Novel PCM phase change cold storage system for central air conditioner

Abstract

The invention provides a novel PCM phase change cold storage system for a central air conditioner, which comprises a refrigeration host, a water collector, a water segregator, a chilled water pump and a cooling water circulation pipeline, and further comprises an ice storage tank, a cold water release pump, a first electric valve, an electric three-way valve, a first check valve, a second electric valve, a second check valve and a third electric valve, pCM (phase change material) is mounted in the ice storage tank; an ice storage tank, a cold water releasing pump, a first electric valve, an electric three-way valve, a first check valve, a second electric valve, a second check valve and a third electric valve are additionally arranged in the system, a PCM phase change material is installed in the ice storage tank, and a PLC of the central air conditioning system is used for controlling connection switching of pipelines; and the positive temperature phase change characteristic of the phase change material can realize multiple modes of cold storage and cold supply of the refrigeration host, pure cold storage of the ice storage tank, pure cold discharge of the ice storage tank, combined cold supply of the ice storage tank and the refrigeration host and the like, so that the requirements of multiple complicated working conditions can be better met.

Description

Technical Field

[0001] The invention relates to the technical field of central air conditioning refrigeration, and in particular to a novel PCM phase change cold storage system for central air conditioning. Background Art

[0002] Due to industrial development and the improvement of people's material and cultural living standards, the popularity of air conditioners has increased year by year, electricity consumption has increased rapidly, peak power is tight, and off-peak power is not fully utilized. Therefore, how to shift peak power demand, "shift peak to fill valley", balance power supply, and improve the effective use of electricity has become a problem that many countries are paying attention to and solving, which has led to the attention and development of central air conditioning cold storage technology. At present, the traditional and relatively widely used cold storage air conditioning technologies on the market are "water storage" and "ice storage".

[0003] For places that need to run central air-conditioning systems 24 hours a day, whether water storage or ice storage is used, an additional refrigeration host and corresponding auxiliary chilled water pumps, cooling water pumps, cooling towers and other equipment need to be turned on during the cold storage process to store cold. At the same time, water storage has factors such as low cold storage density, large footprint, high maintenance cost and heat loss. Ice storage has factors such as complex system, poor cold storage efficiency, high system energy consumption and low ice making efficiency. As a result, no matter which cold storage solution is adopted, the energy-saving effect cannot be achieved, and it can only play the role of "peak shaving and valley filling" and transferring the electricity price difference (there are peak and valley electricity prices). Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a new PCM phase change cold storage system for central air conditioning to solve the problem that existing places need to run central air conditioning systems 24 hours a day. Water cold storage has the disadvantages of low cold storage density, large floor space, high maintenance cost and heat loss, while ice cold storage has the disadvantages of complex system, poor cold storage efficiency, high system energy consumption and low ice making efficiency. As a result, no matter which cold storage scheme is adopted, the energy-saving effect cannot be achieved.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: A novel PCM phase change cold storage system for central air conditioning comprises a refrigeration main unit, a water collector, a water distributor, a chilled water pump and a cooling water circulation pipeline, and also comprises an ice storage tank, a cold water release pump, a first electric valve, an electric three-way valve, a first check valve, a second electric valve, a second check valve and a third electric valve, wherein PCM phase change material is installed in the ice storage tank; the outlet of the ice storage tank is connected to the refrigeration outlet end of the refrigeration main unit through the cold water release pump, the first electric valve and the electric three-way valve, the other end of the electric three-way valve is connected to the first check valve, the other end of the first check valve is respectively connected to the second electric valve and the inlet of the ice storage tank through a three-way pipe, the other end of the second electric valve is connected to the water collector, the second check valve is connected in parallel to the two ends of the chilled water pump, the inlet end of the second check valve is connected to the third electric valve, and the other end of the third electric valve is connected to the outlet of the cold water release pump.

[0006] Preferably, a pressure differential bypass valve group is installed between the water collector and the water distributor.

