Heat pump system for multi-stage heat supply

Abstract

The utility model provides a heat pump system for multi-stage heat supply, which comprises a water supply end, a water supply pump and a water supply main path, and further comprises multi-stage heat supply units which are sequentially connected in series along the water supply main path, each stage of heat supply unit comprises a heat supply side and a heat load side, the heat supply side comprises a compressor, a water side heat exchanger, an expansion valve and an evaporator, and the heat load side comprises a water side heat exchanger. The water side heat exchanger is provided with a first branch and a second branch which can conduct heat exchange, and the second branch is located on the water supply main line. The heat load side comprises a water inlet electromagnetic valve, a water storage tank, a recirculation electromagnetic valve, a recirculation pump and a water outlet pump, and the water storage tank is provided with a water inlet allowing working medium water to flow in, a water outlet allowing the working medium water to flow out and a recirculation opening allowing the working medium water to flow out. The second branch, the water inlet electromagnetic valve, the water inlet, the recirculation port, the recirculation electromagnetic valve and the recirculation pump are in fluid communication in sequence and form a recirculation loop for working medium water to circularly flow; the water outlet pump is in fluid communication with the water outlet of the water storage tank so as to provide heated working medium water outwards.

Description

Technical Field

[0001] The utility model relates to the technical field of heating, in particular to a heat pump system for multi-stage heating. Background Art

[0002] A heat pump is a highly efficient and energy-saving device that can make full use of low-grade thermal energy. Based on the reverse Carnot cycle, it can transfer part of the heat from an external heat source (such as air, water or geothermal source) to the heated working water through a small amount of work.

[0003] In some heat pump application scenarios, the heat pump system needs to provide multi-stage heating to provide working water of various temperatures. For example, a laundry factory needs the heat pump system to provide warm water for soaking clothes and for washing clothes at the same time. For clothes of different materials and detergents with different characteristics, the required soaking warm water and washing warm water temperatures are also different.

[0004] Existing multi-stage heating heat pump systems usually use multiple heat pump units in series to heat the working water successively according to a preset temperature gradient, so as to provide working water of multiple temperatures to the outside at the same time. In this type of application scenario, the demand for working water at each temperature is not stable (for example, in a laundry factory, the demand for working water at each temperature needs to be determined based on the work schedule of the day and the type of laundry to be washed), so these heat pump systems are usually also equipped with a water tank that can store a certain amount of water and an electric water heater that can heat the working water. Among them, the electric water heater is used to heat the working water whose temperature has dropped due to long-term storage in the water tank. However, compared with the heat pump, the electric heater consumes more electricity when providing the same amount of heat, which increases the operating cost of the heat pump system to a certain extent. Utility Model Content

[0005] In view of the above technical problems, the purpose of the utility model is to provide a heat pump system for multi-stage heating with low operating cost.

[0006] In order to achieve the above-mentioned purpose, the utility model provides the following technical solutions: a heat pump system for multi-stage heating, comprising a water supply end for working medium water to flow into, a water supply pump adjacent to the downstream of the water supply end and a water supply main road, the water supply pump is located on the water supply main road, the heat pump system also includes a multi-stage heating unit connected in series along the water supply main road, the heating unit at each stage includes a heat supply side and a heat load side, the heat supply side includes a compressor, a water side heat exchanger, an expansion valve and an evaporator, the water side heat exchanger has a first branch and a second branch for heat exchange, the compressor, the first branch, the expansion valve and the evaporator flow in series The second branch is connected to the water body and forms a loop for circulating the refrigerant, and the second branch is located on the main water supply line; the heat load side includes a water inlet solenoid valve, a water storage tank, a recirculation solenoid valve, a recirculation pump and a water outlet pump, the water storage tank has a water inlet for the working medium water to flow in, a water outlet for the working medium water to flow out and a recirculation port for the working medium water to flow out, the second branch, the water inlet solenoid valve, the water inlet, the recirculation port, the recirculation solenoid valve and the recirculation pump are fluidically connected in sequence and form a recirculation loop for circulating the working medium water; the water outlet pump is fluidically connected to the water outlet of the water storage tank to provide heated working medium water to the outside.

[0007] In the above technical solution, preferably, a communication path is formed between two adjacent water storage tanks for the working medium water to flow from the high temperature side to the low temperature side, and a selectively openable communication solenoid valve is arranged on the communication path.

[0008] In the above preferred scheme, further preferably, each of the water storage tanks is also equipped with a thermometer, and the heat pump system is constructed to selectively open the connecting solenoid valve or the recirculation solenoid valve based on the signal of the thermometer.

