The article is devoted to comparison of thermal and aerodynamic efficiency of two configurations of the regenerative nozzle used in the regenerative heat exchanger for room ventilation. The impact of nozzle channel diameter, nozzle length and stage time on the thermal efficiency of the nozzle, its aerodynamic resistance and the required fan power is considered.

Abstract. Aim. An integral part of an energy audit of buildings and structures consists in thermal imaging diagnostics. This permits an evaluation of the heat-shielding properties of the enclosing structures of buildings in order to control the functional and operational status of engineering systems, as well as to identify implicit (invisible) and explicit (visible) defects in them. The aim of the work is to analyse some features and results of thermal control of an opaque hinged ventilated facade system and translucent enclosing structures in the form of window systems of a capital construction project. Method. Thermal imaging was used as a control for resolving issues of energy and resource conservation. The special importance of thermal control of translucent facade systems and non-translucent hinged ventilated facades of capital construction projects having various functional and operational purposes is highlighted. Results. A detailed algorithm is presented for supporting a comprehensive diagnosis of the heat engineering state of building envelopes for various construction projects by analysing thermograms, using thermal monitoring methods, to take into consideration engineering systems, building materials and finished products, along with technologies of full-scale thermal imaging inspection of translucent building envelopes. The obtained thermograms are presented and analysed. Conclusion. Current problems in the fields of energy efficiency and energy saving in the construction and energy industries are considered in the light of the latest technological developments. The proposed graph-analytical algorithm supporting a diagnosis of the heat engineering state of building envelopes based on the analysis of thermograms is the most comprehensive among known analogues and prototypes

The influence of geometric (length, diameter and wall thickness of a unit equivalent channel of the nozzle), thermophysical (density and heat capacity of the nozzle material) and operating parameters (air flow through the regenerator and the time of one stage of accumulation / regeneration of thermal energy) on the thermal efficiency of stationary switching regenerative heat exchangers was studied . It was revealed that by varying the length and diameter of the channel and air flow, it is possible to increase thermal efficiency up to 10%. It was found that the wall thickness of a single channel, the density and heat capacity of the material of the nozzle, as well as the time of one stage, slightly aff ect the thermal efficiency of the regenerative heat exchanger.

The influence of various parameters of stationary switching regenerative heat exchangers used for ventilation on its thermal efficiency was studied. Considered are the geometric (length, diameter and wall thickness of a single equivalent nozzle channel), thermophysical (density and heat capacity of the nozzle material) and operation (air flow through the regenerator and the time of one stage of accumulation/regeneration of thermal energy) parameters.

Energy conservation is a priority for most of the nation states. Its relevance in modern world energy industry is growing every year. This problem acquires particular importance when a country is characterized by a lack of fuel and energy resources or adverse climatic conditions. The most effective way to reduce heat losses from heat network pipelines to environment is the use of heat insulation. This paper presents the results of application heat-insulating paint on the surface of main pipeline. The infrared thermometry devices (pyrometer and thermal imager) were used to evaluate the energy efficiency of modern high-tech insulation. The thermograms from thermal imager and the readings from pyrometer were analyzed, it was established that the absolute difference in temperatures of an isolated pipeline section and an unpainted section are 5-10 °C. The studies have also shown that when a 250×6 pipeline is coated with a 1 mm thick heat-insulating paint, it will save 126.1 m3 of natural gas per 1 running meter per year. In monetary terms it will be approximately 610 rubles or about $9 (for the first half of 2020). The payback period of this energy-saving measure should not exceed six months. Increasing the thickness of liquid heat insulation layer is not economically feasible. The equivalent fuel economy is approximately 65% when the heat-insulating paint is of 1 mm thickness, and it will increase by only 8% for a thickness of 1.5 mm.