scholarly journals Real Air-Conditioning Performance of Ejector Refrigerator Based Air-Conditioner Powered by Low Temperature Heat Source

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 711
Author(s):  
Tongchana Thongtip ◽  
Natthawut Ruangtrakoon
Keyword(s):  
Heat Source ◽  
Thermal Comfort ◽  
Water Temperature ◽  
Test Performance ◽  
Air Conditioning ◽  
Cooling Water ◽  
Hot Water ◽  
Cooling Load ◽  
Air Conditioner ◽  
Comfort Condition

In this present work, the air-conditioning test performance of an ejector refrigerator-based air-conditioner (ERAC) was proposed. The ERAC was operated as the water chiller to produce the cooling load up to 4.5 kW. The chilled water temperature was later supplied to the fan-coil unit for producing the thermal comfort condition. The cooling water used to cool the condenser was achieved from the cooling tower which was operated under the hot and humid ambient. This is to demonstrate the feasibility of using the ERAC in real working conditions. The cooling load supplied to the air-conditioned space was applied by the air heater. The ERAC could efficiently be operated to produce the thermal comfort condition which was driven by the hot water temperature (Thot) of 90–98 °C. The system performance could vary with the heat source temperatures, cooling load, primary nozzle, and air-conditioned space temperature. The optimal performance was determined when varying the Thot, and, hence, the optimal Thot was indicated. The optimal Thot varied significantly with variations in the working condition. The test results demonstrated high potential to further using the ejector refrigeration system in the actual air conditioning application.

Design and Modeling of One Refrigeration Ton Solar Assisted Adsorption Air Conditioning System

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
M. Alkhair ◽  
M. Y. Sulaiman ◽  
K. Sopian ◽  
C. H. Lim ◽  
E. Salleh ◽  
...  
Keyword(s):  
Air Conditioning ◽  
Cooling Water ◽  
Cooling Capacity ◽  
Hot Water ◽  
Activated Carbon Fiber ◽  
Coefficient Of Performance ◽  
Weather Data ◽  
Adsorption System ◽  
Water Storage Tank ◽  
Chilled Water

The modeling of the performance of a one refrigeration ton (RT) solar assisted adsorption air-conditioning refrigeration system using activated carbon fiber/ethanol as the adsorbent/adsorbate pair has been undertaken in this study. The effects of hot water, cooling water, chilled water inlet temperatures, and hot water and chilled water flow rates were taken into consideration in the optimization of the system and in the design of the condenser, evaporator, and hot water storage tank. The study includes analysis of the weather data and its effect on both the adsorption system and the cooling load. This is then followed by estimation of the cooling capacity and coefficient of performance (COP) of the adsorption system as a function of the input parameters. The results of the model will be compared to experimental data in a next step.

Experimental Study on the Organic Rankine Cycle Power System Adopting Dual Expanders in Parallel

2014 ◽  
Author(s):  
Eunkoo Yoon ◽  
Hyun Jun Park ◽  
Hyun Dong Kim ◽  
Kyung Chun Kim ◽  
Sang Youl Yoon
Keyword(s):  
Heat Source ◽  
Power System ◽  
Water Temperature ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Hot Water ◽  
Working Fluid ◽  
Electric Heater ◽  
Shaft Power ◽  
Scroll Expanders

This study aims to evaluate the performance of an organic Rankine cycle (ORC) power system adopting dual expanders in parallel by experiment. A dual-expander ORC system was designed to provide competitive advantages over a general single expander ORC system in typical applications with large thermal fluctuation of heat sources such as solar heat, marine waste heat, and etc. The ORC system consists of two scroll expanders installed in parallel, a hydraulic diaphragm type pump to feed and pressurize the working fluid, R-245fa, two plate heat exchangers for the evaporator and the condenser, and two generators with shaft power torque meters. The two scroll expanders were modified from two oil-free air scroll compressors, and were tested in the ORC loop with R245fa. The maximum isentropic efficiency of each expander was measured about 53%, and the shaft power was reached to about 2kW. The hot water was used as heat source, and the water temperature was controlled up to 150 °C by the 100 kW-class electric heater. A circulating air-cooled chiller was utilized for the control of the cooling water temperature. In order to determine the static performance of the system, efficiencies and shaft powers were measured with 130 °C heat source temperature. In addition, performance tests were conducted with various working fluid mass flow rates to control pressure ratios. The characteristics and total thermal efficiency of the dual parallel expander ORC system and optimal operating modes are addressed.

