scholarly journals Calculation algorithm for operating parameters of steam-compressive chilling machine with adsorptive chillling unit

2020 ◽  
Vol 8 (2) ◽  
pp. 3-9
Author(s):  
E.A. Belyanovskaya ◽  
◽  
G.M. Pustovoy ◽  
A.I. Sklyarenko ◽  
M.P. Sukhyy ◽  
...  
Keyword(s):  
Silica Gel ◽  
Thermal Energy ◽  
Sodium Acetate ◽  
Operating Conditions ◽  
Energy Utilization ◽  
Coefficient Of Performance ◽  
Adsorptive Capacity ◽  
Operating Parameters ◽  
Adsorption Refrigeration ◽  
Refrigeration Unit

The work is focused on the development of an effective algorithm for calculating the operational characteristics of a steamcompressive chilling machine with an adsorptive chilling unit, which involves a cold box, an adsorber, an evaporator and a condenser, water being used as a refrigerant. An algorithm for calculating the operating parameters of the adsorptive chilling unit has been developed, which includes the determination of the cooling capacity of the steam compressor refrigeration unit, the heat load on the condenser, the power consumed by the compressor, the coefficient of performance of the steam compressor refrigeration unit, as well as the calculation of the mass of water, the mass of the adsorbent, the refrigerating capacity, the coefficient of performance of the adsorptive chilling unit and the coefficient of useful energy utilization of a steam compressive chilling machine with an adsorption chilling unit. The chilling capacity and the coefficient of performance of the adsorption chilling unit are estimated under the operating conditions of a typical steam compression chilling machine. The crucial factors affecting the efficiency of the adsorptive chilling unit are analyzed. It has been established that the chilling capacity, the coefficient of performance of the adsorption refrigeration module and the energy efficiency of the installation are determined by the thermal load on the condenser, and, therefore, by the mass of water that is desorbed and evaporated. The coefficient of performance of the adsorption chilling unit and the efficiency of the steam compressor chilling machine with the adsorptive chilling unit are estimated to be 0.878 and 4.64. The criteria for the selection of adsorbents for the adsorption module are analyzed. The temperature of regeneration is determined by the temperatures in the condenser, and the limit adsorption affects the mass of the adsorbent and the size of the adsorber. A comparison of the efficiency of adsorptive chi l l ing uni t based on silicoaluminophosphates and composite adsorbents «silica gel – sodium acetate» is carried out. The prospects of using composites «silica gel – СН3СООNa» are shown. The optimal composition of the composite was established, which corresponds to the minimal size of the adsorber, (80% sodium acetate and 20% silica gel). The prospects of using adsorptive conversion of thermal energy for utilization of low-potential thermal energy during the operation of steam compressive chilling machine are shown. Keywords: adsorptive conversion of heat energy, composite adsorbent, steam compressive chilling unit, adsorption, adsorptive capacity.

A Small Gas Turbine Plant for Cogeneration of Electricity, Thermal and Cooling Thermal Energy With an Absorption Unit

1997 ◽  
Author(s):  
Maurizio De Lucia ◽  
Carlo Lanfranchi ◽  
Antonio Matucci
Keyword(s):  
Gas Turbine ◽  
Thermal Energy ◽  
Operating Conditions ◽  
Hot Water ◽  
Plant Performance ◽  
Cooling Power ◽  
Operating Parameters ◽  
The European Union ◽  
Cogeneration Plant ◽  
Two Stage

A cogeneration plant with a small gas turbine was installed in a pharmaceutical factory and instrumented for acquiring all the values necessary to appraise both its energetic and cost advantages. The plant was designed and built as a demonstrative project under a program for energy use improvement in industry, partially financed by the European Union. The system comprises as its main components: 1) a gas turbine cogeneration plant for production of power and thermal energy under the form of hot water, superheated water, and steam; 2) a two-stage absorption unit, fueled by the steam produced in the cogeneration plant, for production of cooling thermal energy. The plant was provided with an automatized control system for the acquisition of plant operating parameters. The large amount of data thus provided made it possible to compare the new plant, under actual operating conditions, with the previously existing cooling power station with compression units, and with a traditional power plant. This comparative analysis was based on measurements of the plant operating parameters over nine months, and made it possible to compare actual plant performance with that expected and ISO values. The analysis results reveal that gas turbine performance is greatly affected by part-load as well as ambient temperature conditions. Two-stage absorber performance, moreover, turned out to decrease sharply and more than expected in off-design operating conditions.

