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Study of the Influence of the Connection Mode of the STI Brand Aluminum Radiator on its Thermal Characteristics

Aluminum radiators of various brands have become widespread on the market of heating equipment nowadays. It is possible to reduce the cost of manufacturing radiators by reducing the surface of the heat-emitting internal fins, while maintaining their appearance, and the heat transfer claimed by the manufacturer is being maintained high enough. Decree of the Government of the Russian Federation No 717 of June 17, 2017 introduced mandatory certification of all types of heating appliances. Deviations of the nominal thermal power of the section indicated in the device passport from the indicators established by the test results should not exceed the maximum permissible values (from –4 to +5 %). As a rule, no previous tests were carried out by the manufacturer. Thus, the study of the influence of the radiator connection mode with a reduced fin surface on its thermal characteristics is an urgent task. The article presents the results of the studies of a factory aluminum radiator with a reduced surface of STI Classic brand fins with a heat output of 1.92 kW under design conditions. The specified heat transfer of the device does not take into account its connection mode. The reduction of the inner and rear fins reduced its surface area by 28.8 %. As a result of the experiments carried out, it was found that the thermal power of the device is 22 % lower than the declared value when connected from top to bottom and 48 % lower when connected from bottom to top under design conditions. During the warmer period of the heating season, with a small temperature difference between the coolant and the indoor air, the average heat output of the radiator coincides with the declared value.