Cascade water source heat pump unit adopting deep supercooling technology
By adding a subcooler to the cascade water source heat pump unit and using the low-temperature drainage after the evaporator as the subcooling source, the problem of insufficient subcooling is solved, the system efficiency and safety are improved, and a deep subcooling effect is achieved.
Patent Information
- Application Number
- CN202520581316.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-31
- Publication Date
- 2026-03-03
- Estimated Expiration
- 2035-03-31
AI Technical Summary
Existing cascade water source heat pump units suffer from limited subcooling, low efficiency, and compromised safety during the subcooling process. This is especially true in open-source water source heat pump systems, where the subcooling effect of the high-temperature, high-pressure liquid after condensation is limited, and obtaining a cold source is difficult.
In a cascade water source heat pump unit, first and second subcoolers are added so that the low-temperature drainage after the evaporator and the high-temperature and high-pressure refrigerant liquid after condensation can exchange heat in the subcooler. The low-temperature drainage is used as the subcooling cold source, and the subcooled drainage is mixed with the inlet water to increase the inlet water temperature, thereby achieving deep subcooling.
It significantly improves the efficiency of the refrigeration system, reduces system energy consumption, enhances the safety and subcooling effect of the unit, and utilizes the heat from the drainage to increase the inlet water temperature, further improving the circulation efficiency.
Smart Images
Figure CN223965629U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the fields of refrigeration, air conditioning and heat pump technology, specifically a cascade water source heat pump unit using deep subcooling technology. Background Technology
[0002] Subcooling is an important mode of refrigeration cycle. In a subcooling cycle, the condensed liquid refrigerant is cooled to below its saturation temperature. Because the refrigerant in this state has a lower temperature before entering the throttling mechanism (such as an expansion valve), losses due to flashing during throttling are reduced, and it can more effectively absorb heat during subsequent evaporation. In a refrigeration system, the greater the subcooling degree of the subcooling cycle, the stronger the cooling capacity per unit mass of refrigerant, and the higher the compressor efficiency, thus improving the overall system efficiency.
[0003] Cascade water source heat pump units generally consist of two independent refrigeration cycles. They use water bodies (such as groundwater, lake water, sewage, etc.) as heat sources and couple the two independent refrigeration cycles through an intermediate heat exchanger (such as a condenser-evaporator) to achieve heating over a larger temperature range. However, it is precisely because of this larger temperature range that the problem of overcooling is more prominent.
[0004] Based on thermodynamic principles, a heat pump is a reverse refrigeration cycle, and therefore the aforementioned subcooling technology is also applied to the heat pump cycle.
[0005] A water source heat pump is a type of heat pump. Broadly speaking, a water source heat pump is a refrigeration system that utilizes low-grade heat energy resources, including surface water, shallow groundwater, and some industrial and domestic wastewater, as a heat source for heating, domestic hot water supply, and some industrial hot water supply. It converts energy through the heat pump principle. Water source heat pump systems are divided into closed-loop and open-loop systems. An open-loop system utilizes low-grade heat energy resources such as groundwater or surface water, and after heat exchange and cooling in the evaporator, the water is directly discharged back to its source. Compared to air conditioning systems, heat pump systems have a larger temperature difference between the evaporation and condensation temperatures. Therefore, the necessity of subcooling the high-temperature, high-pressure liquid after condensation is more prominent, especially for cascade heat pump units, which have lower overall efficiency due to the larger temperature range.
[0006] Currently, heat pump units used in refrigeration and air conditioning systems often rely solely on further cooling within the condenser for subcooling. However, due to the limitation imposed by the temperature of the condensing cooling medium, the degree of subcooling achieved through this method is quite limited. Furthermore, while some systems utilize lower-temperature gaseous refrigerant from the evaporator to further cool the liquid refrigerant and achieve deep subcooling, this approach is not widely adopted. Firstly, the overheating of some refrigerant negatively impacts refrigeration efficiency. Secondly, it often results in the refrigerant not maximizing heat absorption within the evaporator, thus reducing the overall performance of the refrigeration system and making its application highly unprofitable. Additionally, the excessively high return temperature after subcooling not only raises the exhaust temperature of the compressed refrigerant but also affects the safety of unit operation, further restricting this subcooling method.
[0007] In summary, although deep subcooling technology has significant advantages in the refrigeration and air conditioning fields, its application is still severely limited by several constraints. The most important of these is the requirement for a low-temperature cold source with a certain temperature difference between the deep subcooling and the high-temperature, high-pressure liquid after condensation. Furthermore, obtaining such a cold source must not affect the system's original efficiency or increase its energy consumption. In open-source water source heat pump systems, because groundwater or surface water is directly discharged back to its source after heat exchange and cooling, and its temperature is close to the system's evaporation temperature, this drainage is undoubtedly the ideal cold source for the subcooling cycle of the heat pump system without additional energy consumption.
