Solar-heat pump combined heating system

Abstract

This utility model relates to a solar-heat pump combined heating system, comprising: a main heat exchanger having a water inlet and an outlet for domestic water to flow in and out respectively; a heat pump unit having a compressor, a throttling valve, and an evaporator, the evaporator having a first branch and a second branch, the main heat exchanger having a first medium inlet and a first medium outlet, the compressor, the first medium inlet, the first medium outlet, the throttling valve, and the first branch being fluidly connected in sequence; and a solar unit including a plurality of vacuum tube groups, a water pump providing flow power for a second medium, and an automatic switching valve, the main heat exchanger having a second medium inlet and a second medium outlet, the second medium outlet and the outlet of the second branch being fluidly connected to the inlets of the plurality of vacuum tube groups, the automatic switching valve having a first interface fluidly connected to the outlets of the plurality of vacuum tube groups, a second interface fluidly connected to the second medium inlet, and a third interface fluidly connected to the inlet of the second branch.

Description

Technical Field

[0001] This utility model relates to the field of heating technology, and in particular to a solar-heat pump combined heating system. Background Technology

[0002] A heat pump is a highly efficient and energy-saving device that fully utilizes low-grade heat energy. Based on a reverse Carnot cycle, it transfers a portion of the heat from an external heat source (such as an air source, water source, or geothermal source) to the heated heating or domestic water supply with minimal work. Solar energy refers to the thermal radiation energy of the sun, a renewable resource primarily manifested as sunlight. In modern times, solar energy is generally used for power generation or to power water heaters, such as solar thermal collectors, solar photovoltaic power generation, and solar thermal power generation.

[0003] Existing solar-heat pump combined heating systems mostly adopt a parallel operation mode between solar units and heat pump units. That is, when solar energy is abundant, the solar units provide heating independently or together with the heat pump units; when solar energy is insufficient, the heat pump provides heating alone. This heating mode means that in winter and other times when solar energy supply is insufficient, the solar units are in a shutdown state, and solar energy cannot be fully utilized. Utility Model Content

[0004] To address the aforementioned technical problems, the purpose of this utility model is to provide a solar-heat pump combined heating system that can fully utilize solar energy even when solar energy supply is insufficient.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a solar-heat pump combined heating system, comprising: a main heat exchanger for exchanging heat between a first medium and / or a second medium and domestic water, the main heat exchanger having a water inlet and a water outlet for domestic water to flow in and out respectively; a heat pump unit, comprising a compressor, a throttling valve, and an evaporator for exchanging heat between the first medium and the second medium, the evaporator having a first branch and a second branch, the main heat exchanger having a first medium inlet and a first medium outlet for the first medium to flow in and out respectively, the compressor, the first medium inlet, the first medium outlet, the throttling valve, and the first branch being sequentially fluidly connected and forming a system for supplying heat to the second medium. A first loop for circulating medium; and a solar unit, including a plurality of vacuum tube assemblies, a water pump providing flow power for a second medium, and an automatic switching valve, wherein the main heat exchanger has a second medium inlet and a second medium outlet for the second medium to flow into and out of, respectively, the second medium outlet and the outlet of the second branch are fluidly connected to the inlets of the plurality of vacuum tube assemblies, the automatic switching valve has a first interface fluidly connected to the outlet of the plurality of vacuum tube assemblies, a second interface fluidly connected to the second medium inlet, and a third interface fluidly connected to the inlet of the second branch, the automatic switching valve having a direct supply state connecting the first interface and the second interface and a combined supply state connecting the first interface and the third interface.

[0006] In the above technical solution, preferably, the heat pump unit is configured with a bypass for the second medium to bypass the plurality of vacuum tube groups. Further preferably, the solar unit also includes a first three-way valve and a second three-way valve. The first three-way valve has a first inlet, a first outlet fluidly connected to the inlet of the plurality of vacuum tube groups, and a second outlet. The second three-way valve has a second inlet fluidly connected to the outlet of the plurality of vacuum tube groups, a third inlet fluidly connected to the second outlet, and a third outlet fluidly connected to the first interface. The second branch and the second medium outlet are simultaneously fluidly connected to the first inlet, and the bypass is formed between the second outlet and the third inlet. Further preferably, the solar unit also includes a water thermometer disposed at the outlet of the plurality of vacuum tube groups, and both the first three-way valve and the second three-way valve are signal-connected to the water thermometer.

