Cooling system capable of stably and continuously operating at low load

Abstract

The utility model provides a cooling system capable of stably and continuously operating at low load. The cooling system comprises a first circulating pipeline, a second circulating pipeline and a heat recovery subsystem, a first cooling device, a first pump body and a refrigerating unit evaporator are arranged on the first circulating pipeline; a second cooling device, a second pump body and a refrigerating unit condenser are arranged on the second circulating pipeline; the refrigerating unit evaporator is used for transferring heat into the refrigerating unit condenser; the heat recovery subsystem is used for transmitting part of heat in the second circulation pipeline back to the first circulation pipeline in the starting state of the heat recovery subsystem. According to the utility model, the refrigerating unit can stably and continuously operate under low load.

Description

Technical Field

[0001] The utility model relates to the technical field of cooling, in particular to a cooling system capable of stable and continuous operation at low load. Background Art

[0002] Electric refrigeration and water-cooled chillers are the main cooling sources of centralized air-conditioning systems. The cooling capacity of the unit can be reduced according to the reduction of air-conditioning load, and the control strategy of unloading without stopping the unit is adopted to reduce the cooling capacity of the unit. When the cooling capacity is too small, the unit adopts the start-stop control strategy to reduce the cooling capacity of the unit. Generally, when the cooling capacity of the chiller is less than 20% of the rated cooling capacity of the unit, it will enter the start-stop control condition. When the air-conditioning load continues to maintain a low load state, the chiller will start and stop frequently, which will not only shorten the life of the equipment, but also increase its energy consumption and reduce its efficiency during operation. Too many starts and stops will make it difficult for the unit to maintain a constant temperature, affecting the overall stability of the equipment. Therefore, avoiding frequent starts and stops of chillers is crucial for energy saving and consumption reduction and stable operation of equipment.

[0003] In order to avoid frequent start and stop of the unit at low load, the commonly used technical solutions are: (1) Setting up hot gas bypass inside the chiller to adapt to low load conditions and increase the stability of the unit operation. (2) Adding a cold water storage tank to the cold water system to increase the water capacity of the cold water system to extend the interval between unit starts and stops and reduce the number of starts and stops. These two solutions are suitable for new projects. For renovation projects, if the original main unit is not replaced and there is no space to add a cold water storage tank, the chiller cannot achieve stable and continuous operation at low load. This technical problem lacks a simple and effective solution. Utility Model Content

[0004] The utility model aims to provide a cooling system capable of stable and continuous operation at low load, and utilizes heat recovery to enable the refrigeration unit to operate stably and continuously at low load.

[0005] To achieve the above-mentioned purpose, the utility model provides a cooling system that can operate stably and continuously at a low load, including a first circulation pipeline, a second circulation pipeline and a heat recovery subsystem; the first circulation pipeline is provided with a first cooling device, a first pump body and a refrigeration unit evaporator, and the first pump body is used to drive the refrigerant to circulate between the first cooling device and the refrigeration unit evaporator; the second circulation pipeline is provided with a second cooling device, a second pump body and a refrigeration unit condenser, and the second pump body is used to drive the refrigerant to circulate between the second cooling device and the refrigeration unit condenser; the refrigeration unit evaporator is used to transfer heat to the refrigeration unit condenser; the heat recovery subsystem is used to transfer part of the heat in the second circulation pipeline back to the first circulation pipeline when it is started.

[0006] Optionally, a first forked input end is provided between the outlet end of the first cooling device of the first circulation pipeline and the inlet end of the evaporator of the refrigeration unit, and a first forked output end is provided between the inlet end of the second cooling device of the second circulation pipeline and the outlet end of the condenser of the refrigeration unit; a second forked output end is provided between the inlet end of the first cooling device of the first circulation pipeline and the outlet end of the evaporator of the refrigeration unit, and a second forked input end is provided between the outlet end of the second cooling device of the second circulation pipeline and the inlet end of the condenser of the refrigeration unit; the heat recovery subsystem includes a first shunt pipe and a second shunt pipe, the first shunt pipe is connected with the first forked input end and the first forked output end, the second shunt pipe is connected with the second forked input end and the second forked output end, and valves are provided on the first shunt pipe and the second shunt pipe.

[0007] Optionally, the second cooling device includes a closed cooling tower.

[0008] Optionally, a third bifurcated input end is provided between the outlet end of the first cooling device of the first circulation pipeline and the inlet end of the evaporator of the refrigeration unit, and a third bifurcated output end is provided between the inlet end of the second cooling device of the second circulation pipeline and the outlet end of the condenser of the refrigeration unit; a fourth bifurcated output end is provided between the inlet end of the first cooling device of the first circulation pipeline and the outlet end of the evaporator of the refrigeration unit, and a fourth bifurcated input end is provided between the outlet end of the second cooling device of the second circulation pipeline and the inlet end of the condenser of the refrigeration unit; the heat recovery subsystem includes a third diverter pipe and a fourth diverter pipe, the third diverter pipe is connected to the third bifurcated input end and the fourth bifurcated output end, and the fourth diverter pipe is connected to the third bifurcated output end and the fourth bifurcated input end; the heat recovery subsystem also includes a heat exchanger, the heat exchanger is used to transfer the heat of the fourth diverter pipe to the third diverter pipe, and valves are provided on the third diverter pipe and the fourth diverter pipe.

