scholarly journals Heat Pump Cycle Efficiency for Heat Supply

2020 ◽  
pp. 136-142
Author(s):  
Mykola Bosiy ◽  
◽  
Olexandr Kuzyk ◽  
Keyword(s):  
Heat Pump ◽  
Heat Supply ◽  
Exergy Analysis ◽  
Conversion Factor ◽  
Working Fluid ◽  
Heating Systems ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Heat Supply Systems ◽  
Supply Systems

The aim of the article is to analyze the literature and scientific publications on the effectiveness of the heat pump in heat supply systems and to study the efficiency of using the steam compression cycle of a heat pump in a heat supply system. Тo conduct energy and exergy analysis of heat pump efficiency indicators, the working fluid of which is freon R134a, when using natural waters as a source of low-potential thermal energy. The article analyzes the literature sources and scientific publications on the effectiveness of the heat pump in heat supply systems. The results of research of efficiency of application of the heat pump in systems of heat supply at use of natural waters as a source of low-potential thermal energy are presented. Energy and exergy analysis of heat pump efficiency indicators, the working fluid of which is R134a freon, was performed. The energy efficiency of the heat pump cycle was determined by the conversion factor of the heat pump. The thermodynamic efficiency of the heat pump in heat supply systems was evaluated using exergetic efficiency, which is one of the main indicators of the efficiency of heat pump processes and cycles. The calculation of energy indicators of the heat pump, such as: specific heat load in the evaporator and condenser, as well as the conversion factor of the heat pump. The calculation of exergetic efficiency for ambient temperature from +10 to -10 ºC. Thus, the energy and exergy analysis of the efficiency of the heat pump, the working fluid of which is Freon R134a with a conversion factor = 4.8. This indicates that the heat pump is a reliable, highly efficient, environmentally friendly source of energy for use in heating systems. A heat pump heating system will always consume less primary energy than traditional heating systems if natural water is used as a low-temperature heat source for the heat pump. The efficiency of the steam compression cycle of the heat pump largely depends on the temperature of low-potential heat sources. The use of HV in heating systems reduces greenhouse gas emissions compared to conventional types of heat supply, which is relevant to the ecological state of the environment.

Analyzing the Application of Heat Pump Units in Heat Supply Systems

Vestnik MEI ◽  
2018 ◽  
Vol 2 (2) ◽  
pp. 42-52
Author(s):  
Aleksandr Ya. Shelginsky ◽  
◽  
Igor V. Yakovlev ◽  
Keyword(s):  
Heat Pump ◽  
Heat Supply ◽  
Heat Supply Systems ◽  
Supply Systems

Design and Performance of Adsorptive Heat Pumps

2021 ◽  
pp. 223-250
Keyword(s):  
Heat Pump ◽  
Silica Gel ◽  
Heat Supply ◽  
Sodium Acetate ◽  
Energy Performance ◽  
Heat Pumps ◽  
Sodium Sulphate ◽  
Heat Supply Systems ◽  
And Performance ◽  
Supply Systems

The chapter is devoted to design and performance of adsorptive heat pumps. In the first sub-division, state-of-the-art of the adsorptive heat pumping is analyzed. It involves analysing operating principle of adsorptive heat pumps, comparing of the properties of adsorbents used, bed specifications, and operating conditions. Original construction of the adsorptive heat pump is designed by authors for independent heat supply systems or hot water supply of buildings and other structures for various purposes. The composites ‘silica gel – sodium sulphate' or ‘silica gel – sodium acetate' were used as adsorbents. Discharging was performed in a daytime, when heat pump supplied heating system with water warmed to 45 – 35°C. The regeneration mode proceeded at night from 0.00 to 8.00 a.m. Efficiency of suggested adsorptive heat pump is estimated by two methods: as ratio of adsorption heat to sum of desorption heat and external heat supplied to sorbent during its heating up to regeneration temperature (coefficient of performance of cycle) and as ratio of heat of adsorption to heat supplied by solar collector (net coefficient of performance). Suggested heat pump coefficients of energy performance of cycle are stated to be 2.084 when composite ‘silica gel – sodium sulphate' used and 2.021 when ‘silica gel – sodium acetate' used. Seasonal dependence of net coefficient energy performance for suggested adsorptive heat pump based on composites ‘silica gel – sodium sulphate' and ‘silica gel – sodium acetate' is revealed. Correlation of coefficients of energy performance of adsorptive heat pump and composite sorbents properties (sorption capacity and regeneration temperature) is stated. Insignificant decreasing of coefficients of energy performance when ‘silica gel – sodium acetate' used is explained by lower sorptive capacity as compared to ‘silica gel – sodium sulphate'. Suggested heat pump application perspectives are shown for heat supply systems to result from traditional energy sources independence and environmental advantages. Adsorptive heat pumps development challenges, major limitations for commercialization of adsorptive heat pumping, and requirements to ongoing innovations are analysed. The present chapter can be useful for energy efficient decentralized heat supply systems based on adsorptive heat pump unit.

scholarly journals Energy and Exergy Analysis of Combined Organic Rankine Cycle-Single and Dual Evaporator Vapor Compression Refrigeration Cycle

2019 ◽  
Vol 9 (23) ◽  
pp. 5028 ◽  
Author(s):  
Pektezel ◽  
Acar
Keyword(s):  
Exergy Analysis ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Vapor Compression ◽  
Exergy Destruction ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Vapor Compression Refrigeration

