Performance of liquid thermal insulation applied to the section of a main pipeline of the heat supply system
Energy saving is a top-priority task for any country. Presently, power engineering and its relevance grow year after year. The problem accrues particular significance in the following two cases: in the event of energy resources deficiency or in the event of adverse climatic conditions in a country. For example, in some regions of the Russian Federation, where the lowest outside temperature can reach 50 °C and below during the cold season, heat losses for heating systems can exceed 50 % of the heat supplied by heat sources.Thermal insulation is a universally recognized effective method of control over heat emissions into the environment. The authors present the performance of a liquid thermal insulation applied to the surface of a pipeline. Infrared thermometry devices (a pyrometer and a thermal imager) and classical equations of the steady-state heat transfer are applied to analyze the efficiency of advanced methods of heat insulation. The authors present a graph of linear heat loss for a steel pipeline depending on the thickness of the thermal insulation layer. Images, generated by the thermal imager, are analyzed together with the data obtained by the pyrometer. They demonstrate a gap between the temperature of an isolated section of a pipeline and the temperature of the unpainted pipeline, which is equal to 5—10 °C.The authors also present a histogram characterizing the annual fuel consumption (in standard measurement units) depending on the thickness of the heat insulation layer. The findings have demonstrated that 1 mm layer of thermal isolation saves 126.1 m3 of natural gas per one running meter of a pipeline a year, which is equal to approx. 500 rubles (in prices of 2013). The payback period this energy-saving project should not exceed six months. It is noteworthy that the increase of the liquid thermal insulation layer is not a criterion for its economic expediency. If the thickness of liquid thermal insulation is equal to 1 mm, fuel savings will reach approx. 65 %; if it goes up to 1,5 mm, fuel savings go up by mere 8 %.The paper demonstrates the authors' findings in terms of the heat conductivity declared by the producer. Some problems remain unresolved, including the issue of identification of the properties of liquid heat insulation, if the heat insulation layer is exposed to external factors (such as the temperature and humidity of the environment, heat transfer temperature), etc.