[0007] Preferably, the outlet end of the chilled water pump is connected to the refrigeration inlet of the refrigeration host through a first manual valve, and the inlet end of the chilled water pump is connected to the water collector through a first refrigeration electric valve.

[0008] Preferably, the cooling water circulation pipeline includes a cooling tower and a cooling water pump, one end of the cooling tower is connected to the cooling outlet of the refrigeration main unit, and the other end of the cooling tower is connected to the cooling inlet of the refrigeration main unit through the cooling water pump, a second manual valve is installed at both ends of the cooling water pump, a third manual valve is installed at both ends of the cooling tower, and a fourth manual valve is installed at both ends of the cooling water pump.

[0009] Preferably, the refrigeration host, the chilled water pump, the cooling tower and the cooling water pump are all multiple in number and are arranged in parallel, and the outlet ends of adjacent chilled water pumps are connected via a second chilled electric valve.

[0010] Preferably, the system includes a storage-while-supply mode: The outlet water temperature of the refrigeration host is adjusted to 5℃, the electric three-way valve is opened, and the flow direction of the chilled water is switched, so that the low-temperature chilled water of 5℃ enters the ice storage tank and directly contacts with the PCM phase change material for heat exchange. The PCM in the ice storage tank absorbs the cold between 5℃ and 8℃ and stores it. Then the ice storage tank outputs 8℃ chilled water, the first electric valve is opened, the second electric valve and the third electric valve are closed, and the 8℃ chilled water is supplied to the terminal equipment that needs cooling through the cooling water release pump. The high-temperature water returned from the terminal water collector flows to the refrigeration host, and the refrigeration host cools the high-temperature water to low-temperature water of 5℃, and the cycle is repeated to form a complete cycle.

[0011] Preferably, the system includes a pure cold storage mode: The outlet water temperature of the refrigeration host is adjusted to 5℃, the electric three-way valve is opened, the flow direction of the chilled water is switched, and the low-temperature chilled water of 5℃ enters the ice storage tank and directly contacts the PCM phase change material for heat exchange. The PCM in the ice storage tank absorbs the cold between 5℃ and 8℃ and stores it. Then the ice storage tank outputs 8℃ chilled water, the third electric valve is opened, the first electric valve and the second electric valve are closed, and the 8℃ chilled water returns to the refrigeration host through the cold water release pump. The refrigeration host recools the chilled water to 5℃ and stores all the cold generated by the refrigeration host in the ice storage tank.

[0012] Preferably, the system includes a pure cooling mode: Shut down the refrigeration main unit, chilled water pump, cooling water pump and cooling tower, open the first electric valve, close the third electric valve, and the ice storage tank outputs 8℃ chilled water. The 8℃ chilled water is supplied to the equipment at the end that needs cooling through the cooling water release pump. The high-temperature water returned from the end water collector flows to the ice storage tank. The second electric valve is opened, and the high-temperature water returned from the end passes through the second electric valve into the ice storage tank, and is cooled into low-temperature water by the phase change material in the ice storage tank. The cooled low-temperature water is supplied to the equipment at the end that needs cooling through the cooling water release pump, forming a cycle.

[0013] Preferably, the system includes a combined cooling series mode: The refrigeration host, chilled water pump, cooling water pump, and cooling tower are operated to reduce the number of startups or the equipment is operated at low load by frequency conversion. The PCM ice storage tank and the refrigeration host supply the terminal cooling demand together. The second electric valve is opened, and the high-temperature water returned from the terminal water collector enters the ice storage tank and is cooled to medium-temperature water by the phase change material. Then the first electric valve is closed and the third electric valve is opened. The cooled medium-temperature water returns to the refrigeration host through the cold water release pump. The refrigeration host cools the medium-temperature water to low-temperature water to meet the terminal cooling demand.