This paper presents energy and exergy analysis of two vapor compression refrigeration cycles powered by organic Rankine cycle. Refrigeration cycle of combined system was designed with single and dual evaporators. R134a, R1234ze(E), R227ea, and R600a fluids were used as working fluids in combined systems. Influences of different parameters such as evaporator, condenser, boiler temperatures, and turbine and compressor isentropic efficiencies on COPsys and ƞex,sys were analyzed. Second law efficiency, degree of thermodynamic perfection, exergy destruction rate, and exergy destruction ratio were detected for each component in systems. R600a was determined as the most efficient working fluid for proposed systems. Both COPsys and ƞex,sys of combined ORC-single evaporator VCR cycle was detected to be higher than the system with dual evaporator.

FORMATION OF STRUCTURAL GRAPHS FOR SOLVING LOAD FLOW ANALYSIS IN THE PROBLEMS OF SECURITY OF HEAT SUPPLY SYSTEMS

2016 ◽  
Vol 8 (4) ◽  
pp. 49-53
Author(s):  
Мезенцев ◽  
A. Mezentsev ◽  
Сазонова ◽  
Svetlana Sazonova
Keyword(s):  
Heat Supply ◽  
Flow Analysis ◽  
Flow Distribution ◽  
Load Flow ◽  
Practical Implementation ◽  
Heating Systems ◽  
Structural Graph ◽  
Load Flow Analysis ◽  
Heat Supply Systems ◽  
Supply Systems

The article is devoted to the formation of structural graph technology for heating systems in solving problems of analysis. Variants subscriber subsystem hardware design of heating systems and the corresponding fragments of the structural graph to solve the problems of the analysis of flow distribution in the unperturbed and perturbed states, respectively. Analysis of flow distribution is required for the practical implementation of tasks in order to ensure the safety of the systems under consideration.

scholarly journals Hybrid Carbon Dioxide Heat Pump for the Multifamily Residential Buildings in the Heat Supply System Based on CHP

2021 ◽  
pp. 91-98
Author(s):  
Mihail Sit ◽  
◽  
Anatoliy Juravliov ◽  
Keyword(s):  
Heat Exchanger ◽  
Heat Pump ◽  
Heat Supply ◽  
Single Phase ◽  
Control Valve ◽  
Heating System ◽  
Heat Pumps ◽  
Hydraulic Circuit ◽  
Heat Supply Systems ◽  
Supply Systems

The work is devoted to centralized heat supply systems based on CHP plants and the use with them heat pumps (HP) on carbon dioxide as refrigerant. Heat pumps are used in heat supply systems for buildings and use the heat of the outside air and, at the same time, the heat of the return network water (WWR) as a source of low-grade heat (LHP). The aim of the study is to develop a structural diagram of such a heat pump, where the outside air is heated by a heat exchanger installed in the return water line of the heating system, to develop a hydraulic circuit of a heat pump taking into account the law of regulation of the building heating system, to develop an algorithm for controlling the operating modes of the so-called balancing heat exchanger installed after gas cooler and internal heat exchanger of the heat pump. The most significant results were the hydraulic circuit of the heat pump, the aerodynamic circuit of the air supply path to the heat pump evaporator, the balancing heat exchanger control system, taking into account the requirement to ensure the operation of the control valve in a single-phase flow. The significance of the results obtained consisted in obtaining the dependences between the CO temperature graph and the parameters of the thermodynamic cycle of the heat pump, which ensured the operation of the control valve of the heat pump in a single-phase environment.

scholarly journals Improving the efficiency of heat release regulation in centralized heat supply systems

2020 ◽  
pp. 81-97
Author(s):  
O Shelimanova ◽  
◽  
A. Kolienko ◽  
Keyword(s):  
Energy Source ◽  
Energy Efficiency ◽  
Control Systems ◽  
Heat Supply ◽  
Heat Dissipation ◽  
District Heating ◽  
Heating Systems ◽  
District Heating Systems ◽  
Heat Supply Systems ◽  
Supply Systems

Ensuring optimal hydraulic and thermal regimes in district heating systems (DHS) in the regulation of heat supply is an important factor in improving the energy and economic efficiency of DHS. In addition, high efficiency of the HS system is a factor that can ensure the preservation of its vital functions. Solving the problem of increasing the energy efficiency of the heat supply system is a complex problem that requires changes at all stages of heat transformation: in the energy source, heating networks and subscriber heating systems of heat consumers. The purpose of this study is to identify the impact of heat dissipation control processes in district heating systems on their energy and economic efficiency, provide recommendations for improving control processes taking into account modern challenges and regulatory requirements, analyze heat dissipation temperature schedules and select the optimal temperature schedule. It is shown that the optimal is the combined quantitative and qualitative regulation of heat release, which should be carried out both at the energy source and at consumers. The paper considers the possibility of using combined control systems in the existing district heating systems of Ukrainian cities. It is shown that the achievement of high energy efficiency is possible only with the introduction of automatic individual heating points with weather control and pressure drop regulators at the inlet to the buildings in the subscriber heating systems. Calculations of the amount of heat consumption reduction of centralized heat supply systems with the introduction of optimal control systems are performed.

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