Water heating system and method

Abstract

To provide a system and a method for heating warm water to be used both for heating (warming) at least one environment of a building, and for hygienic water to be used in the building.SOLUTION: A system for heating water comprises: a circuit (2) in which working fluid is circulated, and including heating means (20) for heating the working fluid; a first supply line (31) for supplying hygienic water; a second supply line (32) for supplying water 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); and second heat exchange means (4) for exchanging heat between the circuit (2) and the second supply line (32). The heating means (20) comprises a piston pump (21).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a system and method for heating hot water, which is used both for heating at least one environment of a building and for sanitary water use within the building.

[0002] This is therefore a civil water heating system. [Background technology]

[0003] Building heating systems are known. In this case, the hot water sent to the convection heaters and the hot water used as sanitary water can be obtained by a boiler burning a fuel. An alternative solution can use a heat pump, which uses the classical elements of the reverse refrigeration cycle, namely a compressor, a condenser, an evaporator and a throttling member acting on an at least partially gaseous fluid. The coefficient of performance (COP) of this kind of heat pump is usually less than 7. The COP is the efficiency index of a heat pump and is given by the ratio between the energy delivered (for example the heat transferred to the environment to be heated) and the electrical energy consumed. Summary of the Invention [Problem to be solved by the invention]

[0004] In this context, the technical problem underlying the present invention is to propose a system and a heating method that makes it possible to obtain high performance and at the same time optimize energy consumption. It also aims to facilitate maintenance. A further objective is to provide a noiseless solution. [Means for solving the problem]

[0005] The defined technical problem and specific objectives are substantially achieved by the system and heating method described below.

[0006] According to a first aspect, the present invention relates to a system for heating water, the system comprising: a circuit in which a working fluid circulates, the circuit including a means for heating the working fluid and not including an evaporator; a first line for supplying sanitary water; a second line for supplying water for heating at least one environment of the building; a first heat exchange means for exchanging heat between said circuit and said first supply line; and second heat exchange means for exchanging heat between said circuit and a second supply line.

[0007] The system is characterized in that the heating means comprises a piston pump.

[0008] In other words, the circuit in which the working fluid circulates does not comprise an evaporator and the heating means consist only of a piston pump which heats the working fluid circulating in said circuit. As a result, no air or liquid from the external environment is required to heat the working fluid. This means that the heating of the system is not dependent on the external temperature or on the external temperature.

[0009] According to another feature, the circuit comprises an electric motor for driving the piston pump, the electric motor comprising or being an asynchronous magneto-electric motor.

[0010] In a preferred embodiment, the working fluid is selected from the group consisting of R1233ZD(E), R1234ZE, and R295.

[0011] More advantageously, the working fluid is R1233ZD(E), which has a Global Warming Potential (GWP) of 5, ie a low greenhouse effect.

[0012] According to a particular embodiment, the first heat exchange means comprises: a closed passage through which a heat transfer fluid circulates; a first heat exchanger that thermally communicates the working fluid circulating in the circuit with the heat transfer fluid circulating in the path; a heat exchange tank in thermal communication with the first supply line.

[0013] More advantageously, said first water supply line for sanitary use comprises a coil passing through the interior of the tank.

[0014] In this embodiment, the system advantageously includes an additional heat exchanger for exchanging heat between the circuit and the first supply line.

[0015] The system preferably includes a throttle valve interposed between the first heat exchanger and the additional heat exchanger.

[0016] The present invention also relates to a method for heating water, comprising the system disclosed above.

[0017] The method comprises: Circulates the working fluid within the circuit, Heating a working fluid circulating in the circuit; transferring heat from the working fluid to sanitary water, the sanitary water moving along a first supply line; Transferring heat from the working fluid to water for heating at least one environment of a building, the water for heating traveling along a second supply line.

[0018] More advantageously, the working fluid has a pressure of between 6 and 8 bar and preferably remains in liquid phase at all times in the circuit.