[0014] Preferably, a combined cooling parallel mode is also included: The high-temperature water coming back from the terminal is divided into two parts. One part enters the ice storage tank through the opened second electric valve for cooling. At this time, the first electric valve is opened and the third electric valve is closed. The cooled chilled water is directly sent to the water distributor of the system. The other part goes directly back to the refrigeration main unit through the bypass pipeline of the chilled water pump. The cooled chilled water of the refrigeration main unit is also sent to the water distributor. The two are mixed at the water distributor and supplied to the terminal together.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: (1) In the above scheme, by adding an ice storage tank, a cold water release pump, a first electric valve, an electric three-way valve, a first check valve, a second electric valve, a second check valve and a third electric valve to the central air-conditioning system, and installing PCM phase change material in the ice storage tank, the connection and switching of the central air-conditioning system's PLC control pipelines, and the positive temperature phase change characteristics of the phase change material can realize a variety of modes such as the refrigeration host storing cold while supplying cold, the ice storage tank storing cold only, the ice storage tank releasing cold only, and the ice storage tank and the refrigeration host jointly supplying cold, so as to better cope with various complex working conditions; (2) In the above scheme, cold storage is carried out by using the latent heat of phase change materials during phase change. The cold storage density is much greater than that of water. The cold storage capacity of each 1m3 ice storage tank is about 12.5RTH. Therefore, under the same cold storage capacity, the volume of the ice storage tank is much smaller than that of the water storage tank. At the same time, since the PCM phase change cold storage system freezes at a positive temperature, it does not need to use ethylene glycol as a coolant. Compared with ice storage, it can also omit large equipment such as ethylene glycol pumps and plate heat exchangers, which expands the application scope of cold storage technology and makes it possible for some buildings with limited space to apply cold storage technology. (3) In the above scheme, only ice storage tanks, cooling water pumps, and some pipes and valves are added to the original central air-conditioning system. In the daily operation process, only the cooling water pump needs to be maintained. The system is simple, with a small number of auxiliary equipment, few possible failure points in the system operation, and low maintenance costs. At the same time, since the system stores and releases cold at positive temperatures, it avoids problems such as excessive icing and pipe freezing, greatly improving the system reliability. (4) In the above scheme, the chilled water outlet temperature range that can be set for conventional refrigeration hosts on the market is 5~15℃, and the chilled water outlet temperature under standard working conditions is 7℃. The general storage temperature of water storage is 4℃ (water density is the largest at 4℃, which is conducive to the formation of a temperature gradient layer in the water storage tank), which requires a specially customized low-temperature host; the general storage temperature of ice storage is -5.6℃, and it is also necessary to invest in additional equipment such as ethylene glycol pumps and plate heat exchangers. The PCM phase change storage system has a storage temperature of 5℃, and conventional refrigeration hosts can be used for cold storage. In addition to the cold water pump, no additional investment in other equipment is required, which greatly reduces the amount of equipment investment; (5) In the above scheme, the PCM phase change cold storage system can adjust the outlet water temperature of the conventional refrigeration host to 5°C, and change the flow direction through the host outlet three-way valve, so that the chilled water first passes through the PCM ice storage tank. The phase change material in the ice storage tank absorbs the cold between 5°C and 8°C and stores it. Then the ice storage tank outputs 8°C chilled water to continue to supply the terminal equipment for use, realizing storage and supply. Since the refrigeration host, the corresponding chilled water pump, cooling water pump, and cooling tower used in the storage and supply are all the same set of equipment, the surplus cooling capacity of the refrigeration host is used to store cold when the load is reduced at night. There is no need to open an additional refrigeration host and the corresponding attached chilled water pump, cooling water pump, cooling tower and other equipment to store cold like water storage and ice storage. Therefore, this PCM phase change cold storage system can truly achieve energy saving effect while shaving peaks and filling valleys. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of a new PCM phase change cold storage system for central air conditioning; Figure 2 This is a schematic diagram of the structure of the new PCM phase change cold storage system for central air conditioning in the storage and supply mode; Figure 3 It is a schematic diagram of the pure cold storage mode structure of the new PCM phase change cold storage system for central air conditioning; Figure 4 This is a schematic diagram of the pure cooling mode structure of the new PCM phase change thermal storage system for central air conditioning; Figure 5 It is a structural schematic diagram of the combined cooling series mode of the new PCM phase change cold storage system for central air conditioning; Figure 6 It is a schematic diagram of the combined cooling parallel mode structure of the new PCM phase change cold storage system for central air conditioning; Figure numerals: 1, refrigeration main unit; 2, water collector; 3, water distributor; 4, chilled water pump; 401, second chilled electric valve; 5, cooling water circulation pipeline; 6, ice storage tank; 7, chilled water release pump; 8, first electric valve; 9, electric three-way valve; 10, first check valve; 11, second electric valve; 12, second check valve; 13, third electric valve; 14, pressure difference bypass valve group; 15, first manual valve; 16, first chilled electric valve; 17, fourth manual valve; 501, cooling tower; 502, cooling water pump; 503, second manual valve; 504, third manual valve. DETAILED DESCRIPTION