Performance Investigation of Single Adsorption Refrigeration System Driven by Solar Heat Storage

2018 ◽  
Vol 26 (03) ◽  
pp. 1850025
Author(s):  
Hicham Boushaba ◽  
Abdelaziz Mimet
Keyword(s):  
System Performance ◽  
Heat Storage ◽  
Cooling Capacity ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Solar Irradiation ◽  
Cooling Power ◽  
Condensation Temperature ◽  
Adsorption Refrigeration ◽  
Solar Heat

The aim of this paper is to provide a global study of an adsorption refrigeration machine driven by solar heat storage and collected by parabolic trough collector. The system operates with ammonia (as refrigerant) and activated carbon (as adsorbent). A mathematical model interpreting the progression of the heat and the mass transfer at each element of the prototype has been developed. The solar irradiation and the real ambient temperature variations corresponding to a usual summer day in Tetouan (Morocco) are considered. The system performance is evaluated trough specific cooling power (SCP) as well as solar coefficient of performance (SCOP), which was estimated by a dynamic simulation cycle. The pressure, temperature and adsorbed mass profiles in the Adsorber have been calculated. The effects of significant design and operating parameters on the system performance have been investigated. The results show the capability of our system to realize an encouraging performance and to overcome the intermittence of the adsorption refrigeration machines. For a daily solar irradiation of 18[Formula: see text]MJ[Formula: see text]m[Formula: see text] and operating conditions of evaporation temperature [Formula: see text]C, condensation temperature [Formula: see text]C and generation temperature [Formula: see text]C, the results show that the process could achieve an SCP of 115[Formula: see text]W[Formula: see text]kg[Formula: see text] and it could produce a daily specific cooling capacity of 3310[Formula: see text]kJ[Formula: see text]kg[Formula: see text], whereas its SCOP could attain 0.141.

Two-Stage Non-Regenerative Silica Gel-Water Adsorption Refrigeration Cycle

2000 ◽  
Author(s):  
B. B. Saha ◽  
K. C. A. Alam ◽  
A. Akisawa ◽  
T. Kashiwagi ◽  
K. C. Ng ◽  
...  
Keyword(s):  
Heat Pump ◽  
Silica Gel ◽  
Water Adsorption ◽  
Waste Heat ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Adsorption Refrigeration ◽  
Two Stage ◽  
Adsorption Chiller ◽  
Adsorption Heat Pump

Abstract Over the past two decades there have been considerable efforts to use adsorption (solid/vapor) for cooling and heat pump applications, but intensified efforts were initiated only since the imposition of international restrictions on the production and use of CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons). Closed-type, conventional adsorption refrigeration and heat pump systems have an increasing market share in Japan. In this paper, a two-stage non-regenerative, silica gel-water adsorption chiller design is outlined. Experimental measurements are performed on a prototype of a 3.5 kW rated cooling capacity adsorption heat pump in order to determine its performance under different operating temperatures (hot, cooling and chilled water). The chiller performance is analyzed in terms of cooling capacity and coefficient of performance (COP). The main innovative feature in the two-stage adsorption chiller is the ability to utilize low-temperature waste heat (∼55°C) as the driving source with a cooling source of 30°C. The technological difficulty inherent in operating a thermally activated cycle with such a small regenerating temperature lift (temperature difference between heat source and heat sink inlets) is overcome by use of a two-stage cycle.

scholarly journals Experimental analysis of triple fluid vapour absorption refrigeration system driven by electrical energy and engine waste heat