[0019] Further features and advantages of the present invention will become more apparent from the thus non-limiting description of a preferred but not exclusive embodiment of the system and heating method as shown diagrammatically in FIG. [Brief description of the drawings]

[0020] [Figure 1]In the attached figure, the number 1 designates a system for heating water. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The system 1 comprises a circuit 2 in which a working fluid circulates.

[0022] The working fluid may be a hydrofluoroolefin-based (HFO) fluid such as R1366Mzz or R1233 ZD, or based on ammonia or precipitated calcium carbonate or even others. It is advantageously R1233ZD(E).

[0023] Suitably, the working fluid in circuit 2 remains in liquid phase at all times, advantageously between 6 and 8 bar.

[0024] The circuit 2 includes means 20 for heating a working fluid.

[0025] The circuit 2 comprises a first line 31 supplying water for sanitary purposes. The first supply line 31 typically receives tap water (typically at 3 bar and 15° C.) as input. Such input is indicated with the reference numeral 310.

[0026] The system 1 comprises a second line 32 for supplying heating water for at least one environment of the building. This is water intended to pass through an element adapted to disperse heat in the environment of the building (for example a convection heater 7). The second supply line 32 is closed on itself and thus defines a circulation line. The first and second lines 31, 32 are separate and distinct.

[0027] It should be noted that the numerical adjectives "first" and "second" are used in advance only to distinguish the supply lines, and do not indicate an order or priority (the same applies below).

[0028] The system 1 comprises first heat exchange means 5 for exchanging heat between the circuit 2 and a first supply line 31 .

[0029] The first heat exchange means 5 comprises a closed passage 50 in itself, in which a heat transfer fluid circulates (the closed passage 50 is therefore a circuit). The heat transfer fluid in such a passage 50 remains in liquid form at all times.

[0030] The first heat exchange means 5 comprises a first heat exchanger 52 which provides thermal communication between the working fluid circulating in the circuit 2 and the heat transfer fluid circulating in the path 50. In a particular operating mode, the working fluid enters the first exchanger 52 at a temperature between 110°C and 130°C and leaves at a temperature between 30°C and 50°C. In such an operating mode, the heat transfer fluid circulating in the path 50 leaves the first exchanger 52 at a temperature above 80°C (for example comprised between 80°C and 90°C).

[0031] The first heat exchange means 5 comprises a heat exchange tank 53 in thermal communication with said first supply line 31. For example, such tank 53 has a volume of 10-30 liters, typically 15 liters. The tank 53 also comprises an expansion vessel 530. Suitably, the system 1 comprises a pump 501 (typically a centrifugal pump) for circulating the heat transfer fluid in the passage 50. The pump 501 is arranged downstream of the first exchanger 52 and upstream of the tank 53.

[0032] In particular, the first line 31 supplying sanitary water has a coil 311 passing through a tank 53. A heat transfer fluid is present within the tank 53 and wraps around the outside of the coil 311. Preferably, in the above described mode of operation, the sanitary water exiting the tank 53 is at a temperature between 55°C and 65°C. Suitably, the tank 53 has a temperature probe 531 which measures the temperature of the heat transfer fluid.

[0033] Advantageously, the system comprises an additional heat exchanger 54 through which said working fluid and sanitary water pass. Suitably, the additional heat exchanger 54 performs the function of a pre-heater for the sanitary water (before it enters the tank 53, or rather before it enters the coil 311 present in the tank 53). The exchanger 54 is arranged upstream in the flow direction of the sanitary water from the tank 53. The first exchanger 52 and the additional exchanger 54 are arranged at a distance from each other.

[0034] Suitably, the circuit 2 includes a throttle valve 23 interposed between the heat exchanger 52 and said further heat exchanger 54. The throttle valve 23 is provided at the input to the further heat exchanger 54. Suitably, the throttle valve 23 is capable of receiving a control input as a function of the pressure downstream of the further heat exchanger 54.

[0035] 1, the first heat exchanger 52, the second heat exchanger 55 and the 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.