[0017] The following is a detailed description of a new PCM phase change cold storage system for central air conditioning provided by the present invention in combination with the accompanying drawings and specific embodiments. At the same time, it is explained here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and those skilled in the art may also adopt other alternative methods to implement some known technologies; and the accompanying drawings are only for a more specific description of the embodiments, and are not intended to specifically limit the present invention.

[0018] It should be noted that the references to "one embodiment", "embodiment", "exemplary embodiments", "some embodiments" and the like in the specification indicate that the embodiments described may include specific features, structures or characteristics, but not every embodiment may include the specific features, structures or characteristics. In addition, when a specific feature, structure or characteristic is described in conjunction with an embodiment, it should be within the knowledge of a person skilled in the art to implement such feature, structure or characteristic in conjunction with other embodiments (whether or not explicitly described).

[0019] In general, a term can be understood, at least in part, from its use in context. For example, depending, at least in part, on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in the singular sense, or can be used to describe a combination of features, structures, or characteristics in the plural sense. Additionally, the term "based on" can be understood as not necessarily intended to convey an exclusive set of factors, but can instead, depending, at least in part, on the context, allow for the presence of other factors that are not necessarily explicitly described.

[0020] It will be understood that the meaning of “on,” “over,” and “above” in this disclosure should be interpreted in the broadest manner, so that “on” means not only “directly on” something, but also includes the meaning of being “on” something with intervening features or layers therebetween, and “on” or “over” means not only “on” or “above” something, but also includes the meaning of being “on” or “above” something with no intervening features or layers therebetween.

[0021] Additionally, spatially relative terms such as "under," "beneath," "lower," "above," "upper," and the like may be used herein for descriptive convenience to describe the relationship of one element or feature to another element or features, as shown in the accompanying drawings. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the accompanying drawings. The device may be oriented in other ways, and the spatially relative descriptors used herein may be similarly interpreted accordingly.

[0022] like Figure 1-6As shown, an embodiment of the present invention provides a novel PCM phase change cold storage system for central air conditioning, comprising a refrigeration host 1, a water collector 2, a water distributor 3, a chilled water pump 4 and a cooling water circulation pipeline 5, which are the structural components of the original central air conditioning system and are not described in detail herein, and also include an ice storage tank 6, a cold water release pump 7, a first electric valve 8, an electric three-way valve 9, a first check valve 10, a second electric valve 11, a second check valve 12 and a third electric valve 13, wherein a PCM phase change material is installed in the ice storage tank 6; the PCM phase change material can phase change in an environment below positive 8°C, from a liquid to a solid PCM phase change material, and realizes cold storage and cold release based on the characteristic of the phase change material absorbing or releasing a large amount of latent heat in the solid-liquid phase change process, and since the phase change temperature of the phase change material is relatively high, the plate heat exchanger, acetylene oxide and the like can be optimized. Equipment and pipelines such as a glycol solution system; the outlet of the ice storage tank 6 is connected to the refrigeration outlet end of the refrigeration host 1 through a cold water release pump 7, a first electric valve 8 and an electric three-way valve 9, the other end of the electric three-way valve 9 is connected to a first check valve 10, the other end of the first check valve 10 is respectively connected to a second electric valve 11 and an inlet of the ice storage tank 6 through a three-way pipe, the other end of the second electric valve 11 is connected to a water collector 2, the second check valve 12 is connected in parallel to both ends of the chilled water pump 4, the inlet end of the second check valve 12 is connected to a third electric valve 13, the other end of the third electric valve 13 is connected to the outlet of the cold water release pump 7; the electric three-way valve 9 and the electric valve can be controlled by the PLC of the original central air-conditioning system to switch the flow direction of the chilled water, wherein the electric three-way valve 9 is a conventionally used pipeline valve used to switch the flow direction of the fluid in the pipeline.