[0009] Optionally, the second cooling device includes an open cooling tower.

[0010] Optionally, the refrigeration unit evaporator and the refrigeration unit condenser are arranged in the refrigeration unit, and the valve is communicatively connected with the refrigeration unit.

[0011] Optionally, the valve is communicatively connected to a controller, the controller is communicatively connected to the refrigeration unit, and the controller is configured to: when the cooling capacity of the refrigeration unit is lower than a preset percentage of the rated cooling capacity of the refrigeration unit, open the valve to enable the heat recovery subsystem to enter a startup state.

[0012] Optionally, the refrigeration unit evaporator and the refrigeration unit condenser are arranged in the refrigeration unit, and the valve is communicatively connected with the first cooling device and the refrigeration unit.

[0013] Optionally, the valve is communicatively connected to a controller, the controller is communicatively connected to the first cooling device and the refrigeration unit, and the controller is configured to: when the cooling capacity of the first cooling device is lower than a preset percentage of the cooling capacity of the refrigeration unit, open the valve to enable the heat recovery subsystem to enter a startup state.

[0014] Optionally, the valve is an electric control valve.

[0015] The cooling system provided by the utility model which can operate stably and continuously at low load has the following beneficial effects:

[0016] The utility model provides a cooling system capable of stable and continuous operation at low load, comprising a first circulation pipeline, a second circulation pipeline and a heat recovery subsystem; a first cooling device, a first pump body and a refrigeration unit evaporator are arranged on the first circulation pipeline, so that the refrigerant can circulate between the first cooling device and the refrigeration unit evaporator; a second cooling device, a second pump body and a refrigeration unit condenser are arranged on the second circulation pipeline, so that the refrigerant can circulate between the second cooling device and the refrigeration unit condenser; the refrigeration unit evaporator is used to transfer heat to the refrigeration unit condenser; the heat recovery subsystem is used to transfer part of the heat in the second circulation pipeline back to the first circulation pipeline in its startup state.

[0017] As can be understood by those skilled in the art, the refrigerant flows in the first circulation pipeline and the second circulation pipeline, and heat exchange occurs when the refrigerant passes through the first cooling device, the second cooling device, the evaporator of the refrigeration unit, and the condenser of the refrigeration unit, thereby achieving indoor cooling. For example, in an exemplary embodiment, the first cooling device is an air conditioner, the second cooling device is a cooling tower, the refrigerant in the first circulation pipeline is chilled water, and the refrigerant in the second circulation pipeline is cooling water. After the low-temperature refrigerant flows through the first cooling device, the first cooling device can transfer the heat in the room to the refrigerant. After the high-temperature refrigerant flows out from the outlet end of the first cooling device, it continues to flow through the evaporator of the refrigeration unit in the first circulation pipeline. The evaporator of the refrigeration unit absorbs the heat of the high-temperature refrigerant, and converts the high-temperature refrigerant into a low-temperature refrigerant that flows back to the first cooling device, thereby forming a circulating heat dissipation. The evaporator of the refrigeration unit transfers heat to the condenser of the refrigeration unit, thereby transferring heat to the second circulation pipeline. The refrigerant flowing through the condenser of the refrigeration unit in the second circulation pipeline will exchange heat with the condenser of the refrigeration unit to form a high-temperature refrigerant. The high-temperature refrigerant continues to flow through the second cooling device in the second circulation pipeline. The second cooling device can transfer the heat in the refrigerant to the outside, thereby achieving cooling of the indoor room.

[0018] When the first cooling device is running at a low load, the heat transferred to the refrigerant by the first cooling device will decrease, and the heat that the evaporator of the refrigeration unit can absorb will decrease. At this time, in the prior art, the refrigeration unit will enter the start-stop control condition. In order to prevent the refrigeration unit from starting and stopping frequently, we introduce a heat recovery subsystem. When the first cooling device enters a low-load working state, the heat recovery subsystem is started to transfer part of the heat in the second circulation pipeline back to the first circulation pipeline, which is equivalent to recovering part of the heat transferred from the evaporator of the refrigeration unit, so that the heat that the evaporator of the refrigeration unit can absorb increases, thereby preventing the refrigeration unit from starting and stopping frequently under low load. This solution is particularly suitable for old house renovation projects. The heat recovery subsystem can be directly connected to the existing equipment pipeline, which is simple and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the structure of a cooling system capable of stable and continuous operation at low load provided by the first embodiment of the utility model;

[0020] Figure 2 A schematic structural diagram of a cooling system capable of stable and continuous operation at low load provided in the second embodiment of the utility model.