scholarly journals ПІДВИЩЕННЯ ЕФЕКТИВНОСТІ КОНДИЦІЮВАННЯ ЗОВНІШНЬОГО ПОВІТРЯ СИСТЕМИ КОМБІНОВАНОГО ТИПУ

2019 ◽  
pp. 9-14
Author(s):  
Євген Іванович Трушляков ◽  
Андрій Миколайович Радченко ◽  
Микола Іванович Радченко ◽  
Сергій Анатолійович Кантор ◽  
Веніамін Сергійович Ткаченко
Keyword(s):  
Heat Load ◽  
Air Conditioning ◽  
Rational Design ◽  
Cooling Capacity ◽  
Climatic Conditions ◽  
Energetic Efficiency ◽  
Cooling Load ◽  
Air Conditioner ◽  
Outdoor Air ◽  
Air Conditioning System

One of the most attractive reserves of enhancing the energetic efficiency of air conditioning systems is to provide the operation of refrigeration compressors in nominal or close to nominal modes by choosing rational design cooling loads (cooling capacities) and their distribution according to a cooling load behaviour within the overall design (installed) cooling load band to match current changeable climatic conditions and provide close to maximum annual cooling capacity generation according to cooling duties. The direction of increasing the efficiency of outdoor air conditioning in combined central-local type systems by rationally distributing the heat load - cooling capacity of the central air conditioner into zones of variable heat load in accordance with current climatic conditions and its relatively stable value, i.e. cooling capacity required for further air cooling at the entrance to the indoor recirculation air conditioning system is justified. By comparing the values of the excessive production of cold and its deficit within every 3 days for a rational design heat load of the air conditioning system (cooling capacity of the installed refrigeration machine), which provides close to maximum annual production of cold, and the corresponding values of the excess and deficit of cooling capacity in accordance with current climatic conditions during July substantiated the feasibility of accumulating the excess of cooling capacity of a central air conditioner at low current loads and its use for covering cooling deficit at elevated heat loads through pre-cooling the outdoor air. It is developed a scheme of a combined central-local air conditioning system, which includes the subsystems for the outdoor air conditioning in a central air conditioner and the local indoor recirculated air conditioning.

Feasibility Study of Absorption Chillers With a Low Temperature Heat Source

2004 ◽  
Author(s):  
Viktoria Martin ◽  
Fredrik Setterwall
Keyword(s):  
Low Temperature ◽  
Heat Source ◽  
Heat Sink ◽  
Waste Heat ◽  
Temperature Drop ◽  
Cooling Water ◽  
Hot Water ◽  
Dramatic Effect ◽  
Absorption Chillers ◽  
Custom Made

Low temperature energy powering an absorption chiller will make more energy sources available for comfort cooling as compared to conventional heat driven chillers. Solar energy, industrial waste heat and heat from combined power and heat generation are examples of sources for driving energy. Also, the distribution of energy for comfort cooling could be made efficiently by transportation of hot water to the chiller situated near to the customers. Absorption chillers driven by temperatures lower than 90°C (194°F) are in general not available as an “off-the-shelf product.” Usually the low temperature driven chillers are custom made to fit to the local conditions with respect to temperatures of the driving energy and of the cooling water. The optimal design of a chiller is dependant on the temperature of the driving energy as well as on the temperature of the available heat sink for cooling the absorber and the condenser. A scheme for optimization of the chiller with respect to the size of the heat transfer surfaces and of the temperature drop of the driving energy and of the cooling water is presented herein. Presented results illustrate the dramatic effect on the size of the absorber by changing the cooling water temperature, and the equally dramatic effect on the size of the condenser and generator by changing the temperature of the driving energy. Clearly, lowering the heat source temperature and/or increasing the heat sink temperature increases the capital cost for a chiller. However, when coupled to combined heat and power generation, reasonable pay-back times have here been demonstrated for low temperature driven absorption chillers due to the increased electricity production in the overall system.

