A cold and hot dual-purpose centrifugal heat source tower heat pump system

Abstract

The utility model relates to a kind of cold and hot dual-purpose centrifugal heat source tower heat pump system, refrigeration condition, low-pressure centrifugal compressor is communicated with condenser by low-pressure level exhaust line two, condenser is communicated with intermediate economizer by high-pressure liquid line, intermediate economizer is communicated with low-pressure centrifugal compressor by low-pressure air supplement line, intermediate economizer is communicated with evaporator by low-pressure liquid line;When heating condition, low-pressure centrifugal compressor is communicated with intermediate economizer by low-pressure level exhaust line one, intermediate economizer transports gaseous refrigerant to high-pressure centrifugal compressor, high-pressure centrifugal compressor is communicated with condenser by high-pressure level exhaust line, condenser is communicated with intermediate economizer by high-pressure liquid line, intermediate economizer transports gaseous refrigerant to high-pressure centrifugal compressor by high-pressure level suction line, intermediate economizer transports liquid refrigerant to evaporator.Compressor is always operated in high efficiency point, energy-saving and efficient.

Description

Technical Field

[0001] This utility model relates to the technical field of heat source tower heat pump units, specifically to a centrifugal heat source tower heat pump system that can be used for both cooling and heating. Background Technology

[0002] Currently, most heat source tower systems that can be used for both cooling and heating employ a single compressor for both cooling and heating. While this method is simple to control and has low cost, it suffers from the following prominent problems: 1. Limited heating capacity and high pressure ratio: The pressure ratio of a single compressor increases significantly under low-temperature heat pump conditions in winter, resulting in excessively high exhaust temperature, which can easily lead to deterioration of lubricating oil, decreased compressor efficiency, or even system failure.

[0003] 2. Low efficiency under partial load: The operating structure cannot be switched according to the load. For example, in the case of light load in summer, the high voltage level still needs to be involved, resulting in unnecessary energy consumption.

[0004] 3. The gas supply path of the economizer cannot adapt to different operating conditions: The existing structure generally adopts a fixed gas supply connection method, which cannot adjust the gas supply direction for the two modes of cooling and heating respectively, resulting in low energy efficiency, chaotic control, and even backflow interference in the condenser or compressor.

[0005] 4. Lack of automatic flow path switching mechanism: Existing systems generally rely on manual or program switching of compressor working status, lacking automatic flow path control logic that is linked to valve action, resulting in delayed switching and easy errors.

[0006] 5. Lack of dedicated heat pump control logic: Most dual-purpose cooling and heating units use the control strategy of cooling mode and do not consider the specific requirements of series operation in heat pump mode for the economizer gas supply path and compressor suction mode. Utility Model Content

[0007] This utility model addresses existing technical problems by providing a centrifugal heat source tower heat pump system that can be used for both cooling and heating.

[0008] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: A centrifugal heat source tower heat pump system for both cooling and heating includes a low-pressure stage centrifugal compressor, an intermediate economizer, a high-pressure stage centrifugal compressor, a condenser and an evaporator, wherein the evaporator is connected to the low-pressure stage centrifugal compressor through a low-pressure stage suction pipe; In refrigeration mode, the low-pressure stage centrifugal compressor is connected to the condenser through the low-pressure stage exhaust pipe second, the condenser is connected to the intermediate economizer through the high-pressure liquid pipe, the intermediate economizer is connected to the low-pressure stage centrifugal compressor through the low-pressure gas injection pipe, and the intermediate economizer is connected to the evaporator through the low-pressure liquid pipe. In heating mode, the low-pressure centrifugal compressor is connected to the intermediate economizer via the low-pressure exhaust pipe. The intermediate economizer delivers gaseous refrigerant to the high-pressure centrifugal compressor via the high-pressure suction pipe. The high-pressure centrifugal compressor is connected to the condenser via the high-pressure exhaust pipe. The condenser is connected to the intermediate economizer via the high-pressure liquid pipe. The intermediate economizer delivers mixed gaseous refrigerant to the high-pressure centrifugal compressor via the high-pressure suction pipe. The intermediate economizer delivers liquid refrigerant to the evaporator via the low-pressure liquid pipe.