[0036] The system 1 comprises a second heat exchange means 4 between the circuit 2 and the second supply line 32. The second heat exchange means 4 for example include or are a second heat exchanger 55, typically a plate heat exchanger. These define the area of ​​thermal contact between the circuit 2 and the second supply line 32. The second exchanger 55 therefore influences both the circuit 2 and the second supply line 32. For example, the working fluid may enter the second heat exchange means 4 at a temperature between 150 and 130 °C and leave the second heat exchange means 4 at a temperature between 130 and 110 °C. Advantageously, the heating water of at least one environment of the building leaves the exchanger at a temperature between 80 and 90 °C.

[0037] Preferably, the working fluid and the heated water of the at least one environment of the building are in counter-current flow within the second heat exchange means 4 .

[0038] A temperature probe 321 is disposed along the second line 32 .

[0039] The system 1 includes a water circulation pump 322 along the second line 32. The water circulation pump 322 is typically a centrifugal pump, which allows water to be circulated along the second line between the second heat exchange means and the convection heater 7.

[0040] 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 a measure of the efficiency of a heat pump and is given by the ratio of the energy delivered to the electrical energy consumed. Nevertheless, in contrast to standard heat pumps, the system of the invention does not include an evaporator.

[0041] The pump 21 therefore heats the working fluid, which is caused by the compression effect on the incompressible working fluid, which forces the working fluid along the ducts of the pump 21, increasing its kinetic energy and causing it to heat up due to friction.

[0042] Suitably, the circuit 2 comprises only said piston pump 21 for heating the working fluid circulating therein.

[0043] The piston pump 21, considered as such, is a positive displacement pump of known type. It may be an axial piston pump, but also another type of piston pump. For example, it has a piston housed in a corresponding pump chamber. The pump chamber is advantageously integrated into a rotatable body. The rotation of this body, and therefore of the pump chamber, causes the piston to rotate, thus determining an alternating back and forth movement of the piston in the corresponding pump chamber. In fact, one end of the piston is pressed by elastic means against a plate inclined with respect to the axis of rotation of the pump chamber.

[0044] The system 1 comprises an electric motor 22 for driving the piston pump 21. The electric motor 22 preferably comprises or is a magnetic asynchronous electric motor 22, which allows the system 1 to be noiseless. Preferably, the motor 22 includes an inverter. Furthermore, the operation of the motor 22 is regulated as a function of feedback provided by a temperature probe 321 arranged along the second line 32.

[0045] Between the first exchanger 52 and the piston pump 21 an additional exchanger 54 is interposed.

[0046] The system 1 comprises a filter 61, an inspection hole 62 and a liquid receiver 63. Preferably, these are located downstream of the first heat exchanger 52 and upstream of the additional heat exchanger 54.

[0047] The system 1 suitably includes a soundproof casing that houses the piston pump 21 .

[0048] The system 1 also comprises a control unit which controls the overall operation and regulation of the temperature and pressure required to maintain the working fluid circulating in the circuit 2 in liquid phase.

[0049] The object of the invention is also a method for heating water.

[0050] The method is advantageously implemented by a system 1 having one or more of the characteristics described above.

[0051] The method comprises: Circulating a working fluid in circuit 2, suitably this working fluid always remaining a liquid circulating in circuit 2 (which may therefore also be referred to as working liquid); Heating the working fluid circulating in the circuit 2.

[0052] The heating of the working fluid passing through the circuit 2 occurs during its passage through a piston pump 21 arranged along the circuit 2. The piston pump 21 thereby heats the working fluid. Suitably, at least in the pump 21 (but preferably everywhere), the working fluid is liquid. The piston pump 21 acts on the working fluid such that the pressure of the working fluid is between 6 and 8 bar, for example with R1233ZD(E). In some embodiments, the piston pump 21 acts on the working fluid, causing a pressure increase of at least 10 bar and / or a temperature increase of at least 90° C. Downstream of the piston pump 21, a temperature of the working fluid higher than 110° C. or 120° C. can be obtained. In addition to causing the heating of the working fluid, the pump 21 also causes its movement alone.

