A cascade dual-heat-source multi-mode heat pump device

Abstract

The application provides a kind of cascade double heat source multi-mode heat pump device, including low temperature stage evaporator, low temperature stage compressor, evaporative condenser, low temperature stage liquid tank, low temperature stage expansion valve, high temperature stage compressor, high temperature stage condenser, high temperature stage liquid tank, high temperature stage expansion valve, stop valve, high temperature stage evaporator, gas-liquid separator, check valve.The application adopts single heat source single stage operation mode, single heat source cascade operation mode, double heat source cascade operation mode three kinds of operation modes according to heat source characteristics and heat sink side heat supply demand, can effectively improve heat pump device performance and realize heat source according to grade configuration, and improve low temperature heat energy utilization efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of heat pumps, and more particularly, to a double-heat-source multi-mode heat pump device. BACKGROUND

[0002] A heat pump is a high-efficiency energy-saving device that makes full use of low-grade heat energy, and has been widely used in life and production heating. In recent years, various types of heat pumps have been widely used in winter heating for farmers, which is conducive to improving the rural living environment. On the other hand, heat pumps use low-temperature waste heat or other forms of low-grade heat energy as a heat source, and output higher-grade heat energy for production process heating, which has obvious energy-saving and efficiency-increasing effects. Therefore, heat pumps have received widespread attention from people.

[0003] However, most of the current heat pumps are single-heat-source configurations, although a few multi-heat-source heat pumps can switch different heat sources, but their operation process is still single-heat-source operation. As known from the characteristics of heat pumps, the smaller the temperature difference between the heat source and the heat sink, the more conducive to improving the operating efficiency of the heat pump. For scenarios where multiple different grade heat energy exists simultaneously, it is of great significance to improve the performance of the heat pump and the utilization rate of low-grade heat energy by realizing parallel utilization of the above heat sources, but the coexisting heat sources often have great differences in "quality" and "quantity". For example, in industrial production, there are often different types of waste heat with different temperatures and quantities, and in rural heating scenarios, in addition to air energy, there is also solar energy, but the temperature time-varying characteristics of the two types of heat energy are very obvious.

[0004] Therefore, there is an urgent need in the prior art for a heat pump technical solution that can flexibly utilize two different heat sources according to their characteristics. SUMMARY

[0005] In view of the above deficiencies in the prior art, the present application provides a double-heat-source multi-mode heat pump device, which is suitable for flexible utilization of heat energy with different characteristics in parallel.

[0006] To achieve the above purpose, the present application is realized by the following technical solutions:

[0007] A cascaded dual-heat-source multi-mode heat pump device includes a low-temperature stage evaporator, a low-temperature stage compressor, an evaporative condenser, a low-temperature stage liquid storage tank, a low-temperature stage expansion valve, a high-temperature stage compressor, a high-temperature stage condenser, a high-temperature stage liquid storage tank, a high-temperature stage expansion valve, a shut-off valve, a high-temperature stage evaporator, a gas-liquid separator, and a check valve. The low-temperature stage working fluid outlet of the low-temperature stage evaporator is connected to the inlet of the low-temperature stage compressor. The outlet of the low-temperature stage compressor is connected to the low-temperature stage working fluid inlet of the evaporative condenser. The low-temperature stage working fluid outlet of the evaporative condenser is connected to the inlet of the low-temperature stage liquid storage tank. The outlet of the low-temperature stage liquid storage tank is connected to the inlet of the low-temperature stage expansion valve. The outlet of the low-temperature stage expansion valve is connected to the low-temperature stage working fluid inlet of the low-temperature stage evaporator. The high-temperature stage working fluid outlet of the evaporative condenser is connected to the gas-liquid separator via a check valve. The high-temperature stage compressor is connected to the inlet; the outlet of the high-temperature stage compressor is connected to the high-temperature stage working fluid inlet of the high-temperature stage condenser; the outlet of the high-temperature stage working fluid of the high-temperature stage condenser is connected to the inlet of the high-temperature stage liquid storage tank; the outlet of the high-temperature stage liquid storage tank is connected to the inlet of the high-temperature stage expansion valve; the outlet of the high-temperature stage expansion valve is connected to the high-temperature stage working fluid inlet of the high-temperature stage evaporator and the high-temperature stage working fluid inlet of the evaporative condenser via shut-off valves; the outlet of the high-temperature stage working fluid of the high-temperature stage evaporator is connected to the inlet of the gas-liquid separator and the inlet of the high-temperature stage compressor via shut-off valves; the outlet of the liquid high-temperature stage working fluid of the gas-liquid separator is connected to the high-temperature stage working fluid inlet of the evaporative condenser via a shut-off valve; and the outlet of the gaseous high-temperature stage working fluid of the gas-liquid separator is connected to the inlet of the high-temperature stage compressor via a check valve.