[0009] Based on the above technical solution, the present invention can be further improved as follows: Preferably, it also includes a hot gas bypass pipeline, which is equipped with a hot gas bypass electric ball valve. One end of the hot gas bypass pipeline is connected to the evaporator, and the other end is connected to the exhaust end of the high-pressure centrifugal compressor or the condenser.

[0010] Preferably, it also includes a bypass liquid line, which is equipped with a bypass electric ball valve. One end of the bypass liquid line is connected to the condenser, and the other end is connected to the evaporator.

[0011] Preferably, the low-pressure liquid pipeline is provided with a low-pressure regulating orifice plate.

[0012] Preferably, the high-pressure liquid pipeline is equipped with a high-pressure regulating ball valve and a high-pressure throttling orifice plate.

[0013] The beneficial effects of this invention are as follows: In summer cooling mode, only the low-pressure centrifugal compressor operates, resulting in high efficiency and energy saving; in winter heating mode, the low-pressure compressor and high-pressure compressor operate in series, adapting to the high-pressure specific heat pump operation, improving winter heating capacity, and reducing the burden on the high-pressure stage; during cooling, gas is supplied to the intermediate port of the low-pressure centrifugal compressor through an intermediate economizer, and during heating, the gas is directly supplied to the high-pressure centrifugal compressor, achieving dynamic adjustment of the economizer's gas supply path. Different operating paths are executed according to different operating conditions, ensuring the compressor always operates at its highest efficiency point, resulting in energy saving and high efficiency. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the centrifugal heat source tower heat pump system for both cooling and heating of this utility model; Reference numerals: 1. Low-pressure stage centrifugal compressor; 2. Intermediate economizer; 3. High-pressure stage centrifugal compressor; 4. Condenser; 5. Evaporator; 11. High-pressure stage exhaust electric butterfly valve; 12. High-pressure stage regulating ball valve; 13. High-pressure stage throttling orifice plate; 14. Bypass electric ball valve; 15. Low-pressure stage regulating orifice plate; 16. Low-pressure stage exhaust electric butterfly valve one; 17. Hot gas bypass electric ball valve; 18. Low-pressure stage exhaust electric butterfly valve two; 19. Low-pressure stage air replenishment electric butterfly valve; 102. Low-pressure stage exhaust pipe line one; 203. High-pressure stage intake pipe line; 304. High-pressure stage exhaust pipe line; 402. High-pressure liquid pipe line; 205. Low-pressure liquid pipe line; 405. Bypass liquid pipe line; 501. Low-pressure stage intake pipe line; 305. Hot gas bypass pipe line; 201. Low-pressure make-up air pipe line; 104. Low-pressure stage exhaust pipe line two. Detailed Implementation

[0015] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0016] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. The terms "vertical," "upper," "lower," "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this utility model.