[0021] The accompanying drawings are denoted as follows:

[0022] 1-first circulation pipeline; 11-first cooling device; 12-first pump body; 13-refrigeration unit evaporator;

[0023] 2-second circulation pipeline; 21-second cooling device; 22-second pump body; 23-refrigeration unit condenser;

[0024] 30-valve; 31-first shunt pipe; 32-second shunt pipe; 100-first bifurcated input end; 101-first bifurcated output end; 201-second bifurcated output end; 200-second bifurcated input end;

[0025] 33 third shunt tube; 34 fourth shunt tube; 300 third bifurcated input end; 301 third bifurcated output end; 400 fourth bifurcated input end; 401 fourth bifurcated output end;

[0026] 40-Heat exchanger. DETAILED DESCRIPTION

[0027] In order to make the purpose, advantages and features of the utility model clearer, the utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the utility model. In addition, the structure shown in the drawings is often a part of the actual structure. In particular, the emphasis of each drawing is different, and sometimes different scales are used.

[0028] It should be understood that when an element or layer is referred to as "on...", "connected to" other elements or layers, it can be directly on other elements or layers, connected to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on...", "directly connected to" other elements or layers, there is no intervening element or layer. Although the terms first, second, third, etc. can be used to describe various elements, dried objects, areas, layers and / or parts, these elements, dried objects, areas, layers and / or parts should not be limited by these terms. These terms are only used to distinguish an element, dried object, area, layer or part from another element, dried object, area, layer or part. Therefore, without departing from the teaching of the present invention, the first element, dried object, area, layer or part discussed below can be expressed as a second element, dried object, area, layer or part. Spatial relationship terms such as "under...", "below", "below", "above...", "above", "above", etc., can be used here for the convenience of description to describe the relationship between an element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, the spatial relationship terms are intended to include different orientations of the devices in use and operation. For example, if the device in the accompanying drawings is turned over, then, the elements or features described as "under...", "below", "below" will be oriented to be "on" other elements or features. The device can be oriented in addition (rotated 90 degrees or other orientations) and the spatial descriptors used here are interpreted accordingly. The purpose of the terms used here is only to describe specific embodiments and is not a limitation of the utility model. When used here, the singular forms of "one", "one" and "said / the" are also intended to include plural forms, unless the context clearly indicates another way. It should also be understood that the term "including" is used to determine the existence of features, steps, operations, elements and / or dried objects, but does not exclude the existence or addition of one or more other features, steps, operations, elements, dried objects and / or groups. When used here, the term "and / or" includes any and all combinations of the relevant listed items.

[0029] The utility model aims to provide a cooling system capable of stable and continuous operation at low load, and utilizes heat recovery to enable the refrigeration unit to operate stably and continuously at low load.

[0030] To achieve the above object, the utility model provides a cooling system capable of stable and continuous operation at low load, comprising a first circulation pipeline, a second circulation pipeline and a heat recovery subsystem;

[0031] The first circulation pipeline is provided with a first cooling device, a first pump body and a refrigeration unit evaporator, and the first pump body is used to drive the refrigerant to circulate between the first cooling device and the refrigeration unit evaporator;

[0032] The second circulation pipeline is provided with a second cooling device, a second pump body and a refrigeration unit condenser, and the second pump body is used to drive the refrigerant to circulate between the second cooling device and the refrigeration unit condenser;

[0033] The refrigeration unit evaporator is used to transfer heat to the refrigeration unit condenser;

[0034] The heat recovery subsystem is used for transferring part of the heat in the second circulation pipeline back to the first circulation pipeline in the startup state.

[0035] In order to explain the technical principle of the utility model, the working principle of the refrigeration unit is first explained.

[0036] The following is a detailed explanation of the working principle of the refrigeration unit:

[0037] Compression process: The compressor is the core component of the refrigeration unit, usually using a piston, screw or scroll structure. Its main function is to absorb and compress the low-temperature and low-pressure gaseous refrigerant (or working fluid vapor) into a high-temperature and high-pressure gas state. This process requires external energy to drive the compressor to work.

[0038] Condensation process: After compression, the high-temperature and high-pressure gas refrigerant enters the condenser. In the condenser, the gas releases heat through the action of fans or other heat dissipation equipment and gradually cools and condenses into medium-temperature and high-pressure liquid refrigerant. The heat released in this process is taken away by the surrounding air.

[0039] Throttling process: The medium-temperature and high-pressure liquid refrigerant coming out of the condenser will flow through the expansion valve (also called the throttling valve). Here, the pressure and temperature of the refrigerant will be reduced, turning into a low-temperature and low-pressure wet vapor state, ready to enter the evaporator for evaporation and heat absorption. The function of the expansion valve is to regulate and control the flow and pressure of the refrigerant to ensure the normal operation of the system.

