Novel double-warm-water-path air conditioning system and control method thereof

Abstract

The invention relates to a novel double-temperature water path air conditioning system and a control method thereof. A main loop of a cold water (heat pump) unit in the system comprises a compressor, a four-way reversing valve, a first / second / third heat exchanger, a first throttling / second throttling element and a gas-liquid separator, and a bypass branch (with a bypass valve) is additionally arranged; and two independent secondary refrigerant loops are arranged to be connected with the indoor environment in a heat exchange manner. Cold generated by evaporation heat absorption of a refrigerant and heat generated by condensation heat release are synchronously utilized and conveyed into a room through a secondary refrigerant, and the flow of the secondary refrigerant at the tail end is adjusted, so that the heat-humidity ratio in the air treatment process is adjusted, and decoupling treatment and dynamic matching of a single unit to heat and humidity loads are achieved. And under the high-humidity load working condition, one path of secondary refrigerant utilizes cold energy to cool and dehumidify indoor air, and the other path of secondary refrigerant utilizes supercooling heat and / or condensation heat to carry out reheating temperature control on the air. Under the working condition of high sensible heat load, the two paths of secondary refrigerants cooperate for refrigerating / heating, and the unified output capacity meets the peak load requirement.

Description

Technical Field

[0001] The present invention relates to an air-conditioning system, in particular to a novel dual-temperature water-circuit air-conditioning system and a control method thereof. Background Art

[0002] HVAC systems account for over 50% of a building's total operating energy consumption, making them a key area for building energy conservation and emission reduction. Air conditioning systems primarily address heat and moisture loads within a building, and a building's load characteristics (the proportion of heat and moisture loads) vary dynamically over time and space.

[0003] Over time, the proportion of a building's heat and humidity load fluctuates significantly with season, climate, and even day and night. For example, southern my country experiences continuous rain during the transition season, resulting in high humidity load and low heat load. The tropical monsoon climate in Guangdong, Guangxi, Hainan, and Southeast Asia leads to long periods of high temperature and humidity in the summer, resulting in consistently high heat and humidity loads. In winter, however, the humidity decreases, requiring the primary focus on sensible heat loads.

[0004] Spatially, different functional areas within a building experience varying loads depending on their orientation, building envelope, occupancy density, and user preferences. For example, equipment rooms primarily generate heat loads with relatively low moisture loads, requiring only cooling. However, crowded conference rooms require both heat and moisture loads. In winter, rooms near the building's perimeter require heating, while core areas within the building may require cooling due to heat generated by equipment.

[0005] Traditional air conditioning systems generally utilize coupled heat and moisture management technology. The key reason for their high energy consumption is that a single system or device cannot adapt to the spatiotemporal dynamics of building loads, necessitating the use of additional equipment to address gaps or redundancies in heat and moisture loads. Currently, mainstream VRFs and chillers utilize air cooling for dehumidification. In high-humidity conditions (such as the summer in Guangdong and Guangxi or the rainy season in Southeast Asia), the supply air temperature is forced to drop below the dew point to meet dehumidification requirements. To avoid compromising thermal comfort, additional electric heating or boiler reheating is necessary, significantly increasing energy consumption.

[0006] To overcome this shortcoming, the industry has developed a dual-cooling-source air conditioning system, utilizing a high-temperature cooling source (16-20°C) to process sensible heat and a low-temperature cooling source (7°C) to process latent heat, thereby achieving independent control of temperature and humidity. This system has two main implementations: one employs two independent subsystems to generate high and low-temperature cooling sources, respectively. Patent CN 110953668 A utilizes a combination of a chiller (high-temperature cooling source) and ice storage (low-temperature cooling source), processing sensible and latent heat separately through parallel terminals. Because the two treated air streams in this system need to be mixed to achieve the desired state, to minimize mixing losses, each air stream must be treated to a lower temperature and humidity, increasing energy consumption and increasing processing time. This system also presents challenges with high equipment investment and complex system design. The other approach utilizes a single refrigeration system to generate two evaporation temperatures, thus achieving dual-temperature cooling sources. Patent CN 117167859 A utilizes stepped air intake to achieve two evaporation temperature levels, alleviating the issue of heat and moisture coupling. However, this approach creates significant coupling between the two cooling sources, making control difficult and hindering dynamic matching of heat and moisture loads. Furthermore, existing dual-cooling-source air conditioning systems are unable to synchronously respond to the simultaneous heating and cooling demands of different spaces within a building, failing to address the problem of load coordination across time and space.

[0007] In summary, the current industry has not yet broken through the technical bottleneck of dynamically adjusting the heat and humidity ratio with a single device. It is unable to flexibly respond to changes in load characteristics outside the building in different seasons, and it is difficult to meet the heat and humidity treatment needs of different spaces inside the building. Summary of the Invention

[0008] The present invention aims to overcome the shortcomings of the aforementioned prior art by providing a novel dual-temperature water-circuit air conditioning system. This system utilizes a brine loop as an intermediate medium, connecting the chiller (heat pump) unit to the air conditioning environment in a heat exchange manner. This system allows for flexible indoor expansion, stable regulation, and enhanced safety. Unlike conventional air conditioning systems that utilize heat-moisture coupling, this system flexibly distributes the refrigerant's evaporative cooling and condensation heat between two independent brine loops. Control valves are used to control the brine flow at the end points, thereby meeting differentiated load requirements within the room. This achieves decoupling and dynamic matching of heat and moisture loads within a single unit. Under high-humidity load conditions, one brine loop utilizes cooling capacity for dehumidification, while the other utilizes supercooling heat and / or condensation heat for reheating and temperature control. This achieves heat-moisture decoupling while increasing the subcooling level of the unit's refrigeration cycle, thereby improving system energy efficiency. Under high sensible heat load conditions, the two brine loops provide coordinated cooling / heating, with unified output capacity to meet peak load demands. Under low-load conditions, cold storage / heat storage operation is achieved by switching a small number of regulating valves, thereby realizing the effect of load peak regulation.

[0009] This invention achieves decoupled control of temperature and humidity using a single chiller (heat pump), resulting in a more compact system structure and significantly reducing equipment complexity and initial investment costs. The use of series terminals allows for simultaneous treatment of air to the target temperature and humidity, effectively avoiding the air mixing losses and control lag associated with parallel terminals in dual-cold-source air conditioning systems. The overall vapor compression cycle of this invention is minimally altered, resulting in reliable control and stable operation of the chiller (heat pump). It also allows for targeted improvements in cycle efficiency (for example, leveraging indoor reheat demand to increase cycle subcooling), reducing overall power consumption. Regarding energy utilization, this invention achieves synergistic utilization of heat and cold sources: condensation heat is used for reheating in summer, while evaporative cooling is used for internal cooling in winter, significantly improving energy efficiency. Compared to traditional dual-cold-source air conditioning systems, this invention offers superior dynamic adaptability and control range to heat and humidity loads, better adapting to the spatiotemporal variations in a building's thermal and humidity environment.

[0010] The first object of the present invention is to protect a novel dual-temperature water-circuit air-conditioning system, which includes a refrigerant circulation circuit, a coolant circulation circuit and an air flow circuit.

[0011] The refrigerant circulation circuit includes a refrigerant main circulation circuit and a bypass branch.

[0012] The refrigerant main circulation loop includes a compressor, a four-way reversing valve, a first heat exchanger, a first throttling element, a second heat exchanger, a second throttling element, a third heat exchanger and a gas-liquid separator which are connected in sequence.

[0013] One end of the bypass branch is connected to the pipeline between the second heat exchanger and the first throttling element, and the other end is connected to the pipeline between the first heat exchanger and the four-way reversing valve.

[0014] The brine circulation circuit includes a first brine circulation circuit and a second brine circulation circuit.

[0015] The first coolant circulation loop includes:

[0016] The first brine unit side circuit connects the second heat exchanger to the first water tank in a heat exchange manner, and includes the first water tank, the brine channel of the second heat exchanger, and the first brine circulation pump;

[0017] The first brine user-side circuit connects the first water tank to the terminal heat exchanger in a heat exchange manner, and includes the first water tank, the first brine delivery pump, the first to Nth post-processing regulating valves at the terminal, and brine channels of the first to Nth post-processing heat exchangers at the terminal;

[0018] The second coolant circulation loop includes:

[0019] The second brine unit side circuit connects the third heat exchanger to the second water tank in a heat exchange manner, and includes the second water tank, the second brine circulation pump, and the brine channel of the third heat exchanger;

[0020] The second refrigerant user-side circuit connects the second water tank with the terminal heat exchanger in a heat exchange manner, and includes a second water tank, a second refrigerant delivery pump, the first to Nth pre-treatment regulating valves at the terminal, and the refrigerant channels of the first to Nth pre-treatment heat exchangers at the terminal.

