scholarly journals TWO-STAGE HEAT PUMPS FOR ENERGY SAVING TECHNOLOGIES

2017 ◽  
Vol 53 (1) ◽  
Author(s):  
A. E. Denysova ◽  
G. V. Luzhanska ◽  
I. O. Bodnar ◽  
A. S. Denysova
Keyword(s):  
Energy Saving ◽  
Heat Pump ◽  
Heat Supply ◽  
High Efficiency ◽  
Heat Supply System ◽  
Heat Pumps ◽  
Supply System ◽  
Alternative Methods ◽  
Ground Waters ◽  
Two Stages

The problem of energy saving becomes one of the most important in power engineering. It is caused by exhaustion of world reserves in hydrocarbon fuel, such as gas, oil and coal representing sources of traditional heat supply. Conventional sources have essential shortcomings: low power, ecological and economic efficiencies, that can be eliminated by using alternative methods of power supply, like the considered one: low-temperature natural heat of ground waters of on the basis of heat pump installations application. The heat supply system considered provides an effective use of two stages heat pump installation operating as heat source at ground waters during the lowest ambient temperature period. Proposed is a calculation method of heat pump installations on the basis of groundwater energy. Calculated are the values of electric energy consumption by the compressors’ drive, and the heat supply system transformation coefficient µ for a low-potential source of heat from ground waters allowing to estimate high efficiency of two stages heat pump installations.

scholarly journals Exergy Evaluation of a Heat Supply System with Vapor Compression Heat Pumps

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1028 ◽  
Author(s):  
Agata Rijs ◽  
Tomasz Mróz
Keyword(s):  
Heat Pump ◽  
Heat Supply ◽  
Heat Supply System ◽  
Heat Pumps ◽  
Supply System ◽  
Exergy Efficiency ◽  
Vapor Compression ◽  
Outdoor Temperature ◽  
Pump System ◽  
Heat Pump System

The vapor compression heat pumps are very popular solutions regarding heat supply systems of modern, low energy buildings. It is partly due to the fact that they are treated as a sustainable heat supply. The question arises: Can a vapor compression heat pump be treated as a sustainable heat supply? To answer this question; the exergy model of a heat pump system operation has been proposed. The proposed model has been employed for evaluation of exergy efficiency of an existing heat supply system equipped with two heat pumps installed in an educational building located on the campus of Poznan University of Technology, Poznan, Poland. The analysis shows that the system exergy efficiency decreases with an increase in outdoor temperature and its values are in the range of 10.9% to 42.0%. The primary exergy efficiency, which considers the conversion of fossil fuel into electricity, is on average 3.2 times lower than the system exergy efficiency for the outdoor temperature range of −9 °C to 11 °C. The performed analysis allowed for the identification of a set of solutions that may increase the exergy and primary exergy efficiency of the system. The first solution is to cover a part of the electricity demand by a renewable energy source. The second proposition is to apply a low-temperature emission system for heating. The third idea is to apply a district heating network as the heat supply instead of the heat pump. The conclusion is that the exergy performance of systems with heat pumps is rather poor because they generate low-quality heat from high-quality electricity. The best way to improve the primary exergy efficiency of a heat pump system is to power the system by electricity generated from a renewable energy source.

scholarly journals Energy efficient heat supply system for electric power facilities

2019 ◽  
Vol 124 ◽  
pp. 01011
Author(s):  
K. H. Gilfanov ◽  
N. Tien ◽  
R. N. Gaynullin ◽  
I. Hallyyev
Keyword(s):  
Energy Saving ◽  
Electric Power ◽  
Heat Recovery ◽  
Heat Supply ◽  
Eddy Currents ◽  
Computer Modelling ◽  
Short Circuit ◽  
Heat Supply System ◽  
Supply System ◽  
Heat Extraction