[0040] Evaporation process: After the low-temperature, low-pressure wet vapor refrigerant enters the evaporator, it begins to absorb the surrounding heat and vaporize (i.e. evaporate), thereby cooling the evaporator and the air around it. This achieves a cooling effect on the air. Finally, the completely vaporized low-temperature, low-pressure gas refrigerant returns to the compressor inlet again, and the above cycle is repeated to achieve continuous cooling.

[0041] As can be understood by those skilled in the art, the refrigerant flows in the first circulation pipeline and the second circulation pipeline, and heat exchange occurs when the refrigerant passes through the first cooling device, the second cooling device, the evaporator of the refrigeration unit, and the condenser of the refrigeration unit, thereby achieving indoor cooling. For example, in an exemplary embodiment, the first cooling device is an air conditioner, the second cooling device is a cooling tower, the refrigerant in the first circulation pipeline is chilled water, and the refrigerant in the second circulation pipeline is cooling water. After the low-temperature refrigerant flows through the first cooling device, the first cooling device can transfer the heat in the room to the refrigerant. After the high-temperature refrigerant flows out from the outlet end of the first cooling device, it continues to flow through the evaporator of the refrigeration unit in the first circulation pipeline. The evaporator of the refrigeration unit absorbs the heat of the high-temperature refrigerant, and converts the high-temperature refrigerant into a low-temperature refrigerant that flows back to the first cooling device, thereby forming a circulating heat dissipation. The evaporator of the refrigeration unit transfers heat to the condenser of the refrigeration unit, thereby transferring heat to the second circulation pipeline. The refrigerant flowing through the condenser of the refrigeration unit in the second circulation pipeline will exchange heat with the condenser of the refrigeration unit to form a high-temperature refrigerant. The high-temperature refrigerant continues to flow through the second cooling device in the second circulation pipeline. The second cooling device can transfer the heat in the refrigerant to the outside, thereby achieving cooling of the indoor room.

[0042] When the first cooling device is running at a low load, the heat transferred to the refrigerant by the first cooling device will decrease, and the heat that the evaporator of the refrigeration unit can absorb will decrease. At this time, in the prior art, the refrigeration unit will enter the start-stop control condition. In order to prevent the refrigeration unit from starting and stopping frequently, we introduce a heat recovery subsystem. When the first cooling device enters a low-load working state, the heat recovery subsystem is started to transfer part of the heat in the second circulation pipeline back to the first circulation pipeline, which is equivalent to recovering part of the heat transferred from the evaporator of the refrigeration unit, so that the heat that the evaporator of the refrigeration unit can absorb increases, thereby preventing the refrigeration unit from starting and stopping frequently under low load. This solution is particularly suitable for old house renovation projects. The heat recovery subsystem can be directly connected to the existing equipment pipeline, which is simple and reliable.

[0043] The technical principle of the present utility model is explained below in combination with two embodiments. It should be noted that the embodiments are preferred embodiments and the present utility model is not limited to the embodiments.

[0044] Example 1

[0045] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a cooling system that can operate stably and continuously at low loads provided by the first embodiment of the utility model. Figure 1As shown, the heat recovery subsystem is implemented in such a manner that a first bifurcated input end 100 is provided between the outlet end of the first cooling device 11 of the first circulation pipeline 1 and the inlet end of the refrigeration unit evaporator 13, and a first bifurcated output end 101 is provided between the inlet end of the second cooling device 21 of the second circulation pipeline 2 and the outlet end of the refrigeration unit condenser 23; a second bifurcated output end 201 is provided between the inlet end of the first cooling device 11 of the first circulation pipeline 1 and the outlet end of the refrigeration unit evaporator 13, and a second bifurcated input end 200 is provided between the outlet end of the second cooling device 21 of the second circulation pipeline 2 and the inlet end of the refrigeration unit condenser 23;

[0046] The heat recovery subsystem includes a first shunt pipe 31 and a second shunt pipe 32. The first shunt pipe 31 is connected to the first forked input end 100 and the first forked output end 101, and the second shunt pipe 32 is connected to the second forked input end 200 and the second forked output end 201. Valves 30 are provided on the first shunt pipe 31 and the second shunt pipe 32.

[0047] Under normal working conditions, the valve 30 is not opened. At this time, the working principle of the cooling system capable of stable and continuous operation at low load is as follows: driven by the first pump body 12 and the second pump body 22, the refrigerant flows in the first circulation pipeline 1 and the second circulation pipeline 2. The first cooling device 11 (such as an air conditioner) transfers the heat in the room to the refrigerant flowing through the first cooling device 11. The refrigerant flowing out of the first cooling device 11 in the first circulation pipeline 1 will become a high-temperature refrigerant. The high-temperature refrigerant continues to flow into the refrigeration unit evaporator 13 in the first circulation pipeline 1, and the heat of the high-temperature refrigerant is transferred to the refrigeration unit evaporator 13, and the high-temperature refrigerant becomes a low-temperature refrigerant. The low-temperature refrigerant continues to return to the first cooling device 11 in the first circulation pipeline 1. The refrigeration evaporator 13 transfers the heat to the refrigeration unit condenser 23, and the heat enters the second circulation pipeline 2 from the first circulation pipeline 1. When the refrigerant in the second circulation pipeline 2 flows through the refrigeration unit condenser 23, the refrigeration unit condenser 23 transfers heat to the refrigerant in the second circulation pipeline 2, turning it into a high-temperature refrigerant. The high-temperature refrigerant continues to flow into the second cooling device 21 (e.g., a cooling tower) in the second circulation pipeline 2, and the second cooling device 21 transfers the heat of the high-temperature refrigerant to the outside, turning the high-temperature refrigerant back into a low-temperature refrigerant. The low-temperature refrigerant continues to flow back to the refrigeration unit condenser 23 in the second circulation pipeline 2, thereby realizing a heat dissipation cycle.