[0017] like Figure 1 As shown, this utility model discloses a centrifugal heat source tower heat pump system for both cooling and heating, including a low-pressure centrifugal compressor 1, an intermediate economizer 2, a high-pressure centrifugal compressor 3, a condenser 4, and an evaporator 5. The evaporator 5 is connected to the low-pressure centrifugal compressor 1 through a low-pressure suction pipe 501. In refrigeration mode, such as summer refrigeration, the low-pressure centrifugal compressor 1 is connected to the condenser 4 through the low-pressure exhaust pipe 104. The low-pressure exhaust pipe 104 is equipped with a low-pressure exhaust electric butterfly valve 16. The condenser 4 is equipped with a cooling water inlet and a cooling water outlet. The condenser 4 is connected to the intermediate economizer 2 through the high-pressure liquid pipe 402. The high-pressure liquid pipe 402 is equipped with a high-pressure regulating ball valve 12 and a high-pressure throttling orifice plate 13. The intermediate economizer 2 is connected to the low-pressure centrifugal compressor 1 through the low-pressure gas supply pipe 201. The low-pressure gas supply pipe 201 is equipped with a low-pressure gas supply electric butterfly valve 19. The intermediate economizer 2 is connected to the evaporator 5 through the low-pressure liquid pipe 205. The low-pressure liquid pipe 205 is equipped with a low-pressure regulating orifice plate 15. The evaporator 5 is equipped with a hot water inlet and a hot water outlet. During operation, the low-pressure stage exhaust electric butterfly valve 16 and the low-pressure stage replenishment electric butterfly valve 19 are opened. The low-temperature, low-pressure gaseous refrigerant from the evaporator 5 enters the low-pressure stage centrifugal compressor 1 through the low-pressure stage suction pipe 501, where it is compressed into a high-temperature, high-pressure gaseous refrigerant. Then, it enters the condenser 4 through the low-pressure stage exhaust electric butterfly valve 16 and the low-pressure stage exhaust pipe 104, where it exchanges heat with cooling water. The high-temperature, high-pressure refrigerant gas is condensed into a high-temperature, high-pressure refrigerant liquid.

[0018] After passing through the high-pressure stage throttling orifice plate 13 and the high-pressure stage regulating ball valve 12 of the high-pressure liquid pipeline 402, the high-temperature and high-pressure refrigerant liquid is throttled and depressurized into a medium-temperature and medium-pressure gas-liquid two-phase state and enters the intermediate economizer 2. The gaseous part of the intermediate economizer 2 enters the intermediate gas injection port of the low-pressure stage centrifugal compressor 1 through the low-pressure gas injection pipeline 201, increasing the cooling capacity of the low-pressure stage centrifugal compressor 1 and improving the cooling efficiency. The medium-temperature liquid refrigerant in the intermediate economizer 2 enters the low-pressure liquid pipeline 205 and is throttled and depressurized again by the low-pressure stage regulating orifice plate 15 into a low-temperature and low-pressure gas-liquid two-phase refrigerant.

[0019] The low-temperature, low-pressure gas-liquid two-phase refrigerant from the low-pressure stage regulating orifice plate 15 enters the evaporator 5, where it exchanges heat with a relatively high-temperature heat transfer fluid, such as hot water, absorbing heat from the heat transfer fluid to cool it down. The low-temperature, low-pressure gas-liquid two-phase refrigerant evaporates into a low-temperature, low-pressure gaseous refrigerant, which then passes through the low-pressure stage suction pipe 501 and is drawn into the low-pressure stage centrifugal compressor 1, where it is compressed again into a high-temperature, high-pressure gaseous refrigerant. This refrigeration cycle is repeated.

[0020] In heating mode, such as during winter heating, the low-pressure centrifugal compressor 1 is connected to the intermediate economizer 2 through the low-pressure exhaust pipe 102. The low-pressure exhaust pipe 102 is equipped with a low-pressure exhaust electric butterfly valve 18. The intermediate economizer 2 delivers gaseous refrigerant to the high-pressure centrifugal compressor 3 through the high-pressure suction pipe 203. The high-pressure centrifugal compressor 3 is connected to the condenser 4 through the high-pressure exhaust pipe 304. The high-pressure exhaust pipe 304 is equipped with a high-pressure exhaust electric butterfly valve 11. The liquid phase of the condenser 4 is connected to the liquid phase of the intermediate economizer 2 through the high-pressure liquid pipe 402. The intermediate economizer 2 delivers gaseous refrigerant to the high-pressure centrifugal compressor 3 through the high-pressure suction pipe 203. The intermediate economizer 2 delivers liquid refrigerant to the evaporator 5 through the low-pressure liquid pipe 205.