[0008] Therefore, a cascade water source heat pump unit employing deep subcooling technology is proposed to address the aforementioned problems. Utility Model Content
[0009] The purpose of this utility model is to provide a cascade water source heat pump unit using deep subcooling technology to solve the problems mentioned in the background art.
[0010] To achieve the above objectives, this utility model provides the following technical solution: a cascade water source heat pump unit employing deep subcooling technology, comprising a first compressor, a second compressor, a condenser-evaporator, a first subcooler, a second subcooler, an evaporator, a condenser, a water source-side pump, a first throttle valve, a second throttle valve, a first control valve, a second control valve, a third control valve, a water source side, and a user side. The discharge end of the first compressor is connected to the first input end of the condenser-evaporator, the first output end of the condenser-evaporator is connected to the first input end of the first subcooler, the first output end of the first subcooler is connected to the inlet of the first throttle valve, the outlet of the first throttle valve is connected to the first input end of the evaporator, and the first output end of the evaporator is connected to the suction end of the first compressor.
[0011] The discharge end of the second compressor is connected to the first input end of the condenser, the first output end of the condenser is connected to the first input end of the second subcooler, the first output end of the second subcooler is connected to the inlet of the second throttle valve, the outlet of the second throttle valve is connected to the second input end of the condenser-evaporator, and the second output end of the condenser-evaporator is connected to the suction end of the second compressor.
[0012] Preferably, the second input end of the evaporator is connected to the water inlet pipe on the water source side, its second output end is connected to the inlet of the first control valve, the second control valve and the third control valve respectively, the outlet of the second control valve is connected to the second input end of the first subcooler, the outlet of the third control valve is connected to the second input end of the second subcooler, and the outlet of the first control valve is connected to the water return pipe on the water source side.
[0013] Preferably, the second output terminal of the first subcooler is connected to the second output terminal of the second subcooler and the input terminal of the water pump on the water source side.
[0014] Preferably, a first control valve is provided on the connecting pipe between the second output end of the evaporator and the return water pipe on the water source side.
[0015] Compared with the prior art, the beneficial effects of this utility model are:
[0016] This invention adds a subcooler to each stage of the refrigeration cycle in a cascade water source heat pump unit. This allows the low-temperature wastewater from the evaporator in the first-stage refrigeration cycle to exchange heat with the high-temperature, high-pressure refrigerant liquid condensed in each stage of the refrigeration cycle. The groundwater or surface water from the water source serves as both the heat source and the cold source for subcooling. Since the temperature of the low-temperature wastewater after the evaporator in a heat pump system is often significantly lower than the system's condensation temperature, the condensed high-temperature, high-pressure refrigerant liquid achieves deep subcooling without requiring additional energy consumption from the system, thus significantly improving the efficiency of the refrigeration system. Simultaneously, this invention mixes the wastewater from the two subcoolers after subcooling heat exchange with the inlet water from the water source side. This increases the inlet water temperature to some extent, allowing the heat carried by the subcooler wastewater to be utilized, further improving the cycle efficiency of the unit's low-temperature stage. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the structure of this utility model.
[0018] In the diagram: 1-1 First compressor, 1-2 Second compressor, 2 Condenser evaporator, 3-1 First subcooler, 3-2 Second subcooler, 4 Evaporator, 5 Condenser, 6 Water pump on the water source side, 7-1 First throttle valve, 7-2 Second throttle valve, 8-1 First control valve, 8-2 Second control valve, 8-3 Third control valve. Detailed Implementation
[0019] The technical solutions of the present utility model 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 utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0020] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They 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.
[0021] Example:
[0022] Please see Figure 1 This utility model provides a technical solution:
[0023] A cascade water source heat pump unit employing deep subcooling technology includes a first compressor 1-1, a second compressor 1-2, a condenser-evaporator 2, a first subcooler 3-1, a second subcooler 3-2, an evaporator 4, a condenser 5, a water source-side pump 6, a first throttling valve 7-1, a second throttling valve 7-2, a first control valve 8-1, a second control valve 8-2, a third control valve 8-3, a water source side, and a user side. The discharge end of the first compressor 1-1 is connected to the first input end of the condenser-evaporator 2, the first output end of the condenser-evaporator 2 is connected to the first input end of the first subcooler 3-1, the first output end of the first subcooler 3-1 is connected to the inlet of the first throttling valve 7-1, the outlet of the first throttling valve 7-1 is connected to the first input end of the evaporator 4, and the first output end of the evaporator 4 is connected to the suction end of the first compressor 1-1, thereby forming a low-temperature refrigerant circulation loop.
[0024] The discharge end of the second compressor 1-2 is connected to the first input end of the condenser 5, the first output end of the condenser 5 is connected to the first input end of the second subcooler 3-2, the first output end of the second subcooler 3-2 is connected to the inlet of the second throttle valve 7-2, the outlet of the second throttle valve 7-2 is connected to the second input end of the condenser-evaporator 2, and the second output end of the condenser-evaporator 2 is connected to the suction end of the second compressor 1-2. This forms a high-temperature refrigerant circulation loop. The two stages are coupled by sharing the condenser-evaporator 2, thereby improving the efficiency of the entire system and the water supply temperature.