[0007] In the above technical solution, preferably, the solar unit further includes an air heat exchanger for heat exchange between the second medium and the ambient air, and the air heat exchanger is disposed between the plurality of vacuum tube groups and the first interface.

[0008] In the above preferred embodiment, and more preferably, the solar unit further includes a water thermometer disposed at the outlet of the plurality of vacuum tube groups for monitoring the outlet water temperature. The automatic switching valve and the air heat exchanger are both signal-connected to the water thermometer. The automatic switching valve switches to direct supply mode when the outlet water temperature of the plurality of vacuum tube groups is higher than a preset first threshold. The air heat exchanger is activated when the outlet water temperature of the plurality of vacuum tube groups is higher than a preset second threshold, wherein the second threshold is greater than the first threshold.

[0009] In the above preferred embodiment, it is further preferred that the air heat exchanger is equipped with a thermometer and a water thermometer for monitoring the ambient air temperature and the temperature of the second medium, respectively, and the air heat exchanger automatically starts when the ambient air temperature is higher than the temperature of the second medium.

[0010] In the above technical solution, preferably, the solar unit further includes a hot water tank that can accommodate a second medium.

[0011] In the above technical solution, preferably, the main heat exchanger includes a box with a heat exchange cavity, a first heat exchange coil located in the box, and a second heat exchange coil located in the box. The water inlet and the water outlet are opened on the box and are in fluid communication with the heat transfer cavity. The first medium inlet, the first heat exchange coil, and the first medium outlet are in fluid communication in sequence. The second medium inlet, the second heat exchange coil, and the second medium outlet are in fluid communication in sequence.

[0012] In the above technical solution, preferably, the first medium is a carbon dioxide fluid.

[0013] Compared to existing technologies, the solar-heat pump combined heating system provided by this utility model allows for direct supply heating when solar energy supply is sufficient. In this case, the automatic switching valve can be set to direct supply mode, and the heat pump unit can be stopped. The second medium, heated by the vacuum tube assembly, directly heats the domestic water. When solar energy supply is insufficient, the automatic switching valve can be set to combined supply mode, and the compressor of the heat pump unit can be turned on. The heat absorbed by the vacuum tube assembly is then transferred to the domestic water via the heat pump unit. Furthermore, in this mode, the evaporation temperature of the first medium in the heat pump unit remains at a high level, thereby improving the COP value of the heat pump unit. Attached Figure Description

[0014] Figure 1 This is a system diagram of the solar-heat pump combined heating system provided by this utility model.

[0015] 100. Solar-heat pump combined heating system;

[0016] 11. Vacuum tube assembly; 12. Water pump; 13. Automatic switching valve; 14. Hot water tank; 15. Bypass; 16. First three-way valve; 17. Second three-way valve; 18. Water thermometer; 19. Air heat exchanger

[0017] 21. Compressor; 22. Expansion valve; 23. Evaporator;

[0018] 31. Main heat exchanger; 311. First heat exchange coil; 312. Second heat exchange coil. Detailed Implementation

[0019] To explain in detail the technical content, structural features, achieved objectives and effects of this application, the technical solutions in the embodiments of this application will be described below with reference to the accompanying drawings.

[0020] In this application, spatial relative terms such as “below,” “under,” “below,” “down,” “above,” “above,” “higher,” and “side” (e.g., as in a “sidewall”) are used to describe the relationship between one element and another (other) element as shown in the accompanying drawings. Spatial relative terms are intended to include different orientations of the device in use, operation, and / or manufacture other than those depicted in the drawings. For example, if the device in the drawings is flipped, an element described as “below” or “under” another element or feature would then be positioned “above” said other element or feature. Thus, the exemplary term “below” can include both above and below orientations. Furthermore, the device may be otherwise positioned (e.g., rotated 90 degrees or in other orientations), thus interpreting the spatial relative descriptive terms used herein accordingly.