[0053] The method includes a step of transferring heat from the working fluid present in the circuit 2 to the sanitary water. Typically, a flow rate of 12 to 16 liters / min is assumed. The sanitary water moves along a first supply line 31. Such heat transfer from the working fluid present in the circuit 2 to the sanitary water is performed indirectly. In practice, heat transfer between the working fluid circulating in the circuit 2 and the heat transfer fluid circulating in the closed path 50, and heat transfer from the heat transfer fluid circulating in the closed path 50 to the sanitary water transported along the first line 31 are assumed.

[0054] The heat transfer from the heat transfer fluid circulating in the closed path 50 to the sanitary water during transport along the first line 31 takes place in a heat exchanger, which preferably comprises: a tank 53 in which a heat transfer fluid is present; A section of the first line 31 passing through the tank 53.

[0055] Typically, such a section defines a coil 311. Preferably, the coil 311 is embedded in a heat transfer fluid present in the tank 53. The heat transfer fluid is a liquid. It may be, for example, the same type as the working fluid.

[0056] A first line 31 is a path that winds between a tap water inlet zone and one or more water taps that make water (typically in the form of running water) available to a user.

[0057] The method also comprises a step of transferring heat from the working fluid present in the circuit 2 to water in order to heat at least one environment of the building. This is for example carried out by means of a second heat exchange means 4. Typically, the second heat exchange means 4 comprises a plate heat exchanger.

[0058] The heating water travels along the second supply line 32. In particular, the side line 32 circulates on itself, so that the heating water receives heat, reaches the convection heater 7 to heat at least one environment of the building, and returns to be heated again.

[0059] The present invention achieves important advantages.

[0060] Firstly, it is possible to obtain a remarkable heating performance which is fully compatible with the heating performance for at least part of the building and for heating the sanitary water, and it is also possible to facilitate maintenance.

[0061] Also, a compact and noise-free solution can be obtained.

[0062] The invention is, as conceivably, susceptible to many modifications and variations, all of which are within the scope of the inventive concept characterized thereby, and all of the detailed elements may be replaced by technically equivalent elements, and in fact all materials and dimensions used may be of any suitable type as required.

Claims

1. A system for heating water, a circuit (2) in which a working fluid circulates, the circuit (2) including a heating means (20) for heating said working fluid and not including an evaporator; a first supply line (31) for supplying sanitary water; a second supply line (32) for supplying water for heating at least one environment of the building; a first heat exchange means (5) for exchanging heat between said circuit (2) and a first supply line (31); a second heat exchange means (4) for exchanging heat between the circuit (2) and a second supply line (32); The heating means (20) comprises a piston pump (21). A system characterized in that

2. 2. The system according to claim 1, further comprising an electric motor (22) for driving the piston pump (21), the electric motor (22) including or being an asynchronous magneto-electric motor (22).

3. 2. The system of claim 1, wherein the working fluid is R1233ZD(E).

4. The first heat exchange means (5) a closed passage (50) through which a heat transfer fluid circulates; a first heat exchanger (52) for thermally connecting the working fluid circulating in the circuit (2) with a heat transfer fluid circulating in the path (50); a heat exchange tank (53) in thermal communication with the first supply line (31); The system of claim 1 , comprising:

5. 5. The system according to claim 4, characterized in that the first sanitary water supply line (31) comprises a coil (311) passing through the interior of the heat exchange tank (53).

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

7. 7. The system according to claim 6, further comprising a throttle valve (23) interposed between said first heat exchanger (52) and said additional heat exchanger (54).

8. 2. A system according to claim 1, characterized in that it includes a control unit for regulating the temperature and pressure necessary to maintain the working fluid circulating in the circuit (2) in the liquid phase.

9. 13. A method for heating water comprising the system of claim 1, comprising: Circulating a working fluid in the circuit (2); Heating the working fluid circulating in the circuit (2); transferring heat from the working fluid to sanitary water, the sanitary water moving along a first supply line (31); Transferring heat from said working fluid to water for heating at least one environment of the building, said water for heating travelling along a second supply line (32). A method comprising:

10. 10. The method according to claim 9, characterized in that the working fluid is R1233ZD(E).

11. The method according to claim 10, characterized in that the working fluid has a pressure of 6 to 8 bar.

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