[0021] The air flow path includes first to Nth air flow paths. The i-th air flow path includes the air passage of the i-th pre-processing heat exchanger at the terminal, the air passage of the i-th post-processing heat exchanger at the terminal, and the i-th indoor fan. i is any integer between 1 and N. N ≥ 1.

[0022] Furthermore, the four ports of the four-way reversing valve are respectively connected to the exhaust port of the compressor, the intake port of the compressor (via the gas-liquid separator), the refrigerant channel of the first heat exchanger and the refrigerant channel of the third heat exchanger.

[0023] Furthermore, the first heat exchanger is a refrigerant-air heat exchanger. The first heat exchanger is typically a fin-tube heat exchanger or a microchannel heat exchanger. The first heat exchanger is equipped with a fan to drive air circulation.

[0024] Furthermore, the second and third heat exchangers are refrigerant-coolant heat exchangers. The second and third heat exchangers are typically plate heat exchangers, double-tube heat exchangers, or shell-and-tube heat exchangers. The coolant is preferably water, which is readily available at a relatively low cost.

[0025] Furthermore, the first through Nth pre- and post-processing heat exchangers at the terminal are brine-to-air heat exchangers. The terminal heat exchanger is not restricted to a specific structural form, and various components of the heat exchanger at the same indoor terminal can be installed together. The terminal heat exchanger is typically a water coil.

[0026] Furthermore, the first throttling element and the second throttling element preferably have valve components of an electronically controlled actuator, such as an electronic expansion valve or an electric ball valve, so as to facilitate accurate and rapid adjustment of the opening degree by the control unit.

[0027] Furthermore, a bypass valve is provided on the bypass branch, preferably an electric ball valve.

[0028] Furthermore, the first to Nth pre- and post-processing regulating valves at the end are preferably solenoid valves.

[0029] A second objective of the present invention is to provide a control method for the aforementioned novel dual-temperature water-circuit air conditioning system. By regulating the valves of the chiller (heat pump) unit, the cold and heat generated by the refrigeration cycle are stored in a water tank, serving as a stable source of cold and heat. A regulating valve at the indoor terminal controls the flow of the brine, thereby adjusting the heat-humidity ratio of the air handling process to meet the processing requirements of different loads.

[0030] This technical solution can mainly realize the following 7 operating modes:

[0031] 1. Temperature control and dehumidification mode: Suitable for high humidity load conditions, for dehumidification and temperature control in the room.

[0032] In the temperature-controlled dehumidification mode, the following component states are present: the compressor is on. Ports D and C of the four-way reversing valve are connected; ports S and E are connected. The first throttle element is partially open, and the second throttle element is partially open. The bypass valve is partially open. The fan associated with the first heat exchanger is on. The indoor fan is on. The first and second refrigerant circulation pumps are on. The first and second refrigerant delivery pumps are on. The terminal regulating valve is partially open.

[0033] In the temperature-controlled dehumidification mode, the refrigerant circulation loop operates as follows: high-temperature, high-pressure refrigerant gas discharged from the compressor passes through a four-way reversing valve and is divided into: ① a portion enters the first heat exchanger, where it releases heat to the outdoor air and then flows through the first throttling element; ② the other portion passes directly through a bypass valve to the inlet of the second heat exchanger. The two refrigerant streams mix at the inlet of the second heat exchanger, releasing heat to the first refrigerant to form a subcooled liquid. After being throttled by the second throttling element to a low-temperature, low-pressure two-phase state, they enter the third heat exchanger, where they absorb heat from the second refrigerant to form a superheated gas. The gas then passes through the four-way reversing valve and the gas-liquid separator and returns to the compressor.

[0034] In the temperature control and dehumidification mode, the state of the refrigerant circulation loop is as follows: on the unit side, the first refrigerant is heated in the second heat exchanger and transported to the first water tank by the first refrigerant circulation pump. The second refrigerant is cooled in the third heat exchanger and transported to the second water tank by the second refrigerant circulation pump. On the user side, the second refrigerant flows out of the second water tank, is pressurized by the second refrigerant delivery pump, and then is split and enters the corresponding terminal pre-treatment heat exchanger to cool and dehumidify the indoor air, and finally is mixed and flows back to the second water tank. The first refrigerant flows out of the first water tank, is pressurized by the first refrigerant delivery pump, and then is split and enters the corresponding terminal post-treatment heat exchanger to reheat the indoor air, and finally is mixed and flows back to the first water tank.

[0035] In the temperature control and dehumidification mode, the indoor air flow path state is: driven by the corresponding fan, the indoor air flows through the terminal pre-treatment heat exchanger in sequence for cooling and dehumidification, and then flows through the terminal post-treatment heat exchanger to be reheated to a suitable temperature before being sent back to the room.

[0036] In the temperature-controlled dehumidification mode, the control strategy is as follows: the compressor speed is controlled to adjust the cooling temperature of the second refrigerant. The second throttling element is controlled to adjust the refrigerant suction superheat. The first throttling element and the bypass valve opening are controlled to adjust the first refrigerant heating temperature. The terminal pre-treatment regulating valve opening is controlled to adjust the indoor humidity, and the terminal post-treatment regulating valve opening is controlled to adjust the indoor temperature.

[0037] 2. Cooling mode: Suitable for working conditions with high heat load and for indoor cooling.

[0038] In cooling mode, on the unit side, the first throttle element is partially open, and the second throttle element is fully open. The bypass valve is closed. The first heat exchanger now functions as a condenser, releasing heat to the outdoor air. The second and third heat exchangers are both evaporators, cooling the first and second refrigerants, respectively.

[0039] In the cooling mode, on the user side, the first and second brine pumps are turned on. The terminal regulating valve is partially open. The second brine pre-cools the indoor air, while the first brine further cools the indoor air.

[0040] In the cooling mode, the control strategy is as follows: the compressor speed is controlled to adjust the cooling temperature of the first and second refrigerants. The first throttling element is controlled to adjust the refrigerant suction superheat. The second throttling element is controlled to be fully open, without throttling, and equivalent to connecting the pipeline. The terminal control valve opening is controlled to adjust the indoor temperature.

[0041] 3. Low-load cooling + cold storage mode: Suitable for low heat load conditions. On the basis of meeting the cooling mode function, part of the cold energy is stored in the water tank to balance the peak cooling load.

[0042] In the low-load cooling + cold storage mode, on the unit side, the operating status of each component is the same as that in the cooling mode.

[0043] In the low-load cooling + cold storage mode, on the user side, the first brine pump is turned on. The second brine pump is turned off. The terminal pre-treatment regulating valve is closed. The terminal post-treatment regulating valve is partially opened. At this time, the first brine cools the indoor air, and the second brine circulation loop is shut off.

[0044] In the low-load cooling + cold storage mode, the control strategy is as follows: The compressor speed is controlled to adjust the cold storage temperature of the second refrigerant. The first throttling element is controlled to adjust the refrigerant suction superheat. The second throttling element is controlled to be fully open, without throttling, equivalent to connecting the pipeline. The second refrigerant delivery pump and the terminal pre-treatment regulating valve are controlled to be closed to prevent the second refrigerant from exchanging heat with the terminal indoor air, thereby achieving cold storage. The speed of the first refrigerant circulation pump is controlled to adjust the cooling temperature of the first refrigerant. The terminal post-treatment regulating valve is controlled to adjust the indoor temperature.

[0045] 4. Temperature control, dehumidification + cooling mode: Suitable for situations where the heat and humidity load ratios in different areas of a building are inconsistent in summer. Temperature control and dehumidification are performed in areas with high humidity loads, and cooling is performed in areas with high heat loads.

[0046] In the temperature-controlled dehumidification + cooling mode, on the unit side, the first throttle element is fully open, and the second throttle element is partially open. The bypass valve is closed. At this point, the first heat exchanger acts as a condenser, releasing heat to the outdoor air. The second heat exchanger acts as a condenser, heating the first refrigerant. The third heat exchanger acts as an evaporator, cooling the second refrigerant.

[0047] In the temperature-controlled dehumidification + cooling mode, on the user side, the first and second brine pumps are turned on. The pre- and post-processing control valves in the temperature-controlled dehumidification zone are partially open. The pre-processing control valve in the cooling zone is partially open, while the post-processing control valve is closed. The second brine cools and dehumidifies the indoor air in each zone, while the first brine reheats the indoor air only in the temperature-controlled dehumidification zone.

