to distinguish the supply lines and do not indicate an order or priority (the same applies to the following text).

[0040] The system 1 comprises a first heat exchange device 5 for exchanging heat between the circuit 2 and the first supply line 31 .

[0041] The first heat exchange device 5 comprises a path 50 which is closed in itself and in which a heat transfer fluid circulates (the closed path 50 is therefore a loop). Such heat transfer fluid in the path 50 is always kept in a liquid state.

[0042] The first heat exchange device 5 includes a first heat exchanger 52, which thermally connects the working fluid circulating in the loop 2 and the heat transfer fluid circulating in the path 50. In a specific working mode, the working fluid enters the first heat exchanger 52 at a temperature between 110° C. and 130° C. and flows out at a temperature between 30° C. and 50° C. In this operating mode, the heat transfer fluid circulating in the path 50 flows out of the first heat exchanger 52 at a temperature higher than 80° C. (for example, between 80° and 90° C.).

[0043] The first heat exchange device 5 comprises a heat exchange tank 53 in thermal communication with the first supply line 31. For example, the capacity of such a heat exchange tank 53 is between 10 and 30 litres, typically 15 litres. The heat exchange tank 53 also comprises an expansion vessel 530. Suitably, the system 1 comprises a pump 501 (typically of the centrifugal type) for recirculating the heat transfer fluid in the path 50. The pump 501 is located downstream of the first heat exchanger 52 and upstream of the heat exchange tank 53.

[0044] In particular, the first supply line 31 for supplying sanitary water comprises a coil 311 running inside a heat exchange box 53. A heat transfer fluid is present in the heat exchange box 53 and externally surrounds the coil 311. Suitably, in the above-mentioned operating mode, the temperature of the sanitary water output from the heat exchange box 53 is between 55° C. and 65° C. Suitably, a temperature probe 531 is provided at the heat exchange box 53, which measures the temperature of the heat transfer fluid.

[0045] Advantageously, the system comprises an additional heat exchanger 54, in which the working fluid and the sanitary water are transported. Suitably, the additional heat exchanger 54 realizes the function of a preheater for the sanitary water (before the sanitary water enters the heat exchange box 53, or more precisely, before the sanitary water enters the coil 311 in the heat exchange box 53). The additional heat exchanger 54 is located upstream of the heat exchange box 53 along the flow direction of the sanitary water. The first heat exchanger 52 and the additional heat exchanger 54 are spaced apart from each other.

[0046] Suitably, the circuit 2 comprises a throttle valve 23 disposed between the first heat exchanger 52 and the additional heat exchanger 54. The throttle valve 23 is located at the input end of the additional heat exchanger 54. Suitably, the throttle valve 23 may receive a control input according to the pressure downstream of the additional heat exchanger 54.

[0047] like Figure 1As shown, the first heat exchanger 52, the second heat exchanger 55 and the additional heat exchanger 54 are arranged in series along the loop 2. The first heat exchanger 52 is located downstream of the second heat exchanger 55 and upstream of the additional heat exchanger 54.

[0048] The system 1 comprises a second heat exchange device 4 between the loop 2 and the second supply line 32. The second heat exchange device 4 comprises / is for example a second heat exchanger 55, typically a plate heat exchanger. They define an area of ​​thermal contact between the loop 2 and the second supply line 32. Thus, the second heat exchanger 55 affects the loop 2 and the second supply line 32. For example, the working fluid can enter the second heat exchange device 4 at a temperature between 150°C and 130°C and flow out of the second heat exchange device 4 at a temperature between 130°C and 110°C. Suitably, the heating water of at least one environment of the building flows out of the heat exchanger at a temperature between 80°C and 90°C.

[0049] Suitably, in the second heat exchange device 4, the working fluid and the heating water of at least one environment of the building are in a counter-current state.

[0050] A temperature probe 321 is placed along the second supply line 32 .

