scholarly journals Performance Evaluation of LiBr-H2O Vapours Absorption System for an Office Building Cooling

2020 ◽  
pp. 9-21
Author(s):  
Abhishek Ajay ◽  
R. S. Gill ◽  
Rupinder Pal Singh
Keyword(s):  
Room Temperature ◽  
Cooling System ◽  
Thermodynamic Simulation ◽  
Lithium Bromide ◽  
Energy Performance ◽  
Coefficient Of Performance ◽  
Low Grade ◽  
Absorption System ◽  
Climate Conditions ◽  
Condenser Temperature

The aim of this paper is to assess the energy performance by simulation of a single effect LiBr-H2O vapour absorption system for office room cooling under Ludhiana (31°N) climate conditions. In an absorption cooling system, compressor which is using high grade energy, replaced by a combination of generator and absorber. The low grade heat is supplied to the generator which produces the cooling effect in the evaporator section. In the present work, lithium bromide is used as absorbent and water as refrigerant. A thermodynamic simulation of the cycle is carried out to investigate the effects of office room temperature and condenser temperature on the performance of the LiBr-H2O vapour absorption system. It was concluded that coefficient of performance (COP) increases from 0.55 to 0.75 as office room temperature increases from 22 to 30°C for fixed value of condenser temperature of 46°C. The maximum COP was observed when system runs on least value of condenser temperature.

scholarly journals Parametric Theoretical Study of Solar Assisted Cooling System Using Lithium Bromide-Water Pair

2021 ◽  
Vol 877 (1) ◽  
pp. 012020
Author(s):  
Ahmed A Shahhath ◽  
Haroun A K Shahad ◽  
Alaa A Mahdi
Keyword(s):  
Theoretical Study ◽  
Cooling System ◽  
Lithium Bromide ◽  
Coefficient Of Performance ◽  
Cooling Load ◽  
Absorption System ◽  
Solar Absorption ◽  
Circulation Ratio

Abstract In this paper, the effect of parameters of solar absorption system such as evaporator, absorber, condenser, generator temperatures and the mass of the solution on the evaporator cooling load and the coefficient of performance has been explained theoretically. The results show that, increasing of evaporator and condenser temperatures increase the evaporator cooling load, performance coefficient and the Ratio of Circulation while increasing the temperature of condenser and absorber decreases the evaporator cooling load, performance coefficient and the Circulation Ratio. In addition, increasing the solution mass increases the refrigeration power while the performance coefficient and the Circulation Ratio was constant at increasing the solution mass. The reached maximum cooling load was (1.932 kW) at 15 kg solution mass and 100 °C generator temperature, the maximum COP was 0.774 at (10 °C) temperature of evaporator and the peak Circulation Ratio was 0.3066 at (30 °C) temperature of absorber and (100 °C) temperature of generator.

scholarly journals A New Design of an Integrated Solar Absorption Cooling System Driven by an Evacuated Tube Collector: A Case Study for Baghdad, Iraq

2020 ◽  
Vol 10 (10) ◽  
pp. 3622 ◽  
Author(s):  
Adil Al-Falahi ◽  
Falah Alobaid ◽  
Bernd Epple
Keyword(s):  
Thermal Performance ◽  
Air Conditioning ◽  
Cooling System ◽  
Electrical Power ◽  
Energy Performance ◽  
Coefficient Of Performance ◽  
Solar Absorption ◽  
Air Conditioning System ◽  
Solar Fraction ◽  
Design Variables

The electrical power consumption of refrigeration equipment leads to a significant influence on the supply network, especially on the hottest days during the cooling season (and this is besides the conventional electricity problem in Iraq). The aim of this work is to investigate the energy performance of a solar-driven air-conditioning system utilizing absorption technology under climate in Baghdad, Iraq. The solar fraction and the thermal performance of the solar air-conditioning system were analyzed for various months in the cooling season. It was found that the system operating in August shows the best monthly average solar fraction (of 59.4%) and coefficient of performance (COP) (of 0.52) due to the high solar potential in this month. Moreover, the seasonal integrated collector efficiency was 54%, providing a seasonal solar fraction of 58%, and the COP of the absorption chiller was 0.44, which was in limit, as reported in the literature for similar systems. A detailed parametric analysis was carried out to evaluate the thermal performance of the system and analyses, and the effect of design variables on the solar fraction of the system during the cooling season.

