A multi-energy complementary system and method for secondary heating at the end of a central heating system

Abstract

The present invention relates to a multi-energy complementary system and method for secondary heating at the end of a centralized heating system. Through the modification of the front end and the back end of the end user, a water ring heat pump secondary heating is formed. The PVT system increases the return water temperature and stores heat in a water storage tank. The return water with increased temperature is then passed through a water ring heat pump to provide heat for the water supply. At the same time, based on distance as a scale, each area in the centralized heating pipe network system is divided into a parallel mode. Each area is independent of each other and does not affect each other. Each area is a system, which reduces linkage. The present invention not only makes full use of multiple energy sources and reduces the use of fossil energy and electric energy, but also provides energy for users through a solar energy + heat pump system, and divides the area to make the supply and demand more efficiently matched. Based on centralized heating, this invention provides a practical technical path and model for carbon peak in the construction field. This model is combined with ultra-low energy consumption buildings, etc., and it is very easy to achieve the zero energy consumption and zero carbon goals of buildings.

Description

Technical Field

[0001] The present invention belongs to the technical field of comprehensive utilization of energy, and in particular to a multi-energy complementary system and method for secondary heating at the end of a centralized heating system. Background Art

[0002] The country has deepened its energy reform, continuously reduced the consumption of fossil energy, and increased the utilization rate of green, clean and renewable energy. The development of urban centralized heating functions has also developed from "single energy" to "multi-energy combination and complementarity", and the heating energy has gradually transformed from single fossil energy and electric power generation to a multi-energy comprehensive utilization heating system. This move can effectively mobilize resource allocation. Through the combined collaborative heating method, under the premise of a stable and reliable system, it can increase the proportion of green, clean and renewable energy in the entire heating system, avoid the large amount of capital investment and insufficient heating capacity consumed in the construction or reconstruction of centralized heating pipe network systems, solve the practical problem of large demand for centralized heating in winter, reduce the operating cost of centralized heating, and improve environmental benefits.

[0003] The current common problem is that the heating temperature of users far away from the heat exchange station is insufficient due to the loss of the pipe network system. If the overall heating temperature is increased, the temperature of users close to the heat exchange station will be higher, far exceeding the load and causing energy waste. The water ring heat pump is a system that uses a water loop to connect small water / heat pump units in parallel to form a closed loop. This system constitutes a heat pump heating system that recycles the waste heat inside the building as its low-level heat source. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art, and to propose a multi-energy complementary system and method for secondary heating at the end of a centralized heating system, so as to improve the centralized heating system and comprehensively utilize technologies such as heat pumps and solar energy to efficiently achieve the heating problem for end users. By dividing independent heating areas based on distance, the diversified and personalized characteristics of heating, domestic hot water, etc. in each area can be achieved, thereby realizing a heating system based on a PVT-coupled water ring heat pump. At the same time, the present invention is combined with a water ring heat pump to provide an energy supply mode suitable for buildings with cold and hot zones, and heat is stored in a phase change energy storage tank to achieve energy storage, solve the problem of uneven heating water temperature in different rooms of the building due to factors such as the distance from the heat source and the height of the floor, and finally meet the winter heating needs of end users and improve the thermal comfort of people in the room.

[0005] The present invention solves the technical problem by adopting the following technical solutions:

[0006] A multi-energy complementary system for secondary heating at the end of a centralized heating system is installed at both ends of a water supply pipe and a return pipe, and includes an expansion water tank, a main water supply valve, a branch water supply valve, a return water valve and a water ring heat pump system, wherein the water supply pipe is connected to the water ring heat pump systems in different areas and the corresponding expansion water tanks after passing through the main water supply valve and various branch water supply valves.

[0007] Moreover, the water ring heat pump system includes a water ring heat pump, a hot water storage tank, a PVT system, a constant pressure expansion tank, a control valve FM1, a control valve FM2, a control valve FM3, a control valve FM4, a control valve FM5, a control valve FM6, a control valve FM7, a control valve FM8 and a control valve FM9, wherein the water supply pipe is connected to the water ring heat pump through the control valve FM1, the return pipe is connected to the water ring heat pump through the control valve FM2, the water ring heat pump provides heating and water supply to the user through the control valve FM3, the water ring heat pump is connected to the hot water storage tank through the control valve FM4, and the hot water storage tank is connected to the domestic hot water storage tank through the control valve FM5. Water supply pipe, the heat storage tank is connected to the heating return water through control valve FM6, control valve FM8 and control valve FM9, the heating return water is connected to one end of the PVT system through control valve FM9 and control valve FM7, the other end of the PVT system is connected to one end of the constant pressure expansion tank, and the other end of the constant pressure expansion tank is connected to the heat storage tank through control valve FM6, among which control valve FM1, control valve FM3 and control valve FM5 are used as water supply pipe control valves, and control valve FM2, control valve FM4, control valve FM6, control valve FM7, control valve FM8 and control valve FM9 are used as return pipe control valves.