[0051] The system 1 comprises a water recirculation pump 322 along the second supply line 32. The water recirculation pump 322 is typically a centrifugal pump and allows water to be recirculated along the second supply line between the second heat exchange device and the convection heater 7.

[0052] The heating device 20 is a piston pump 21, typically a high pressure piston pump 21. The system 1 can be considered a heat pump, since its COP is greater than 7, preferably greater than 10. The COP (coefficient of performance) is an efficiency index of a heat pump and is the ratio of the energy delivered to the electrical energy consumed. However, in contrast to a standard heat pump, the system of the invention does not include an evaporator.

[0053] Therefore, due to the compression effect on the incompressible working fluid, the pump 21 causes the working fluid to heat up. This compression forces the working fluid to flow along the pipes of the pump 21, thereby increasing kinetic energy and heating through friction.

[0054] Suitably, the circuit 2 comprises only said piston pump 21 for heating the working fluid circulating in the circuit 2 .

[0055] If considered separately, the piston pump 21 is a positive displacement pump of a known type. The piston pump can be an axial piston pump or a piston pump of another type. For example, the piston pump comprises a piston accommodated in a respective pump chamber. The pump chamber is conveniently integrated into a rotatable body. The rotation of the body and thus of the pump chamber causes the piston to rotate and thereby determines the alternating back and forth movement of the piston in the respective pump chamber. In fact, one end of the piston is pressed by elastic means against a plate inclined relative to the axis of rotation of the pump chamber.

[0056] The system 1 comprises an electric motor 22 for driving the piston pump 21. The electric motor 22 preferably comprises / is a magnetic asynchronous motor 22. This contributes to the noiseless operation of the system 1. Suitably, the electric motor 22 comprises a frequency converter. The operation of the electric motor 22 is also regulated according to the feedback provided by the temperature probe 321 placed along the second supply line 32.

[0057] The additional heat exchanger 54 is located between the first heat exchanger 52 and the piston pump 21 .

[0058] The system 1 may include a filter 61 , an inspection hole 62 , a liquid reservoir 63 . Suitably, these components are arranged downstream of the first heat exchanger 52 and upstream of the additional heat exchanger 54 .

[0059] The system 1 suitably comprises a soundproof housing housing the piston pump 21 .

[0060] The system 1 also comprises a control unit for controlling the overall operation and adjusting the temperature and pressure required to keep the working fluid circulating in the loop 2 in the liquid phase.

[0061] The invention also relates to a method for heating water.

[0062] The method is advantageously implemented by a system 1 having one or more of the above-mentioned features.

[0063] The method comprises the following steps:

[0064] - circulate a working fluid in the circuit 2, suitably this working fluid always remaining liquid recirculating in the circuit 2 (hence it may also be called working fluid); and

[0065] - Heating the working fluid circulating in circuit 2.

[0066] When the working fluid flows in the piston pump 21 placed along the loop 2, a step of heating the working fluid flowing in the loop 2 is performed. Therefore, the piston pump 21 warms up the working fluid. Suitably, at least at the pump 21 (but preferably anywhere), the working fluid is a liquid. The piston pump 21 acts on the working fluid so that the pressure of the working fluid is between 6 bar and 8 bar (for example when R1233ZD (E) is used). In some embodiments, the piston pump 21 acts on the working fluid so that the pressure increases by at least 10 bar and / or the temperature increases by at least 90°C. Downstream of the piston pump 21, the temperature of the working fluid can even be higher than 110°C or 120°C. In addition to warming up the working fluid, the pump 21 is solely responsible for the movement of the working fluid.

[0067] The method comprises the step of transferring heat from the working fluid in the loop 2 to the sanitary water. Typically, a flow rate of 12-16 liters / minute is envisaged. The sanitary water flows along the first supply line 31. Heat is indirectly transferred from the working fluid in the loop 2 to the sanitary water. In practice, it is envisaged that heat is transferred between the working fluid circulating in the loop 2 and the heat transfer fluid circulating in the closed path 50, and that heat is transferred from the heat transfer fluid circulating in the closed path 50 to the sanitary water transported along the first supply line 31.