Optimized Refrigerant Flow Rate and Dimensions of the Ejector Employed in a Modified Ejector Vapor Compression System

2020 ◽  
Vol 28 (04) ◽  
pp. 2050038
Author(s):  
Dishant Sharma ◽  
Gulshan Sachdeva ◽  
Dinesh Kumar Saini
Keyword(s):  
Flow Rate ◽  
Cooling System ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Vapor Compression ◽  
Evaporator Temperature ◽  
Proposed Model ◽  
Condenser Temperature ◽  
Vapor Compression System ◽  
Vapor Compression Cooling

This paper presents the analysis of a modified vapor compression cooling system which uses an ejector as an expansion device. Expanding refrigerant in an ejector enhances the refrigeration effect and reduces compressor work. Therefore, it yields a better coefficient of performance. Thermodynamic analysis of a constant area ejector model has been done to obtain primary dimensions of the ejector for given condenser and evaporator temperature and cooling capacity. The proposed model has been used to design the ejector for three refrigerants; R134a, R152a and R1234yf. The refrigerant flow rate and the diameters at various sections of the ejector have been obtained by doing numerical modeling in Engineering Equation Solver (EES). Refrigerant R1234yf demanded the highest diameter requirements at a fixed 5∘C evaporator temperature and 40∘C condenser temperature for a given range of cooling load. Both primary and secondary refrigerants flow rates are higher for R1234yf followed by R134a and then R152a.

scholarly journals Performance Analysis of Air-to-Water Heat Pump in Latvian Climate Conditions

2014 ◽  
Vol 14 (1) ◽  
pp. 18-22 ◽  
Author(s):  
Janis Kazjonovs ◽  
Andrejs Sipkevics ◽  
Andris Jakovics ◽  
Andris Dancigs ◽  
Diana Bajare ◽  
...  
Keyword(s):  
Heat Pump ◽  
Air Temperature ◽  
Residential Buildings ◽  
Winter Season ◽  
Pump Energy ◽  
Energy Performance ◽  
Coefficient Of Performance ◽  
Heating Period ◽  
Climate Conditions ◽  
Eu Directive

Abstract Strategy of the European Union in efficient energy usage demands to have a higher proportion of renewable energy in the energy market. Since heat pumps are considered to be one of the most efficient heating and cooling systems, they will play an important role in the energy consumption reduction in buildings aimed to meet the target of nearly zero energy buildings set out in the EU Directive 2010/31/EU. Unfortunately, the declared heat pump Coefficient of Performance (COP) corresponds to a certain outdoor temperature (+7 °C), therefore different climate conditions, building characteristics and settings result in different COP values during the year. The aim of this research is to investigate the Seasonal Performance factor (SPF) values of air-to-water heat pump which better characterize the effectiveness of heat pump in a longer selected period of time, especially during the winter season, in different types of residential buildings in Latvian climate conditions. Latvia has four pronounced seasons of near-equal length. Winter starts in mid-December and lasts until mid-March. Latvia is characterized by cold, maritime climate (duration of the average heating period being 203 days, the average outdoor air temperature during the heating period being 0.0 °C, the coldest five-day average temperature being −20.7 °C, the average annual air temperature being +6.2 °C, the daily average relative humidity being 79 %). The first part of this research consists of operational air-towater heat pump energy performance monitoring in different residential buildings during the winter season. The second part of the research takes place under natural conditions in an experimental construction stand which is located in an urban environment in Riga, Latvia. The inner area of this test stand, where air-to-water heat pump performance is analyzed, is 9 m2. The ceiling height is 3 m, all external wall constructions (U = 0.16 W/(m2K)) have ventilated facades. To calculate SPF, the experimental stand is equipped with sensors which provide measurements for electricity consumption and gained heat energy.

Simulation of a Double-Effect Solar Absorption System for Traditional House in Yemen

2014 ◽  
Vol 695 ◽  
pp. 797-800 ◽  
Author(s):  
Osamah Zaid Ahmed ◽  
Farid Nasir Ani
Keyword(s):  
High Pressure ◽  
Lithium Bromide ◽  
Double Effect ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Absorption System ◽  
Alternative Source ◽  
Solar Absorption ◽  
Lithium Bromide Solution ◽  
Pressure Generator

During the last few years, the awareness of the pollution and the global warming has dramatically increased which encourage the researchers around the world to find an alternative source of energy. One of the most efficient sources of energy is the solar energy especially for cooling and heating applications. This paper, described the simulation of a double-effect solar absorption system in Yemen using water lithium bromide solution as a working fluid. The system will be applied to a typical traditional house in Yemen. The performance of the system will be analyzed based on different high pressure generator temperature for the yearly solar radiation data. At higher pressure generator temperature, the results show a higher coefficient of performance of the system. This simulation also estimate high pressure generator heat transfer required to operate the system. As a result, the size of solar collector area and the cost of such system will be calculated.

Performance Analysis of Heat Pipe Heat Exchanger for Solar Hybrid Desiccant Air-Conditioning System

2015 ◽  
Vol 1115 ◽  
pp. 488-493
Author(s):  
Zuraini Mohd Enggsa ◽  
Arfidian Rachman ◽  
Lisa Nesti ◽  
Sohif Mat ◽  
Kamaruzzaman Sopian
Keyword(s):  
Heat Exchanger ◽  
Heat Pipe ◽  
Air Conditioning ◽  
Cooling System ◽  
Energy Performance ◽  
Coefficient Of Performance ◽  
Air Conditioning System ◽  
External Power ◽  
Set Up ◽  
Pipe Heat

