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KR-20260064828-A - COOLING SYSTEM AND CONTROL METHOD THEREOF

KR20260064828AKR 20260064828 AKR20260064828 AKR 20260064828AKR-20260064828-A

Abstract

The present invention relates to a multi-purpose cooling system using a phase change material, comprising a central thermal storage tank in which a refrigerant is transferred to a central heat exchanger by an AC chiller and stored in a PCM, and a plurality of cooling devices that receive cold air from the central thermal storage tank as brine, wherein the central heat exchanger is composed of a double pipe consisting of an inner pipe and an outer pipe so that the refrigerant and brine are transferred in a single pipe, thereby enabling simultaneous heat exchange between the refrigerant, brine, and PCM.

Inventors

  • 김승모
  • 홍주표

Assignees

  • 한국기술교육대학교 산학협력단

Dates

Publication Date
20260508
Application Date
20241029

Claims (6)

  1. In a cooling system that transfers the cooling power of a refrigerant cooled by an AC chiller to a phase-change material (PCM) through a heat exchanger of a central thermal storage tank, The cold air from one of the above-mentioned central thermal storage tanks installed outdoors is distributed and supplied to a plurality of cooling devices with different cooling temperature ranges through the flow rate distribution of brine, The above AC chiller is an integrated type that directly cools the PCM and brine of the central thermal storage tank to minimize the installation area and prevent heat loss, and The heat exchanger of the central thermal storage tank mentioned above is a double-pipe system in which the refrigerant and brine are transported in a single pipe and is installed within the PCM storage tank, and The above double tube is composed of a spiral tube type or a coaxial tube type in which the inner tube and the outer tube periodically come into contact at certain parts, and A multi-purpose cooling system characterized by the fact that brine is circulated in the outer tube by a circulation pump, and refrigerant is transferred in the inner tube by an AC chiller, so that the refrigerant simultaneously cools the brine and PCM and performs heat exchange.
  2. In paragraph 1, A multi-purpose cooling system characterized in that the above-described circulation pump supplies brine independently to each cooling device or supplies a distribution flow rate of brine in conjunction with a two-way or three-way valve, and the valves are electronically controlled.
  3. In paragraph 1, A multi-purpose cooling system characterized by using a plurality of AC chillers to rapidly store the above PCM, or including an auxiliary battery that operates electrically operated components other than the AC chillers in the event of a power outage.
  4. In paragraph 1, The above-described cooling device is a multi-purpose cooling system characterized by having a plurality of PCM packs further installed on the inner wall surface.
  5. In paragraph 1, the cooling device is, A controller that individually controls temperature, brine circulation flow rate, or fan motor speed, and A multi-purpose cooling system characterized by including an additional auxiliary battery for power outage.
  6. A control method for a multi-purpose cooling system comprising a central thermal storage tank that stores cold in a PCM through a refrigerant cooled by an AC chiller, and a plurality of cooling devices with different cooling temperature ranges that receive cold air from the central thermal storage tank through the flow rate distribution of brine, The heat exchanger of the central thermal storage tank mentioned above is a double-pipe system in which the refrigerant and brine are transported in a single pipe and is installed within the PCM storage tank, and The above double tube is composed of a spiral tube type or a coaxial tube type in which the inner tube and the outer tube periodically come into contact at certain parts, and The above outer tube is an integrated type in which brine is circulated by a circulation pump, and refrigerant is transferred by an AC chiller to the above inner tube, so that the refrigerant simultaneously cools the brine and PCM and performs heat exchange. The power connection, fan rotation speed, or brine circulation flow rate is individually controlled by a PLC (programmable logic controller) to maintain a set temperature according to the power status or usage status of the cooling device, A step of operating the AC chiller when the PCM in the central thermal storage tank rises above a predetermined temperature; A step of stopping the operation of the AC chiller when the PCM in the central thermal storage tank is sufficiently cooled; A step of including an auxiliary battery in addition to an AC power source in the central thermal storage tank, operating the circulation pump of the central thermal storage tank using the auxiliary battery in the event of a power outage, and recharging the auxiliary battery when the AC power is supplied normally; A step of including an auxiliary battery in the above cooling device and operating a fan and a circulation pump in the above cooling device using the auxiliary battery in the event of a power outage, and A control method for a multi-purpose cooling system characterized by including a temperature controller in the cooling device and a step of automatically or manually controlling the speed of the fan motor according to the set temperature inside the cooling device.