[0021] The term "fluid connectivity" refers to the existence of a fluid path between one fluid space (such as the internal space of a water tank, pipe, or pump) and another fluid space, allowing fluid to flow between them. Understandably, "fluid connectivity" in this application includes both direct communication between two fluid spaces and communication via several third fluid spaces. Furthermore, it is a simplified expression for fluid connectivity between one device (such as a pump or evaporator) and another device, i.e., fluid connectivity between the fluid spaces within the two devices.

[0022] In this application, the term "medium" means a fluid that can circulate and exchange heat in a thermal loop to transfer heat, such as water, antifreeze, carbon dioxide fluid, silicone oil, etc.

[0023] See Figure 1This utility model provides a solar-heat pump combined heating system 100, which can still fully utilize solar energy to provide external heating when solar energy supply is insufficient (such as in winter). Specifically, the solar-heat pump combined heating system 100 includes a solar unit for recovering solar energy, a heat pump unit for external heating, and a main heat exchanger 31 for exchanging heat between the first medium and / or the second medium and domestic water.

[0024] The solar power unit includes several vacuum tube assemblies 11 capable of absorbing solar energy, a water pump 12 capable of applying flow power to a fluid, and an automatic switching valve 13. The vacuum tube assemblies 11 convert solar energy into heat energy to heat a first medium flowing through them. Specifically, each vacuum tube assembly 11 consists of several vacuum tubes, each including a glass outer tube with high light transmittance and high heat resistance, an inner tube with a heat-absorbing coating on its inner wall, and heat transfer elements (such as fins, heat pipes, etc.) that transfer the heat absorbed by the heat-absorbing coating to the fluid. The first medium flows through the inner tube of each vacuum tube and is heated by the heat transfer elements.

[0025] Furthermore, in order to maximize the COP value (i.e., the ratio of the heat pump's heating capacity to its input power) of the heat pump unit, the outlet temperature of the first medium at the aforementioned vacuum tube assemblies 11 should be maximized (i.e., the evaporation temperature of the heat pump unit should be increased). Therefore, the solar unit in this embodiment is equipped with three vacuum tube assemblies 11, which are connected in series.

[0026] The automatic switching valve 13 has a first interface, a second interface, and a third interface that are fluidly connected to the outlets of the aforementioned plurality of vacuum tube assemblies 11. The automatic switching valve 13 has a direct supply state when the first interface and the second interface are connected, and a combined supply state when the first interface and the third interface are connected.

[0027] The main heat exchanger 31 allows domestic water to exchange heat with the first medium. It has a water inlet for domestic water to enter, a water outlet for domestic water to exit, a first medium inlet connected to the second interface of the automatic switching valve 13, and a first medium outlet connected to the inlet of the aforementioned vacuum tube assemblies 11. When the automatic switching valve 13 is in the direct supply state, the vacuum tube assemblies 11, the automatic switching valve 13, the first medium inlet, and the first medium outlet are sequentially connected in fluid order to form a first loop for the circulation of the first medium.

[0028] The first medium of the solar power unit and the second medium of the heat pump unit exchange heat via the evaporator 23 of the heat pump unit. Specifically, the evaporator 23 has a first branch and a second branch for heat exchange. The inlet and outlet of the first branch are fluidly connected to the third interface of the automatic switching valve 13 and the inlet of the aforementioned vacuum tube assemblies 11, respectively. When the automatic switching valve 13 is in the combined supply state, the vacuum tube assemblies 11, the automatic switching valve 13, and the first branch are fluidly connected in sequence to form a second loop for the circulation of the first medium.

