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 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.

Design of Adsorptive Heat Storage Devices

2021 ◽  
pp. 89-123
Keyword(s):  
Silica Gel ◽  
Heat Supply ◽  
Sodium Acetate ◽  
Heat Storage ◽  
Sodium Sulphate ◽  
Silica Gels ◽  
Storage Devices ◽  
Composite Adsorbents ◽  
Supply Systems

The chapter is devoted to prospects of application of adsorptive heat storage devices, principles of operating the adsorptive heat storage systems, design of adsorptive storage devices and main factors determining the design of adsorptive heat storage unit. Perspectives of application of adsorptive heat storage devices in heat supply systems were analyzed. Basic principles of operating of heat storage devices were considered. Adsorptive heat storage units operating in close and open modes were compared. Constructions of adsorptive heat storage units operating in open and close mode were described. An efficient algorithm for calculating the volume of the adsorptive thermal energy storage device for a decentralised heat supply system of a private house is suggested by authors. The following procedure of computation is proposed to involve: calculation of thermal load for heating including the determination of thermal losses through external fences, thermal losses due to infiltration and internal heat dissipation, the evaluation of maximal adsorption, adsorption heat, and determination of adsorbent mass and adsorbent volume. The maximal adsorption value is suggested to be calculated by the characteristics of the adsorbent, that is, its maximal adsorption or in the absence of data for a composite adsorbent, as a linear superposition for a mechanical mixture. The adsorbent mass is suggested to calculate as a ratio of a thermal load for heating and heat of adsorption. The adsorbent volume is calculated as ratio of mass and density of adsorbent. An evaluative calculation of the heat load for a private house was carried out with the proposed algorithm. Mass and volumes of conventional silica gels were compared with composite adsorbents ‘silica gel – sodium sulphate' and ‘silica gel – sodium acetate' obtained by sol gel method developed by authors. Mass and volume of silica gels occur to surpass the suggested composite at least by 1.5 – 5 times. This is shown to result from higher maximal adsorption and heat of adsorption of suggested composite adsorbents. The optimal composition of the composite adsorbents ‘silica gel – sodium sulphate' and ‘silica gel – sodium acetate' was determined according to the minimal volume of the layer of heat storage material. Both the lowest volume values and the highest efficiency of a composite adsorbents with a mass ratio of silica gel and Na2SO4 or CH3COONa 20: 80 are explained by the maximum value of adsorption heat. Suggested composite adsorbent ‘silica gel – sodium sulphate' and ‘silica gel – sodium acetate' are shown to be promising for heat supply systems.

Potential for the use of heat pumps for heat supply of metro stations

2018 ◽  
Vol 77 (4) ◽  
pp. 200-204 ◽  
Author(s):  
S. N. Naumenko ◽  
B. N. Minaev ◽  
I. A. Rebrov ◽  
G. B. Gusev
Keyword(s):  
Energy Saving ◽  
Heat Pump ◽  
Heat Supply ◽  
Heat Pumps ◽  
Operating Conditions ◽  
Hot Water ◽  
Energy Saving Technology ◽  
Heat Supply Systems ◽  
Metro Systems ◽  
Supply Systems

At present, specialists of foreign and domestic research organizations and industrial firms pay much attention to the use of steam compression heat pump plants (HPP) as an energy-saving technology. Modern compressor units allow receiving 3-4 kW for 1 kW of power consumed by HPP, and under certain conditions up to 5-6 kW of useful power. Today HPPs are most used in heat supply systems for residential and office buildings, especially in Scandinavia, Germany, Switzerland, USA, Japan, China. The paper discusses features of the operation of steam compressor heat pump plants as systems for improving energy efficiency with a description of the device of a heat pump plant; its main components are also listed. Review of the existing practice of introducing such systems in foreign countries is presented, including in Minsk - the Minsk metro, and in Russia - the Moscow Metro. The project, performed by specialists of JSC “VNIIZhT” and MIIT, is considered for the Moscow Metro (with reference to the heating systems of the Nagatinskaya and Pushkinskaya metro stations) for the use of dumping heat of ventilation shafts for heating and hot water supply, proposed by scientists of JSC “VNIIZhT” in 2012 within the framework of the exhibition of technical achievements. Authors presented information on the implementation of the pilot project at the station “Salar’yevo” (Moscow Metro) on the use of HPP in the heat and cooling supply system of the station for further comprehensive analysis of the effectiveness of the HPP application in the operating conditions of the metro. From the analysis of the data given in the work, it is concluded that metro systems are significant sources of low-potential heat, which can be used for the heat supply of stations and/or nearby urban sites by means of HPP. By now, there is a lot of experience (especially abroad) of the practical application of HPP in the heat supply systems of facilities. Nevertheless, for a reliable and comprehensive assessment of the feasibility and cost-effectiveness of projects using low-potential heat of metro systems as an energy-saving technology, a complex of studies is needed, including operational tests of currently implemented pilot projects.