The aim of the work is to confirm the possibility of creating an energy-saving heat supply system for power facilities by using computer modelling, analysis of the potential use of heat losses of electromagnetic energy in magnetic circuits and windings of transformers of substations, as well as the development of schemes for heat recovery losses for heat supply of power facilities. Computer simulation of electromagnetic and thermophysical processes in the power oil-filled transformer is carried out. Energy losses in windings, hysteresis and eddy currents in the magnetic circuit, as well as temperature and heat flux fields in the longitudinal and transverse sections of the oil-filled power transformer in idle and short-circuit modes were determined. The transformer performance in terms of heat recovery losses was evaluated. The possible volumes of heat extraction for heat supply depending on the power of the transformer are determined. The automated oil-water system of heat recovery of the transformer for heating of electric power facilities is proposed. The significance of the obtained results for the construction industry is to confirm the possibility of creating an energy-saving heat supply system for electric power facilities while maintaining the operational characteristics of the transformer based on computer modelling; the significant potential of using the heat loss of power transformers of substations is shown, an automated heat supply system for electric power facilities is proposed.

scholarly journals Study of the Total Heat Supply System Using CO2-Heat Pump : Part 3 Effect of the Division of Gas Cooler (1)

2002 ◽  
Vol 2002 (0) ◽  
pp. 347-348
Author(s):  
Masaharu KATO ◽  
Takuro SAKAMAKI ◽  
Takumi HASHIZUME ◽  
Hirokazu YONEDA ◽  
Katsumi FUJIMA ◽  
...  
Keyword(s):  
Heat Pump ◽  
Heat Supply ◽  
Heat Supply System ◽  
Supply System ◽  
Total Heat

122 Study of the Total Heat Supply System Using CO2-Heat Pump : Part 5 Heat Transfer Characteristics of a Gas Cooler

2004 ◽  
Vol 2004.39 (0) ◽  
pp. 44-45
Author(s):  
Takuro SAKAMAKI ◽  
Toshihiro HORIKI ◽  
Takumi HASHIZUME ◽  
Hirokazu YONEDA ◽  
Katsumi FUJIMA ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Pump ◽  
Heat Supply ◽  
Heat Supply System ◽  
Supply System ◽  
Total Heat ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

Integration of a heat pump into the heat supply system of a cheese production plant

Energy ◽  
2008 ◽  
Vol 33 (6) ◽  
pp. 882-889 ◽  
Author(s):  
P KAPUSTENKO ◽  
L ULYEV ◽  
S BOLDYRYEV ◽  
A GAREV
Keyword(s):  
Heat Pump ◽  
Heat Supply ◽  
Heat Supply System ◽  
Supply System ◽  
Production Plant ◽  
Cheese Production

scholarly journals Performance Efficiency of an Energy-Saving Mini Dryer with a Combined Heat Supply System

2018 ◽  
Vol 12 (6) ◽  
pp. 9-14
Author(s):  
Umudvar R. Gasanov ◽  
Sevil A. Magerramova
Keyword(s):  
Energy Saving ◽  
Heat Supply ◽  
Heat Storage ◽  
Heating Surface ◽  
Heat Supply System ◽  
Supply System ◽  
Convective Drying ◽  
Drying Methods ◽  
Drying Process ◽  
Grain Drying

Abstract. The paper presents the description and operating principle of energy-saving mini-grain dryers for drying small grain batches on farms using conductive and convective drying methods and the process of grain cooling with heat obtained from a traditional heat source and a heat carrier prepared with a solar collector or a charged heat storage. (Research purpose) To develop and study a compact energy-saving grain dryer, with a heat supply system based on both a traditional source and a heat transfer fluid heated by a solar collector or a charged heat storage. (Materials and methods) The authors have carried out experimental studies of the drying process of wheat grain to determine the effectiveness of the developed unit for grain drying; the main condition for saving energy has been taken as the minimization of the total unit cost of the evaporation of one kilogram of moisture. (Results and discussion) The authors have conducted a two-factor experiment to determine the main optimal parameters affecting the grain drying process - the speed of grain movement in the conductive chamber and the temperature of the heating surface of its casing based on the calculated mathematical model. In the first variant, the drying process was carried out only by the conductive method using the heat from a traditional energy source. In the second variant, the drying was carried out by successive use of conductive and convective methods, and the grain was cooled using both thermal energy received from a traditional source and solar radiation heat along with the heat of the spent heat carrier. (Conclusions) The study has revealed that the most effective option in terms of saving thermal energy is grain drying with the consistent use of conductive and convective drying methods followed by grain cooling. The heat supply of the drying unit was partially carried out by using the heat of solar radiation and the heat obtained from the spent coolant recycling. In this optimal variant, the heat consumption for evaporation of one kilogram of moisture from the grain is minimal and amounts to 1.53-2.50 MJ per kilogram with a grain movement speed of in the dryer of 0.007-0.011 m per second and a heating surface temperature of 85-91 degrees Celsius.