[0008] The gas-liquid separator has a liquid high-temperature working fluid outlet at the bottom, a gaseous high-temperature working fluid outlet at the top, and a gas-liquid two-phase high-temperature working fluid inlet in the upper middle part.

[0009] The aforementioned cascade dual-heat-source multi-mode heat pump device is characterized in that the working fluid flowing through the low-temperature stage evaporator, low-temperature stage compressor, and low-temperature stage expansion valve is a low-temperature stage working fluid, and the working fluid flowing through the high-temperature stage compressor, high-temperature stage condenser, high-temperature stage expansion valve, high-temperature stage evaporator, and gas-liquid separator is a high-temperature stage working fluid, wherein both the low-temperature stage working fluid and the high-temperature stage working fluid are organic working fluids.

[0010] The advantages of this invention compared to the prior art are:

[0011] 1. This device can realize different heat pump operation modes by controlling the opening and closing of valves and low-temperature compressor according to the characteristics of heat source and heating demand. This device has three operation modes: single heat source single stage operation mode, single heat source cascade operation mode, and dual heat source cascade operation mode.

[0012] 2. When the heat sink side requires a large amount of heat and there are heat sources of different grades, the system adopts a dual heat source cascade operation mode. The low-temperature stage evaporator and the high-temperature stage evaporator respectively incorporate low-grade heat energy and high-grade heat energy, so as to realize the configuration according to the heat source grade, which has higher operating efficiency than single heat source heat pump.

[0013] 3. A gas-liquid separator is installed in the high-temperature stage loop to ensure sufficient gas-liquid separation of the working fluid before it enters the evaporator-condenser. This reduces the dryness of the working fluid at the inlet of the high-temperature stage of the evaporator-condenser and effectively improves the problem of reduced heat exchange efficiency caused by uneven distribution of the working fluid in the evaporator-condenser. Attached Figure Description

[0014] Figure 1 This is a system diagram of the present invention.

[0015] Reference numerals in the attached diagram: 1-Low-temperature stage evaporator, 2-Low-temperature stage compressor, 3-Evaporator-condenser, 4-Low-temperature stage liquid receiver, 5-Low-temperature stage expansion valve, 6-High-temperature stage compressor, 7-High-temperature stage condenser, 8-High-temperature stage liquid receiver, 9-High-temperature stage expansion valve, 10-Stop valve, 11-Stop valve, 12-High-temperature stage evaporator, 13-Stop valve, 14-Stop valve, 15-Gas-liquid separator, 16-Check valve, 17-Stop valve, 18-Check valve. Detailed Implementation

[0016] The present invention will be further described below with reference to specific embodiments.

[0017] like Figure 1 The cascaded dual-heat-source multimode heat pump device shown includes a low-temperature stage evaporator 1, a low-temperature stage compressor 2, an evaporator-condenser 3, a low-temperature stage liquid storage tank 4, a low-temperature stage expansion valve 5, a high-temperature stage compressor 6, a high-temperature stage condenser 7, a high-temperature stage liquid storage tank 8, a high-temperature stage expansion valve 9, a shut-off valve 10, a shut-off valve 11, a high-temperature stage evaporator 12, a shut-off valve 13, a shut-off valve 14, a gas-liquid separator 15, a check valve 16, a shut-off valve 17, and a check valve 18.

[0018] The low-temperature working fluid outlet of the low-temperature evaporator 1 is connected to the inlet of the low-temperature compressor 2. The outlet of the low-temperature compressor 2 is connected to the low-temperature working fluid inlet of the evaporator-condenser 3. The low-temperature working fluid outlet of the evaporator-condenser 3 is connected to the inlet of the low-temperature liquid receiver 4. The outlet of the low-temperature liquid receiver 4 is connected to the inlet of the low-temperature expansion valve 5. The outlet of the low-temperature expansion valve 5 is connected to the low-temperature working fluid inlet of the low-temperature evaporator 1. The high-temperature working fluid outlet of the evaporator-condenser 3 is connected to the inlet of the high-temperature compressor 6 via check valve 18. The outlet of the high-temperature compressor 6 is connected to the high-temperature working fluid inlet of the high-temperature condenser 7. The high-temperature working fluid outlet of the high-temperature condenser 7 is connected to the inlet of the high-temperature liquid receiver 8. The outlet of the high-temperature liquid storage tank 8 is connected to the inlet of the high-temperature expansion valve 9. The outlet of the high-temperature expansion valve 9 is connected to the high-temperature working fluid inlet of the high-temperature evaporator 12 via shut-off valve 11 and to the high-temperature working fluid inlet of the evaporator-condenser 3 via shut-off valve 10. The outlet of the high-temperature working fluid of the high-temperature evaporator 12 is connected to the inlet of the gas-liquid separator 15 via shut-off valve 14 and to the inlet of the high-temperature compressor 6 via shut-off valve 13. The outlet of the liquid high-temperature working fluid of the gas-liquid separator 15 is connected to the high-temperature working fluid inlet of the evaporator-condenser 3 via shut-off valve 17. The outlet of the gaseous high-temperature working fluid of the gas-liquid separator 15 is connected to the inlet of the high-temperature compressor 6 via check valve 16.