[0048] When the first cooling device 11 is in a low-load working scenario, the valve 30 is opened to start the heat recovery subsystem. At this time, after the high-temperature refrigerant flows out from the outlet of the refrigeration unit condenser 23, it will be bifurcated at the first bifurcated output end 101, and a part of it will flow into the first shunt pipe 31, and merge with the high-temperature refrigerant in the first circulation pipeline 1 at the first bifurcated input end 100, and continue to flow into the evaporator 13 of the refrigeration unit to achieve partial heat recovery. The refrigerant flowing out of the outlet of the refrigeration unit evaporator 13 will be bifurcated at the second bifurcated output end 201, and a part of it will flow into the second shunt pipe 32, and merge with the low-temperature refrigerant in the second circulation pipeline 2 at the second bifurcated input end 200, and flow back to the condenser 23 of the refrigeration unit.

[0049] It should be noted that the low-load working scenario can be determined based on the cooling capacity of the first cooling device 11 or the rated cooling capacity of the refrigeration unit, and the opening of the valve 30 can be manually controlled or automatically controlled based on logical judgment. It should be understood that the controller based on logical judgment can be directly obtained in the form of a physical module in the prior art, and the controller itself does not involve methodological improvements.

[0050] When the low-load working scenario is determined based on the cooling capacity of the first cooling device 11, the utility model further provides the following technical solution: the evaporator 13 of the refrigeration unit and the condenser 23 of the refrigeration unit are arranged in the refrigeration unit, and the valve 30 is communicatively connected with the first cooling device 11 and the refrigeration unit. The valve 30 is communicatively connected with the controller, and the controller is communicatively connected with the first cooling device 11 and the refrigeration unit, that is, the controller is communicatively connected with the valve 30 and the refrigeration unit respectively. The controller is configured to: when the cooling capacity of the first cooling device 11 is lower than a preset percentage of the cooling capacity of the refrigeration unit (for example, 20 percent or 25 percent), open the valve 30 to enable the heat recovery subsystem to enter a startup state.

[0051] When the low-load working scenario is determined based on the rated cooling capacity of the refrigeration unit, the utility model further provides the following technical solution: the refrigeration unit evaporator 13 and the refrigeration unit condenser 23 are arranged in the refrigeration unit, and the valve 30 is communicatively connected with the refrigeration unit. The valve 30 is communicatively connected with the controller, and the controller is communicatively connected with the refrigeration unit, that is, the controller is communicatively connected with the valve 30, the first cooling device 11 and the refrigeration unit respectively. The controller is configured to: when the cooling capacity of the refrigeration unit is lower than a preset percentage of the rated cooling capacity of the refrigeration unit (for example, 20 percent or 25 percent), open the valve 30 to enable the heat recovery subsystem to enter a startup state.

[0052] It should be noted that the first embodiment is more suitable for the scenario where the second cooling device 21 includes a closed cooling tower, because in the scenario of the closed cooling tower, a connected refrigerant pipeline can be established between the second circulation pipeline 2 and the first circulation pipeline 1. The working principle of the embodiment of the open cooling tower will be further described below.

[0053] The first embodiment of the utility model is particularly suitable for old house renovation projects, such as an office building that has been in operation for many years. It is only necessary to find the first circulation pipeline 1 and the second circulation pipeline 2 corresponding to the office building, and set the first bifurcated input end 100 between the outlet end of the first cooling device 11 (such as air conditioner) of the first circulation pipeline 1 and the inlet end of the evaporator 13 of the refrigeration unit, and set the first bifurcated output end 101 between the inlet end of the second cooling device 21 (such as closed cooling tower) of the second circulation pipeline 2 and the outlet end of the condenser 23 of the refrigeration unit; The second bifurcated output end 201 is arranged between the inlet end of the first cooling device 11 and the outlet end of the refrigeration unit evaporator 13, and the second bifurcated input end 200 is arranged between the outlet end of the second cooling device 21 of the second circulation pipeline 2 and the inlet end of the refrigeration unit condenser 23; the first shunt pipe 31 is connected with the first bifurcated input end 100 and the first bifurcated output end 101, the second shunt pipe 32 is connected with the second bifurcated input end 200 and the second bifurcated output end 201, and the valve 30 is arranged on the first shunt pipe 31 and the second shunt pipe 32. Based on this, there is no need for large-scale dismantling and modification, and only pipelines need to be added.