[0048] In the temperature-controlled dehumidification + cooling mode, the control strategy is as follows: The compressor speed is controlled to adjust the cooling temperature of the second refrigerant. The second throttle element opening is controlled to adjust the refrigerant suction superheat. In the temperature-controlled dehumidification area, the terminal pre-treatment regulating valve opening is controlled to adjust the indoor humidity, and the terminal post-treatment regulating valve opening is controlled to adjust the indoor temperature. In the cooling area, the terminal pre-treatment regulating valve opening is controlled to adjust the indoor temperature. The terminal post-treatment regulating valve is closed to prevent the first refrigerant from exchanging heat with the indoor air.

[0049] 5. Heating mode: Suitable for working conditions with high cooling loads. It takes heat from the outdoor air to provide heat for heating the first and second refrigerants, thereby heating the room.

[0050] In heating mode, the following component states are present: the compressor is on. Ports D and E of the four-way reversing valve are connected; ports S and C are connected. The first throttle element is partially open, and the second throttle element is fully open. The bypass valve is closed. The fan associated with the first heat exchanger is on. The indoor fan is on. The first and second refrigerant circulation pumps are on. The first and second refrigerant delivery pumps are on. The terminal control valve is partially open.

[0051] In heating mode, the refrigerant circulation loop operates as follows: high-temperature, high-pressure refrigerant gas discharged from the compressor passes through the four-way reversing valve, enters the third heat exchanger, and releases heat to the second refrigerant. It then flows through the second throttling element and enters the second heat exchanger, releasing heat to the first refrigerant, becoming a subcooled refrigerant liquid. Afterwards, it is throttled by the first throttling element to form a low-temperature, low-pressure two-phase refrigerant. It then enters the first heat exchanger, where it removes heat from the outdoor air, becoming a superheated refrigerant gas. It then passes through the four-way reversing valve and the gas-liquid separator and returns to the compressor.

[0052] In the heating mode, the state of the refrigerant circulation loop is as follows: on the unit side, the first refrigerant is heated in the second heat exchanger and transported to the first water tank by the first refrigerant circulation pump. The second refrigerant is heated in the third heat exchanger and transported to the second water tank by the second refrigerant circulation pump. On the user side, the second refrigerant flows out of the second water tank, is pressurized by the second refrigerant delivery pump, and then is split and enters the corresponding terminal pre-treatment heat exchanger to preheat the indoor air, and finally flows back to the second water tank after being mixed. The first refrigerant flows out of the first water tank, is pressurized by the first refrigerant delivery pump, and then is split and enters the corresponding terminal post-treatment heat exchanger to further heat the indoor air, and finally flows back to the first water tank after being mixed.

[0053] In the heating mode, the indoor air flow path state is: driven by the corresponding fan, the indoor air flows through the terminal pre-treatment heat exchanger for preheating, and is further heated by the terminal post-treatment heat exchanger before being sent back to the room.

[0054] In the heating mode, the control strategy is as follows: the compressor speed is controlled to adjust the heating temperature of the first and second refrigerants. The first throttling element is controlled to adjust the refrigerant suction superheat. The second throttling element is fully opened, without throttling, effectively connecting the pipes. The terminal control valve opening is controlled to adjust the indoor temperature.

[0055] 6. Low-load heating + heat storage mode: Suitable for low cooling load conditions. On the basis of meeting the heating mode function, part of the heat is stored in the water tank to balance the peak heating load.

[0056] In the low-load heating + heat storage mode, on the unit side, the first throttle element is partially open, and the second throttle element is fully open. The bypass valve is closed. In this state, the first heat exchanger acts as an evaporator, drawing heat from the outdoor air. The second and third heat exchangers act as condensers, heating the first and second refrigerants, respectively.

[0057] In the low-load heating + heat storage mode, on the user side, the first brine pump is turned off, the second brine pump is turned on, and the terminal post-processing regulating valve is closed. At this point, the first brine circulation loop is shut off, and the second brine heats the indoor air.

[0058] In the low-load heating + heat storage mode, the control strategy is as follows: The compressor speed is controlled to adjust the heat storage temperature of the first refrigerant. The first throttling element is controlled to adjust the refrigerant suction superheat. The second throttling element is controlled to be fully open, without throttling, effectively connecting the pipes. The first refrigerant delivery pump and the terminal post-processing regulating valve are controlled to be closed to prevent the first refrigerant from exchanging heat with the indoor air, thereby achieving heat storage. The speed of the second refrigerant circulation pump is controlled to adjust the heating temperature of the second refrigerant. The terminal pre-processing regulating valve is controlled to adjust the indoor temperature.

[0059] 7. Heating + Cooling Mode: Suitable for winter when the heating and cooling loads in different areas of a building are inconsistent. It heats areas with high cooling loads and cools areas with high heating loads.

[0060] In the heating + cooling mode, on the unit side, the first throttle element is partially open, the second throttle element is partially open, and the bypass valve is partially open. In this case, the first heat exchanger acts as the evaporator, removing heat from the outdoor air. The second heat exchanger acts as the evaporator, cooling the first refrigerant. The third heat exchanger acts as the condenser, heating the second refrigerant.

[0061] In the heating + cooling mode, on the user side, the first and second brine pumps are turned on. The terminal pre-treatment regulating valve in the heating zone is partially open, while the terminal post-treatment regulating valve is closed. The terminal pre-treatment regulating valve in the cooling zone is closed, while the terminal post-treatment regulating valve is opened. The first brine cools the indoor air in the cooling zone, while the second brine heats the indoor air in the heating zone.

[0062] In the heating + cooling mode, the control strategy is as follows: The compressor speed is controlled to adjust the heating temperature of the second refrigerant. The second throttling element is controlled to adjust the refrigerant suction superheat. The first throttling element and the bypass valve opening are controlled to adjust the cooling temperature of the first refrigerant. In the heating area, the terminal pre-treatment regulating valve opening is controlled to adjust the indoor temperature, and the terminal post-treatment regulating valve is closed to prevent the first refrigerant from exchanging heat with the indoor air. In the cooling area, the terminal post-treatment regulating valve opening is controlled to adjust the indoor temperature, and the terminal pre-treatment regulating valve is closed to prevent the second refrigerant from exchanging heat with the indoor air.

[0063] The novel dual-temperature water-circuit air conditioning system of the present invention has the following features and innovations:

[0064] 1. A single chiller (heat pump) unit is used to provide both a cold source and a heat source, thereby achieving decoupling of the heat and humidity load inside the building. The present invention is based on only one vapor compression cycle, which simultaneously utilizes the evaporative cooling capacity and condensation heat of the refrigerant, and delivers them to the indoor terminal through two refrigerant circulation loops. One low-temperature refrigerant cools and dehumidifies the indoor air, while the other high-temperature refrigerant uses supercooling heat and / or condensation heat to reheat the dehumidified air for temperature control. At the user end, the flow rates of the two refrigerants are controlled by regulating valves, and the cooling and heating demands and the heat and humidity ratio of the air treatment process can be independently adjusted to match the heat and humidity load ratios in different spaces and at different times.

[0065] 2. A dual refrigerant loop connects the chiller (heat pump) to the air conditioning environment via heat exchange, allowing for flexible expansion. When providing different conditioning functions to a room (such as dehumidification and reheating within the same room, or cooling and heating in different zones), refrigerant corresponding to different temperature requirements can be generated and then distributed as needed. This makes the chiller (heat pump) itself easier to adjust. Simple internal valve switching allows for the use of cooling / heating at different locations in the cycle. The overall vapor compression cycle itself remains largely unchanged, eliminating the need to worry about drastic fluctuations from mode switching or difficulty balancing charge levels.

[0066] 3. A series terminal air treatment system is used, unlike the parallel terminal system commonly used in dual-cooling-source air conditioning systems. Air first passes through the cooling coil for deep dehumidification before entering the heating coil for temperature control. The final air supply reaches the target temperature and humidity directly, eliminating the need for mixing and preventing mixed air losses. This allows for faster and more precise control of indoor temperature and humidity.

[0067] 4. Dual throttling elements control the temperature of two refrigerant lines based on different operating load characteristics. Under high-humidity load conditions, the throttling element adjusts one refrigerant line to a low temperature (for cooling and dehumidification) and the other to a high temperature (for reheating and temperature control), achieving simultaneous and independent cooling and heating output. Under high sensible heat load conditions, the throttling element switches and adjusts the two refrigerant lines to work together, uniformly outputting cooling or heating, effectively meeting peak sensible heat load demands.