[0023] like Figure 1 As shown, in this embodiment, a pressure difference bypass valve group 14 is installed between the water collector 2 and the water distributor 3. The main function of the pressure difference bypass valve group 14 is to ensure the stable operation of the system by adjusting the pressure difference of the system.

[0024] As shown in Figure 1, in this embodiment, the outlet end of the chilled water pump 4 is connected to the refrigeration inlet of the refrigeration host 1 through the first manual valve 15, and the inlet of the chilled water pump 4 is connected to the water collector 2 through the first refrigeration electric valve 16; the cooling water circulation pipeline 5 includes a cooling tower 501 and a cooling water pump 502, one end of the cooling tower 501 is connected to the cooling outlet of the refrigeration host 1, and the other end of the cooling tower 501 is connected to the cooling inlet of the refrigeration host 1 through the cooling water pump 502, and the second manual valve 503 is installed at both ends of the cooling water pump 502, and the third manual valve 504 is installed at both ends of the cooling tower 501, and the fourth manual valve 17 is installed at both ends of the cooling water pump 7; during the system installation and commissioning stage, the technicians can use the manual valves to adjust each branch pipeline so that the entire system reaches the operating state required by the design, and when inspecting or maintaining certain equipment of the system, the corresponding manual valves can be closed to cut off the medium flow of the equipment to avoid affecting the normal operation of other parts, while also ensuring the safety of maintenance personnel.

[0025] like Figure 1 As shown, in this embodiment, the number of the refrigeration host 1, the chilled water pump 4, the cooling tower 501 and the cooling water pump 502 are all multiple and arranged in parallel, and the outlet ends of adjacent chilled water pumps 4 are connected through the second refrigeration electric valve 401. This arrangement allows multiple hosts to be used together in the central air-conditioning system; the cold storage process of the PCM phase change cold storage system: at night or other power off-peak hours, the refrigeration host 1 is running, and the low-temperature water is transported to the ice storage tank 6. The water contacts the phase change material, and the phase change material absorbs the cold of the water. When the temperature drops below the phase change temperature, the phase change material changes from liquid to solid. A large amount of latent heat will be released in this process, but the temperature of the phase change material itself remains relatively stable, thereby storing the cold. Taking water as an example, under a standard atmospheric pressure, when water is heated from a normal temperature of 20°C to 100°C, the heat absorbed by the temperature change of 80°C is sensible heat, which is manifested as a rise in the water temperature; when the water continues to be heated, the water will vaporize into water vapor, and the heat absorbed in the process of water changing from liquid to gas is latent heat, which is manifested as a change in the form of matter, and the water temperature remains unchanged at 100°C, so the latent heat can be understood as the energy required to support the change in the form of matter, and the material temperature remains basically unchanged during the entire phase change process until the phase change is completed; cooling process: during the daytime or during peak hours when cooling is required, the cooling water pump 7 in the system transports the water with a higher temperature to the ice storage tank 6, and the water exchanges heat with the solid phase change material. The phase change material absorbs the heat of the water and gradually changes from a solid state to a liquid state. In this process, cooling is continuously provided to the water to reduce the water temperature, and then the low-temperature water is transported to the water distributor 3 to the places that need cooling, such as the air conditioning terminal, to realize the cooling function.