[0054] Example 2

[0055] Please refer to Figure 2 , Figure 2 The schematic diagram of the structure of the cooling system capable of low-load stable and continuous operation provided by the second embodiment of the utility model. Figure 2 As shown, the second embodiment is different from the first embodiment in that a third bifurcated input end 300 is provided between the outlet end of the first cooling device 11 of the first circulation pipeline 1 and the inlet end of the refrigeration unit evaporator 13, and a third bifurcated output end 301 is provided between the inlet end of the second cooling device 21 of the second circulation pipeline 2 and the outlet end of the refrigeration unit condenser 23; a fourth bifurcated output end 401 is provided between the inlet end of the first cooling device 11 of the first circulation pipeline 1 and the outlet end of the refrigeration unit evaporator 13, and a fourth bifurcated output end 401 is provided between the outlet end of the second cooling device 21 of the second circulation pipeline 2 and the outlet end of the refrigeration unit condenser 23 is provided with a fourth bifurcated input end 400; the heat recovery subsystem includes a third branch pipe 33 and a fourth branch pipe 34, the third branch pipe 33 is connected with the third bifurcated input end 300 and the fourth bifurcated output end 401, and the fourth branch pipe 34 is connected with the third bifurcated output end 301 and the fourth bifurcated input end 400; the heat recovery subsystem also includes a heat exchanger 40, the heat exchanger 40 is used to transfer the heat of the fourth branch pipe 34 to the third branch pipe 33, and valves are provided on the third branch pipe 33 and the fourth branch pipe 34.

[0056] Similarly, under normal working conditions, the valve 30 is not opened. At this time, the working principle of the cooling system capable of stable and continuous operation at low load is as follows: driven by the first pump body 12 and the second pump body 22, the refrigerant flows in the first circulation pipeline 1 and the second circulation pipeline 2. The first cooling device 11 (such as an air conditioner) transfers the heat in the room to the refrigerant flowing through the first cooling device 11. The refrigerant flowing out of the first cooling device 11 in the first circulation pipeline 1 will become a high-temperature refrigerant. The high-temperature refrigerant continues to flow into the refrigeration unit evaporator 13 in the first circulation pipeline 1, and the heat of the high-temperature refrigerant is transferred to the refrigeration unit evaporator 13, and the high-temperature refrigerant becomes a low-temperature refrigerant. The low-temperature refrigerant continues to return to the first cooling device 11 in the first circulation pipeline 1. The refrigeration evaporator 13 transfers the heat to the refrigeration unit condenser 23, and the heat enters the second circulation pipeline 2 from the first circulation pipeline 1. When the refrigerant in the second circulation pipeline 2 flows through the refrigeration unit condenser 23, the refrigeration unit condenser 23 transfers heat to the refrigerant in the second circulation pipeline 2, turning it into a high-temperature refrigerant. The high-temperature refrigerant continues to flow into the second cooling device 21 (e.g., a cooling tower) in the second circulation pipeline 2, and the second cooling device 21 transfers the heat of the high-temperature refrigerant to the outside, turning the high-temperature refrigerant back into a low-temperature refrigerant. The low-temperature refrigerant continues to flow back to the refrigeration unit condenser 23 in the second circulation pipeline 2, thereby realizing a heat dissipation cycle.

[0057] When the first cooling device 11 is in a low-load working scenario, the valve 30 is opened to start the heat recovery subsystem. At this time, the high-temperature refrigerant flowing out of the outlet end of the condenser 23 of the refrigeration unit will fork at the third fork output end 301, and part of it will flow into the fourth diversion pipe 34, while the low-temperature refrigerant flowing out of the evaporator 13 of the refrigeration unit will fork at the fourth fork output end 401, and part of it will flow into the third diversion pipe 33. The fourth diversion pipe 34 and the third diversion pipe 34 are connected. The tubes 33 all pass through the heat exchanger 40, and the high-temperature refrigerant in the fourth branch pipe 34 and the low-temperature refrigerant in the third branch pipe 33 generate heat exchange in the heat exchanger 40. The heat in the high-temperature refrigerant in the fourth branch pipe 34 will be transferred to the low-temperature refrigerant in the third branch pipe 33, so that the low-temperature refrigerant in the third branch pipe 33 is changed back to high-temperature refrigerant and merges with the refrigerant in the first circulation pipeline 1 again through the third bifurcated input end 300, and flows into the evaporator 13 of the refrigeration unit again. Here we can compare the above-mentioned first embodiment, and it can be found that the essential difference between the two embodiments is that in the second embodiment, there is no direct exchange of refrigerant between the first circulation pipeline 1 and the second circulation pipeline 2, and heat exchange is not performed by the exchange of refrigerant, but the heat exchange is performed by the heat exchanger 40. Therefore, the connection logic of the pipelines is different, which should be compared and distinguished.

