Domestic Refrigerator


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domestic refrigerator

[də′mes·tik ri′frij·ə‚rād·ər]
(mechanical engineering)
A refrigeration system for household use which typically has a compression machine designed for continuous automatic operation and for conservation of the charges of refrigerant and oil, and is usually motor-driven and air-cooled. Also known as refrigerator.

Refrigerator, Domestic

 

(also household refrigerator), an appliance that is used for the short-term preservation of food products in the home by means of refrigeration. Depending on the type of refrigerating machine used, domestic refrigerators are classified as compression-type, absorption-type, and thermoelectric.

The first domestic refrigerators, which used vapor-compression machines, appeared in 1910 in the USA. Absorption-type domestic refrigerators were first produced in 1925 in Sweden. The first thermoelectric domestic refrigerators were manufactured in the second half of the 1950’s. In the USSR, the first compression-type domestic refrigerators (the KhTZ-120) were produced in 1939, the first absorption-type domestic refrigerators (the Gazoapparat) were manufactured in 1945, and the first prototypes of a thermoelectric refrigerator, which uses thermoelectric cooling, were produced in 1951. The mass production of Soviet compression-type domestic refrigerators (the ZIL) began in 1951.

A domestic refrigerator is a metal cabinet with a built-in hermetically sealed refrigerating unit (Figure 1). Inside the cabinet is a cold chamber with shelves for storing products. Heat insulation is placed between the walls of the cold chamber and the case of the refrigerator. The air in the cold chamber is cooled by means of heat transfer between the air and the cold surface of the evaporator. The necessary temperature conditions in the refrigerator are provided by the brief periodic—that is, cyclic—operation of the refrigerating unit, which is switched on by means of a thermal relay. Domestic refrigerators have a storage space of 20 to 800 liters.

Figure 1. A compression refrigerating unit: (1) compressor, (2) evaporator, (3) condenser, (4) filter drier, (5) throttler (capillary tube)

Depending on their purpose, Soviet domestic refrigerators are divided into the following four categories: those intended for the storage of unfrozen products (such refrigerators lack a freezer compartment), those intended for the short-term storage (for several days) of frozen products, those intended for the mediumterm storage (up to several weeks) of frozen products, and those intended for the long-term storage (up to three months) of frozen products. The assignment of a refrigerator to one of these categories depends on whether the refrigerator has a freezer compartment and on the air temperature in the freezer compartment. For the information of consumers, refrigerators intended for short-term storage bear one star, those intended for medium-term storage bear two stars, and those intended for long-term storage bear three stars. The temperature in the freezer compartment is –6°C in one-star models, –12°C in two-star models, and not higher than –18°C in three-star models.

The one-, two-, and three-star models are two-temperature refrigerators; the two- and three-star models have one, two, or more compartments. In two-compartment models, a thick insulated partition separates the freezer compartment and the main compartment, where the temperature is above freezing. Each of the two compartments has its own door. Multiple-compartment refrigerators have at least three compartments, each with its own door, for the storage of various products. According to the extent to which their operation is automated, refrigerators are classified as having manual, semiautomatic, or automatic defrosting. Depending on the method used for circulating the air in a refrigerator, a distinction is made between refrigerators with natural circulation and those with forced circulation, which is maintained by a fan.

In three-star refrigerators with natural convection, each compartment, as a rule, is cooled by a separate evaporator. In refrigerators with forced circulation, a fan draws air through a single evaporator, which is a pipe coil with plate fins. The evaporator and fan are usually installed behind the rear wall of the freezer compartment. Most of the cold air (75–85 percent) is supplied to the freezer compartment; the rest of the cold air is delivered to the main compartment, where the temperature is above freezing. In such refrigerators, absolutely no frost is deposited on the products or the walls. The moisture contained in the air accumulates as frost on the evaporator, which is located behind the wall of the freezer compartment, so that only dry air enters the compartment. Since the evaporator is not in contact with the products, the heating of the evaporator during defrosting does not affect the temperature of frozen products. Therefore, automatic defrosting may be carried out several times a day.