2019 ◽  
Vol 23 (5 Part B) ◽  
pp. 2995-3001 ◽  
Author(s):  
Andi Balasubramanian ◽  
Venkatesan Jayaraman ◽  
Suresh Sivan ◽  
Mariappan Vairavan
Keyword(s):  
Thermal Energy ◽  
Waste Heat ◽  
Electrical Energy ◽  
Coefficient Of Performance ◽  
Test Time ◽  
Absorption Refrigeration ◽  
Engine Exhaust ◽  
Power Sources ◽  
Refrigeration Unit ◽  
Absorption Refrigeration System

In this study, performance analysis of absorption refrigeration cycle has been carried out under variable power sources namely electrical and thermal energy sources. The triple fluid vapour absorption system was used in this work. The temperatures at each point in the cycle such as generator, absorber, evaporator and condenser have been measured. The coefficient of performance of the system was calculated and then compared. The results showed that when the cycle driven by electricity, the coefficient of performance varied from 0.28-1.6 along the test time and the generator temperature changed from 66?C to 106?C. When thermal energy used to generate power, the coefficient of performance varied between 0.16 and 0.6 under the generator temperature of 98?C and 150?C. It was observed that the waste heat energy from engine exhaust can be used efficiently and can replace the conventional power source to drive the absorption refrigeration unit.

scholarly journals Performance evaluation of an adsorption refrigeration system powered by solar heat storage based on Moroccan irradiation

2020 ◽  
Vol 307 ◽  
pp. 01014
Author(s):  
Hicham BOUSHABA ◽  
Abdelaziz MIMET ◽  
Mohammed El GANAOUI ◽  
Abderrahman MOURADI
Keyword(s):  
Heat Storage ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Solar Irradiation ◽  
Cooling Power ◽  
Condensation Temperature ◽  
Refrigeration System ◽  
Adsorption Refrigeration ◽  
The Real ◽  
Solar Heat

The aim of this paperwork is to provide a performance comparative study of an adsorption refrigeration system powered by solar heat storage based on Moroccan irradiation. The system operates with ammonia as refrigerant and activated carbon as adsorbent. A parabolic through collector is used to collect the solar energy and store it in a heat storage tank. A dynamic simulation program interpreting the real behavior of the system has been developed. The pressure, temperature and adsorbed mass profiles in the Adsorber have been revealed. The system performance is estimated in terms of the specific cooling power (SCP) and the solar coefficient of performance (SCOP). The solar irradiation and the real ambient temperature variations corresponding to the six climatic zones in Morocco are considered. The effect of those conditions on the performance of the system has been investigated. The results show the capability of our system to realize more than one cycle and produce cold during the day. For an optimal configuration of the system and operating conditions of evaporation temperature, Tev=0 °C, condensation temperature, Tcon=30 °C and generation temperature, T3=100 °C, the process could achieve a SCP of 151 W.kg-1and its solar COP could attain 0.148. The system performances improve especially in sunny area.

scholarly journals Adsorbents, Working Pairs and Coated Beds for Natural Refrigerants in Adsorption Chillers—State of the Art

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4707
Author(s):  
Piotr Boruta ◽  
Tomasz Bujok ◽  
Łukasz Mika ◽  
Karol Sztekler
Keyword(s):  
Cooling System ◽  
Fundamental Problem ◽  
Thermodynamic Cycle ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Cooling Power ◽  
Adsorption Refrigeration ◽  
Cooling Systems ◽  
Sustainable Solutions ◽  
Improved Performance

