- Added: 13.12.2021
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The refrigeration unit is a complex of machines and apparatus used to obtain and stabilize In cooled objects temperatures are lower than in the environment. The plant consists of one or more refrigeration machines equipped for heat removal into the environment of the cold distribution and use system
Depending on the thermal load on the refrigerating unit, the variety of cooling objects, the type of refrigerating machines and the type of energy consumed, either centralized or centralized is used. or local cold supply system. The centralized system involves the use of a single complex of machines and apparatus for the generation of cold of various parameters and its distribution. The system may include separate aggregated refrigeration machines or may be a combination of refrigeration equipment having common or interchangeable elements (e.g. capacitor unit, receivers, refrigerating machine working medium communications). As a rule, when designing a centralized refrigeration unit, a cooling system for process objects with an intermediate coolant is used. This cold supply option involves a slight increase in power consumption (compared to direct cooling of cold consumers by the cooling machine working medium), one: it simplifies the technological scheme, provides ease of installation and maintenance of equipment, safety and reliability of its operation. The insulation of the cooling machine working medium circuit allows the use of ammonia as the cheapest and thermodynamically efficient working medium.
A cooling water cooling system is usually used to remove heat to the environment. In general, a centralized cold supply system provides a high degree of reliability with a smaller equipment reserve and a smaller number of maintenance personnel.
With low heat loads, significant dispersion of cooling objects, as well as with the direct inclusion of cooling cycle elements in the main production circuit, for example, during gas separation, it is advisable to use a local cold production system with direct cooling of objects by the cooling machine working medium. At the same time, energy costs are slightly reduced. In refrigeration plants used in the chemical industry, almost all types of refrigeration machines are used, but steam compression and absorption are most common. As the feasibility study shows, the use of absorption chillers is justified when using secondary energy resources in the form of flue exhaust gases, gas flares, process products, waste steam of low parameters. In a number of industries, the integrated use of both types of machines in the creation of power engineering schemes is economically profitable.
Calculation of the refrigeration plant includes the following stages: calculation of the refrigeration cycle, thermal calculations, selection of refrigeration equipment and calculation of communication of the working medium circuit, calculation of coolant and cooling water systems, calculation of thermal insulation of low-temperature devices and pipelines, assessment of the energy efficiency of the refrigeration plant and its technical and economic analysis. (, page 351)
In this course design, a cooling plant for cooling brine CaCl2 from 0 ° C to 15 ° C with ammonia is calculated. At the same time, there were
knowledge on PAKHT course "Refrigeration processes" was used and fixed.
Designed for process parameters: working medium cycle - ammonia and its required amount in evaporation system, evaporator, condenser and pump for brine supply.