[0009] In the above preferred scheme, it is further preferred that the installation height of each water storage tank is gradually increased in order from low temperature to high temperature.

[0010] In the above preferred solutions, it is further preferred that a selectively activatable communication pump is arranged on the communication path. It is also further preferred that a water level gauge is arranged on the water storage tank, and the heat pump system is configured to selectively activate the communication solenoid valve and the communication pump based on the water level gauge.

[0011] In the above technical solution, preferably, the heating unit further comprises a check valve, and the check valve is arranged on the main water supply line and located upstream of the recirculation loop.

[0012] Compared with the prior art, the heat pump system for multi-stage heating provided by the technical solution of the utility model can open the recirculation solenoid valve and the recirculation pump when the temperature of the working medium water in the water storage tank needs to be increased, so that the working medium water circulates in the recirculation loop, and then the temperature of the working medium water is increased by the water side heat exchanger. This technical solution eliminates the traditional electric water heater and reduces the power consumption and operating cost of the heat pump system. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A heat pump system for multi-stage heating provided by the utility model;

[0014] Figure 2 This is a schematic diagram of another structure provided by the utility model for achieving selective fluid communication between adjacent water storage tanks. DETAILED DESCRIPTION

[0015] In order to explain in detail the technical content, structural features, objectives and effects of the present application, the technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0016] In this application, spatially relative terms such as "under", "below", "under", "lower", "above", "upper", "above", "higher", "side" (for example, as in "sidewall"), etc., are used to describe the relationship of one element to another (other) element as shown in the accompanying drawings. The spatially relative terms are intended to include different orientations of the device in use, operation and / or manufacture in addition to the orientation depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, the elements described as "under" or "beneath" other elements or features will then be positioned as "above" the other elements or features. Therefore, the exemplary term "under" can include both above and below orientations. In addition, the device can be positioned otherwise (for example, rotated 90 degrees or at other orientations), so the spatially relative descriptors used herein are interpreted accordingly.

[0017] In the present application, the term "upstream" (or "downstream") means that one object is located upstream (or downstream) of another object with respect to the flow direction of water.

[0018] Figure 1The heat pump system 100 for multi-stage heating provided by the utility model is shown. The heat pump system 100 has a water supply end 10 for the working medium water to flow in, a water supply pump 1 that can provide flow power for the working medium water, a water supply main path 20, and a multi-stage heating unit connected in series to the water supply main path 20. The heat pump system 100 can gradually increase the temperature of the working medium water according to a preset temperature gradient through the multi-stage heating unit, and simultaneously provide working medium water of different temperatures to the outside. Among them, the water supply pump 1 is adjacent to the downstream of the water supply end 10 and is located on the water supply main path 20. The heat pump system 100 also has a plurality of water outlets (in the same number of stages as the heating unit) Figure 1 In the diagram, the first, second and third water outlets are marked with 30, 40 and 50 respectively).

[0019] It should be noted that the technical solution provided by the utility model can determine the number of stages and temperature gradient of the heating unit according to the actual application situation. Here, for the convenience of explanation, only three stages of heating units are shown in this embodiment and the second stage heating unit is mainly used as an example for explanation. In the legend, for the convenience of distinction, the markings of each device in each stage of the heating unit are distinguished by the first digit of the marking. For example, the compressor of the first stage heating unit is 11, the compressor of the second stage heating unit is 21, and the compressor of the third stage heating unit is 31, and so on.

[0020] like Figure 1 As shown, the second-stage heating unit includes a heat supply side formed by a heat pump unit and a heat load side that can provide working medium water to the outside. Among them, the heat supply side includes a compressor 21, a water-side heat exchanger 22, an expansion valve 23 and an evaporator 24. The water-side heat exchanger 22 has a first branch and a second branch for heat exchange. The compressor 21, the first branch of the water-side heat exchanger 22, the expansion valve 23 and the evaporator 34 are fluidly connected in sequence and form a loop for the circulation of refrigerant. The second branch of the water-side heat exchanger 22 is located on the main water supply line 20.