[0021] During operation, the high-pressure stage exhaust electric butterfly valve 11 and the low-pressure stage exhaust electric butterfly valve 18 are open, while the low-pressure stage exhaust electric butterfly valve 16 and the low-pressure stage make-up electric butterfly valve 19 are closed. The low-temperature, low-pressure gaseous refrigerant from the evaporator 5 enters the low-pressure stage centrifugal compressor 1 through the low-pressure stage suction line 501, where it is compressed into a medium-temperature, medium-pressure gaseous refrigerant. It then enters the intermediate economizer 2 through the low-pressure stage exhaust line 102 and mixes with the gaseous refrigerant in the intermediate economizer 2. The gaseous refrigerant is formed by the flash evaporation of high-temperature, high-pressure liquid refrigerant through the high-pressure stage throttling orifice plate 13. The mixed gaseous refrigerant is then transported to the high-pressure stage centrifugal compressor 3 through the high-pressure stage suction line 203, where it is compressed into a high-temperature, high-pressure gaseous refrigerant. After that, it enters the condenser 4 through the high-pressure stage exhaust electric butterfly valve 11 and the high-pressure stage exhaust line 304.

[0022] The high-temperature, high-pressure liquid refrigerant flowing out of the condenser 4 is throttled and depressurized into a medium-temperature, medium-pressure gas-liquid two-phase refrigerant after passing through the high-pressure stage throttling orifice plate 13 and the high-pressure stage regulating ball valve 12. It then enters the intermediate economizer 2 through the high-pressure liquid pipeline 402. In the intermediate economizer 2, the gaseous refrigerant mixes with the exhaust gas from the low-pressure stage centrifugal compressor 1 and is then drawn into the high-pressure stage centrifugal compressor 3 through the high-pressure stage suction pipeline 203. The medium-temperature liquid refrigerant is throttled and depressurized again by the low-pressure stage regulating orifice plate 15 along the low-pressure liquid pipeline 205, becoming a low-temperature, low-pressure gas-liquid two-phase refrigerant.

[0023] The low-temperature, low-pressure gas-liquid two-phase refrigerant flowing out from the low-pressure stage regulating orifice plate 15 enters the evaporator 5, where it exchanges heat with a relatively high-temperature heat transfer fluid such as hot water, absorbing heat from the heat transfer fluid to cool it down. The low-temperature, low-pressure gas-liquid two-phase refrigerant evaporates into a low-temperature, low-pressure gaseous refrigerant, and then passes through the low-pressure stage suction pipe 501 and is drawn into the low-pressure stage centrifugal compressor 1, where it is compressed again into a medium-temperature, medium-pressure gaseous refrigerant. This heating cycle is repeated.

[0024] The dual-purpose centrifugal heat source tower heat pump system also includes a hot gas bypass pipe 305, which is equipped with a hot gas bypass electric ball valve 17. One end of the hot gas bypass pipe 305 is connected to the evaporator 5, and the other end is connected to the discharge end of the high-pressure centrifugal compressor 3 or the condenser 4. During operation, when the system is operating at low load, causing the guide vanes of the low-pressure centrifugal compressor 1 and the high-pressure centrifugal compressor 3 to fail to open, or when the pressure ratio is too high, the hot gas bypass electric ball valve 17 is opened. The high-temperature and high-pressure refrigerant discharged from the high-pressure centrifugal compressor 3 is then discharged into the lower-pressure evaporator 5 through the hot gas bypass pipe 305, preventing compressor surge or unit shutdown and ensuring the stability of system operation.

[0025] The dual-purpose centrifugal heat source tower heat pump system also includes a bypass liquid line 405, which is equipped with a bypass electric ball valve 14. One end of the bypass liquid line 405 is connected to the liquid phase portion of the condenser 4, and the other end is connected to the evaporator 5. During operation, when the evaporation pressure monitored by the evaporator 5 is lower than the system preset value, the bypass electric ball valve 14 is opened, allowing high-pressure, high-temperature refrigerant liquid to bypass into the evaporator 5 through the bypass liquid line 405. This increases the liquid level in the evaporator 5, increases the suction pressure of the evaporator 5, improves heat exchange, and simultaneously prevents abnormal conditions such as compressor surge.