Domestic refrigerators may be stationary or portable. Stationary refrigerators are classified as free-standing, wall-type, and built-in (that is, built into a kitchen or reception-room furniture unit). Portable models are mainly absorption-type and thermoelectric refrigerators. In addition, absorption-type refrigerators are classified, depending on the heat source, as electric, gas-fired, kerosene-burning, and combination-type. Electric refrigerators are the most widely used. The limited use of gas-fired refrigerators is due mainly to safety considerations and also to difficulties associated with the connection of such refrigerators to a gas distribution system. Kerosene-burning refrigerators are used mainly aboard ships and as portable appliances.

Most of the domestic refrigerators manufactured today are of the compression type. Absorption-type refrigerators account for 5–10 percent of the total production. In comparison with compression-type refrigerators, absorption-type refrigerators are bulkier and heavier, consume more electrical energy (more by a factor of 1.5–2), and have a smaller freezer compartment. Thermoelectric refrigerators are not widely used, since they are expensive and have higher power requirements than compression-type refrigerators. Most thermoelectric refrigerators have a small storage space (up to 60 liters).

Domestic refrigerators are produced in more than 60 countries. More than 25 million such refrigerators are manufactured each year. The USSR (with 5.6 million domestic refrigerators produced in 1975), the USA, and Italy manufacture the largest number of domestic refrigerators each year.

L. N. VAIN

References in periodicals archive ?
Experimental Study Of Alternative Refrigerants To Replace R134a In A Domestic Refrigerator, International Journal Of Research In Aeronautical And Mechanical Engineering, pp: 2321-3051.
Kim, Domestic refrigerators: recent developments, International Journal of Refrigeration: 19 (1), 61-69 (1996).
Determination of optimum refrigerant charge for domestic refrigerator units, International Journal of Refrigeration 7: 178-180.
In the present work, a theoretical investigation is carried out to evaluate the performance of domestic refrigerator and effect of Suction-liquid heat exchanger with the R-12,R-134a,M09 .This paper also discuss the reasons to continue investigation of nonazeotropic refrigerant mixtures.
Practically all current domestic refrigerators have a Rankine-cycle cooling system, driven by a motor-compressor.
The Penn State team has also built a solar-powered thermoacoustic engine that produces 120 decibels of sound, which may drive a thermoacoustic ice maker in the near future, and another unit that looks and operates much like a domestic refrigerator.
Narasimha, "Heat transfer Enhancement in Domestic Refrigerator using R600a/mineral oil/nano-AEOs as working fluid", International Journal of Computational Engineering, 03(4).
One four cubic feet domestic refrigerator has about 260 grammes of CFC in its insulation, and the 3.2m fridges and freezers scrapped each year equate to about 600 tonnes of CFC which could be reclaimed, together with 45,000 tonnes of ferrous metals, 5,000 tonnes of non-ferrous metals, 1,500 tonnes of glass and 14,000 tonnes of plastic.
Asda are introducing three new premium juices in 1 litre leakprrof cartons that can be stored on their sides in the domestic refrigerator, even after opening, we are assured.
Tenders are invited for Domestic refrigerator (single door)size 180-190ltr
High pressure variable ratio three stream PU foam dispenser with one mixing head and a nominal capacity of up to 100 kg/min to insulate domestic refrigerator cabinets and doors based on cyclopentane technology
Tenders are invited for Purchase Cut-out & Demo models of refrigeration system at shirgaon ,Cut Section Model of Open Type Reciprocating Compressor,Cut Section Model of Shell and Tube Condenser,Cut Section Model of Centrifugal ,Compressor,Cut Section Model of Automatic Expansion Valve ,Cut Section Model of Thermostatic Exnansion Valve,Model of Domestic Refrigerator,Model of Cooling Tower,Model of Ammonia Ice Plant,Model of Evaporative Condenser Opening date : 17 Jan 2018

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