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2: Refrigerated display cases: (a) Vertical multi-shelf (b) Horizontal single-shelf (c) Closed door reach-in.  

2: Refrigerated display cases: (a) Vertical multi-shelf (b) Horizontal single-shelf (c) Closed door reach-in.  

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This thesis consists of two different research problems. In the first one, the aim is to model and simulate a solar-powered, single-effect, absorption refrigeration system using a flat-plate solar collector and LiBr-H2O mixture as the working fluid. The cooling capacity and the coefficient of performance of the system are analyzed by varying all in...

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... These cycles mostly work on ammonia/water and lithium bromide/water as working pairs [26]. Bahman [27] studied comprehensively a single effect aqueous Li-Br vapor absorption system that was driven by a Flat plate solar collectors. The small absorption systems (LiBr/water) were observed for their cooling capacities and COP by Asdrubali et al. [28]. ...
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The application of the nanofluids is suggested to enhance and improve the efficiency of solar thermal power system. In the present study, three different nanofluids (Fe2O3/therminol VP1, SiO2/therminol VP1, and Cu/therminol VP1) are numerically investigated in parabolic dish solar collector that is further integrated to a combined cycle for power and hydrogen production. Heat rejects from the power cycle is also utilized to drive a single effect absorption (LiBr-water) system. Furthermore, a comprehensive energy, exergy and exergo-environmental analysis are carried out by varying several input parameters and their influence on overall energetic and exergetic efficiencies, network output and rate of hydrogen generation is assessed. The engineering equation solver is employed to conduct the parametric study. Outcomes of the study demonstrate that the SiO2/VP1 has the better characteristics among the investigated nanofluids. The overall energetic efficiency of the SiO2/VP1, Fe2O3/VP1, and Cu/VP1 is almost 38.79%, 38.74%, and 37.53%, while overall exergetic efficiency is 41.72%, 41.66%, and 40.36%, respectively at 1000 Wm-2. The exergoenvironmental impact coefficient and impact index are noticed to be reduced for all the three nanofluids as mass-flow rate increases. The hy-drogen production rate for SiO2/VP1 is maximum and has observed to be increased by increasing the ambient temperature. Increase in nanoparticles concentration also rises the exergetic efficiency but reduces the thermal conductivity of the nanofluids. Coefficient of performance is noticed to be increased with rise in evaporator temperature, whereas, it is reduced by increasing the generator temperature.
... Several theoretical studies in this field are done on the single-stage ( Sencan et al., 2005, Aphornratana and Sriveerakul, 2007, Kim et al., 2009, Bahman, 2011, and Ha, 2013 and double-stage cycles ( Misra et al., 2005, Figueredo et al. 2008, Kaushik and Arora, 2009, Marcos et al., 2011 ). For instance, Saghiruddin and Siddiqui, 2001 conducted economic analysis and thermodynamic of the single effect absorption cycle. ...
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This paper represents a numerical study of a triple-stage series flow absorption cycle operating with LiBr-H2O pair. A computational model is implemented using Engineering Equation Solver (EES) software. This model includes equations of mass, species and energy conservation. The analysis is used to simulate a triple stage absorption chiller utilization for an air conditioning applications with a nominal capacity of 300kW manufactured by Thermax company. This chiller is indirect fired type which uses steam from boiler of the HPG as heat source. The variations of performance parameters with different ranges of operation conditions have been calculated. The operating parameters are selected as follows: the HPG, MPG and LPG temperatures: THPG= 150-230°C, TMPG= 100-130°C and TLPG= 60-95°C, respectively, LPC temperature TLPC= 28-37°C, evaporator temperature Tevap = 5-14°C; flow rate of refrigerant mr= 1 kg/s; four values of heat exchangers effectiveness 0.4, 0.5, 0.6 and 0.65. In addition, the comparison between the present study and other study obtained in literature review has been done. The analysis revealed that maximum COP is found as a function of both MPG and LPG temperatures. The results outline that the COP increases with an increase in the evaporator and generators temperature but decreases with condenser temperature.
... A single-effect absorption refrigeration cycle using aqueous lithium-bromide was investigated thoroughly by Bahman. 1 The system was designed to be operated by solar heat produced using flat plate solar collectors. The parametric analysis was carried out in order to observe the effect of different operating parameters on the COP of the absorption cycle. ...
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The performance comparison of multi-effect absorption refrigeration systems has been conducted in the present study. The absorption cooling cycles are operated on the solar heat in order to improve the utilization of high temperature heat sources for absorption systems. The absorption refrigeration cycles of multi-effect are modeled and designed for the identical refrigeration capacity along with the similar operating conditions. The engineering equation solver tool is deployed to analyze the coefficient of performance (COP) and exergetic efficiency of the absorption cooling cycles. Performance simulations were carried out over a range of operating conditions, including the effect of heat transfer fluids (nanofluids) used in solar parabolic trough collectors. The COP of the triple effect absorption refrigeration cycle (TEARC) is observed to be 1.752. The COP of the double effect absorption refrigeration cycle (DEARC) is perceived to be 51.9% higher as compared with single effect absorption refrigeration cycle (SEARC) which has a COP of 0.852. The exergetic efficiency of the TEARC is witnessed to be 16% higher than DEARC, and it is 31% higher than SEARC at an evaporator temperature of 7 ̊C. The effect of nanoparticle's (Al2O3) concentration and percentage of weak and strong solutions of LiBr-H2O is also evaluated at design conditions. A high temperature heat reservoir is required to operate the TEARC, whereas, the SEARC and DEARC operate on lower temperatures than triple effect cycle.
Thesis
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Air conditioning system is one of the major consumers of electrical energy consumption in many hot and humid climate regions around the world. The demand for cooling energy is the main reason that caused the effect of global warming as most of the electrical energy generation comes from fossil fuel which is the primary cause of carbon dioxide emission to the environment. Therefore, an urgent need is required to change the air conditioning systems from fossil fuel energy to greener energy source. So that, new technologies should be developed and applied to overcome some of conventional air conditioning systems which are currently used in the building sector. These alternative systems should be environmentally friendly and efficient to reduce the global warming and/or electricity costs. Solar energy has great potential in supplying sustainable energy source which can be used in driving solar assisted air conditioning systems. There are mainly two types of solar assisted air conditioning systems namely the solar absorption and solar adsorption cooling system. Solar assisted adsorption air conditioning system utilizing activated carbon fiber and ethanol as the refrigeration pair. A prototype system has been designed, fabricated and tested under local hot and humid climatic conditions. The main objective of this thesis is to enhance the performance of the adsorption air conditioning system that is directly driven by solar energy as the main source of heat collected by using evacuated tube solar collector. To fulfill the objectives of the thesis, both theoretical and experimental analyses have been presented with variable operating conditions under local weather conditions and cooling load. High temperature of inlet hot water into the system could improve the efficiency and the performance as well as increasing the COP. Besides that, the design of condenser and evaporator with an optimized adsorption bed will also enhance the overall performance. The test rig was designed and fabricated based on the fundamentals of heat and mass transfer. The most effective parameters that influence the efficiency as well as the performance of the system are the hot water inlet temperature, the cooling water inlet temperature, the switching time and the amount of ethanol. It was found that the adequate amount of ethanol is 700 g, and the optimum inlet hot water and cooling water temperatures are 85 and 25ºC respectively. The optimum cycle switching time between the two adsorption beds for the system is 5 min. The outlet chilled water temperature could reach 16.3ºC after 10 cycles. The indoor and outdoor temperatures and humidity also been investigated during the operating of the adsorption air conditioning system with the electricity consumption of water pumps and control valves.