[0058] It should be noted that the low-load working scenario can be determined based on the cooling capacity of the first cooling device 11 or the rated cooling capacity of the refrigeration unit, and the valve 30 can be opened manually or automatically based on logic determination. When automatically controlled, the valve 30 should be an electric control valve. It should be understood that the controller based on logic determination can be directly obtained in the prior art in the form of a physical module, and the controller itself does not involve methodological improvements.

[0059] When the low-load working scenario is determined based on the cooling capacity of the first cooling device 11, the utility model further provides the following technical solution: the evaporator 13 of the refrigeration unit and the condenser 23 of the refrigeration unit are arranged in the refrigeration unit, and the valve 30 is communicatively connected with the first cooling device 11 and the refrigeration unit. The valve 30 is communicatively connected with the controller, and the controller is communicatively connected with the first cooling device 11 and the refrigeration unit, that is, the controller is communicatively connected with the valve 30 and the refrigeration unit respectively. The controller is configured to: when the cooling capacity of the first cooling device 11 is lower than a preset percentage of the cooling capacity of the refrigeration unit (for example, 20 percent or 25 percent), open the valve 30 to enable the heat recovery subsystem to enter a startup state.

[0060] When the low-load working scenario is determined based on the rated cooling capacity of the refrigeration unit, the utility model further provides the following technical solution: the refrigeration unit evaporator 13 and the refrigeration unit condenser 23 are arranged in the refrigeration unit, and the valve 30 is communicatively connected with the refrigeration unit. The valve 30 is communicatively connected with the controller, and the controller is communicatively connected with the refrigeration unit, that is, the controller is communicatively connected with the valve 30, the first cooling device 11 and the refrigeration unit respectively. The controller is configured to: when the cooling capacity of the refrigeration unit is lower than a preset percentage of the rated cooling capacity of the refrigeration unit (for example, 20 percent or 25 percent), open the valve 30 to enable the heat recovery subsystem to enter a startup state.

[0061] It should also be noted that the second embodiment mainly corresponds to a scenario in which the second cooling device includes an open cooling tower. Since the open cooling tower, as an open system, cannot directly contact the closed system of the first circulation pipeline 1, the heat exchanger 40 is introduced in this case so that the first circulation pipeline 1 and the second circulation pipeline 2 are not directly connected while achieving heat exchange, and are spatially isolated from each other.

[0062] The second embodiment of the utility model is particularly suitable for old house renovation projects, such as an office building that has been in operation for many years. It is only necessary to find the first circulation pipeline 1 and the second circulation pipeline 2 corresponding to the office building, and set a third bifurcated input end 300 between the outlet end of the first cooling device 11 (such as air conditioner) of the first circulation pipeline 1 and the inlet end of the evaporator 13 of the refrigeration unit, and set a third bifurcated output end 301 between the inlet end of the second cooling device 21 (such as open cooling tower) of the second circulation pipeline 2 and the outlet end of the condenser 23 of the refrigeration unit; between the inlet end of the first cooling device 11 of the first circulation pipeline 1 and the outlet end of the condenser 23 of the refrigeration unit; A fourth bifurcated output end 401 is provided between the outlet end of the evaporator 13 of the refrigeration unit, and a fourth bifurcated input end 400 is provided between the outlet end of the second cooling device 21 of the second circulation pipeline 2 and the inlet end of the condenser 23 of the refrigeration unit; the third shunt pipe 33 is connected with the third bifurcated input end 300 and the fourth bifurcated output end 401, and the fourth shunt pipe 34 is connected with the third bifurcated output end 301 and the fourth bifurcated input end 400; the heat exchanger 40 is provided to transfer the heat of the fourth shunt pipe 34 to the third shunt pipe 33, and valves are provided on the third shunt pipe 33 and the fourth shunt pipe 34. Based on this, there is no need for large-scale dismantling and modification, and only pipelines need to be added.

[0063] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0064] It should also be noted that, although the present invention has been disclosed as a preferred embodiment, the above embodiment is not intended to limit the present invention. For any technician familiar with the art, without departing from the scope of the technical solution of the present invention, the above disclosed technical content can be used to make many possible changes and modifications to the technical solution of the present invention, or modified into equivalent embodiments of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

[0065] It should also be understood that, unless otherwise specified or indicated, the terms "first", "second", "third", etc. in the specification are merely used to distinguish between the various components, elements, steps, etc. in the specification, and are not used to indicate the logical relationship or sequential relationship between the various components, elements, steps, etc.