[0008] Moreover, the water ring heat pump serves as a secondary heating system for heating end users. It relies on the water ring heat pump to extract heat from the low-temperature heat source to supply water, increase the water supply temperature, and meet heating requirements; the PVT system and constant pressure expansion tank increase the return water temperature by absorbing heat.

[0009] Moreover, the PVT system includes a photovoltaic system and a phase change energy storage water tank, wherein the photovoltaic system is connected to the water ring heat pump system through the phase change energy storage water tank, and the waste heat of the photovoltaic system is released to the water tank and transferred to the water ring heat pump through heat exchange, and when the water ring heat pump is saturated with heat, it is stored inside the water tank through phase change material.

[0010] Moreover, the phase change energy storage water tank includes a shell, a cold water inlet, a PCM unit, a hot water outlet, an insulation layer, a support frame and a collector return port, wherein the shell is arranged inside the support frame, the cold water inlet is arranged below the side of the shell, the hot water outlet is arranged above the side of the shell, the collector return port is arranged at the bottom of the shell, the PCM unit is arranged inside the shell, the support frame is arranged on the bottom surface of the shell, and is used to support the PCM unit. The medium in the phase change energy storage water tank is water, which is used to provide domestic hot water needs.

[0011] A method for a multi-energy complementary system for secondary heating at the end of a central heating system comprises the following steps:

[0012] Step 1: Different areas are supplied with water through the main water supply valve and branch water supply valve;

[0013] Step 2: The water ring heat pump heats the supply water, reheats it to the specified temperature, and provides it to the user;

[0014] Step 3: When returning water, if the water temperature is low, open the control valve FM8 to allow the return water to pass through the PVT collector to increase the return water temperature, and then enter the water ring heat pump through the phase change energy storage tank to store heat, and serve as a low-temperature heat source to provide heat for the high-temperature heat source; if the temperature of the PVT system is not high, the return water directly enters the phase change energy storage tank to store heat and then exchanges heat in the water ring heat pump.

[0015] Step 4: The return water flows into the return pipe through the return valve.

[0016] The advantages and positive effects of the present invention are:

[0017] The present invention forms a water ring heat pump secondary heating system by modifying the front end and the back end of the end user. The PVT system increases the return water temperature and stores heat in the water storage tank. The return water with increased temperature then passes through the water ring heat pump to provide heat for the water supply. At the same time, based on distance, the various areas in the centralized heating pipe network system are divided into a parallel mode. Each area is independent of each other and does not affect each other. Each area is a system, which reduces the linkage. The present invention not only makes full use of various energy sources and reduces the use of fossil energy and electric energy, but also provides energy for users through the solar energy + heat pump system, and divides the area to make the supply and demand more efficiently matched. Based on centralized heating, this invention provides a practical technical path and model for carbon peak in the construction field. This model is combined with ultra-low energy consumption buildings, etc., and it is very easy to achieve the zero energy consumption and zero carbon goals of buildings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a structural diagram of the water ring heat pump system of the present invention;

[0019] Figure 2 This is a pipeline network transformation diagram of the present invention;

[0020] Figure 3 This is a structural diagram of the phase change energy storage water tank of the present invention.

[0021] Description of labels:

[0022] 1-water ring heat pump, 2-heat storage tank, 3-PVT system, 4-constant pressure expansion tank, 5-control valve FM1, 6-control valve FM2, 7-control valve FM3, 8-control valve FM4, 9-control valve FM5, 10-control valve FM6, 11-control valve FM7, 12-control valve FM8, 13-control valve FM9, 14-expansion tank, 15-different areas, 16-water ring heat pump system, 17-main water supply valve FM10, 18-return valve FM11, 19-branch water supply valve FM12, 20-branch water supply valve FM13, 21-branch water supply valve FM14, 22-return valve FM15, 23-return valve FM16, 24-cold water inlet, 25-PCM unit, 26-hot water outlet, 27-insulation layer, 28-support frame and 29-collector return port. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below with reference to the accompanying drawings.