scholarly journals INCREASING THE RELIABILITY OF HEATING SYSTEMS

2020 ◽  
Vol 46 (4) ◽  
pp. 197-204
Author(s):  
R. A. Shershenov ◽  
A. Yu. Efimov ◽  
V. Yu. Shmakov
Keyword(s):  
Heat Supply ◽  
High Efficiency ◽  
Heat Supply System ◽  
Heating System ◽  
Supply System ◽  
The State ◽  
Additional Costs ◽  
Heat Supply Systems ◽  
Reliability Of Operation ◽  
Supply Systems

Objectives. The study was aimed at improving the reliability of heat supply systems. At present, this is one of the most relevant topics in the field of heat supply. The issue of reliability of heat supply is of great importance in terms of the safety of citizens and the state as a whole. Due to the severity of winter conditions and risk of hypothermia, heat supply security can be considered to be as critical as food security. Therefore, the reliability of heat supply systems becomes one of the most important aspects of the security of the state.Method. The study was carried out using the method of reservation of the heat supply system by looping.Result. In order to avoid the defrosting of the heat supply system and reduce additional costs, a redundancy scheme was proposed with one-way connection to the looped main pipelines, additionally looping the pipelines of the heat supply systems between two boiler rooms. The calculation of losses in the event of an emergency in the heating system was carried out.Conclusion. The most important problem requiring immediate solution is how to increase the reliability and redundancy of the heat supply system itself, in order to achieve minimal discomfort for consumers of heat energy at the time of failure of the source or transmission of the heat supply system. The proposed method for increasing the reliability of operation of heat supply systems is characterized by a high efficiency, since allows the number of idle hours and the total amount of short-received heat to be reduced. 

scholarly journals The energy efficiency concept and implementation prospects of the jet thermocompression principle in small heat energy

2021 ◽  
pp. 39-51
Author(s):  
M. Prokopov ◽  
◽  
S. Sharapov ◽  
Yu. Merzlyakov ◽  
D. Gusev ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Heat Pump ◽  
Thermodynamic Analysis ◽  
Heat Supply ◽  
Heat Supply System ◽  
Supply System ◽  
Combined Cycle ◽  
Working Process ◽  
Step Down ◽  
Thermal Transformer

The expediency of the implementation of the principle of steam thermal compression to improve the energy efficiency of sources of electricity and heat supply of small heat power engineering is substantiated. The results of thermodynamic analysis and numerical optimization of the parameters of the compressor steam-turbine cycle of a small cogeneration power plant are presented. A jet step-down thermotransformer has been tested - as an alternative to traditional boiler heating. On the basis of the conducted thermodynamic analysis, a new combined cycle of a step-down thermotransformer has been developed, which ensures efficient conversion of the supplied energy (mainly in the form of fuel heat) into the heat carrier flow of the heat supply system with the required temperature level 50 ... 90 °C). The fundamental difference between the considered thermal transformer and steam compressor heat pumps is the replacement of a mechanical compressor with a steam thermocompressor module (STC-unit). The working process in the STK-module is realized by using the liquid phase of the refrigerant, which boils up during expiration, subcooled to saturation, as an active medium of a jet compressor. Injection of steam from the evaporator is provided due to the fine-dispersed vapor-droplet structure formed in the outlet section of the active flow nozzle. A program for the numerical study of the working process of a step-down thermal transformer was prepared and tested, on the basis of which multivariate calculations were carried out. On the basis of computational studies, the area of achievable indicators of the proposed heat supply system has been established; the area of initial operating parameters corresponding to the maximum values of the conversion coefficient and exergy efficiency was determined; comparative indicators of the main parameters of the investigated thermal transformer on various working substances in the range of operating modes as a heat pump or a refrigerating machine were obtained. Key words: workflow, steam thermocompressor, step-down thermotransformer, energy efficiency, heat pump mode

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