[0026] The heat pump system of this utility model adopts multi-stage compression and gas injection enthalpy enhancement technology. It uses intermediate economizer 2 to inject gas into the low-pressure centrifugal compressor 1 to reduce the exhaust temperature. At the same time, it uses low-pressure regulating orifice plate 15 to deeply subcool the liquid refrigerant, reducing the dryness and enthalpy of the low-temperature and low-pressure gas-liquid refrigerant entering the evaporator 5, thereby effectively improving the cooling capacity and cooling energy efficiency of the unit.

[0027] This invention dynamically combines and switches four electric butterfly valves according to the operating status of the heat pump system, automatically adjusting the refrigerant flow direction to achieve dynamic and efficient operation of the heat pump system in both cooling and heating modes. The control strategy is simple and the adjustment is highly efficient.

[0028] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A centrifugal heat source tower heat pump system for both cooling and heating, characterized in that, It includes a low-pressure centrifugal compressor (1), an intermediate economizer (2), a high-pressure centrifugal compressor (3), a condenser (4), and an evaporator (5), wherein the evaporator (5) is connected to the low-pressure centrifugal compressor (1) through a low-pressure suction line (501); In refrigeration mode, the low-pressure centrifugal compressor (1) is connected to the condenser (4) through the low-pressure exhaust pipe (104), the condenser (4) is connected to the intermediate economizer (2) through the high-pressure liquid pipe (402), the intermediate economizer (2) is connected to the low-pressure centrifugal compressor (1) through the low-pressure gas supply pipe (201), and the intermediate economizer (2) is connected to the evaporator (5) through the low-pressure liquid pipe (205). In heating mode, the low-pressure centrifugal compressor (1) is connected to the intermediate economizer (2) through the low-pressure exhaust pipe (102). The intermediate economizer (2) delivers gaseous refrigerant to the high-pressure centrifugal compressor (3) through the high-pressure suction pipe (203). The high-pressure centrifugal compressor (3) is connected to the condenser (4) through the high-pressure exhaust pipe (304). The condenser (4) is connected to the intermediate economizer (2) through the high-pressure liquid pipe (402). The intermediate economizer (2) delivers mixed gaseous refrigerant to the high-pressure centrifugal compressor (3) through the high-pressure suction pipe (203). The intermediate economizer (2) delivers liquid refrigerant to the evaporator (5) through the low-pressure liquid pipe (205).

2. The dual-purpose centrifugal heat source tower heat pump system for both cooling and heating according to claim 1, characterized in that, It also includes a hot gas bypass pipeline (305), on which a hot gas bypass electric ball valve (17) is provided. One end of the hot gas bypass pipeline (305) is connected to the evaporator (5), and the other end is connected to the exhaust end of the high-pressure centrifugal compressor (3) or the condenser (4).

3. The dual-purpose centrifugal heat source tower heat pump system for both cooling and heating according to claim 2, characterized in that, It also includes a bypass liquid line (405), on which a bypass electric ball valve (14) is provided. One end of the bypass liquid line (405) is connected to the condenser (4), and the other end is connected to the evaporator (5).

4. The dual-purpose centrifugal heat source tower heat pump system for both cooling and heating according to claim 1, 2, or 3, characterized in that, The low-pressure liquid pipeline (205) is provided with a low-pressure regulating orifice plate (15).

5. The dual-purpose centrifugal heat source tower heat pump system for both heating and cooling according to claim 1, 2, or 3, characterized in that, The high-pressure liquid pipeline (402) is equipped with a high-pressure regulating ball valve (12) and a high-pressure throttling orifice plate (13).

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