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

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.

Construction and Operating Parameters of Adsorptive Chillers

2021 ◽  
pp. 251-289
Keyword(s):  
Silica Gel ◽  
Density Ratio ◽  
Energy Performance ◽  
Sodium Sulphate ◽  
Efficiency Factor ◽  
Radiant Flux ◽  
Coefficient Of Performance ◽  
Solar Collectors ◽  
Optical Efficiency ◽  
And Performance

The chapter is devoted to the design and performance of adsorptive chillers. Basic types of design and operating principle of adsorptive chillers were analyzed. Advantages and disadvantages performance of one-, two-, three-, and four-bed solar power adsorptive chillers are compared. Performance of adsorptive refrigerators based on composite adsorbents was studied. The correlation between the adsorbent composition and the coefficient of energy performance of the adsorptive chiler was revealed. An optimal composition of adsorbent 'silica gel – sodium sulphate' is stated to be of 20% silica gel and 80% sodium sulphate. The maximal values of the coefficient of performance of cycle of studied solar adsorptive chiller about of 1.14 are stated for composites containing about 20 wt. % silica gel and 80 wt% sodium sulphate. As a consequence of decreasing of adsorbent mass, the coefficient of performance is shown to increase when sodium sulphate content in the composite increased. Regeneration process parameters of the composite were shown to strongly affect on the coefficient of performance of the adsorptive chiller. The growth of the coefficient of performance is stated to result from decreasing the difference between adsorbent temperature and regeneration temperature from 85 to 55°C. The basic factors affecting the net coefficient of energy performance of the adsorptive solar refrigerator were stated daily solar radiant flux alongside with composition of the adsorbent and difference between adsorbent temperature and temperature regeneration. Net coefficients of performance of solar adsorptive refrigerator based on composite ‘silica gel – sodium sulphate' were stated to change from 0.25 to 0.34 during operating period. Utilization of the adsorption heat is suggested to warm the heat carrier which applied to heat adsorbent during regeneration. The ways to improve the design and performance of adsorptive solar chillers are suggested. The first one involves the introduction of solar collectors made of cellular polycarbonate plastics in the design of adsorptive solar chiller. Instantaneous efficiency coefficient were calculated as special thermal performance-solar radiant flux surface density ratio, optical efficiency factor is determined as special thermal performance-solar radiant flux surface density ratio at the equal temperatures of heat transfer medium and environment, reduced heat loss factor being calculated as the product of solar collector efficiency factor and net heat loss coefficient. The environmental test of developed collectors PSK-AV2-3, PSK-AV1-2, PSK-AV2-1, PSK-VS1-2, PSK-VS2-2, PSK-VS2-3, PSK-ST10-PW were conducted. The correlation of their results with laboratory tests when the thermohydraulic stand applied is shown. Relative accuracy of laboratory and environment tests was shown to be not exceeding 5 – 7%. The optical efficiency factor and the coefficient of thermal losses of polymeric solar collectors were determined. On the basis of the dependencies of the efficiency of the solar collectors vs. the reduced temperature, optimal designs of the polymeric solar collectors for the adsorption chilling solar systems are determined to be depended on the temperature of the regeneration temperature of the sorbents. As the temperatures of the regeneration of composite adsorbent ranged from 50ºС to 60ºС, appliance of the collectors PSK-AV2-1, PSK-CT10-PW occur to be expedient, and PSK-AB2-3, PSK-VS2-3, PSK-AB1-2, PSK-VS2-2, and PSK-VS1-2 are revealed to be more efficient when regeneration temperatures increased over 80 ºС. Thermotechnical characteristics of designed polymeric solar collectors are shown to surpass conventional metal and vacuum collectors. The perspectives of polymeric solar collectors in the design of adsorptive chilling solar plants were shown. Another way to improve the performance of adsorptive solar chillers concerns with equipping it with a photosensitive element and an electric drive, which will allow changing the angle of slope of the adsorber to the horizon depending on the intensity of the solar radiation. The chapter can be useful for design the efficient adsorptive chilling plants.

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