Possibilities of improving the design of sectional aluminium radiator

Abstract

The main trend in the development of district heating systems in recent years is a decrease in the temperature of heat carrier, based on the desire to include renewable energy sources in such systems. Despite the ever-increasing demands on the thermal envelope of buildings, lowering the temperature entails the need to increase the area of heating appliances. In turn, this leads to an increase in material consumption of heating systems, increasing their hydraulic resistance and design problems. In order to avoid or at least reduce these negative consequences of the struggle to increase the environmental friendliness and energy efficiency of district heating systems, it is necessary to intensify the heat dissipation of heating appliances. The existing designs of sectional aluminium radiators, which are the most promising for improving their thermal performance, have reached a certain limit in the design, to overcome which it is necessary to change the technology of manufacturing the heat dissipating element of the section. The article shows the reasons for the emergence of such a limit for the existing design of devices, formulates requirements for advanced designs and shows the way to achieve higher thermal performance. The article presents the results of calculations that confirm the presence of the detected limit of thermal performance of existing structures of sectional aluminium radiators. Based on the analysis of existing designs and the identified limits of their further development, a new design of aluminium sectional heating device is proposed, which allows to bypass and overcome the limitations that are characteristic of existing ones. The results of calculations showing the possibilities of intensification of heat transfer of a sectional aluminium device are given. At the same heat output, the dimensions of the proposed radiator will be about thirty percent smaller than the size of existing appliances. The article presents the results of tests of prototypes of sectional radiators of the new design, manufactured using new technology. Devices consisting of seven sections of three sizes in height were investigated: 293 mm, 596 mm, 1097 mm. The results of the study confirmed previous theoretical developments. The tests were conducted in a laboratory certified according to European Union standards at the Institute of Heating and Sanitary Engineering in Radom (Poland).