[0068] Compared with the existing technology, this solution has the following beneficial effects:

[0069] 1. Simplified equipment structure, flexible and precise control. Unlike dual-cooling-source air conditioning systems that rely on two cooling sources to process sensible and latent heat separately, this solution relies on a single conventional vapor compression cycle, rationally utilizing the generated heat and cold. Two refrigerant loops connect the chiller (heat pump) to the indoor air handling unit in a heat exchange manner. One refrigerant utilizes its cold capacity for cooling and dehumidification, while the other utilizes its heat for reheating and temperature control. This architecture achieves heat and moisture decoupling without adding additional cooling-source equipment. Furthermore, by effectively utilizing supercooling / condensation heat, it increases the subcooling degree of the refrigeration cycle, improving system energy efficiency and specific cooling capacity. A regulating valve controls the refrigerant flow rate at the indoor terminal, precisely matching the heat and moisture ratio requirements across different spaces and time periods. This effectively overcomes the control difficulties and inflexible response to temporal and spatial load variations inherent in dual-cooling-source systems, which often require multiple devices or complex vapor compression cycles. Furthermore, the series connection of the terminal air treatments avoids mixed air losses.

[0070] 2. Stable unit operation and simplified mode switching. Existing air-conditioning systems are directly affected by the dynamic and changeable heat and humidity demands of the terminal, which can easily cause frequent fluctuations in operating status and excessive start and stop times, reducing energy efficiency and damaging equipment life. At the same time, switching operating modes usually relies on a four-way reversing valve to change the flow direction of the refrigerant, resulting in large pressure fluctuations on the high and low pressure sides and unbalanced distribution of the filling amount. This solution can use a water tank to isolate the direct interference of terminal fluctuations on the chiller (heat pump) unit, absorb excess cold and heat, improve the continuity and stability of the unit's operation, and reduce starts and stops. When switching operating modes within a single season, this solution only needs to switch the throttling element and the bypass valve, without operating the four-way reversing valve. The refrigerant filling amount distribution changes little, the pressure is more stable, and the operation is reliable and efficient.

[0071] 3. Reduce energy consumption by shaving peak loads and fill valleys, and increase efficiency by sharing cooling and heating. Existing air-conditioning systems lack the ability to transfer loads. In order to cope with peak load pressure, the host configuration has high redundancy and high operating costs. This solution can use water tanks to store energy during low-load / off-peak periods and release energy during high-load / peak periods to achieve peak shaving and fill valleys, reducing host capacity requirements and operating costs. This solution uses the condensing heat of the refrigeration cycle for reheating temperature control in summer and uses the evaporative cooling capacity for core equipment area cooling in winter, achieving coordinated utilization of cold and heat sources. Compared with dual-cold-source air-conditioning systems, it can better match the spatiotemporal dynamic characteristics of heat and humidity loads, has a larger temperature and humidity adjustment range, and improves the system's adaptability and overall energy efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 This is a schematic structural diagram of Example 1 of the present invention;

[0073] Figures 2 to 6 Schematic diagrams of the processes of Example 1 of the present invention in the temperature control and dehumidification mode, the cooling mode, the low-load cooling + cold storage mode, the heating mode, and the low-load heating + heat storage mode;

[0074] Figure 7 This is a schematic diagram of the process of Example 2 of the present invention in the temperature control dehumidification + cooling mode;

[0075] Figure 8 This is a schematic diagram of the process of Example 2 in the heating + cooling mode of the present invention;

[0076] Figure 9 This is a schematic structural diagram of Example 3 of the present invention;

[0077] In the figure: 1- compressor, 2- four-way reversing valve, 3- first heat exchanger, 4- first throttling element, 5- second heat exchanger, 6- second throttling element, 7- third heat exchanger, 8- gas-liquid separator, 9- bypass valve, 10- fan, 11- first refrigerant circulation pump, 12- first water tank, 13- second refrigerant circulation pump, 14- second water tank, 15- outdoor air, 16- first refrigerant, 17- second refrigerant, 18- first room air, 19- Nth room air, 20- second refrigerant input Delivery pump, 21-terminal first pre-treatment regulating valve, 22-terminal first pre-treatment heat exchanger, 23-terminal Nth pre-treatment regulating valve, 24-terminal Nth pre-treatment heat exchanger, 25-first indoor fan, 26-Nth indoor fan, 30-first refrigerant delivery pump, 31-terminal first post-treatment regulating valve, 32-terminal first post-treatment heat exchanger, 33-terminal Nth post-treatment regulating valve, 34-terminal Nth post-treatment heat exchanger, 35-integrated terminal first heat exchanger, 36-integrated terminal Nth heat exchanger. DETAILED DESCRIPTION

[0078] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific embodiments. Any features such as component models, material names, connection structures, control methods, algorithms, etc. not explicitly described in this technical solution are considered to be common technical features disclosed in the prior art.

[0079] Example 1

[0080] In this embodiment, a new dual-temperature water-circuit air-conditioning system is provided, and its structure is as follows: Figure 1 As shown, it includes a refrigerant circulation path, a coolant circulation circuit and an air flow path.

[0081] In this embodiment, the compressor 1, four-way reversing valve 2, first heat exchanger 3, first throttling element 4, second heat exchanger 5, second throttling element 6, third heat exchanger 7, and gas-liquid separator 8 are sequentially connected to form a primary refrigerant circulation loop. Of the four ports of the four-way reversing valve 2, port D is connected to the exhaust port of compressor 1, port S is connected to the intake port of compressor 1 (via gas-liquid separator 8), port C is connected to the refrigerant channel of the first heat exchanger 3, and port E is connected to the refrigerant channel of the third heat exchanger 7.

[0082] In this embodiment, a bypass branch is further provided in the refrigerant circulation circuit.

[0083] A bypass valve 9 is provided on the bypass branch, one end of which is connected to the pipeline between the second heat exchanger 5 and the first throttling element 4 , and the other end is connected to the pipeline between the first heat exchanger 3 and the four-way reversing valve 2 .

[0084] The brine circulation circuit in this embodiment includes first and second brine circulation circuits.

[0085] The first brine circulation loop in this embodiment includes:

[0086] The first brine unit side circuit connects the second heat exchanger 5 with the first water tank 12 in a heat exchange manner, and includes the first water tank 12, the brine channel of the second heat exchanger 5, and the first brine circulation pump 11;

[0087] The first brine user-side loop connects the first water tank 12 to the terminal heat exchanger in a heat exchange manner, and includes the first water tank 12, the first brine delivery pump 30, and brine channels of the first to Nth post-processing heat exchangers at the terminal;

[0088] The first to Nth post-processing heat exchangers at the end are respectively provided with regulating valves.

[0089] The second coolant circulation loop in this embodiment includes:

[0090] The second brine unit side circuit connects the third heat exchanger 7 to the second water tank 14 in a heat exchange manner, and includes the second water tank 14, the second brine circulation pump 13, and the brine channel of the third heat exchanger 7;

[0091] The second brine user-side loop connects the second water tank 14 to the terminal heat exchanger in a heat exchange manner, and includes the second water tank 14, the second brine delivery pump 20, and the brine channels of the first to Nth pre-treatment heat exchangers at the terminal;

[0092] Regulating valves are respectively provided on the first to Nth pre-treatment heat exchangers at the end.

[0093] The air flow paths in this embodiment include first through Nth air flow paths. The i-th air flow path includes the air passage of the i-th pre-processing heat exchanger at the terminal, the air passage of the i-th post-processing heat exchanger at the terminal, and the i-th indoor fan. i is any integer between 1 and N. N ≥ 1.

[0094] In this embodiment, the second heat exchanger 5 and the third heat exchanger 7 are refrigerant-to-coolant heat exchangers, where the coolant is preferably water. The second heat exchanger 5 and the third heat exchanger 7 are plate heat exchangers, double-tube heat exchangers, or shell-and-tube heat exchangers. The first heat exchanger 3 is a refrigerant-to-air heat exchanger, typically a fin-tube heat exchanger or a microchannel heat exchanger. The first through Nth pre- and post-processing heat exchangers at the end are coolant-to-air heat exchangers, typically water coils.

[0095] The water ring air conditioning system in this embodiment mainly responds to the load characteristics changes outside the building in different seasons and can realize the following five operating modes:

[0096] 1. Temperature control and dehumidification mode (see Figure 2 )

[0097] In the temperature control and dehumidification mode, the air conditioning system of this embodiment performs indoor dehumidification and temperature control, and is suitable for high humidity environment conditions.