[0026] like Figure 2 As shown, in this embodiment, the system includes a storage-while-supply mode: The outlet water temperature of the refrigeration host 1 is adjusted to 5°C, the electric three-way valve 9 is opened, and the flow direction of the chilled water is switched, so that the low-temperature chilled water of 5°C enters the ice storage tank 6 and directly contacts with the PCM phase change material for heat exchange. The PCM in the ice storage tank 6 absorbs the cold between 5°C and 8°C and stores it. Then the ice storage tank 6 outputs 8°C chilled water, the first electric valve 8 is opened, the second electric valve 11 and the third electric valve 13 are closed, and the 8°C chilled water is supplied to the terminal equipment requiring cooling through the cold water release pump 7. The high-temperature water returned from the terminal water collector 2 flows to the refrigeration host 1, and the refrigeration host 1 cools the high-temperature water to low-temperature water of 5°C. This cycle is repeated to form a complete cycle. While ensuring that the cold supply required by the terminal remains unchanged, the surplus capacity of the refrigeration host 1 is used to complete the cold storage of the ice storage tank.

[0027] like Figure 3 As shown, in this embodiment, the system also includes a pure cold storage mode: The outlet water temperature of the refrigeration host 1 is adjusted to 5°C, the electric three-way valve 9 is opened, and the flow direction of the chilled water is switched, so that the low-temperature chilled water of 5°C enters the ice storage tank 6 and directly contacts with the PCM phase change material for heat exchange. The PCM in the ice storage tank 6 absorbs the cold between 5°C and 8°C and stores it. Then the ice storage tank 6 outputs 8°C chilled water, the third electric valve 13 is opened, the first electric valve 8 and the second electric valve 11 are closed, and the 8°C chilled water returns to the refrigeration host 1 through the cold water release pump 7. The refrigeration host 1 recools the chilled water to 5°C, and all the cold generated by the refrigeration host 1 is stored in the ice storage tank 6.

[0028] like Figure 4 As shown, in this embodiment, the system also includes a pure cooling mode: The refrigeration host 1, the chilled water pump 4, the cooling water pump 502, and the cooling tower 501 are all shut down, the first electric valve 8 is opened, the third electric valve 13 is closed, the ice storage tank 6 outputs 8°C chilled water, and the 8°C chilled water is supplied to the terminal equipment that needs cooling through the cold water release pump 7. The high-temperature water returned from the terminal water collector 2 flows to the ice storage tank 6, the second electric valve 11 is opened, and the high-temperature water returned from the terminal passes through the second electric valve 11 into the ice storage tank 6, and is cooled into low-temperature water by the phase change material in the ice storage tank 6. The cooled low-temperature water is supplied to the terminal equipment that needs cooling through the cold water release pump 7, forming a cycle. At this time, the PCM ice storage tank 6 fully supplies the cooling demand of the terminal.

[0029] like Figure 5 As shown, in this embodiment, the system also includes a combined cooling series mode: The refrigeration host 1, the chilled water pump 4, the cooling water pump 502, and the cooling tower 501 are operated to reduce the number of startups or the equipment is operated at low load by frequency conversion. The PCM ice storage tank 6 and the refrigeration host 1 supply the terminal cooling demand together. This is mainly to release the cooling capacity stored in the ice storage tank 6 as much as possible under the premise of ensuring the temperature and humidity requirements of the terminal environment. The second electric valve 11 is opened, and the high-temperature water returned from the terminal water collector 2 enters the ice storage tank 6 and is cooled to medium-temperature water by the phase change material. Then the first electric valve 8 is closed, and the third electric valve 13 is opened. The cooled medium-temperature water returns to the refrigeration host 1 through the cold water release pump 7. The refrigeration host 1 cools the medium-temperature water to low-temperature water to meet the terminal cooling demand.