[0029] Furthermore, to address the temporal discrepancy between solar energy supply and heat demand, this embodiment also includes a hot water collection tank 14 capable of storing a certain amount of the first medium. When solar energy supply is strong (e.g., during the day in summer), the hot water collection tank 14 can store some unused heat within itself in the form of a high-temperature first medium. Conversely, when solar energy supply is weak (e.g., at night and in the morning in summer), the hot water collection tank 14 maintains the inlet temperature of the first branch of the evaporator 23 using the high-temperature first medium stored within it, thereby continuing to supply heat to the heat pump unit and maintaining the evaporation temperature of the heat pump unit at a high level. It is understood that the hot water collection tank 14 and the water pump 12 can be located anywhere in the common area of ​​the first and second circuits; therefore, this invention does not limit their specific location.

[0030] Furthermore, considering that the pipeline of the vacuum tube assembly 11 is relatively long and has many bends, when the solar energy supply is insufficient, the first medium will inevitably experience a large pressure drop and temperature drop when flowing through the aforementioned vacuum tube assemblies 11. Therefore, the solar unit of this embodiment is also equipped with a bypass 15 for the first medium to bypass the aforementioned vacuum tube assemblies 11.

[0031] Specifically, the solar unit is also equipped with a first three-way valve 16 and a second three-way valve 17. The first three-way valve has a first inlet (not shown in the figure) for the first medium to flow in, a first outlet (not shown in the figure) fluidly connected to the inlet of the aforementioned vacuum tube assemblies 11, and a second outlet (not shown in the figure). The second three-way valve 17 has a second inlet (not shown in the figure) fluidly connected to the outlet of the aforementioned vacuum tube assemblies 11, a third inlet (not shown in the figure) fluidly connected to the second outlet of the first three-way valve 16, and a third outlet (not shown in the figure) fluidly connected to the first interface of the automatic switching valve 13. A bypass 15 is formed between the second outlet of the first three-way valve 16 and the third inlet of the second three-way valve 17. Thus, when the solar energy supply is insufficient, the first medium can bypass the aforementioned vacuum tube assemblies 11 through the bypass 15, thereby avoiding the pressure drop and temperature drop caused by the aforementioned vacuum tube assemblies 11.

[0032] Furthermore, this embodiment also includes a water thermometer 18 at the outlet of each of the aforementioned vacuum tube assemblies 11 to detect the outlet water temperature. The first and second three-way valves are signal-connected to the water thermometer 18 and can adjust the opening of their respective valves based on the temperature feedback from the water thermometer 18. Understandably, when the temperature of the water thermometer 18 decreases, it indicates a decline in solar energy supply. The first three-way valve 16 can decrease the opening of the second port while simultaneously increasing the opening of the third port, and the second three-way valve 17 can decrease the opening of the fourth port while simultaneously increasing the opening of the fifth port. As a result, the flow rate of the first medium entering the vacuum tube assembly 11 decreases, but since the outlet temperature of the vacuum tube assembly 11 does not reach the upper limit of the first medium, this portion of the first medium can still fully recover solar energy. In addition, the flow rate of the first medium entering the bypass 15 increases, reducing the pressure drop in the solar unit caused by the vacuum tube assembly 11, further improving the overall efficiency of the solar unit.

[0033] Furthermore, the solar unit is also equipped with an air heat exchanger 19 for heat exchange between the first medium and the ambient air. The air heat exchanger 19 is located between the outlet of the aforementioned vacuum tube group 11 and the first interface of the automatic switching valve 13.

[0034] Continue reading Figure 1 The heat pump unit includes a compressor 21, a throttle valve 22, and an evaporator 23. The main heat exchanger 31 has a second medium inlet and a second medium outlet for the second medium to flow in and out, respectively. The compressor 21, the second medium inlet, the second medium outlet, the throttle valve 22, and the second branch of the evaporator 23 are sequentially fluidly connected to form a heat pump circuit for the second medium to circulate.

[0035] In this process, compressor 21 compresses the second medium, which has a certain degree of superheat, into a high-temperature, high-pressure fluid, providing the power for its circulation in the heat pump circuit. After the high-temperature, high-pressure second medium releases heat to the outside through the main heat exchanger 31, it transforms into a low-temperature, high-pressure second medium fluid. Throttling valve 22 can transform the low-temperature, high-pressure second medium into a low-temperature, low-pressure second medium through a throttling effect. Finally, the low-temperature, low-pressure second medium in evaporator 23 exchanges heat with the first medium of the solar unit, transforming it into a second medium with a certain degree of superheat. Thus, through the above cycle, the second medium in this circuit transfers part of the heat from the first medium to the heating water to heat it.