[0098] In temperature-controlled dehumidification mode, compressor 1 is on. Port D of four-way reversing valve 2 is connected to port C (compressor 1's exhaust port is connected to first heat exchanger 3); port S is connected to port E (compressor 1's intake port is connected to third heat exchanger 7 via gas-liquid separator 8). The first throttle element 4 is partially open, and the second throttle element 6 is partially open. The bypass valve 9 is partially open. The fan 10 driving outdoor air 15 through first heat exchanger 3 is on. The first through Nth indoor fans are on, driving indoor air through the corresponding air flow paths. The first brine circulation pump 11 driving the first brine 16 through second heat exchanger 5 is on. The second brine circulation pump 13 driving the second brine 17 through third heat exchanger 7 is on. The first brine delivery pump 30 is on, maintaining flow in the first brine user-side circuit. The second brine delivery pump 20 is on, maintaining flow in the second brine user-side circuit. The first through Nth pre- and post-processing control valves at the terminal are partially open.

[0099] In temperature-controlled dehumidification mode, the high-temperature, high-pressure refrigerant gas discharged from compressor 1 passes through four-way reversing valve 2 and is split: ① one portion enters the first heat exchanger 3, where it releases heat to the outdoor air 15 and then flows through the first throttling element 4; ② the other portion passes through bypass valve 9 and directly to the inlet of the second heat exchanger 5. The two refrigerant streams mix at the inlet of the second heat exchanger 5, releasing heat to the first brine 16 to become a subcooled liquid. After being throttled by the second throttling element 6 to a low-temperature, low-pressure two-phase state, they enter the third heat exchanger 7, where they absorb heat from the second brine 17 to become a superheated gas. The gas then passes through the four-way reversing valve 2 and gas-liquid separator 8 and returns to compressor 1. The outdoor air 15 releases heat in the first heat exchanger 3. The first brine 16 is heated in the second heat exchanger 5 and delivered to the first water tank 12 by the first brine circulating pump 11. The second brine 17 is cooled in the third heat exchanger 7 and delivered to the second water tank 14 by the second brine circulating pump 13.

[0100] In temperature-controlled dehumidification mode, the second brine 17 flows from the second water tank 14, is pressurized by the second brine delivery pump 20, and then splits. It passes through the first through Nth pre-treatment regulating valves at the terminal and enters the corresponding terminal pre-treatment heat exchanger, cooling and dehumidifying the first through Nth indoor air. The second brine 17 is mixed and then returns to the second water tank 14. The first brine 16 flows from the first water tank 12, is pressurized by the first brine delivery pump 30, and then splits. It passes through the first through Nth post-treatment regulating valves at the terminal and enters the corresponding terminal post-treatment heat exchanger, reheating the first through Nth indoor air. The first brine 16 is mixed and then returns to the first water tank 12.

[0101] In temperature-controlled dehumidification mode, the first through Nth indoor air flows sequentially through the terminal pre-treatment heat exchanger, driven by the corresponding indoor fans, for cooling and dehumidification. It is then reheated to a suitable temperature by the terminal post-treatment heat exchanger before being returned to the room. For example, the first indoor air 18, driven by the first indoor fan 25, flows sequentially through the terminal first pre-treatment heat exchanger 22 for cooling and dehumidification. It is then reheated to a suitable temperature by the terminal first post-treatment heat exchanger 32 before being returned to the room.

[0102] In the temperature control dehumidification mode, the speed of the compressor 1 is controlled to adjust the cooling temperature of the second refrigerant 17. The second throttling element 6 is controlled to adjust the refrigerant suction superheat. The opening of the first throttling element 4 and the bypass valve 9 is controlled to adjust the heating temperature of the first refrigerant 16. When the first throttling element 4 is close to fully open and the bypass valve 9 is close to fully closed, the condensation heat of the refrigerant is released to the outdoor air 15, and the supercooling heat is released to the first refrigerant 16. At this time, the temperature of the first refrigerant 16 is close to the refrigerant supercooling liquid temperature, and its reheating capacity for indoor air is relatively weak; on the basis of the above, the opening of the bypass valve 9 is increased and the opening of the first throttling element 4 is reduced, then part of the refrigerant exhaust gas is directly bypassed to the inlet of the second heat exchanger 5, increasing its inlet. Due to the dryness of the refrigerant, some of the heat of condensation is also released to the first brine 16 via the second heat exchanger 5. At this point, the temperature of the first brine 16 is between the condensing temperature and the subcooled liquid temperature, enhancing its reheating capacity for the indoor air. If the first throttle element 4 is nearly fully closed and the bypass valve 9 is nearly fully open, nearly all of the heat of condensation is released to the first brine 16 via the second heat exchanger 5. At this point, the temperature of the first brine 16 is close to the condensing temperature, achieving maximum reheating capacity. The first heat exchanger 3 undergoes almost no heat exchange, and the fan 10 above it can be turned off. Furthermore, the opening of the terminal pre-treatment control valve is controlled to adjust the indoor humidity, and the opening of the terminal post-treatment control valve is controlled to adjust the indoor temperature. For example, the opening of the terminal first pre-treatment control valve 21 is controlled to adjust the humidity of the first indoor air 18, and the opening of the terminal first post-treatment control valve 31 is controlled to adjust the temperature of the first indoor air 18.

[0103] 2. Cooling mode (see Figure 3 )

[0104] In cooling mode, the air-conditioning system of this embodiment cools the room and is suitable for high-temperature environment conditions.

[0105] In cooling mode, on the unit side, the first throttle element 4 is partially open, and the second throttle element 6 is fully open. Bypass valve 9 is closed. At this point, the first heat exchanger 3 functions as a condenser, releasing heat to the outdoor air 15. The second heat exchanger 5 functions as an evaporator, cooling the first brine 16. The third heat exchanger 7 functions as an evaporator, cooling the second brine 17.

[0106] In cooling mode, on the user side, the first and second brine pumps 30 and 20 are turned on. The terminal control valve is partially open. The second brine 17 precools the air in the first through Nth rooms, while the first brine 16 further cools the air in the first through Nth rooms.

[0107] In cooling mode, the speed of compressor 1 is controlled to adjust the cooling temperature of the first and second brine refrigerants 16, 17. The first throttle element 4 is controlled to adjust the refrigerant suction superheat. The second throttle element 6 is fully opened, without any throttling effect, effectively connecting the pipes. The opening of the terminal control valves is controlled to adjust the indoor temperature. For example, the opening of the first pre-treatment control valve 21 and the first post-treatment control valve 31 are controlled to adjust the temperature of the first indoor air 18.

[0108] 3. Low load cooling + cold storage mode (see Figure 4 )

[0109] In low-load cooling + cold storage mode, this embodiment of the air conditioning system, while still meeting cooling mode requirements, stores some cold energy in the water tank to balance peak cooling loads. The cold storage position can be switched by switching the refrigerant delivery pump on and off and opening and closing the terminal control valve.

[0110] In low-load cooling + cold storage mode, the operating status of each component on the unit side is the same as in cooling mode.

[0111] In low-load cooling + cold storage mode, on the user side, the first brine delivery pump 30 is turned on. The second brine delivery pump 20 is turned off. The first through Nth pre-treatment control valves at the terminal are closed. The first through Nth post-treatment control valves at the terminal are partially opened. At this point, the first brine 16 cools the first through Nth indoor air, and the second brine circulation loop is shut off.

[0112] In low-load cooling + cold storage mode, the speed of the compressor 1 is controlled to adjust the cold storage temperature of the second coolant 17. The first throttling element 4 is controlled to adjust the refrigerant suction superheat. The second throttling element 6 is controlled to be fully open, without throttling effect, which is equivalent to connecting the pipeline. The speed of the first coolant circulation pump 11 is controlled to adjust the cooling temperature of the first coolant 16. The second coolant delivery pump 20 and the terminal pre-treatment regulating valve are controlled to be closed so that the second coolant 17 does not exchange heat with the terminal indoor air, thereby achieving cold storage. The terminal post-treatment regulating valve is controlled to adjust the indoor temperature. For example, the terminal first post-treatment regulating valve 31 is controlled to adjust the cooling temperature of the first indoor air 18.

[0113] 4. Heating mode (see Figure 5 )

[0114] In the heating mode, the air conditioning system of this embodiment takes heat from the outdoor air to provide heat for heating the first refrigerant and the second refrigerant, thereby heating the room, and is suitable for low temperature environment conditions.