[0030] like Figure 6 As shown, in this embodiment, a combined cooling parallel mode is also included: The high-temperature water coming back from the terminal is divided into two parts. One part enters the ice storage tank 6 through the opened second electric valve 11 for cooling. At this time, the first electric valve 8 is opened and the third electric valve 13 is closed. The cooled chilled water is directly sent to the water distributor 3 of the system. The other part is directly returned to the refrigeration main unit 1 through the bypass pipeline of the chilled water pump 4. The cooled chilled water of the refrigeration main unit 1 is also sent to the water distributor 3. The two are mixed at the water distributor 3 and supplied to the terminal together.

[0031] The present invention covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present invention. In order to make the public have a thorough understanding of the present invention, specific details are described in detail in the following preferred embodiments of the present invention, but those skilled in the art can fully understand the present invention without the description of these details. In addition, in order to avoid unnecessary confusion about the essence of the present invention, well-known methods, processes, procedures, components and circuits are not described in detail.

[0032] A person skilled in the art will appreciate that all or part of the steps in the above-mentioned embodiment method can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc.

[0033] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A novel PCM phase change cold storage system for central air conditioning, comprising a refrigeration main unit (1), a water collector (2), a water distributor (3), a chilled water pump (4) and a cooling water circulation pipeline (5), characterized in that: It also comprises an ice storage tank (6), a cold water release pump (7), a first electric valve (8), an electric three-way valve (9), a first check valve (10), a second electric valve (11), a second check valve (12) and a third electric valve (13); the ice storage tank (6) is installed with a PCM phase change material; the outlet of the ice storage tank (6) is connected to the refrigeration outlet end of the refrigeration host (1) through the cold water release pump (7), the first electric valve (8) and the electric three-way valve (9); the other end of the electric three-way valve (9) is connected to the refrigeration outlet end of the refrigeration host (1). The first check valve (10) is connected to the second electric valve (11) and the inlet of the ice storage tank (6) through a three-way pipe. The other end of the second electric valve (11) is connected to the water collector (2). The second check valve (12) is connected in parallel to both ends of the chilled water pump (4). The inlet end of the second check valve (12) is connected to the third electric valve (13). The other end of the third electric valve (13) is connected to the outlet of the chilled water pump (7).

2. The novel PCM phase change cold storage system for central air conditioning according to claim 1 is characterized in that: A pressure differential bypass valve group (14) is installed between the water collector (2) and the water distributor (3).

3. The novel PCM phase change cold storage system for central air conditioning according to claim 2 is characterized in that: The outlet end of the freezing water pump (4) is connected to the refrigeration inlet of the refrigeration main unit (1) via a first manual valve (15), and the inlet end of the freezing water pump (4) is connected to the water collector (2) via a first refrigeration electric valve (16).

4. The novel PCM phase change cold storage system for central air conditioning according to claim 1 is characterized in that: The cooling water circulation pipeline (5) comprises a cooling tower (501) and a cooling water pump (502); one end of the cooling tower (501) is connected to the cooling outlet of the refrigeration main unit (1); the other end of the cooling tower (501) is connected to the cooling inlet of the refrigeration main unit (1) via the cooling water pump (502); a second manual valve (503) is installed at both ends of the cooling water pump (502); a third manual valve (504) is installed at both ends of the cooling tower (501); and a fourth manual valve (17) is installed at both ends of the cooling water pump (7).

5. The novel PCM phase change cold storage system for central air conditioning according to claim 4 is characterized in that: The refrigeration main unit (1), the freezing water pump (4), the cooling tower (501) and the cooling water pump (502) are all provided in plural numbers and are arranged in parallel, and the outlet ends of adjacent freezing water pumps (4) are connected via a second freezing electric valve (401).