This paper reports the development of a novel solar hybrid desiccant cooling system with heat pipe heat exchanger (HPHE). The aim is to achieve higher efficiency to reduce the use of electricity by utilizing the desiccant dehumidification system to remove latent load, while the vapour-compression and heat pipe heat exchanger meet the sensible load. Novelty comes as the heat pipe heat exchanger in the system operates efficiently without external power. Experimental set-up has been built by combining the rotary desiccant wheel, heat pipe heat exchanger with a compressive cooling system. Tests are carried out at typical operative ranges for air-conditioning applications, specifically for high hot and humid locations in Bangi, Malaysia. Acetone is used as refrigerant in the HPHE. Performance of HPHE are tested and proven to have direct impact on Coefficient of performance (COP). The results shows good performance of heat pipe heat exchanger efficiency with average efficiency and capacity of 0.65 and 2kw respectively. It is found that the hybrid system can achieve a higher energy performance in hot humid regions.

scholarly journals Exergetic performance analysis of low GWP alternative refrigerants for R404A in a refrigeration system

2021 ◽  
Author(s):  
Mehmet Altinkaynak
Keyword(s):  
Cooling System ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Refrigeration System ◽  
Alternative Refrigerants ◽  
Condenser Temperature ◽  
Parametric Analyses ◽  
Low Global Warming Potential ◽  
Very High

Abstract According to the regulation of European Union laws in 2014, it was inevitable to switch to low global warming potential (GWP) fluids in the refrigeration systems where the R404A working fluid is currently used. The GWP of R404A is very high, and the potential for ozone depletion is zero. In this study, energetic and exergetic performance assessment of a theoretical refrigeration system was carried out for R404 refrigerant and its alternatives, comparatively. The analyses were made for R448A, R449A, R452A and R404A. The results of the analysis were presented separately in the tables and graphs. According to the results, the cooling system working with R448A exhibited the best performance with a coefficient of performance (COP) value of 2.467 within the alternatives of R404A followed by R449A and R452A, where the COP values were calculated as 2.419 and 2.313, respectively. In addition, the exergy efficiencies of the system were calculated as 20.62%, 20.22% and 19.33% for R448A, R449A and R452A, respectively. For the base calculations made for R404A, the COP of the system was estimated as 2.477, where the exergy efficiency was 20.71%. Under the same operating conditions, the total exergy destruction rates for R404A, R448A, R449A and R452A working fluids were found to be 3.201 kW, 3.217 kW, 3.298 kW and 3.488 kW, respectively. Furthermore, parametric analyses were carried out in order to investigate the effects of different system parameters such as evaporator and condenser temperature.

scholarly journals Analysis of Hybrid Ejector Absorption Cooling System

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Doniazed Sioud ◽  
Ahmed Bellagi
Keyword(s):  
Water Cycle ◽  
Cooling System ◽  
Lithium Bromide ◽  
Steam Pressure ◽  
Entrainment Ratio ◽  
Evaporator Temperature ◽  
Condenser Temperature ◽  
Single Effect ◽  
Absorption Cooling System ◽  
Hybrid Cycle

In this paper, a hybrid ejector single-effect lithium-bromide water cycle is theoretically investigated. The system is a conventional single-effect cycle activated by an external steam-ejector loop. A mathematical model of the whole system is developed. Simulations are carried out to study the effect of the major parameters of the hybrid cycle on its performances and in comparison with the conventional cycle. The ejector performance is also investigated. Results show that the entrainment ratio rises with steam pressure and condenser temperature, while it decreases with increasing generator temperature. The effect of the evaporator temperature on ejector performance is negligible. It is shown also that the hybrid cycle exhibits better performances than the corresponding basic cycle. However, the performance improvement is limited to a specific range of the operating parameters. Outside this range, the hybrid system behaves similar to a conventional cycle. Inside this range, the COP increases, reaches a maximum, and then decreases and rejoins the behavior of the basic cycle. The maximum COP, which can be as large as that of a conventional double-effect cycle, about 1, is obtained at lower temperatures than in the case of single-effect cycles.

scholarly journals Thermal and Energy Evaluation of a Domestic Refrigerator under the Influence of the Thermal Load

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 400 ◽  
Author(s):  
Juan Belman-Flores ◽  
Diana Pardo-Cely ◽  
Miguel Gómez-Martínez ◽  
Iván Hernández-Pérez ◽  
David Rodríguez-Valderrama ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Thermal Load ◽  
Room Temperature ◽  
Energy Performance ◽  
Coefficient Of Performance ◽  
Total Energy Consumption ◽  
Domestic Refrigerator ◽  
Energy Evaluation ◽  
Main Effects

This study seeks to understand the thermal and energetic behavior of a domestic refrigerator more widely by experimentally evaluating the main effects of the thermal load (food) and the variation of the ambient temperature. To carry out the experiments, the thermal load was classified based on the results of a survey conducted on different consumers in the state of Guanajuato, Mexico. The thermal behavior of both compartments of the refrigerator, the total energy consumption, the power of the compressor in its first on-state, and the coefficient of performance, according to the classification of the thermal loads and the room temperature, were evaluated. Finally, it is verified that the thermal load and the room temperature have a significant influence on the energy performance of the refrigerator.

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