[0021] Among them, the compressor 21 can compress the low-temperature and low-pressure refrigerant fluid into a high-temperature and high-pressure refrigerant fluid, and provide the refrigerant fluid with power to circulate in the loop; the water-side heat exchanger 22 allows the refrigerant fluid to exchange heat with the working medium water, and allows the high-temperature and high-pressure refrigerant fluid to release heat to the outside and then be converted into a low-temperature and high-pressure refrigerant fluid; the expansion valve 23 can convert the low-temperature and high-pressure refrigerant fluid into a low-temperature and low-pressure refrigerant fluid through the throttling effect; finally, the evaporator 24 allows the low-temperature and low-pressure refrigerant fluid to exchange heat with the external heat source here, and then be converted into a low-temperature and low-pressure refrigerant fluid. Thus, through the above cycle, the refrigerant in the loop transfers part of the heat from the external heat source to the working medium water to heat the working medium water.

[0022] The water side heat exchangers of each level of heating unit are arranged in sequence, so that the working medium water on the water supply main path 20 is gradually heated according to a preset temperature gradient. It should be noted that the heat pump unit can be any one of a water source heat pump unit, an air source heat pump unit and a geothermal source heat pump unit.

[0023] The heat load side of the second-stage heating unit includes a water tank 25 that can store a certain amount of working medium water, a water inlet solenoid valve 26, and a water outlet pump 27. The water tank 25 has a water inlet for the working medium water to flow in and a water outlet for the working medium water to flow out. The two side ends of the water inlet solenoid valve 26 are respectively connected by fluid to the water outlet of the second branch of the water-side heat exchanger 22 and the water inlet of the water tank 25, so as to provide heated working medium water to the water tank 25. The water outlet of the water tank 25, the water outlet pump 27, and the water outlet end 40 are sequentially connected by fluid, and the water outlet pump 27 can transport the working medium water in the water tank 25 to the water outlet end 40 for external use.

[0024] The heat load side of the second-stage heating unit also includes a recirculation solenoid valve 28 and a recirculation pump 29, and a recirculation port (not shown in the figure) for the working medium water to flow out is opened on the water tank 25. The second branch of the water-side heat exchanger 22, the water inlet solenoid valve 26, the water inlet of the water tank 25, the recirculation port of the water tank 25, the recirculation solenoid valve 28 and the recirculation pump 29 are fluidly connected in sequence and form a recirculation loop for the working medium water to circulate. When it is necessary to heat the working medium water in the water tank 25, the recirculation solenoid valve 28 and the recirculation pump 29 can be opened, that is, the above-mentioned recirculation loop is opened, and then the working medium water is heated through the water-side heat exchanger 22. Compared with the traditional method of using an electric heater, under the same heating amount, the recirculation loop only needs to provide a small amount of current for the recirculation pump 29 and the compressor 21 to transfer part of the heat from the external heat source to the working medium water phase, thereby reducing the operating cost of the heat pump system 100.

[0025] Furthermore, the second heating unit is also equipped with a check valve 210 , which is located on the main water supply path 20 and upstream of the recirculation loop to prevent the working medium water from flowing back along the main water supply path 20 .

[0026] Furthermore, when the heat pump system 100 is actually used, there may be a situation where the demand for water at a certain level of the water outlet is low or even zero. In this case, the temperature of the working medium water in the water tank of the corresponding level of the heating unit continues to decrease due to external heat dissipation, and the lost heat is not effectively utilized. To this end, the heat pump system 100 also forms a communication path between the water tanks of the two adjacent levels of the heating units for the working medium water to flow from the water tank on the high temperature side to the water tank on the low temperature side. The communication path is equipped with a communication solenoid valve ( Figure 1 The connecting solenoid valve between the third and second stage heating units and the connecting solenoid valve between the second and first stage heating units) and the connecting water pump ( Figure 1 The connecting water pumps between the third and second stage heating units and the connecting water pumps between the second and first stage heating units are marked with 312 and 211 respectively). Thus, when the demand at the high temperature side water outlet is low or zero, the corresponding connecting solenoid valve and the connecting water pump can be opened to divert the working medium water in the high temperature side water tank to the adjacent low temperature side water tank, so as to utilize the heat of this part of the working medium water.

[0027] Furthermore, each water tank is also equipped with a thermometer (not shown in the figure). The heat pump system 100 is configured to selectively open the recirculation solenoid valve and / or the connecting battery valve based on the thermometer of each water tank. For example, if the water supply temperature required by the second-stage water outlet 40 is 50°C, if the water temperature of the water tank 25 of the second-stage heating unit is 45°C, the connecting solenoid valve 302 can be opened to increase the water temperature of the water tank 25 in a short time by introducing the working medium water in the water tank 35 with a higher temperature. However, if the water temperature of the water tank 25 is only 25°C, the water temperature of the water tank 35 is low, the demand of the third-stage water outlet 50 is large, etc., the recirculation solenoid valve 28 and the recirculation pump 29 can be opened to increase the water temperature in the water tank 25 in a short time.

