Abstract. Thermotechnical characteristics of heat pipes are considered as high-efficient heat-transfer devices, which can provide energy-saving technologies for heat supply and ventilating systems and for different branches of industry. Thermotechnical and working ("performance capability") characteristics of heat pipes are investigated. By "performance capability" of heat pipes and heat-transfer devices on heat pipes we mean the system state, where it can perform set functions and keep parameter values (thermal power, conductivity, thermal resistance, heat-transfer coefficient, temperature level and differential, etc.) within the regulations of standardized specifications. The article presents theoretical and experimental methods of «gaslock» length determination on noncondensable gases during long-lasting tests of ammonia heat pipes made of aluminum shape АS -КRА 7.5 -R1 (alloy АD -31). The paper gives results of research of thermotechnical characteristics of heat pipes in horizontal and vertical states (separate and as a set part) while using different systems of thermal insulation. The obtained results of thermotechnical and resource tests show the advantages of ammonia heat pipes as basic elements for heat exchanger design in heating and ventilation systems.

Abstract. The paper presents the results of experimental studies of heat pipes and their thermo-technical characteristics (heat power, conductivity, heat transfer resistance, heat-transfer coefficient, temperature level and differential, etc.). The theoretical foundations and the experimental methods of the research of ammonia heat pipes made of aluminum section АS -КRА 7.5 -R1 (made of the alloy AD -31) are explained. The paper includes the analysis of the thermo-technical characteristics of heat pipes as promising highly efficient heat transfer devices, which may be used as the basic elements of heat exchangers -heat recuperators for exhaust ventilation air, capable of providing energy-saving technologies in ventilation systems for housing and public utilities and for various branches of industry. The thermo-technical characteristics of heat pipes (HP) as the basic elements of a decentralized supply-extract ventilation system (DSEVS) and energy-saving technologies are analyzed. As shown in the test report of the ammonia horizontal HP made of the section АS-КRА 7,5-R1-120, this pipe ensures safe operation under various loads.