[0115] In heating mode, compressor 1 is on. Port D of four-way reversing valve 2 is connected to port E (compressor 1's exhaust port is connected to the third heat exchanger 7); port S is connected to port C (compressor 1's intake port is connected to the first heat exchanger 3 via the gas-liquid separator 8). The first throttle element 4 is partially open, and the second throttle element 6 is fully open. The bypass valve 9 is closed. The fan 10 driving outdoor air 15 through the first heat exchanger 3 is on. The first through Nth indoor fans are on, driving indoor air through the corresponding air flow paths. The first brine circulation pump 11 driving the first brine 16 through the second heat exchanger 5 is on. The second brine circulation pump 13 driving the second brine 17 through the third heat exchanger 7 is on. The first brine delivery pump 30 is on, maintaining flow in the first brine user-side circuit. The second brine delivery pump 20 is on, maintaining flow in the second brine user-side circuit. The first through Nth pre- and post-processing regulating valves at the terminal are partially open.

[0116] In heating mode, the high-temperature, high-pressure refrigerant gas discharged from compressor 1 passes through four-way reversing valve 2, enters third heat exchanger 7, and releases heat to second brine 17. It then flows through second throttling element 6 and enters second heat exchanger 5, releasing heat to first brine 16, becoming a subcooled refrigerant liquid. After being throttled by first throttling element 4, it becomes a low-temperature, low-pressure two-phase refrigerant. It then enters first heat exchanger 3, where it absorbs heat from outdoor air 15, becoming a superheated refrigerant gas. It then passes through four-way reversing valve 2 and gas-liquid separator 8 and returns to compressor 1. Outdoor air 15 absorbs heat in first heat exchanger 3. First brine 16 is heated in second heat exchanger 5 and delivered to first water tank 12 by first brine circulation pump 11. Second brine 17 is heated in third heat exchanger 7 and delivered to second water tank 14 by second brine circulation pump 13.

[0117] In heating mode, the second brine 17 flows from the second water tank 14, is pressurized by the second brine delivery pump 20, and then splits. It passes through the first through Nth pre-treatment regulating valves at the terminal and enters the corresponding terminal pre-treatment heat exchanger to preheat the first through Nth indoor air. The second brine 17 is mixed and then returns to the second water tank 14. The first brine 16 flows from the first water tank 12, is pressurized by the first brine delivery pump 30, and then splits. It passes through the first through Nth post-treatment regulating valves at the terminal and enters the corresponding terminal post-treatment heat exchanger to further heat the first through Nth indoor air. The first brine 16 is mixed and then returns to the first water tank 12.

[0118] In heating mode, the first through Nth indoor air streams, driven by their corresponding indoor fans, sequentially flow through the terminal pre-treatment heat exchanger for preheating, then further heat the terminal post-treatment heat exchanger before being returned to the room. For example, the first indoor air 18, driven by the first indoor fan 25, sequentially flows through the terminal first pre-treatment heat exchanger 22 for preheating, then further heats the terminal first post-treatment heat exchanger 32 before being returned to the room.

[0119] In heating mode, the speed of compressor 1 is controlled to adjust the heating temperature of the first and second brine refrigerants 16, 17. The speed of the second brine delivery pump 30 is controlled to adjust the terminal heat exchange temperature difference for a more uniform result. The first throttle element 4 is controlled to adjust the refrigerant suction superheat. The second throttle element 6 is fully opened, without any throttling effect, effectively connecting the pipes. The opening of the terminal control valves is controlled to adjust the indoor temperature. For example, the opening of the first pre-treatment control valve 21 and the first post-treatment control valve 31 are controlled to adjust the heating temperature of the first room air 18.

[0120] 5. Low load heating + heat storage mode (see Figure 6 )

[0121] In low-load heating + heat storage mode, this embodiment of the air conditioning system, while still meeting heating mode requirements, stores some heat in the water tank to balance peak heating loads. The heat storage location can be switched by switching the refrigerant pump on and off and by opening and closing the terminal control valve.

[0122] In low-load heating + heat storage mode, on the unit side, the first throttle element 4 is partially open, and the second throttle element 6 is fully open. Bypass valve 9 is closed. At this point, the first heat exchanger 3 functions as an evaporator, removing heat from outdoor air 15. The second heat exchanger 5 functions as a condenser, heating the first brine 16. The third heat exchanger 7 functions as a condenser, heating the second brine 17.

[0123] In low-load heating + thermal storage mode, on the user side, the first brine delivery pump 30 is turned off. The second brine delivery pump 20 is turned on. The first through Nth post-processing control valves are closed. The first brine circulation loop is now shut off, and the second brine 17 heats the first through Nth indoor air.

[0124] In the low-load heating + heat storage mode, the speed of the compressor 1 is controlled to adjust the heat storage temperature of the first refrigerant 16. The first throttling element 4 is controlled to adjust the refrigerant suction superheat. The second throttling element 6 is controlled to be fully open, without throttling effect, which is equivalent to a connecting pipeline. The speed of the second refrigerant circulation pump 13 is controlled to adjust the heating temperature of the second refrigerant 17. The first refrigerant delivery pump 30 and the terminal post-processing regulating valve are controlled to be closed so that the first refrigerant 16 does not exchange heat with the terminal indoor air to achieve heat storage. The terminal pre-processing regulating valve is controlled to adjust the indoor temperature. For example, the terminal first pre-processing regulating valve 21 is controlled to adjust the heating temperature of the first indoor air 18.

[0125] Example 2

[0126] The structure of this embodiment is exactly the same as that of Example 1. This embodiment mainly addresses the situation where the heat and moisture treatment requirements of different spaces inside a building are inconsistent. For example, in the summer, areas with a large number of people inside the building need to handle both the heat and moisture loads, while areas with fewer people only need to handle the heat load. Alternatively, it can be used to solve the problem of inconsistent heating and cooling requirements inside a building. For example, in the winter, areas close to the building envelope need to be heated, while areas in the inner core may need to be cooled. This embodiment mainly operates in the following two modes:

[0127] 1. Temperature control dehumidification + cooling mode (see Figure 7 )

[0128] In the temperature control dehumidification + cooling mode, the air conditioning system of this embodiment can perform temperature control and dehumidification in high humidity load areas within the building, while cooling high heat load areas. It is suitable for situations where the heat and humidity load ratios in different areas of the building are inconsistent in summer.

[0129] In temperature-controlled dehumidification + cooling mode, compressor 1 is on. Port D of four-way reversing valve 2 is connected to port C (compressor 1's exhaust port is connected to the first heat exchanger 3); port S is connected to port E (compressor 1's intake port is connected to the third heat exchanger 7 via the gas-liquid separator 8). The first throttle element 4 is fully open, and the second throttle element 6 is partially open. The bypass valve 9 is closed. The fan 10 driving outdoor air 15 through the first heat exchanger 3 is on. The first through Nth indoor fans are on, driving indoor air through the corresponding air flow paths. The first brine circulation pump 11 driving the first brine 16 through the second heat exchanger 5 is on. The second brine circulation pump 13 driving the second brine 17 through the third heat exchanger 7 is on. The first brine delivery pump 30 is on, maintaining flow in the first brine user-side circuit. The second brine delivery pump 20 is on, maintaining flow in the second brine user-side circuit. In the temperature-controlled dehumidification area, such as the first room, the first pre-processing regulating valve 21 and the first post-processing regulating valve 31 are partially opened. In the cooling area, such as the Nth room, the Nth pre-processing regulating valve 23 is partially opened and the Nth post-processing regulating valve 33 is closed.

[0130] In temperature-controlled dehumidification + cooling mode, the high-temperature, high-pressure refrigerant gas discharged from compressor 1 passes through four-way reversing valve 2 and enters first heat exchanger 3, releasing heat to outdoor air 15. It then flows through first throttling element 4 and enters second heat exchanger 5, releasing heat to first brine 16, becoming a subcooled refrigerant liquid. It then passes through second throttling element 6, throttling it into a low-temperature, low-pressure two-phase refrigerant. It then enters third heat exchanger 7, absorbing heat from second brine 17, becoming a superheated refrigerant gas. It then passes through four-way reversing valve 2 and gas-liquid separator 8 and returns to compressor 1. Outdoor air 15 releases heat in first heat exchanger 3. First brine 16 is heated in second heat exchanger 5 and delivered to first water tank 12 by first brine circulation pump 11. Second brine 17 is cooled in third heat exchanger 7 and delivered to second water tank 14 by second brine circulation pump 13.