scholarly journals Apprehending Air Conditioning Systems in Context to COVID-19 and Human Health: A Brief Communication

2020 ◽  
Vol 07 (01) ◽  
pp. 28-30
Author(s):  
Shalom Akhai ◽  
Keyword(s):  
Thermal Comfort ◽  
Air Conditioning ◽  
Hvac Systems ◽  
Air Conditioner ◽  
Human Beings ◽  
Human Race ◽  
Question Mark ◽  
Air Conditioners ◽  
Current Article ◽  
Air Conditioning Systems

Nowadays human race which is strongest of all creatures on the planet is frightened to move out without precautions because of coronavirus. In the current article, a brief overview of the use of air-conditioners available in different designs is addressed in context to COVID-19. Since this virus is often transmitted by exhalations from infected airways, so Heating, Ventilation and Air-Conditioning (HVAC) systems may be important to enhance or mitigate the spread of the infection in indoor dwellings. The design of the building is directly related to the airflow through the structure of the building. One of the biggest problems that is mushrooming out of this crisis is the use of air-conditioners. The air-conditioners produce artificial built environment, which in some cases may not be good for human beings. But at home for attaining thermal comfort, it remains a question mark, whether building architecture using air-conditioner is safe or not. The paper herein tries to co-relate the literature available for providing a brief communication to these questions.

Simulation and performance study of a two-bed adsorption cooling system operated with activated carbon-ethanol

2021 ◽  
pp. 095440622110420
Author(s):  
V Baiju ◽  
A Asif Sha ◽  
NK Mohammed Sajid ◽  
K Muhammedali Shafeeque
Keyword(s):  
Water Temperature ◽  
Performance Optimization ◽  
Cooling System ◽  
Cooling Water ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Cooling Power ◽  
Performance Study ◽  
Evaporator Temperature ◽  
Adsorption Cooling System

This paper presents the transient model of a two-bed adsorption cooling system performed in the SIMULINK platform. The inlet chilled water temperature in the evaporator, temperature of cooling water and hot water temperature of the adsorbent bed and its effect on systems coefficient of performance, refrigeration effect and specific cooling power have been studied and presented. It is observed that the systems coefficient of performance is 0.57 when the inlet hot water temperature about 80 °C. In this study, the optimum cooling power and systems coefficient of performance are also determined in terms of the phase time, shifting duration and hot water inflow temperature. The results indicates that the cooling water and hot water inlet temperatures significantly affects the coefficient of performance, specific cooling power and cooling power of the system. The effect of mass flow rate on the cooler efficiency is also presented. A two bed adsorption system of capacity 13.5 kW having an evaporator and condenser temperatures of 6°C and 28°C, respectively, are considered for the present investigation. The adsorbent mass considered is 45 kg with a shifting duration of 20 sec. The result of this study gives the basis for performance optimization of a practical continuous operating vapour adsorption cooler.

Performance of an Absorber With Hydrophobic Membrane Contactor at Aqueous Solution-Water Vapor Interface

2010 ◽  
Vol 2 (3) ◽  
Author(s):  
Ahmed Hamza H. Ali
Keyword(s):  
Aqueous Solution ◽  
Water Vapor ◽  
Water Temperature ◽  
Cooling Water ◽  
Cooling Capacity ◽  
Hot Water ◽  
Membrane Contactor ◽  
Water Coolant ◽  
Hydrophobic Membrane ◽  
Vapor Interface

In this study, a detailed modeling of the heat and mass transfer processes inside a plate-and-frame absorber with hydrophobic microporous membrane contactor at aqueous solution-water vapor interface as a part of a chiller model is developed. The absorber is a component of a 5 kW cooling capacity single effect lithium bromide-water absorption chiller with a hot water thermally driven generator, a water-cooled absorber, and a condenser. The model is used to investigate the performance of the absorber in case the chiller operates at different values of the inlet driving hot water and cooling water (coolant) temperatures. The results clearly indicate that for the same cooling capacity of the chiller and compared with the performance at the design point value, increasing the inlet driving hot water temperature results in an increase in the required absorber size and consequently a decrease in the absorber performance, while decreasing the cooling water (coolant) inlet temperature leads to slight decreases in the required absorber size and consequently an increase in the absorber performance. The effect is prominent and can be used to decrease the absorber size for chillers work in places where the option of lower inlet coolant temperature is available with normal driving hot water temperature.