[0019] The cascade dual-heat-source multi-mode heat pump unit is divided into three operating modes according to the characteristics of the heat source and heat sink: single heat source single-stage operating mode, single heat source cascade operating mode, and dual heat source cascade operating mode.

[0020] The single-heat-source, single-stage operation mode is used in scenarios where there is a high-grade heat source and the heating capacity and temperature of the device meet the requirements. In this case, the low-temperature stage compressor 2, shut-off valves 10, 14, and 17 are closed, while the high-temperature stage compressor 6, shut-off valves 11 and 13 are turned on. The high-temperature stage working fluid exchanges heat with the high-grade heat source in the high-temperature stage evaporator 12, and then enters the high-temperature stage compressor 6. After being compressed, it enters the high-temperature stage condenser 7 and condenses to release heat. Then, it passes through the high-temperature stage liquid storage tank 8, enters the high-temperature stage expansion valve 9, is throttled and depressurized, and returns to the high-temperature stage evaporator 12, completing the single-heat-source, single-stage cycle.

[0021] The single-heat-source cascade operation mode is used in scenarios where only a low-grade heat source exists and the heating temperature of the single-heat-source single-stage operation mode does not meet the requirements. In this case, the low-temperature stage compressor 2, the high-temperature stage compressor 6, and the shut-off valve 10 are turned on, while the shut-off valves 11, 13, 14, and 17 are turned off. The low-temperature stage working fluid exchanges heat with the low-grade heat source in the low-temperature stage evaporator 1. After being compressed by the low-temperature stage compressor 2, it enters the evaporator-condenser 3. After condensing and releasing heat in the evaporator-condenser 3, the low-temperature stage working fluid passes through the low-temperature stage liquid storage tank 4 and the low-temperature stage expansion valve 5 in sequence. After being throttled and depressurized by the low-temperature stage expansion valve 5, it returns to the low-temperature stage evaporator 1. The high-temperature stage working fluid evaporates into a gaseous state in the evaporator-condenser 3. After being compressed by the high-temperature stage compressor 6, it enters the high-temperature stage condenser 7 and condenses and releases heat. After passing through the high-temperature stage liquid storage tank 8 and the high-temperature stage expansion valve 9 in sequence, it is throttled and depressurized by the high-temperature stage expansion valve 9 and returns to the evaporator-condenser 3 to absorb heat, thus completing the single-heat-source cascade cycle.

[0022] The multi-heat-source cascade operation mode is used in scenarios where low-grade and high-grade heat sources coexist and the other two operating modes have low efficiency or cannot meet heating requirements. In this case, shut-off valves 10 and 13 are closed, and low-temperature stage compressor 2, high-temperature stage compressor 6, shut-off valves 11, 14, and 17 are turned on. The low-temperature stage working fluid exchanges heat with the low-grade heat source in the low-temperature stage evaporator 1, and after being compressed by the low-temperature stage compressor 2, it enters the evaporator-condenser 3. After condensing and releasing heat in the evaporator-condenser 3, the low-temperature stage working fluid passes through the low-temperature stage liquid storage tank 4 and the low-temperature stage expansion valve 5 and returns to the low-temperature stage evaporator 1. The high-temperature stage working fluid in the evaporator-condenser 3... The working fluid absorbs heat and evaporates, then is compressed by the high-temperature compressor 6, and enters the high-temperature condenser 7 to release heat before entering the high-temperature liquid storage tank 8. It is then throttled and depressurized by the high-temperature expansion valve 9, becoming a gas-liquid mixture with a certain degree of dryness. This mixture then enters the high-temperature evaporator 12 and exchanges heat with a higher-grade heat source, further increasing the dryness of the gas-liquid mixture. It then enters the gas-liquid separator 15 for gas-liquid separation. The gaseous high-temperature working fluid passes through the check valve 16 and enters the high-temperature compressor 6. The liquid high-temperature working fluid in the gas-liquid separator 15 passes through the shut-off valve 17 and enters the evaporator-condenser to absorb heat and evaporate, then passes through the check valve 18 and enters the high-temperature compressor 6 again.