[0131] In the temperature-controlled dehumidification + cooling mode, the second brine 17 flows from the second water tank 14, is pressurized by the second brine delivery pump 20, and then splits into two streams. Each stream passes through the first to Nth pre-processing regulating valves at the terminal and enters the corresponding terminal pre-processing heat exchanger to cool and dehumidify the indoor air. For example, it enters the first terminal pre-processing heat exchanger 22 to cool and dehumidify the first indoor air 18, and enters the Nth terminal pre-processing heat exchanger 24 to cool the Nth indoor air 19. The above second brine 17 is mixed and then returned to the second water tank 14. The first brine 16 flows from the first water tank 12, is pressurized by the first brine delivery pump 30, and then enters the terminal post-processing heat exchanger in the temperature-controlled dehumidification area to reheat the indoor air. For example, it flows through the first terminal post-processing regulating valve 31 and enters the first terminal post-processing heat exchanger 32 to reheat the first indoor air 18 before returning to the first water tank 12.

[0132] In temperature-controlled dehumidification + cooling mode, in the temperature-controlled dehumidification area, such as the first room, indoor air 18, driven by indoor fan 25, flows through the terminal first pre-treatment heat exchanger 22 for cooling and dehumidification. It is then reheated to a suitable temperature in the terminal first post-treatment heat exchanger 32 before being returned to the room. In the cooling area, such as the Nth room, indoor air 19, driven by indoor fan 26, flows through the terminal Nth pre-treatment heat exchanger 24 for cooling and then returned to the room.

[0133] In the temperature-controlled dehumidification + cooling mode, the speed of the compressor 1 is controlled to adjust the cooling temperature of the second brine 17. The opening of the second throttling element 6 is controlled to adjust the refrigerant suction superheat. In the temperature-controlled dehumidification area, such as the first room, the opening of the first pre-processing regulating valve 21 at the terminal is controlled to adjust the humidity of the air 18 in the first room, and the opening of the first post-processing regulating valve 31 at the terminal is controlled to adjust the temperature of the air 18 in the first room. In the cooling area, such as the Nth room, the opening of the Nth pre-processing regulating valve 23 at the terminal is controlled to adjust the cooling temperature of the air 19 in the Nth room. The Nth post-processing regulating valve 33 at the terminal is controlled to close so that the first brine 16 does not exchange heat with the air 19 in the Nth room at the terminal.

[0134] 2. Heating + cooling mode (see Figure 8 )

[0135] In heating + cooling mode, the air conditioning system of this embodiment can heat areas with high cooling loads in the building (generally near the building envelope) while cooling areas with high heating loads (generally inside the building). This is suitable for situations where the cooling and heating loads in different areas of the building are inconsistent in winter.

[0136] In heating + cooling mode, compressor 1 is on. Port D of the four-way reversing valve 2 is connected to port E (the exhaust port of compressor 1 is connected to the third heat exchanger 7); port S is connected to port C (the intake port of compressor 1 is connected to the first heat exchanger 3 via the gas-liquid separator 8). The first throttle element 4 is partially open, and the second throttle element 6 is partially open. The bypass valve 9 is partially open. The fan 10 driving outdoor air 15 through the first heat exchanger 3 is on. The first through Nth indoor fans are on, driving indoor air through the corresponding air flow paths. The first brine circulation pump 11 driving the first brine 16 through the second heat exchanger 5 is on. The second brine circulation pump 13 driving the second brine 17 through the third heat exchanger 7 is on. The first brine delivery pump 30 is on, maintaining flow in the first brine user-side circuit. The second brine delivery pump 20 is on, maintaining flow in the second brine user-side circuit. In the heating area, for example, in the first room, the first pre-treatment control valve 21 at the terminal is partially open, and the first post-treatment control valve 31 at the terminal is closed. In the refrigeration area, for example, in the Nth room, the Nth pre-processing regulating valve 23 at the terminal is closed, and the Nth post-processing regulating valve 33 at the terminal is partially opened.

[0137] In heating + cooling mode, the high-temperature, high-pressure refrigerant gas discharged from compressor 1 passes through the four-way reversing valve 2 and enters the third heat exchanger 7, releasing heat to the second brine 17, becoming a subcooled refrigerant liquid. It is then throttled by the second throttling element 6 to form a low-temperature, low-pressure two-phase refrigerant, which enters the second heat exchanger 5 to absorb heat from the first brine 16. After exiting the second heat exchanger 5, the refrigerant is split into two streams: ① one stream bypasses the bypass valve 9 to the outlet of the first heat exchanger 3; ② the other stream passes through the first throttling element 4 and enters the first heat exchanger 3 to absorb heat from the outdoor air 15. The two streams of refrigerant mix at the outlet of the first heat exchanger 3, forming a superheated gas. This gas then passes through the four-way reversing valve 2 and the gas-liquid separator 8 and returns to compressor 1. The outdoor air 15 absorbs heat in the first heat exchanger 3. The first brine 16 is cooled in the second heat exchanger 5 and then transported to the first water tank 12 by the first brine circulation pump 11. The second brine 17 is heated in the third heat exchanger 7 and is transported to the second water tank 14 by the second brine circulation pump 13 .

[0138] In the heating + cooling mode, the first brine 16 flows from the first water tank 12, is pressurized by the first brine delivery pump 30, and then flows through the terminal post-processing heat exchanger of the cooling area, for example, through the terminal Nth post-processing regulating valve 33, enters the terminal Nth post-processing heat exchanger 34, cools the Nth indoor air 19, and then flows back to the first water tank 12. The second brine 17 flows from the second water tank 14, is pressurized by the second brine delivery pump 20, and then flows through the terminal pre-processing heat exchanger of the heating area, for example, through the terminal first pre-processing regulating valve 21, enters the terminal first pre-processing heat exchanger 22, heats the first indoor air 18, and then flows back to the second water tank 14.

[0139] In heating + cooling mode, in the heating area, such as the first room, air 18, driven by the first indoor fan 25, flows through the first terminal pre-treatment heat exchanger 22, is heated, and then returned to the room. In the cooling area, such as the Nth room, air 19, driven by the Nth indoor fan 26, flows through the Nth terminal post-treatment heat exchanger 34, is cooled, and then returned to the room.

[0140] In the heating+cooling mode, the speed of the compressor 1 is controlled to adjust the heating temperature of the second secondary refrigerant 17. The second throttling element 6 is controlled to adjust the refrigerant suction superheat. The openings of the first throttle element 4 and the bypass valve 9 are controlled to adjust the cooling temperature of the first brine 16. When the first throttle element 4 is close to fully open and the bypass valve 9 is close to fully closed, only a small amount of cooling energy from the refrigerant evaporation process is carried away by the first brine 16. The temperature of the first brine 16 is relatively high, and the cooling capacity for the indoor air is relatively weak. On the basis of the above, if the opening of the bypass valve 9 is increased and the opening of the first throttle element 4 is reduced, part of the refrigerant is directly bypassed to the suction port of the compressor 1 (via the gas-liquid separator 8). The first brine 16 obtains more cooling energy from the refrigerant evaporation process, the temperature drops, and the cooling capacity for the indoor air is enhanced. If the first throttle element 4 is close to fully closed and the bypass valve 9 is close to fully open, all the cooling energy from the refrigerant evaporation process is carried away by the first brine 16. The temperature of the first brine 16 is the lowest, and the cooling capacity for the indoor air is the strongest. Almost no substantial heat exchange occurs in the first heat exchanger 3, and the fan 10 thereon can be turned off. Furthermore, in the heating area, such as the first room, the opening of the first pre-processing regulating valve 21 at the terminal is controlled to adjust the heating temperature of the first room air 18, and the first post-processing regulating valve 31 at the terminal is controlled to be closed to prevent the first brine 16 from exchanging heat with the first room air 18. In the cooling area, such as the Nth room, the Nth pre-processing regulating valve 23 at the terminal is controlled to be closed to prevent the second brine 17 from exchanging heat with the Nth room air 19. The opening of the Nth post-processing regulating valve 33 at the terminal is controlled to adjust the cooling temperature of the Nth room air 19.

[0141] Example 3

[0142] This embodiment ( Figure 9 ) is completely similar to that of Example 1, with the following differences: ① An integrated heat exchanger is used at the indoor terminal to replace the split heat exchanger in Example 1, which is convenient for production and installation. For example, the first pre-treatment heat exchanger 22 at the terminal and the first post-treatment heat exchanger 32 at the terminal are connected as a whole to form an integrated first heat exchanger 35 at the terminal. The integrated terminal heat exchanger has two refrigerant inlets and outlets, and its function is similar to that of the terminal heat exchanger in Example 1. ② In Example 1, the chilled water (heat pump) unit and the indoor terminal are connected in a heat exchange manner through a refrigerant circulation pump, a water tank and a refrigerant delivery pump. This embodiment is simplified, and the second heat exchanger 5 is directly connected to the integrated terminal heat exchanger through the first refrigerant 16, and the third heat exchanger 7 is directly connected to the integrated terminal heat exchanger through the second refrigerant 17, eliminating the water tank and the refrigerant delivery pump.