Description

Cooling system and control method thereof The present invention relates to a multi-purpose cooling system using a phase-change material and a method for controlling the same. More specifically, it is a technology that utilizes electricity from late-night hours when electricity consumption is low to store cold in a phase-change material (hereinafter referred to as 'PCM') in a central cooling tank, and uses this to simultaneously supply freezing, refrigeration, and cooling to multiple cooling systems, thereby increasing energy distribution efficiency and enabling the overload of blackouts caused by imbalances in power demand. Generally, refrigeration, freezing, and air conditioning equipment apply the principle of a refrigeration cycle, in which phase changes occur as a refrigerant evaporates, compresses, condenses, and expands, and the interior is cooled through the resulting heat exchange. Therefore, essential components for each product include a compressor that compresses the refrigerant, a condenser that condenses it, an expansion valve that expands it, and an evaporator that releases heat into the atmosphere, and each product consumes a large amount of power when operating. Showcases used for the storage or display of food requiring refrigeration, freezing, or cooling in convenience stores, supermarkets, food sections of marts or department stores, butcher shops, restaurants, bars, etc., are energy-intensive refrigeration devices with high operating costs because they must maintain a low temperature of approximately -23℃ to 8℃ year-round. For the cooling of refrigeration devices such as showcases, low-temperature refrigerators, air conditioners, and kimchi refrigerators, a refrigeration unit equipped with a compressor produces low-temperature refrigerant, and the produced low-temperature refrigerant undergoes heat exchange in a heat exchanger installed inside the refrigeration device to lower the internal temperature. As the number of places storing cold-weather foods, such as convenience stores and supermarkets, increases, and the use of air conditioners for indoor cooling rises due to accelerated global warming, this not only increases electricity consumption but also intensifies the daytime peak load during the summer, leading to a shortage of national reserve power and causing energy crises such as blackouts to occur every year due to the shutdown of nuclear power plants and other facilities. Accordingly, research on energy saving measures using ice thermal storage is actively underway in the showcase sector, but it has not been widely adopted to date, and the current situation is that daytime power consumption is not being effectively reduced. In addition, as described above, a refrigeration cycle is applied to each cooling product, resulting in high energy consumption. Furthermore, when the refrigeration cycle of a cooling product installed indoors is in operation, the operating noise of the compressor and fan, as well as the heat generated from the condenser, are degrading the efficiency of indoor temperature and energy thermal management. As a prior art, Patent Document 1 relates to a refrigerated showcase having a thermal storage system, and proposes a refrigerated showcase that stores cold in a PCM with a refrigeration unit and cools through a heat exchange passage by circulating brine. However, since the thermal storage tank and the showcase are not separated, the storage volume is small, and a comfortable environment cannot be maintained due to noise and heat loss caused by the cooler. FIG. 1 is a schematic diagram illustrating a multi-purpose cooling system using a phase change material according to the present invention. FIG. 2 is a cross-sectional view of a central heat exchanger of a multi-purpose cooling system using a phase change material according to the present invention. FIG. 3 is a configuration diagram showing a plurality of cooling devices of a multi-purpose cooling system using a phase change material according to the present invention. FIG. 4 is a cross-sectional view of a PCM pack of a cooling device of a multi-purpose cooling system using a phase change material according to the present invention. FIG. 5 is a configuration diagram of a multi-purpose cooling system installation using a phase change material according to the present invention. Specific embodiments for implementing the present invention will be described below with reference to the drawings. For the clarity of the invention, the illustrated drawings only show the essential contents in enlargement and omit incidental details; therefore, the invention should not be interpreted as being limited to the drawings. The multi-purpose cooling system of the present invention can be classified into refrigeration, freezing, or cooling devices depending on the purpose of use and temperature, but is described as a 'cooling device' as a representative expression. FIG. 1 is a schematic diagram of a multi-purpose cooling system