[0024] A multi-energy complementary system for secondary heating at the end of a central heating system, installed at both ends of the water supply pipe and the return pipe, such as Figure 2 As shown, it includes an expansion water tank 14, different areas 15, a water ring heat pump system 16, a main water supply valve FM10 17, a return water valve FM11 18, a branch water supply valve FM12 19, a branch water supply valve FM13 20, a branch water supply valve FM14 21, a return water valve FM15 22 and a return water valve FM16 23, wherein the water supply pipe is connected to the water inlets of the branch water supply valve FM12, the branch water supply valve FM13 and the branch water supply valve FM14 respectively through the main water supply valve 10, and the water outlets of the branch water supply valve FM12, the branch water supply valve FM13 and the branch water supply valve FM14 are respectively connected to different areas and the water ring heat pump systems and expansion water tanks in different areas.

[0025] The present invention proposes to divide the heating area based on the distance. Buildings that are close and within a certain range can be divided into one heating area, and buildings within a certain range of the next distance can be divided into another heating area. The heating areas are connected in parallel and controlled by their own valves to achieve personalized customization. Each branch has a corresponding expansion water tank and the water ring heat pump system proposed by the present invention. The valve opening and closing of each branch can be controlled according to the actual situation of the building load change.

[0026] like Figure 2As shown, the water ring heat pump system includes a water ring heat pump, a hot water storage tank, a PVT system, a constant pressure expansion tank, a control valve FM1, a control valve FM2, a control valve FM3, a control valve FM4, a control valve FM5, a control valve FM6, a control valve FM7, a control valve FM8 and a control valve FM9, wherein the water supply pipe is connected to the water ring heat pump through the control valve FM1, the return pipe is connected to the water ring heat pump through the control valve FM2, the water ring heat pump provides heating and water supply to the user through the control valve FM3, the water ring heat pump is connected to the hot water storage tank through the control valve FM4, and the hot water storage tank is connected to the domestic hot water through the control valve FM5 Water supply pipe, the heat storage tank is connected to the heating return water through control valve FM6, control valve FM8 and control valve FM9, the heating return water is connected to one end of the PVT system through control valve FM9 and control valve FM7, the other end of the PVT system is connected to one end of the constant pressure expansion tank, and the other end of the constant pressure expansion tank is connected to the heat storage tank through control valve FM6, among which control valve FM1, control valve FM3 and control valve FM5 are used as water supply pipe control valves, and control valve FM2, control valve FM4, control valve FM6, control valve FM7, control valve FM8 and control valve FM9 are used as return pipe control valves.

[0027] As a secondary heating system for heating end users, the water ring heat pump relies on the water ring heat pump to extract heat from the low-temperature heat source to supply water, increase the water supply temperature, and meet the heating requirements; the PVT system and the constant pressure expansion tank absorb heat to increase the return water temperature. In this embodiment, the PVT system can be understood as each end user is equipped with a solar energy utilization device, which can provide electricity to the user in addition to providing heat.

[0028] The PVT system includes a photovoltaic system and a phase change energy storage tank, wherein the photovoltaic system is connected to the water ring heat pump system through the phase change energy storage tank, and the waste heat of the photovoltaic system is released to the water tank and transferred to the water ring heat pump through heat exchange. When the heat of the water ring heat pump is saturated, it is stored in the water tank through phase change materials. Figure 3 As shown, the phase change energy storage water tank includes a shell, a cold water inlet, a PCM unit, a hot water outlet, an insulation layer, a support frame and a collector return port, wherein the shell is arranged inside the support frame, the cold water inlet is arranged below the side of the shell, the hot water outlet is arranged above the side of the shell, the collector return port is arranged at the bottom of the shell, the PCM unit is arranged inside the shell, the support frame is arranged on the bottom surface of the shell, and is used to support the PCM unit. The medium in the phase change energy storage water tank is water, which is used to provide domestic hot water needs.

[0029] The phase change material (PCM) selected for the phase change energy storage water tank is paraffin. In order to avoid direct contact between PCM and water and reaction to pollute the water source, it must be packaged. PCM equal parts can be macro-encapsulated as units through polyethylene bottles, and evenly fixed to the internal space of the water tank with a mesh screen. The horizontal arrangement is tight and a certain gap is left at the top and bottom of the water tank. Cold water is sent into the water tank from the bottom to fully exchange heat with the PCM units on each layer, and then hot water flows out from the top of the water tank. It can achieve uniform horizontal heat distribution in the water tank, and ensure that the upper part has a higher temperature, and the PCM units on each layer fully phase change and store heat. An interface is left at the bottom of the water tank as an outlet for providing the building's domestic hot water needs.

