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2
RECUPERATIVE HEAT EXCHANGER AS A WAY TO INCREASE COOLING
CAPACITY
Bulov A.O.1, Lyalikova A.A.2 (Russian Federation)
1Bulov Artyom Olegovich - postgraduate student, DEPARTMENT OF REFRIGERATION CRYOGENIC ENGINEERING AND AIR CONDITIONING SIBERIAN STATE UNIVERSITY OF SCIENCE AND TECHNOLOGY NAMED AFTER M.F. RESHETNEV; 2Lyalikova Anastasia Alexandrovna - teacher of a foreign language, KRASNOYARSK TECHNOLOGICAL COLLEGE OF FOOD INDUSTRY, KRASNOYARSK
Abstract: within the framework of this article, the issue of increasing the cooling capacity of a refrigeration unit is considered. The main ways of increasing cooling capacity are described in detail. With the help of the software, the operation of the refrigerating machine with and without a regenerative heat exchanger was compared. The fluid flow in such a device is simulated. According to the results of the study, conclusions were drawn about the use of a regenerative heat exchanger as one of the ways to increase the efficiency of the refrigerating machine.
Keywords: cooling capacity, efficiency, heat exchanger.
РЕКУПЕРАТИВНЫЙ ТЕПЛООБМЕННЫЙ АППАРАТ КАК СПОСОБ ПОВЫШЕНИЯ ХОЛОДОПРОИЗВОДИТЕЛЬНОСТИ Булов А.О.1, Ляликова A.A.2 (Российская Федерация)
1Булов Артём Олегович - аспирант, кафедра холодильной криогенной техники и кондиционирования Сибирский государственный университет науки и технологий имени М.Ф. Решетнева; 2Ляликова Анастасия Александровна - преподаватель иностранного языка, Красноярский технологический техникум пищевой промышленности,
г. Красноярск
Аннотация: в рамках данной статьи рассмотрен вопрос повышения холодопроизводительности холодильной установки. Подробно описаны основные способы повышения холодопроизводительности. С помощью программного обеспечения произведено сравнение работы холодильной машины с рекуперативным теплообменным аппаратом и без него. Смоделировано течение жидкости в таком аппарате. По результатам исследования сделаны выводы о применении рекуперативного теплообменного аппарата, как одного из способов повышения эффективности работы холодильной машины.
Ключевые слова: холодопроизводительность, эффективность, теплообменный аппарат.
Refrigeration systems today are large consumers of electricity. Reducing operating costs, as well as increasing the cooling capacity of refrigeration systems is an urgent area of research. It is possible to reduce the energy consumption of refrigeration equipment by increasing the cooling capacity of refrigeration units. One of the ways to increase the cooling capacity is the supercooling of the liquid refrigerant. Hypothermia can be obtained in various ways. One of these methods is to replace single-stage compression with multi-stage compression, when supercooling occurs when the refrigerant boils in an intermediate vessel at an intermediate pressure. The use of an intermediate vessel largely determines the efficiency and economy of the refrigeration unit as a whole [1].
Also, special regenerative heat exchangers of the "pipe in a pipe" type are used for supercooling. In these devices, supercooling occurs due to the vaporization of the refrigerant coming out of the evaporator.
The supercooling process is most effective in low-temperature installations. In such installations, the supercooling of the refrigerant after the condenser by 1 degree allows to increase the cooling capacity by 1% [2].
When using pipe-in-pipe heat exchangers (as a rule, for small refrigerating machines), special attention is paid to the intensification of heat exchange in the apparatus. For this purpose, either finned pipes are used, or all kinds of inserts (wire, tape, etc.) are used in the steam area or in the steam and liquid areas [3].
The current use of efficient oil separators in the schemes of refrigeration units (flushing or cyclonic on the injection side, hydrocyclones in the evaporation system) also makes it possible to use additional non—serpentine intermediate vessels — devices more efficient and simpler in design [4].
As a practical example, let's consider the parameters of a refrigeration unit that cools 5 tons of semi-finished meat in the city of Krasnoyarsk. Using the program "CoolPack 1.50" we will build a diagram of the installation (Fig. 1) [5].
Fig. 1. Diagram of the installation operation without a regenerative heat exchanger.
The specific mass productivity of this unit is 102 kJ / kg. The cooling coefficient of the COP = 2.10. We will install a regenerative heat exchanger in this refrigeration unit (Fig. 2).
Fig. 2. Recuperative heat exchanger of the "pipe in a pipe" type.
Let's determine the cooling capacity of a refrigeration unit with a regenerative heat exchanger. To do this, we will construct a diagram of the operation and calculate the amount of supercooling after the condenser in the regenerative heat exchanger of the working fluid (Fig. 3).
IX L* IM
» in at M M M «
Fig. 3. Diagram of the operation of the installation with regenerative heat exchangers.
The specific mass productivity of the system was 113.3 kJ / kg. The cooling coefficient of the COP = 2.37. With a supercooling value of 6K, we get a difference in cooling capacity of 11.3 kJ / kg. This means that in our installation, 1 K accounts for almost 2 kJ/kg of specific cooling capacity.
Let's simulate the flow of liquid in this device. Intense heat transfer occurs on the entire surface of the device.
Fig. 4. Fluid flow in the apparatus.
Thus, in this article, the issue of increasing the cooling capacity through the use of an additional regenerative heat exchanger is considered. The use of regenerative heat exchangers is an actual trend in refrigeration technology.
References / Список литературы
1. Improving the efficiency of the refrigeration unit due to the supercooling of the refrigerant [Electronic resource]. URL: https://pandia.ru/text/78/372/443.php?ysclid=l7ngrooapv212346154 (accessed 21.03.2023).
2. ZelikovskyI. Handbook of heat exchangers of small refrigerating machines. M.: Food industry, 1978. 178 p.
3. How to measure overheating and supercooling of freon [Electronic resource]. URL: https://rt82.ru/for-institutions/kak-pomerit-peregrev-i-pereohlazhdenie-freona-pereohlazhdenie/h (accessed 03/21/2023).
4. Ionov A. Efficiency of cold production. Kaliningrad: Publishing House, 1990. 174 p.
5. CoolPack1.50 [Electronic resource]. URL: https://coolpack.software.informer.com (accessed 03/21/2023).