[0143] This embodiment shows that there is no restriction on the form of the terminal heat exchanger and the refrigerant circulation loop, and technicians can adjust them according to the application scenario and space limitations.

[0144] While terms such as "first" and "second" are used herein to define components, those skilled in the art will appreciate that the use of terms such as "first" and "second" is merely for the purpose of distinguishing between components for ease of description. Unless otherwise stated, these terms have no special meanings.

[0145] The above embodiments do not fully display all the components of the refrigerant cycle, coolant flow path and air flow path. During implementation, common refrigeration accessories such as high-pressure liquid storage tanks, gas-liquid separators, oil separators, filters, dryers, etc. are set in the refrigerant circuit, filters, power pumps, control valves and other accessories are set in the water flow path, fans, air ducts, air valves, dampers, filters and other accessories are set in the air flow path, or heat exchangers are added without departing from the spirit of the technical solution of the present invention. These cannot be regarded as substantial improvements to the present invention and should fall within the scope of protection of the present invention.

[0146] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, should be within the scope of protection of the present invention.

Claims

1. An air conditioning system comprising a refrigerant circulation circuit, a brine circulation circuit, and an air flow path; The refrigerant circulation circuit comprises: A main refrigerant circulation loop includes a compressor (1), a four-way reversing valve (2), a first heat exchanger (3), a first throttling element (4), a second heat exchanger (5), a second throttling element (6), a third heat exchanger (7), and a gas-liquid separator (8) connected in sequence through pipelines; A bypass branch line has one end connected to the pipeline between the second heat exchanger (5) and the first throttling element (4), and the other end connected to the pipeline between the first heat exchanger (3) and the four-way reversing valve (2); a bypass valve (9) is provided on the bypass branch line. The refrigerant circulation loop includes: A first refrigerant circulation loop connects the second heat exchanger (5) and a portion of the terminal heat exchanger via a refrigerant pipeline; A second coolant circulation loop connects the third heat exchanger (7) and a portion of the terminal heat exchanger via a coolant pipeline; The inlet and / or outlet of each part of the terminal heat exchanger is provided with a regulating valve. The air in the air flow path is connected to the coolant in a heat exchange manner via a terminal heat exchanger.

2. An air conditioning system according to claim 1, characterized in that: The terminal heat exchanger includes a pre-treatment heat exchanger and a post-treatment heat exchanger, wherein the refrigerant channel of the terminal pre-treatment heat exchanger is connected to the second refrigerant circulation loop, and the refrigerant channel of the terminal post-treatment heat exchanger is connected to the first refrigerant circulation loop.

3. The air conditioning system according to claim 1, characterized in that: The first secondary coolant circulation loop comprises a common first water tank (12) and is formed by secondary coolant piping: First refrigerant unit side circuit: the first water tank (12), the first refrigerant circulation pump (11) and the refrigerant channel of the second heat exchanger (5) are fluidically connected in sequence; A first brine user-side circuit: the first water tank (12), the first brine delivery pump (30), and the brine channel of the terminal post-processing heat exchanger are fluidically connected in sequence; The second coolant circulation loop includes a shared second water tank (14) and is formed by a coolant pipeline: Second refrigerant unit side circuit: the second water tank (14), the second refrigerant circulation pump (13) and the refrigerant channel of the third heat exchanger (7) are fluidically connected in sequence; The second refrigerant user-side circuit: the second water tank (14), the second refrigerant delivery pump (20) and the refrigerant channel of the terminal pre-treatment heat exchanger are fluidically connected in sequence.

4. A method for controlling an air conditioning system according to claims 1 to 3, characterized in that: When dehumidifying and / or cooling the room: Compare the actual values ​​of indoor temperature and humidity with the target set values ​​to determine the current cooling and dehumidification loads. When dehumidification load is dominant: The second throttling element (6) is controlled to adjust the refrigerant suction superheat, and the opening of the bypass valve (9) and the opening of the first throttling element (4) are controlled to adjust the heat exchange of the second heat exchanger (5). The second refrigerant (17) is controlled to flow through the third heat exchanger (7) to exchange heat with the refrigerant for cooling, and then enter the terminal pre-treatment heat exchanger. The opening of the corresponding terminal regulating valve is controlled to adjust the indoor humidity. The first refrigerant (16) is controlled to flow through the second heat exchanger (5) to exchange heat with the refrigerant for heating, and then enter the terminal post-treatment heat exchanger. The opening of the corresponding terminal regulating valve is controlled to adjust the indoor temperature. When the cooling load is dominant: The first throttling element (4) is controlled to adjust the refrigerant suction superheat, the bypass valve (9) is controlled to switch from opening adjustment to closing, and the second throttling element (6) is controlled to switch from opening adjustment to full opening. If the cooling load is high, the second coolant (17) and the first coolant (16) are controlled to flow through the corresponding heat exchanger to exchange heat with the refrigerant and cool down, and then enter the terminal pre-treatment and post-treatment heat exchangers; If the refrigeration load is small, the circulation flow path from the second refrigerant (17) to the terminal pre-treatment heat exchanger is controlled to be closed, and the first refrigerant (16) is maintained to flow through the second heat exchanger (5) to exchange heat with the refrigerant for cooling and then enter the terminal post-treatment heat exchanger; or, the circulation flow path from the first refrigerant (16) to the terminal post-treatment heat exchanger is controlled to be closed, and the second refrigerant (17) is maintained to flow through the third heat exchanger (7) to exchange heat with the refrigerant for cooling and then enter the terminal pre-treatment heat exchanger; Control the opening of the corresponding regulating valves on the terminal to adjust the indoor temperature.

5. A control method for an air conditioning system according to claims 1 to 3, characterized in that: When heating the room: The first throttling element (4) is controlled to adjust the refrigerant suction superheat, the second throttling element (6) is controlled to be fully opened, and the bypass valve (9) is controlled to be closed. Compare the actual indoor temperature with the target set value to determine the current heating load. If the heating load is high, the second refrigerant (17) and the first refrigerant (16) are controlled to flow through the corresponding heat exchangers to exchange heat with the refrigerant and heat up, and then enter the terminal pre-treatment and post-treatment heat exchangers. If the heating load is low, the circulation flow path from the first refrigerant (16) to the terminal post-processing heat exchanger is controlled to be closed, and the second refrigerant (17) is maintained to flow through the third heat exchanger (7) to exchange heat with the refrigerant and heat up and enter the terminal pre-processing heat exchanger; or, the circulation flow path from the second refrigerant (17) to the terminal pre-processing heat exchanger is controlled to be closed, and the first refrigerant (16) is maintained to flow through the second heat exchanger (5) to exchange heat with the refrigerant and heat up and enter the terminal post-processing heat exchanger. Control the opening of the corresponding regulating valves on the terminal to adjust the indoor temperature.

6. A method for controlling an air conditioning system according to claims 1 to 3, characterized in that: When controlling temperature and humidity in indoor zones: Controlling the second coolant (17) to flow through the third heat exchanger (7) to exchange heat with the refrigerant for cooling, and controlling the first coolant (16) to flow through the second heat exchanger (5) to exchange heat with the refrigerant for heating; For areas requiring temperature control and dehumidification: open the flow path of the terminal pre-treatment heat exchanger connected to the second refrigerant (17), and control the opening of the regulating valve thereon to adjust the indoor humidity; open the flow path of the terminal post-treatment heat exchanger connected to the first refrigerant (16), and control the opening of the regulating valve thereon to adjust the indoor temperature. For areas that only require cooling: only the flow path connecting the terminal pre-treatment heat exchanger to the second refrigerant (17) is opened, and the opening of the regulating valve on it is controlled to adjust the indoor temperature.

7. A method for controlling an air conditioning system according to claims 1 to 3, characterized in that: When temperature control is performed on indoor zones: Controlling the second coolant (17) to flow through the third heat exchanger (7) to exchange heat with the refrigerant to increase its temperature, and controlling the first coolant (16) to flow through the second heat exchanger (5) to exchange heat with the refrigerant to decrease its temperature; For the area that needs heating: only open the flow path of the terminal pre-treatment heat exchanger connected to the second coolant (17); For the area requiring refrigeration: only the flow path of the terminal post-processing heat exchanger connected to the first refrigerant (16) is opened; Control the opening of the corresponding regulating valves on the terminal to adjust the indoor temperature of the zone.

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