[0068] Heat is transferred from the heat transfer fluid circulating in the closed path 50 to the sanitary water conveyed along the first supply line 31 in a heat exchanger, which preferably comprises:

[0069] - a heat exchange tank 53 containing a heat transfer fluid; and

[0070] - a portion of the first supply line 31 passing through the heat exchange box 53 .

[0071] Typically, such a portion defines the coil 311. Suitably, the coil 311 is embedded in a heat transfer fluid within the heat exchange tank 53. The heat transfer fluid is a liquid. For example, the heat transfer fluid may be of the same type as the working fluid.

[0072] The first supply line 31 is a path that meanders between the mains water intake area and one or more taps through which a user can obtain water (usually in the form of running water).

[0073] The method further comprises a step of transferring heat from the working fluid in the circuit 2 to water for heating at least one environment of the building. This step is performed, for example, by means of the second heat exchange device 4. Typically, the second heat exchange device 4 comprises a plate heat exchanger.

[0074] The water for heating flows along the second supply line 32. In particular, the supply line 32 itself realizes a recirculation. Thus, the water for heating receives heat, reaches the convection heater(s) 7 to heat at least one environment of the building, and then returns to be heated again.

[0075] The present invention has important advantages.

[0076] Firstly, the present invention has a considerable heating performance in heating at least a part of a building and heating sanitary water. In addition, the present invention is easy to maintain.

[0077] By means of the invention, a compact and noise-free solution can also be obtained.

[0078] As conceived, the present invention is susceptible to many modifications and variations, all of which are within the scope of the inventive concept described therein. In addition, all details can be replaced with other technically equivalent elements. In practice, all materials used and sizes can be selected as desired.

Claims

1. A system for heating water, comprising: - a circuit (2) in which a working fluid circulates, said circuit (2) comprising means (20) for heating said working fluid and without an evaporator; - a first supply line (31) for supplying sanitary water; - a second supply line (32) for supplying water intended for heating at least one environment of the building; - a first heat exchange device (5) for exchanging heat between said circuit (2) and said first supply line (31); and - a second heat exchange device (4) for exchanging heat between said circuit (2) and said second supply line (32); It is characterized in that the heating device (20) is composed of a piston pump (21).

2. The system according to claim 1, characterized in that The system comprises an electric motor (22) for driving the piston pump (21); the electric motor (22) comprises / is an asynchronous magnetic motor (22).

3. A system according to any one of the preceding claims, characterised in that The working fluid is R1233ZD(E).

4. A system according to any one of the preceding claims, characterised in that The first heat exchange device (5) comprises: - a self-closed path (50) in which a heat transfer fluid circulates; - a first heat exchanger (52) which places the working fluid circulating in the circuit (2) in thermal communication with the heat transfer fluid circulating in the path (50); and - a heat exchange tank (53) in thermal communication with said first supply line (31).

5. The system according to claim 4, characterized in that The first sanitary water supply line (31) includes a coil (311) running inside the water tank (53).

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

7. The system according to claim 6, characterized in that The system comprises a throttle valve (23) arranged between the first heat exchanger (52) and the additional heat exchanger (54).

8. System according to any one of the preceding claims, characterized in that The system comprises a control unit for adjusting the required temperature and pressure so that the working fluid circulating in the circuit (2) remains in the liquid phase.

9. A method for heating water, involving a 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 the circuit (2); - transferring heat from the working fluid to sanitary water, which flows along a first supply line (31); as well as - transferring heat from the working fluid to water for heating at least one environment of the building, the water for heating flowing along a second supply line (32).

10. The method according to claim 9, characterized in that The pressure of the working fluid is between 6 and 8 bar.

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