[0030] A method for a multi-energy complementary system for secondary heating at the end of a central heating system comprises the following steps:

[0031] Step 1: Different areas are supplied with water through the main water supply valve and branch water supply valve.

[0032] Step 2: The water ring heat pump heats the supply water, reheats it to the specified temperature, and provides it to the user.

[0033] Step 3: When returning water, if the water temperature is low, open the control valve FM8 to allow the return water to pass through the PVT collector to increase the return water temperature, and then enter the water ring heat pump through the phase change energy storage tank to store heat, and serve as a low-temperature heat source to provide heat for the high-temperature heat source; if the temperature of the PVT system is not high, the return water directly enters the phase change energy storage tank to store heat and then exchanges heat in the water ring heat pump.

[0034] Step 4: The return water flows into the return pipe through the return valve.

[0035] System heating includes the following situations:

[0036] Working condition 1: PVT provides heat;

[0037] Working condition 2: PVT does not provide heat.

[0038] The valve switching between various working conditions is based on the temperature conditions provided by the PVT backplane, water tank and indoor temperature monitoring device, combined with the overall heating demand of the project and the operating strategy of each working condition to open or close the valve.

[0039] The valve switching mode for each working condition is shown in the following table

[0040]

[0041] The present invention can improve the heating temperature of the end users of centralized heating, and solve the impact of heat loss caused by the medium in transportation due to the long pipeline network on the end users. The heating problem of end users can be efficiently achieved by improving the centralized heating system and comprehensively utilizing technologies such as heat pumps and solar energy. By dividing independent heating areas based on distance, diversified and personalized characteristics requirements for heating, domestic hot water, etc. in each area can be achieved, thereby realizing a heating system based on PVT coupling water ring heat pump. Combined with a water ring heat pump, a power supply mode suitable for buildings with cold and hot zones is provided, and heat is stored in a phase change energy storage tank to achieve energy storage, solve the problem of uneven heating water temperature in different rooms of the building due to factors such as the distance from the heat source and the height of the floor, and finally meet the winter heating needs of end users and improve the thermal comfort of people in the room.

[0042] In the first aspect, the present invention proposes a water ring heat pump system

[0043] In order to solve the problem that the water temperature supplied to the end user is low because the end user is too far away from the heat exchange station and the heat loss of the pipeline on the way, if the water supply temperature of the heat exchange station is increased, the water temperature of the near-end user will be high, causing waste. The present invention proposes to install a water ring heat pump at the front end of the end user side, and perform secondary heating of the fluid medium before the end user through the operation of the heat pump, so as to ensure that the system is energy-saving and reasonable.

[0044] In the second aspect, the present invention proposes a multi-energy complementary central heating system

[0045] The present invention proposes to add a photovoltaic thermal integration (PVT) system to the user-side return water pipeline. The system can absorb the heat of sunlight and convert it into the heat of the medium, and add a hot water storage tank to the system to store the heat of the medium. When the water temperature rises to a certain temperature, hot water can be transported out for users to use; when the temperature does not reach the set value, it can enter the heat pump system through the return water pipeline, extract heat to supply high-temperature heat source heating, and provide a heat source for secondary heating of users;

[0046] Phase change energy storage water tank, the photovoltaic system and the water ring heat pump system are connected through the water tank. The waste heat of the photovoltaic system can be released to the water tank and transferred to the water ring heat pump through heat exchange. When the heat of the water ring heat pump is saturated, it can be stored in the water tank through phase change materials to achieve heat storage. At the same time, the medium in the hot water storage tank is water, which can also provide domestic hot water and other needs;

[0047] Thirdly, the heating areas are divided by distance, and each area is independent of each other and does not affect each other.

[0048] Considering the large coverage area and long length of the centralized heating network, different building requirements, different loads, and different operating characteristics in each area, the present invention proposes to divide the heating area by distance, and each heating area is connected in parallel, and the opening and closing of the pipelines in each area are controlled by valves. This system facilitates personalized control of each area, reduces the impact range of system failures during operation, reduces the scope of maintenance, and appropriately reduces the diameter of each branch pipe, reducing initial investment.