[0036] Furthermore, to improve the heat exchange efficiency of the main heat exchanger 31, this application employs a coil-type heat exchanger. Specifically, the main heat exchanger 31 includes a housing (not shown in the figure) defining a heat transfer cavity, a first heat exchange coil 311 located within the heat transfer cavity, and a second heat exchange coil 312 also located within the heat transfer cavity. The water inlet and water outlet of the main heat exchanger 31 are both located on the housing and are fluidly connected to the aforementioned heat transfer cavity. The first medium inlet, the first heat exchange coil 311, and the first medium outlet are sequentially fluidly connected, as are the second medium inlet, the second heat exchange coil 312, and the second medium outlet.

[0037] Furthermore, in this embodiment, the second medium of the heat pump unit is carbon dioxide fluid (i.e., the heat pump unit is a carbon dioxide heat pump). This type of heat pump unit has many advantages, such as strong environmental friendliness (global warming potential GWP is only 1), stable chemical properties (non-toxic, non-flammable, and non-explosive), wide operating temperature range (-40℃ to 120℃), and high energy efficiency ratio (COP can reach 4.0 or above). It is suitable for heating ordinary households, especially for households in northern my country where the annual temperature range is large.

[0038] The following explains the working principle of the solar-heat pump combined heating system 100 provided by this utility model.

[0039] When there is sufficient solar energy or the outlet water temperature of the vacuum tube assembly 11 exceeds a preset first threshold, the automatic switching valve 13 switches to direct supply mode and the heat pump unit stops working. The first medium leaving the vacuum tube assembly 11 flows directly to the first medium inlet of the main heat exchanger 31 to heat domestic water.

[0040] During the above-described operating mode, the first medium may boil due to excessive temperature. To avoid this, when the outlet water temperature of the vacuum tube assembly 11 exceeds a preset second threshold, the air heat exchanger 19 is activated to utilize ambient air to lower the temperature of the first medium. The second threshold is greater than the first threshold. Understandably, the above can be automatically controlled via an automatic switching valve 13 and a signal connection between the air heat exchanger 19 and a water thermometer 18 located at the outlet (i.e., when the temperature measured by the water thermometer 18 exceeds the first threshold, the automatic switching valve 13 automatically switches to direct supply mode; when the temperature measured by the water thermometer 18 exceeds the second threshold, the air heat exchanger 19 is activated).

[0041] When solar energy supply is insufficient or the outlet water temperature of the vacuum tube assembly 11 is lower than a preset first threshold, the automatic switching valve 13 switches to combined heat and power mode and the heat pump unit starts. The heat generated by the vacuum tube assembly 11 is transferred to the second medium of the heat pump unit through the evaporator 23, and then transferred to the domestic water through the main heat exchanger 31, thus realizing the effective utilization of solar energy. In addition, the first medium heated by the vacuum tube assembly 11 can also maintain the evaporation temperature of the second medium in the heat pump unit at a higher level, thereby improving the thermal efficiency of the heat pump unit.

[0042] During the above-described operating mode, there may be situations where the ambient temperature is higher than the temperature of the first medium (such as on a summer night). In this case, the air heat exchanger 19 can be activated to heat the first medium using ambient air. It is understood that the above can be achieved automatically by configuring a thermometer and a water thermometer on the air heat exchanger 19 to detect the ambient temperature and the temperature of the first medium, respectively, so that the air heat exchanger 19 automatically starts when the ambient temperature is higher than the temperature of the first medium.

[0043] The above embodiments are only for illustrating the technical concept and features of this application, and are intended to enable those skilled in the art to understand the content of this application and implement it accordingly. They should not be construed as limiting the scope of protection of this application. All equivalent changes or modifications made in accordance with the spirit of this application should be included within the scope of protection of this application.