[0025] The second input end of the evaporator 4 is connected to the water inlet pipe on the water source side, and its second output end is connected to the inlet of the first control valve 8-1, the second control valve 8-2 and the third control valve 8-3 respectively. The outlet of the second control valve 8-2 is connected to the second input end of the first subcooler 3-1, thus forming a low-temperature stage water source circulation loop. The outlet of the third control valve 8-3 is connected to the second input end of the second subcooler 3-2, and the outlet of the first control valve 8-1 is connected to the water return pipe on the water source side.
[0026] The second output end of the first subcooler 3-1 is connected to the second output end of the second subcooler 3-2 and the input end of the water pump 6 on the water source side, thus forming a high-temperature water source circulation loop. Through these two water source circulation loops, the unit achieves the goal of using the low-temperature return water after the evaporator 4 to provide a subcooling source for the two subcoolers, enabling them to achieve deep subcooling at the same time.
[0027] A first control valve 8-1 is installed on the connecting pipe between the second output end of the evaporator 4 and the return water pipe on the water source side.
[0028] The second input end of the condenser 5 is connected to the return water pipe on the user side, and its second output end is connected to the supply water pipe on the user side, thus forming a water circulation loop on the user side.
[0029] The inlet of the first control valve 8-1 is connected to the second output end of the evaporator 4, and its outlet is connected to the return water pipe on the water source side. It is used to control and regulate the return water flow on the water source side to meet the flow requirements of the first subcooler 3-1 and the second subcooler 3-2. The second control valve 8-2 and the third control valve 8-3 respectively control and regulate the water flow of the first subcooler 3-1 and the second subcooler 3-2 to meet their subcooling water volume requirements.
[0030] The two outlets of the second control valve 8-2 and the third control valve 8-3 are connected. The cooling water discharged from the first subcooler 3-1 and the second subcooler 3-2 merges and is connected to the input end of the water pump 6 on the water source side. Since the discharge water temperature of the two subcoolers after subcooling heat exchange is higher than the inlet water temperature on the water source side, the discharge water of the two subcoolers mixed with the inlet water on the water source side can increase the inlet water temperature on the original water source side to a certain extent. This also allows the heat carried by the discharge water of the subcoolers to be utilized, and the circulation efficiency of the low-temperature stage of the unit is further improved.
[0031] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. It is obvious to those skilled in the art that this utility model is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or basic characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of this utility model is defined by the appended claims rather than the foregoing description. Therefore, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this utility model, and no reference numerals in the claims should be construed as limiting the scope of the claims.
[0032] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A cascade water source heat pump unit using a deep subcooling technique, comprising a first compressor (1-1), a second compressor (1-2), a condenser-evaporator (2), a first subcooler (3-1), a second subcooler (3-2), an evaporator (4), a condenser (5), a water source side water pump (6), a first throttling valve (7-1), a second throttling valve (7-2), a first control valve (8-1), a second control valve (8-2), a third control valve (8-3), a water source side, and a user side, characterized in that, The exhaust end of the first compressor (1-1) is connected with the first input end of the condensing evaporator (2), the first output end of the condensing evaporator (2) is connected with the first input end of the first subcooler (3-1), the first output end of the first subcooler (3-1) is connected with the inlet of the first throttling valve (7-1), the outlet of the first throttling valve (7-1) is connected with the first input end of the evaporator (4), and the first output end of the evaporator (4) is connected with the suction end of the first compressor (1-1). The exhaust end of the second compressor (1-2) is connected with the first input end of the condenser (5), the first output end of the condenser (5) is connected with the first input end of the second subcooler (3-2), the first output end of the second subcooler (3-2) is connected with the inlet of the second throttling valve (7-2), the outlet of the second throttling valve (7-2) is connected with the second input end of the condensing evaporator (2), and the second output end of the condensing evaporator (2) is connected with the suction end of the second compressor (1-2).
2. The cascade water source heat pump unit employing the deep subcooling technology according to claim 1, characterized in that: The second input end of the evaporator (4) is connected with the water inlet pipe of the water source side, and the second output end thereof is connected with the inlets of the first control valve (8-1), the second control valve (8-2) and the third control valve (8-3) respectively, the outlet of the second control valve (8-2) is connected with the second input end of the first subcooler (3-1), the outlet of the third control valve (8-3) is connected with the second input end of the second subcooler (3-2), and the outlet of the first control valve (8-1) is connected with the water return pipe of the water source side.
3. The cascade water source heat pump unit employing the deep subcooling technology according to claim 1, characterized in that: The second output end of the first subcooler (3-1) is connected with the second output end of the second subcooler (3-2) and the input end of the water pump (6) of the water source side.
4. The cascade water source heat pump unit employing the deep subcooling technology according to claim 1, characterized in that: The first control valve (8-1) is arranged on the connecting pipe of the second output end of the evaporator (4) and the water return pipe of the water source side.