[0028] Furthermore, in order to avoid the situation where the water level in the water tank is too low (even interruption) or the water level is too high (even overflow), the heat pump system 100 is also equipped with a water level gauge (not shown in the figure) for detecting the water level in the water tank. The heat pump system 100 is configured to selectively open the connecting solenoid valve and the connecting water pump based on the signal of the water level gauge of each water tank. Similarly, taking the water tank 25 as an example, when the water level in the water tank 25 is too low, the connecting solenoid valve 302 and the connecting water pump 312 can be opened without affecting the water tank 35, and water can be injected into the water tank 25 from the water tank 35. Similarly, when the water level in the water tank 25 is too high, the connecting solenoid valve 201 and the connecting water pump 211 can be opened without affecting the water tank 15, and part of the working medium water in the water tank 25 can be injected into the water tank 15. Compared with the traditional method of directly releasing water to lower the water level, this technical solution can effectively utilize the heat of the working medium water.

[0029] Figure 2The second implementation method provided by this embodiment for realizing selective fluid connection between adjacent water tanks is shown. Specifically, the installation height of each water tank is increased in sequence from low temperature to high temperature. In this embodiment, the installation height of each water tank is increased in sequence according to water tank 15, water tank 25 and water tank 35. When the connecting solenoid valve is opened, the working medium water in the water tank on the corresponding high temperature side can flow to the water tank on the low temperature side under the action of gravity. As a result, the connecting water pump is eliminated, further reducing the operating cost of the heat pump system 100. In addition, the protective water level of the water tank can be determined by setting the height of the connection port of the connecting path between the water tank and the corresponding low temperature side, that is, when the water level in the water tank is lower than the height of the corresponding connecting port, even if the connecting solenoid valve on the corresponding connecting path is opened, the working medium water in the water tank will not flow into the water tank on the low temperature side.

[0030] The above embodiments are only for illustrating the technical concept and features of the present application, and their purpose is to enable people familiar with the technology to understand the content of the present application and implement it accordingly, and they cannot be used to limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit of the present application should be included in the protection scope of the present application.

Claims

1. A heat pump system for multi-stage heating, comprising a water supply end for working medium water to flow into, a water supply pump adjacent to the downstream of the water supply end, and a water supply main road, wherein the water supply pump is located on the water supply main road, characterized in that: The heat pump system further comprises a multi-stage heat supply unit connected in series along the water supply main line, each stage of the heat supply unit comprises a heat supply side and a heat load side, the heat supply side comprises a compressor, a water side heat exchanger, an expansion valve and an evaporator, the water side heat exchanger has a first branch and a second branch for heat exchange, the compressor, the first branch, the expansion valve and the evaporator are fluidly connected in sequence and form a loop for circulating the refrigerant, the second branch is located on the water supply main line; the heat load The side includes a water inlet solenoid valve, a water storage tank, a recirculation solenoid valve, a recirculation pump and a water outlet pump. The water storage tank has a water inlet for working medium water to flow in, a water outlet for working medium water to flow out and a recirculation port for working medium water to flow out. The second branch, the water inlet solenoid valve, the water inlet, the recirculation port, the recirculation solenoid valve and the recirculation pump are fluidically connected in sequence to form a recirculation loop for the working medium water to circulate; the water outlet pump is fluidically connected to the water outlet of the water storage tank to provide heated working medium water to the outside.

2. The heat pump system according to claim 1, characterized in that: A communication path is formed between two adjacent water storage tanks for the working medium water to flow from the high-temperature side to the low-temperature side, and a selectively openable communication solenoid valve is arranged on the communication path.

3. The heat pump system according to claim 2, characterized in that: Each of the water storage tanks is also equipped with a thermometer, and the heat pump system is configured to selectively open the communication solenoid valve or the recirculation solenoid valve based on a signal from the thermometer.

4. The heat pump system according to claim 2 or 3, characterized in that: The installation heights of the water storage tanks are gradually increased in order from low temperature to high temperature.

5. The heat pump system according to claim 2 or 3, characterized in that: The communication path is provided with a selectively startable communication pump.

6. The heat pump system according to claim 5, characterized in that: The water storage tank is also provided with a water level gauge, and the heat pump system is constructed to selectively start the communication solenoid valve and the communication pump based on the water level gauge.

7. The heat pump system according to claim 1, characterized in that: The heating unit further comprises a check valve, which is arranged on the main water supply line and located upstream of the recirculation loop.

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