Claims

1. A solar-heat pump combined heating system, characterized by, include: The main heat exchanger allows the first medium and / or the second medium to exchange heat with domestic water, and the main heat exchanger has a water inlet and a water outlet for domestic water to flow in and out respectively. A heat pump unit includes a compressor, a throttling valve, and an evaporator for heat exchange between a first medium and a second medium. The evaporator has a first branch and a second branch. The main heat exchanger has a first medium inlet and a first medium outlet for the first medium to flow into and out of the unit, respectively. The compressor, the first medium inlet, the first medium outlet, the throttling valve, and the first branch are sequentially fluidly connected, forming a first loop for the circulation of the first medium. The solar power unit includes several vacuum tube assemblies, a water pump that provides flow power for a second medium, and an automatic switching valve. The main heat exchanger has a second medium inlet and a second medium outlet for the second medium to flow into and out of, respectively. The second medium outlet and the outlet of the second branch are both fluidly connected to the inlets of the several vacuum tube assemblies. The automatic switching valve has a first interface fluidly connected to the outlet of the several vacuum tube assemblies, a second interface fluidly connected to the second medium inlet, and a third interface fluidly connected to the inlet of the second branch. The automatic switching valve has a direct supply state with the first interface and the second interface connected, and a combined supply state with the first interface and the third interface connected.

2. The solar-heat pump combined heating system according to claim 1, wherein, The heat pump unit is equipped with a bypass for the second medium to bypass the plurality of vacuum tube groups.

3. The solar-heat pump combined heating system according to claim 2, wherein, The solar unit further includes a first three-way valve and a second three-way valve. The first three-way valve has a first inlet, a first outlet fluidly connected to the inlet of the plurality of vacuum tube groups, and a second outlet. The second three-way valve has a second inlet fluidly connected to the outlet of the plurality of vacuum tube groups, a third inlet fluidly connected to the second outlet, and a third outlet fluidly connected to the first interface. The second branch and the second medium outlet are simultaneously fluidly connected to the first inlet. The bypass is formed between the second outlet and the third inlet.

4. The solar-heat pump combined heating system according to claim 3, wherein The solar unit also includes a water thermometer disposed at the outlet of the plurality of vacuum tube groups, and the first three-way valve and the second three-way valve are both signal connected to the water thermometer.

5. The solar-heat pump hybrid heating system of claim 1, wherein, The solar power unit also includes an air heat exchanger that allows the second medium to exchange heat with the ambient air, and the air heat exchanger is disposed between the plurality of vacuum tube groups and the first interface.

6. The solar-heat pump combined heating system according to claim 5, wherein, The solar unit also includes a water thermometer configured at the outlet of the plurality of vacuum tube groups for monitoring the outlet water temperature. The automatic switching valve and the air heat exchanger are both signal-connected to the water thermometer. The automatic switching valve switches to direct supply mode when the outlet water temperature of the plurality of vacuum tube groups is higher than a preset first threshold. The air heat exchanger starts when the outlet water temperature of the plurality of vacuum tube groups is higher than a preset second threshold, wherein the second threshold is greater than the first threshold.

7. The solar-heat pump combined heating system according to claim 5, wherein The air heat exchanger is equipped with a thermometer and a water thermometer for monitoring the ambient air temperature and the temperature of the second medium, respectively. When the ambient air temperature is higher than the temperature of the second medium, the air heat exchanger will start automatically.

8. The solar-heat pump hybrid heating system of claim 1, wherein, The solar unit also includes a hot water tank that can hold a second medium.

9. The solar-heat pump hybrid heating system of claim 1, wherein, The main heat exchanger includes a housing with a heat exchange cavity, a first heat exchange coil located inside the housing, and a second heat exchange coil located inside the housing. The water inlet and the water outlet are located on the housing and are in fluid communication with the heat exchange cavity. The first medium inlet, the first heat exchange coil, and the first medium outlet are in fluid communication in sequence. The second medium inlet, the second heat exchange coil, and the second medium outlet are in fluid communication in sequence.

10. The solar-heat pump hybrid heating system of claim 1, wherein, The first medium is a carbon dioxide fluid.

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