The subject matter of the paper is related to scientific-and-theoretical basis of power engineering characteristics of heat pump directly depending on the quality of treated water for reliable and uninterrupted operation of heat pump evaporator and compressor. On the basis of experimental data, energy parameters of the heat pump are calculated. The method of the combined technology of the heat pump “water – air” operation is considеred, the efficiency of which is based on the preliminary improvement of the quality of water softened with the use of a membrane ultrafiltration unit. This solution made it possible to reduce the load on the filters and to exclude the use of chemical reagents used in the classical schemes of water heating facilities. In order to improve the operation of the heat pump compressor, a method based on altering the speed of rotation of the shaft by means of electronic microprocessor devices has been proposed. To regulate the compressor performance, a frequency converter with a wide range of alternating current frequency is used. The intervals of alteration of frequency of the alternating current corresponding to energy-efficient values of coefficient of transformation of energy of the heat pump are investigated. The values of the energy conversion coefficient of the heat pump obtained in the course of experiments and determined by calculation are consistent within the experimental errors with the regulation of the compressor performance. The suggested experimental device made it possible to determine the dependence of the main characteristics of the unit of the heat pump unit on the number of revolutions of the compressor and to find out an effective range of its control (50–180 %). The development of advanced technologies for natural water treatment under conditions of increased anthropogenic loads on natural water sources is a priority one among the fundamental and applied research in the field of water treatment.

The working characteristics of a laboratory ball drum mill during grinding of Karaganda coal products were studied in order to apply the results obtained to industrial installations. The performed analysis shows that the most complicated and energy-intensive stage of preparation of coal dust is the grinding of fuel. The operational characteristics of the mill productivity, consumed electric power and specific energy consumption in terms of the relative rotational speed of the drum as well as the optimal values of the relative velocity determining the qualitative grinding of the fuel have been determined. The performance of the processed drum mill reaches its maximum at a relative speed of rotation of the drum 0.71 ensuring a waterfall mode of grinding of fuel related to the high-speed mode of a coal-grinding mill. The estimated specific energy consumption for fuel grinding varies in the range from 0.11 kWh/kg up to 0.23 kWh/kg at fuel milling coefficient of Kl = 1.2.

Introduction. The purpose of this investigation is to show what changes introduced in the mathematical model of a district heating system are capable of considerable improving the convergence of simulation results and actual data. The study evaluates the work of heating supply establishments with their customers as well as analysis of the ways of enhancing pump equipment efficiency that allows saving electric energy or increasing output at the same energy consumption. Materials and methods. Engineering acceptance of newly introduced and reconstructed facilities is conducted, heat loads are corrected, disconnections and recurrent connections of indebted consumers are carried out. Studying data submitted by a local heat supply establishment shows that pump seals made from iron and steel are subject accelerated wear in the course of operation. Results. Three variants of the problem solution are suggested: making seals from bronze or stainless steel, prevention of unjustified increase of seal clearances as well as using labyrinth pump seals. This will allow increasing pump equipment efficiency by 5 to 7 % and save about 2 × 105 kW∙h of electrical energy for every pump or increase of output at the same energy consumption. Taking into account that a pump station is a part of the district heating system and unmachined inner surfaces of the pumps have a significant roughness, grinding of these surfaces can improve their hydraulic characteristics of the pumps. In the scope of the suggested method, the entire district heating system is considered not in the situation when actual load is equal to the sum of all the design loads and the pump equipment has manufacturer’s parameters, but accounting actual loads and characteristics. Conclusions. Mathematical model of district heating system heating and hydraulic mode that takes issues mentioned above into consideration would allow simulating joint operation of the heating and hot water supply systems at transient operation modes with higher accuracy.