[0023] Check valve 16 and check valve 18 are respectively installed at the gaseous high-temperature working fluid outlet of gas-liquid separator 15 and the high-temperature working fluid outlet of evaporator-condenser 3 to prevent the backflow of working fluid caused by pressure imbalance at these two locations.

[0024] The gas-liquid separator 15 is located after the high-temperature evaporator 12. It can effectively improve the uneven distribution of the high-temperature working fluid in the evaporator-condenser 3 caused by the resistance imbalance due to the high dryness of the gas-liquid mixture at the outlet of the high-temperature working fluid of the high-temperature evaporator 12. It can also reduce the resistance of the high-temperature working fluid in the evaporator-condenser 3.

[0025] The above description is only a preferred embodiment of the present invention, but the present invention is not limited to the specific embodiments described above. For those skilled in the art, several modifications and improvements can be made without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A cascaded dual-heat-source multi-mode heat pump device, characterized in that, The system includes a low-temperature evaporator (1), a low-temperature compressor (2), an evaporative condenser (3), a low-temperature liquid storage tank (4), a low-temperature expansion valve (5), a high-temperature compressor (6), a high-temperature condenser (7), a high-temperature liquid storage tank (8), a high-temperature expansion valve (9), a first shut-off valve (10), a second shut-off valve (11), a high-temperature evaporator (12), a third shut-off valve (13), a fourth shut-off valve (14), a gas-liquid separator (15), a first check valve (16), a fifth shut-off valve (17), and a second check valve (18). The low-temperature evaporator... The outlet of the low-temperature working fluid of (1) is connected to the inlet of the low-temperature compressor (2), the outlet of the low-temperature compressor (2) is connected to the inlet of the low-temperature working fluid of the evaporator (3), the outlet of the low-temperature working fluid of the evaporator (3) is connected to the inlet of the low-temperature liquid storage tank (4), the outlet of the low-temperature liquid storage tank (4) is connected to the inlet of the low-temperature expansion valve (5), the outlet of the low-temperature expansion valve (5) is connected to the inlet of the low-temperature working fluid of the low-temperature evaporator (1), and the outlet of the high-temperature working fluid of the evaporator (3) is connected to the inlet of the evaporator (3) via a second check valve. Valve (18) is connected to the inlet of the high-temperature compressor (6), the outlet of the high-temperature compressor (6) is connected to the high-temperature working fluid inlet of the high-temperature condenser (7), the high-temperature working fluid outlet of the high-temperature condenser (7) is connected to the inlet of the high-temperature liquid storage tank (8), the outlet of the high-temperature liquid storage tank (8) is connected to the inlet of the high-temperature expansion valve (9), and the outlet of the high-temperature expansion valve (9) is connected to the high-temperature working fluid inlet of the high-temperature evaporator (12) via a second shut-off valve (11) and to the evaporator-condenser (12) via a first shut-off valve (10). 3) The high-temperature working fluid inlet is connected, and the high-temperature working fluid outlet of the high-temperature evaporator (12) is connected to the inlet of the gas-liquid separator (15) through the fourth shut-off valve (14) and to the inlet of the high-temperature compressor (6) through the third shut-off valve (13). The liquid high-temperature working fluid outlet of the gas-liquid separator (15) is connected to the high-temperature working fluid inlet of the evaporator condenser (3) through the fifth shut-off valve (17). The gaseous high-temperature working fluid outlet of the gas-liquid separator (15) is connected to the inlet of the high-temperature compressor (6) through the first check valve (16).

2. The cascaded dual-heat-source multi-mode heat pump device according to claim 1, characterized in that, The first check valve (16) and the second check valve (18) are respectively located at the gaseous high-temperature working fluid outlet of the gas-liquid separator (15) and the high-temperature working fluid outlet of the evaporator-condenser (3).

3. The cascaded dual-heat-source multi-mode heat pump device according to claim 1, characterized in that, The gas-liquid separator (15) has a liquid high-temperature working fluid outlet at the bottom, a gaseous high-temperature working fluid outlet at the top, and a gas-liquid two-phase high-temperature working fluid inlet in the middle and upper part.

4. The cascaded dual-heat-source multi-mode heat pump device according to claim 1, characterized in that, The cascaded dual-heat-source multi-mode heat pump device has three operating modes: a single-heat-source single-stage operating mode, a single-heat-source cascaded operating mode, and a dual-heat-source cascaded operating mode.

Images