An Analytical Comparison of Adsorption and Vapor Compression Air Conditioners for Electric Vehicle Applications

1996 ◽  
Vol 118 (1) ◽  
pp. 16-21 ◽  
Author(s):  
S. M. Aceves
Keyword(s):  
Electric Vehicle ◽  
Air Conditioning ◽  
Cooling System ◽  
Cooling Load ◽  
Air Conditioner ◽  
Vapor Compression ◽  
Adsorption System ◽  
Air Conditioners ◽  
Driving Cycles ◽  
Adsorption Systems

This paper shows an analysis of the applicability of an adsorption system for electric vehicle (EV) air conditioning. Adsorption systems are designed and optimized to provide the required cooling for four combinations of vehicle characteristics and driving cycles. The resulting adsorption systems are compared with vapor compression air conditioners that can satisfy the cooling load. The objective function is the overall system weight, which includes the cooling system weight and the weight of the battery necessary to provide energy for air conditioner operation. The system with the minimum overall weight is considered to be the best. The results show the optimum values of all the variables, as well as temperatures and amounts adsorbed, for the adsorption and desorption processes. The results indicate that, for the conditions analyzed in this paper, vapor compression air conditioners are superior to adsorption systems, not only because they are lighter, but also because they have a higher COP and are more compact.

The Analysis on Energy-Saving Reconstruction on Condensing Heat Recovery System of Air-Conditioning System

2017 ◽  
Vol 865 ◽  
pp. 212-216
Author(s):  
Xiang Dong Wu ◽  
Ze Hua Liu
Keyword(s):  
Water Temperature ◽  
Energy Saving ◽  
Air Conditioning ◽  
Heat Recovery ◽  
Optimization Design ◽  
Hot Water ◽  
Air Conditioning System ◽  
Recovery System ◽  
Heat Recovery System ◽  
In Series

Combining with the energy consumption of air-conditioning system and the characteristics of the cooling and heating load in the hotel, the authors analyse the energy-saving property and necessity of adopting condensing heat recovery from water chillers. Taking the air-conditioning system of a star-hotel as an example, the optimization design for condensing heat recovery system from chillers on raising the temperature difference between supply and return water, the hot-water tanks in series and the water temperature stratification effectively realizes cascade and sequential utilization of hot-water, which keeps the water temperature stable and becomes more energy-saving.

Development of Electric Power Generation Unit Driven by Waste Heat: Study on Working Fluids and Expansion Turbines

2007 ◽  
Author(s):  
Naoyuki Inoue ◽  
Atsushi Kaneko ◽  
Hiroyoshi Watanabe ◽  
Tomoyuki Uchimura ◽  
Kiichi Irie
Keyword(s):  
Heat Source ◽  
Waste Heat ◽  
Design Method ◽  
Cooling Water ◽  
Electric Utility ◽  
Hot Water ◽  
Working Fluid ◽  
Power Generator ◽  
Turbine Performance ◽  
Inverse Design Method

This paper presents the results of the development of a simple and compact power generator driven by waste heat, assuming hot water at a temperature of 80 to 90°C as a heat source. Firstly, a feasibility study on the characteristics of a low temperature power cycle (evaporated at 77°C, condensed at 42°C) was conducted. As a result, TFE (Trifluoroethanol CF3CH2OH), R123, F245fa were selected as suitable for the cycle to optimize the cycle efficiency. Experimental validation of the power generator in which TFE was adopted as a working fluid was also conducted. A radial turbine was adopted as an expander, and was newly designed using an inverse design method, whereby the 3-D blade geometry for specified blade loading distribution was numerically obtained. Turbine performance and flow fields were then validated by CFD (Computational Fluid Dynamics). The test equipment was driven by hot water as a heat source and cooling water as a cooling source, and the generated power was connected with the electric utility. The characteristics of the power generating cycle and those of the turbine were obtained experimentally. The experimental results of the expander turbine performance, using TFE as a working fluid, showed good agreement with CFD results.

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