The increase in production and modernization of existing heat pumps are global trends in the development and implementation of heat pump technology. Application of refrigerant with zero potential ozone depletion relative to fluorinetrichloromethane and minimum values of global warming potentials relative to carbon dioxide is environmentally justified in pumps. Prospective are stage compression heat pump units and, also, consecutive and cascade schemes of inclusion which provide higher temperature of the heat carrier in the system of heat supply. Improving the efficiency of the heat pump depends on the perfection of the thermodynamic cycle, on the choice of the working agent and on the quality of the operation of the unit in off-design conditions of a temperature mode. The article presents the results of a study of the performance of stage compression heat pump. The concepts of application of the heat pump of two-stage compression of the working agent are formulated. Experimental researches has been fulfilled with the use of Altal GWHP26Н heat pump of 24.2 kW capacity operating on an eco-friendly refrigerants of R134a and R600а. The results of comparative calculation of performance indicators of one- and two-stage heat pumps are presented. Various schemes of realization of a thermodynamic cycle for one- and two-stage heat pumps are considered. The efficiency of two-stage heat pumps that implement thermodynamic cycle with supercooling of condensate and regeneration of steam heat of the working agent has been proved. The two-stage thermodynamic cycle of the heat pump is accompanied by minimal losses during the throttling of the liquid refrigerant, and it solves the problem of useful heat use to increase the temperature of the heated coolant for heating and hot water supply systems. Steam regeneration of the working agent at the outlet from the evaporator through the use of regenerative heat exchanger also provides the additional effect of minimization of thermodynamic losses and improving efficiency of cycles with vapor compression heat pumps in the conditions of large temperature differences in the evaporator and the condenser.

Triple ethylene-propylene copolymers (EPDM) are used for the making of structural elements exposed to mechanical loads and are heat-resistant [1, 2], but their widespread use in aviation and shipbuilding equipment and other industries is limited due to Flammability. Double ethylene-propylene rubbers are practically limiting, and triple (EPDM), Dicyclopentadiene is used as the third component, due to the small content of double bonds in the side chains, have high heat resistance compared to diene rubbers [2], and therefore the issues of fire resistance of rubber-technical products based on them remain more and more urgent [3-7]. In [7] it is shown that if the values of the oxygen index (OI) and PP and EPDM are equal 17 % and 18.5 %, respectively, the coke numbers (CN) - 0 % and 0.5 %, and the copolymer is a PP/EPDM = 37,5/62,5 OI increases to 19.5% and CN up to 1.5 %. For copolymer PP / EPDM = 61.5 / 38.5 OI and CN are 21% and 3.4%, respectively, i.e. fire resistance in copolymers does not increase, which is an urgent problem. Polyolefins as it is shown in [7] and other works, at pyrolysis in soft conditions decompose practically without the rest, at thermal blows the mechanism of destruction changes and the carbonized rest is formed. The presence of cross-linked structures in the macromolecules of polyolefins also leads to the appearance of a carbonized residue. In work [8] the formulations of rubber mixtures resistant to wet chlorine, aqueous solutions of sodium hydroxide and sodium chloride, hydrogen, for the production of gaskets for electrolyzers and in [9] the effect of dithiophosphate accelerators on the complex properties of rubbers based on rubber grade EPDM-40. In [10] investigated the effect of a modified alumino-silicate intumescent microfiber filler kaolin microfiber (KMF) on the fire and heat protective properties (FHP) of vulcanizates based on ethylene-propylene-diene rubber EPDM-40. The compositions contained from 3 to 15 Weight Part (W.P.) KMV with a fractional composition of 25-110 microns and a fiber diameter of about 10 microns. As modifiers used a phosphorus boron containing oligomer (FBO), contributing to the increase of fireheat protective properties and multifunctional additive - hexachlor-p-xylene. It has been established that the modification of the kaolin microfiber leads to an improvement in the fire and heat protective properties at high temperature exposure: the rate of linear combustion decreases by 14%, the formation of the coke layer (CL) increases. It is shown that in conditions of erosion ablation, the fire-protective material has a 10 to 15% increase in tearing strength of CL, the time of onset of fire increases by 20-40% and the time of CL separation by 30%. In [ 11 ], the effect of HYPERLINK "https://translate.google.com/translate?hl=ru&prev=_t&sl=ru&tl=en&u=https://elibrary.ru/keyword_items.asp%3Fid%3D12826492" microcarbon fiber, a solution of FBO, HYPERLINK "https://translate.google.com/translate?hl=ru&prev=_t&sl=ru&tl=en&u=https://elibrary.ru/keyword_items.asp%3Fid%3D2483721" elastomers and HYPERLINK "https://translate.google.com/translate?hl=ru&prev=_t&sl=ru&tl=en&u=https://elibrary.ru/keyword_items.asp%3Fid%3D4285142" elastomeric materials on the fire-protective properties of EPDM-40 was investigated. The aim of the study was to investigate the processes of pyrolysis in the condensed phase, improving the properties of incombustibility and the creation of flame retardant rubber based on EPDM-40 for metal constructures.