Adsorption refrigeration systems are promising, sustainable solutions for many cooling applications. The operating range and the performance of an adsorption cooling cycle are strongly dependent on the properties of adsorbents, adsorbates, and bed coatings. Therefore, further research and analysis may lead to improved performance of adsorption coolers. In this paper, studies on working pairs using natural refrigerants and the properties of adsorbent coatings were reviewed. The selected working pairs were then thermodynamically characterised and ranked in terms of refrigerant evaporation temperature values. This was found to be a key parameter affecting the applicability of a given adsorbent/adsorbate pair and the value of SCP (Specific Cooling Power), COP (Coefficient of Performance) parameters, which are now commonly used comparison criteria of adsorption chillers. In the analysis of the coating studies, the focus was on the effect of individual parameters on the performance of the cooling system and the effect of using coated beds compared to packed beds. It was found that a fundamental problem in comparing the performance of different cooling systems is the use of different operating conditions during the tests. Therefore, the analysis compares the performance of the systems along with the most important thermodynamic cycle parameters for the latest studies.

Numerical Modeling and Thermal Analysis of an Adsorption Refrigeration System

2015 ◽  
Vol 23 (04) ◽  
pp. 1550033 ◽  
Author(s):  
Anirban Sur ◽  
Randip K. Das
Keyword(s):  
Thermophysical Properties ◽  
Cooling System ◽  
Isosteric Heat ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Refrigeration System ◽  
Adsorption Refrigeration ◽  
Simulation Code ◽  
Mass Transfer Processes ◽  
Different Temperatures

The aim of this paper is to develop a complete, precise and simple numerical model based on the thermophysical properties of an adsorptive cooling system (using activated carbon–methanol pair), analyze and discuss the heat and mass transfer processes and identify the parameters which influence the system performance. In the design of adsorption refrigeration system, the characteristics of both adsorbate–adsorbent pairs and system operating conditions are very important. So in this model, different thermophysical properties of working pair such as, specific heat, density, isosteric heat of adsorption and desorption, and different temperatures of the system are considered. A simulation code, written in FORTRAN, is carried out. The performance of the system is assessed in terms of refrigeration effect and coefficient of performance (COP).

scholarly journals Integration of solid-oxide fuel cells and absorption refrigeration for efficient combined cooling, heat and power production

Clean Energy ◽  
2020 ◽  
Author(s):  
Krzysztof Matuszny ◽  
Tohid N Borhani ◽  
Seyed A Nabavi ◽  
Dawid P Hanak
Keyword(s):  
Sensitivity Analysis ◽  
Operating Conditions ◽  
Hot Water ◽  
Solid Oxide ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Coefficient Of Performance ◽  
Oxide Fuel ◽  
Absorption Refrigeration ◽  
Combined Cooling

Abstract Combined cooling, heating and power (CCHP) systems are characterized by a substantially higher energy-utilization efficiency compared to standalone systems. In this study, an integrated system comprising a solid-oxide fuel cell (SOFC), hot-water storage tank (HWST) and absorption refrigeration (AR) cycle is considered. The SOFC model was developed in Aspen Plus®. It was used to determine the thermodynamic properties of the exhaust gas that was then used to provide heat for the HWST and to drive the AR cycle. Thermodynamic models for the AR cycles were developed in Engineering Equation Solver, considering LiBr–H2O and NH3–H2O as working fluids. The sensitivity analysis of a number of SOFC output parameters has been carried out. The most optimal case was characterized with the coefficient of performance (COP) and CCHP efficiency of 0.806 and 85.2% for the LiBr–H2O system, and 0.649 and 83.6% for the NH3–H2O system, respectively. Under such optimal operating conditions, the SOFC was characterized by the net electrical efficiency of 57.5% and the net power output of 123.66 kW. Data from the optimal solution were used to perform the thermodynamic study and sensitivity analysis to assess the influence of different absorption cycle operating conditions and to identify possible applications for the considered integrated systems.

scholarly journals Thermodynamic Optimization of Electrical and Thermal Energy Production of PV Panels and Potential for Valorization of the PV Low-Grade Thermal Energy into Cold

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 498
Author(s):  
Anis Idir ◽  
Maxime Perier-Muzet ◽  
David Aymé-Perrot ◽  
Driss Stitou
Keyword(s):  
Thermal Energy ◽  
Operating Conditions ◽  
Gas Absorption ◽  
Coefficient Of Performance ◽  
Low Grade ◽  
Back Side ◽  
Pv Panel ◽  
Recovery Potential ◽  
Potential Improvement ◽  
Refrigeration Machine