[0066] It should also be recognized that the terms described herein are only used to describe specific embodiments and are not used to limit the scope of the utility model. It must be noted that the singular forms "one" and "a kind" used herein and in the appended claims include plural references unless the context clearly indicates the opposite meaning. For example, a reference to "a step" or "a device" means a reference to one or more steps or devices, and may include secondary steps and secondary devices. All conjunctions used should be understood in the broadest sense. And, the word "or" should be understood to have the definition of a logical "or", not a logical "exclusive or" definition, unless the context clearly indicates the opposite meaning. In addition, the implementation of the embodiments of the utility model may include performing the selected tasks manually, automatically, or in combination.

Claims

1. A cooling system capable of stable and continuous operation at low load, characterized in that: It includes a first circulation pipeline, a second circulation pipeline and a heat recovery subsystem; The first circulation pipeline is provided with a first cooling device, a first pump body and a refrigeration unit evaporator, and the first pump body is used to drive the refrigerant to circulate between the first cooling device and the refrigeration unit evaporator; The second circulation pipeline is provided with a second cooling device, a second pump body and a refrigeration unit condenser, and the second pump body is used to drive the refrigerant to circulate between the second cooling device and the refrigeration unit condenser; The refrigeration unit evaporator is used to transfer heat to the refrigeration unit condenser; The heat recovery subsystem is used for transferring part of the heat in the second circulation pipeline back to the first circulation pipeline in the startup state.

2. The cooling system capable of stable and continuous operation at low load as claimed in claim 1, characterized in that: A first bifurcated input end is provided between the outlet end of the first cooling device of the first circulation pipeline and the inlet end of the evaporator of the refrigeration unit, and a first bifurcated output end is provided between the inlet end of the second cooling device of the second circulation pipeline and the outlet end of the condenser of the refrigeration unit; A second bifurcated output end is provided between the inlet end of the first cooling device of the first circulation pipeline and the outlet end of the evaporator of the refrigeration unit, and a second bifurcated input end is provided between the outlet end of the second cooling device of the second circulation pipeline and the inlet end of the condenser of the refrigeration unit; The heat recovery subsystem includes a first shunt pipe and a second shunt pipe, the first shunt pipe is connected to the first fork input end and the first fork output end, the second shunt pipe is connected to the second fork input end and the second fork output end, and valves are provided on the first shunt pipe and the second shunt pipe.

3. The cooling system capable of stable and continuous operation at low load as claimed in claim 2, characterized in that: The second cooling device includes a closed cooling tower.

4. The cooling system capable of stable and continuous operation at low load as claimed in claim 1, characterized in that: A third bifurcated input end is provided between the outlet end of the first cooling device of the first circulation pipeline and the inlet end of the evaporator of the refrigeration unit, and a third bifurcated output end is provided between the inlet end of the second cooling device of the second circulation pipeline and the outlet end of the condenser of the refrigeration unit; A fourth bifurcated output end is provided between the inlet end of the first cooling device of the first circulation pipeline and the outlet end of the evaporator of the refrigeration unit, and a fourth bifurcated input end is provided between the outlet end of the second cooling device of the second circulation pipeline and the inlet end of the condenser of the refrigeration unit; The heat recovery subsystem comprises a third shunt pipe and a fourth shunt pipe, the third shunt pipe is connected to the third bifurcated input end and the fourth bifurcated output end, and the fourth shunt pipe is connected to the third bifurcated output end and the fourth bifurcated input end; The heat recovery subsystem further comprises a heat exchanger, and the heat exchanger is used for transferring the heat of the fourth diverter pipe to the third diverter pipe. Valves are arranged on the third diverter pipe and the fourth diverter pipe.

5. The cooling system capable of low-load stable and continuous operation as claimed in claim 4, characterized in that: The second cooling device comprises an open cooling tower.

6. The cooling system capable of low-load stable and continuous operation according to claim 2 or 4, characterized in that: The refrigeration unit evaporator and the refrigeration unit condenser are arranged in the refrigeration unit, and the valve is communicatively connected with the refrigeration unit.

7. The cooling system capable of stable and continuous operation at low load as claimed in claim 6, characterized in that: The cooling system also includes a controller, which is communicated with the valve and the refrigeration unit respectively, and the controller is configured to: when the cooling capacity of the refrigeration unit is lower than a preset percentage of the rated cooling capacity of the refrigeration unit, open the valve to enable the heat recovery subsystem to enter a startup state.

8. The cooling system capable of low-load stable and continuous operation as claimed in claim 2 or 4, characterized in that: The refrigeration unit evaporator and the refrigeration unit condenser are arranged in the refrigeration unit, and the valve is communicatively connected with the first cooling device and the refrigeration unit.

9. The cooling system capable of low-load stable and continuous operation as claimed in claim 8, characterized in that: The cooling system also includes a controller, which is communicated with the valve, the first cooling device and the refrigeration unit respectively, and the controller is configured to open the valve when the cooling capacity of the first cooling device is lower than a preset percentage of the cooling capacity of the refrigeration unit to enable the heat recovery subsystem to enter a startup state.

10. The cooling system capable of low-load stable and continuous operation according to claim 2 or 4, characterized in that: The valve is an electric control valve.

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