6. The novel PCM phase change cold storage system for central air conditioning according to claim 1 is characterized in that: The system includes a storage and supply mode: the outlet water temperature of the refrigeration main unit (1) is adjusted to 5°C, the electric three-way valve (9) is opened, the flow direction of the chilled water is switched, and the low-temperature chilled water of 5°C enters the ice storage tank (6) and directly contacts with the PCM phase change material for heat exchange. The PCM in the ice storage tank (6) absorbs the cold between 5°C and 8°C and stores it. Then the ice storage tank (6) outputs 8°C chilled water, the first electric valve (8) is opened, the second electric valve (11) and the third electric valve (13) are closed, and the 8°C chilled water is supplied to the terminal equipment requiring cooling through the cold water release pump (7). The high-temperature water returned from the terminal water collector (2) flows to the refrigeration main unit (1), and the refrigeration main unit (1) cools the high-temperature water to low-temperature water of 5°C. This cycle is repeated to form a complete cycle.

7. The novel PCM phase change cold storage system for central air conditioning according to claim 1 is characterized in that: The system includes a pure cold storage mode: the outlet water temperature of the refrigeration main unit (1) is adjusted to 5°C, the electric three-way valve (9) is opened, the flow direction of the chilled water is switched, and the low-temperature chilled water of 5°C enters the ice storage tank (6) to directly contact with the PCM phase change material for heat exchange, the PCM in the ice storage tank (6) absorbs the cold between 5°C and 8°C and stores it, then the ice storage tank (6) outputs 8°C chilled water, the third electric valve (13) is opened, the first electric valve (8) and the second electric valve (11) are closed, the 8°C chilled water returns to the refrigeration main unit (1) through the cold water release pump (7), the refrigeration main unit (1) recools the chilled water to 5°C, and all the cold generated by the refrigeration main unit (1) is stored in the ice storage tank (6).

8. The novel PCM phase change cold storage system for central air conditioning according to claim 5 is characterized in that: The system comprises a pure cooling mode: the refrigeration main unit (1), the chilled water pump (4), the cooling water pump (502), and the cooling tower (501) are all shut down, the first electric valve (8) is opened, the third electric valve (13) is closed, the ice storage tank (6) outputs 8°C chilled water, the 8°C chilled water is supplied to the terminal equipment requiring cooling through the cooling water release pump (7), the high-temperature water returned from the terminal water collector (2) flows to the ice storage tank (6), the second electric valve (11) is opened, the high-temperature water returned from the terminal passes through the second electric valve (11) and enters the ice storage tank (6), is cooled by the phase change material in the ice storage tank (6) into low-temperature water, and the low-temperature water after being cooled is supplied to the terminal equipment requiring cooling through the cooling water release pump (7), thereby forming a cycle.

9. The novel PCM phase change cold storage system for central air conditioning according to claim 5 is characterized in that: The system also includes a combined cooling series mode: the refrigeration host (1), the chilled water pump (4), the cooling water pump (502), and the cooling tower (501) are connected to reduce the number of startups or the equipment is operated at low load by frequency conversion, and the PCM ice storage tank (6) and the refrigeration host (1) supply the terminal cooling demand together, the second electric valve (11) is opened, and the high-temperature water returned from the terminal water collector (2) enters the ice storage tank (6) and is cooled to medium-temperature water by the phase change material, then the first electric valve (8) is closed, and the third electric valve (13) is opened, and the cooled medium-temperature water returns to the refrigeration host (1) through the cold water release pump (7), and the refrigeration host (1) cools the medium-temperature water to low-temperature water to meet the terminal cooling demand.

10. The novel PCM phase change cold storage system for central air conditioning according to claim 9 is characterized in that: The system also includes a combined cooling parallel mode: the high-temperature water returned from the terminal is divided into two parts, one part enters the ice storage tank (6) through the opened second electric valve (11) to cool down, at which time the first electric valve (8) is opened and the third electric valve (13) is closed, and the cooled chilled water is directly sent to the system's water distributor (3), and the other part directly returns to the refrigeration main unit (1) through the bypass pipeline of the chilled water pump (4), and the cooled chilled water of the refrigeration main unit (1) is also sent to the water distributor (3), and the two parts are mixed at the water distributor (3) to supply the terminal with cold water.

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