In the present study, the evaluation of potential improvement of the overall efficiency of a common PV panel, valorizing the heat extracted by a heat exchanger that is integrated on its back side, either into work using an endoreversible Carnot engine or into cold by using an endoreversible tri-thermal machine consisting of a heat-driven refrigeration machine operating between three temperature sources and sink (such as a liquid/gas absorption machine), was carried out. A simplified thermodynamic analysis of the PV/thermal collector shows that there are two optimal operating temperatures and of the panels, which maximize either the thermal exergy or the overall exergy of the PV panel, respectively. The cold produced by the endoreversible tri-thermal machine during the operating conditions of the PV/thermal collector at is higher with a coefficient of performance (COP) of 0.24 thanks to the higher heat recovery potential. In the case of using the cold produced by a tri-thermal machine to actively cool of an additional PV panel in order to increase its electrical performances, the operating conditions at the optimal temperature provide a larger and more stable gain: the gain is about 12.2% compared with the conventional PV panel when the operating temperature of the second cooled panel varies from 15 to 35 °C.

scholarly journals PERFORMANCE EVALUATION OF ADSORPTIVE REFRIGERATORS BASED ON COMPOSITE ADSORBENTS "SILICA GEL – SODIUM SULPHATE" AND "SILICA GEL – SODIUM ACETATE"

2019 ◽  
Vol 2 (83) ◽  
Author(s):  
Олена Анатоліївна Бєляновська ◽  
Григорій Миколайович Pustovoy ◽  
Михайло Порфирович Сухий ◽  
Костянтин Михайлович Сухий ◽  
Роман Дмитрович Литовченко
Keyword(s):  
Surface Area ◽  
Silica Gel ◽  
Solar Collector ◽  
Sodium Acetate ◽  
Sodium Sulphate ◽  
Coefficient Of Performance ◽  
Operational Parameters ◽  
Composite Adsorbents ◽  
Operational Characteristics ◽  
Cold Box

Abstract. Performance of adsorptive refrigerators based on composite adsorbents  ‘silica gel – sodium sulphate’ and ‘silica gel – sodium acetate’ was evaluated. The main characteristics of adsorbents which affect the structural parameters of the adsorptive chilling device are revealed. The method of determining operational characteristics of adsorptive refrigerator has been developed. The main factors affecting the mass of adsorbent are confirmed to be maximal adsorption and the amount of heat required to be taken from the cold box during the day. The advantages of ‘salt in the porous silica gel matrix’ composites are exhibited as compared with conventional silica gels and zeolites. Operational parameters of adsorptive refrigerators based on the composites ‘silica gel – sodium sulphate’ and 'silica gel – sodium acetate' are compared. The calculation procedure to determine the design and operational characteristics is suggested. Proposed procedure includes the calculation of the amount of heat required to be taken from the cold box during the day, water mass, mass of the adsorbent, heat required for regeneration of the adsorbent, computing the surface area of the solar collector, heat supplied by solar collector and net coefficient of performance. The efficiency of operating processes of adsorptive refrigerators based on composites 'silica gel - sodium sulphate' and 'silica gel-sodium acetate' was compared. The correlation between adsorbent composition and design and operational parameters was stated. The surface area of solar collector is stated to be of 9.46 – 9.93. The highest net coefficients of performance of 0.358 and 0.368 are revealed for devices based on composites containing, wt. %: silica gel – 20 and salt (sodium sulphate or sodium acetate) – 80. The influence of meteorological conditions on the net coefficient of performance of the adsorptive refrigerator has been confirmed. The higher efficiency of adsorptive chilling devices based on composites 'silica gel - sodium acetate' is explained by lower values of regeneration temperature, which leads to the decreasing the heat of regeneration. The results of the research can be used for the development of adsorptive chilling devices for domestic needs and warehouse premises.

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