[0049] The PVT coupled water ring heat pump system designed in the present invention can solve the impact of PVT high-temperature waste heat on power generation efficiency and improve power generation; PVT, water ring heat pump and water tank provide energy in multiple dimensions, providing more ideas for building energy supply; the system adds batteries and phase change energy storage tanks to realize energy storage of both electrical energy and thermal energy, providing reliable support for independent operation of the building.

[0050] It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive. Therefore, the present invention includes but is not limited to the embodiments described in the specific implementation manner. Any other implementation manners derived by those skilled in the art based on the technical solution of the present invention also fall within the scope of protection of the present invention.

Claims

1. A multi-energy complementary method for a multi-energy complementary system for secondary heating at the end of a central heating system, characterized in that: The system used is installed at both ends of the water supply pipe and the return pipe, including an expansion water tank, a main water supply valve, a branch water supply valve, a return water valve and a water ring heat pump system. The water supply pipe passes through the main water supply valve and each branch water supply valve to connect the water ring heat pump system in different areas and the corresponding expansion water tank; The water ring heat pump system includes a water ring heat pump, a heat storage tank, a PVT system, a constant pressure expansion tank, a control valve FM1, a control valve FM2, a control valve FM3, a control valve FM4, a control valve FM5, a control valve FM6, a control valve FM7, a control valve FM8 and a control valve FM9, wherein the water supply pipe is connected to the water ring heat pump through the control valve FM1, the return pipe is connected to the water ring heat pump through the control valve FM2, the water ring heat pump provides heating and water supply to the user through the control valve FM3, the water ring heat pump is connected to the heat storage tank through the control valve FM4, the heat storage tank is connected to the domestic hot water supply through the control valve FM5 Water pipe, the heat storage tank is connected to the heating return water through the control valve FM6, the control valve FM8 and the control valve FM9, the heating return water is connected to one end of the PVT system through the control valve FM9 and the control valve FM7, the other end of the PVT system is connected to one end of the constant pressure expansion tank, and the other end of the constant pressure expansion tank is connected to the heat storage tank through the control valve FM6, among which the control valve FM1, the control valve FM3 and the control valve FM5 are used as the water supply pipe control valves, and the control valves FM2, the control valve FM4, the control valve FM6, the control valve FM7, the control valve FM8 and the control valve FM9 are used as the return pipe control valves The multi-energy complementation method comprises the following steps: Step 1: Different areas are supplied with water through the main water supply valve and branch water supply valve; Step 2: The water ring heat pump heats the supply water, reheats it to the specified temperature, and provides it to the user; Step 3: When returning water, if the water temperature is low, open the control valve FM8 to allow the return water to pass through the PVT heat collector to increase the return water temperature, and then enter the water ring heat pump through the phase change energy storage tank to store heat and provide heat for the high-temperature heat source as a low-temperature heat source; if the temperature of the PVT system is not high, the return water directly enters the phase change energy storage tank to store heat and then exchanges heat in the water ring heat pump; Step 4: The return water flows into the return pipe through the return valve.

2. The multi-energy complementary method of a multi-energy complementary system for secondary heating at the end of a central heating system according to claim 1, characterized in that: The water ring heat pump serves as a secondary heating system for heating end users. It relies on the water ring heat pump to extract heat from the low-temperature heat source to supply water, increase the water supply temperature, and meet heating requirements; the PVT system and the constant pressure expansion tank increase the return water temperature by absorbing heat.

3. The multi-energy complementary method of a multi-energy complementary system for secondary heating at the end of a central heating system according to claim 1, characterized in that: The PVT system includes a photovoltaic system and a phase change energy storage water tank, wherein the photovoltaic system is connected to the water ring heat pump system through the phase change energy storage water tank, the waste heat of the photovoltaic system is released to the water tank and transferred to the water ring heat pump through heat exchange, and when the water ring heat pump is saturated with heat, it is stored inside the water tank through phase change material.

4. The multi-energy complementary method of a multi-energy complementary system for secondary heating at the end of a central heating system according to claim 1, characterized in that: The phase change energy storage water tank comprises a shell, a cold water inlet, a PCM unit, a hot water outlet, an insulation layer, a support frame and a collector return port, wherein the shell is arranged inside the support frame, a cold water inlet is arranged below the side of the shell, a hot water outlet is arranged above the side of the shell, a collector return port is arranged at the bottom of the shell, the PCM unit is arranged inside the shell, the support frame is arranged on the bottom surface inside the shell for supporting the PCM unit, and the medium in the phase change energy storage water tank is water for providing domestic hot water demand.

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