Analysis of Heat-Driven Combined Cooling and Desalination

2016 ◽  
Author(s):  
Sami M. Alelyani ◽  
Nicholas W. Fette ◽  
Ellen B. Stechel ◽  
Pinchas Doron ◽  
Patrick E. Phelan
Keyword(s):  
Second Law Of Thermodynamics ◽  
Cooling Capacity ◽  
Operating Conditions ◽  
Water Production ◽  
Exergy Destruction ◽  
Absorption Refrigeration ◽  
Refrigeration System ◽  
Cooling Systems ◽  
Thermally Driven ◽  
Combined Cooling

This paper investigates the opportunities for integrating thermally driven cooling systems with thermally driven desalination systems via cascade of reject heat. Single- and double-stage ammonia-water (NH3–H2O) absorption refrigeration systems with multi-effect distillation (MED) are selected for this study based on technical limitations and practical considerations. Cooling capacity and hourly water production are calculated from thermodynamic properties of the working fluids at different operating conditions using simple models for each of the constituent systems. Additionally, the second law of thermodynamics is applied with the aim of examining the entropy generation of each component as well as the total exergy destruction of the entire system. The results indicate that the total exergy destruction of the combined systems, which consist of an MED unit driven by either a single- or double-stage NH3–H2O refrigeration system, decreases by an average of 55% compared to stand-alone NH3–H2O and MED systems. Relative to stand-alone systems, although water production decreases by 30% and 9% when an MED unit is integrated with single- and double-stage NH3–H2O absorption systems, respectively, cooling capacity remains unchanged for the double-stage NH3-H2O–MED system, and only decreases by 16% for the single-stage NH3-H2O–MED system.

A Parametric Examination of the Factors Affecting the Performance of a Diffusion Absorption Refrigeration System

2021 ◽  
pp. 1-38
Author(s):  
Noman Yousuf ◽  
Timothy Anderson ◽  
Roy Nates
Keyword(s):  
Waste Heat ◽  
Operating Conditions ◽  
Design Parameters ◽  
Working Fluid ◽  
Low Grade ◽  
Absorption Refrigeration ◽  
Factors Affecting ◽  
Thermally Driven ◽  
Mass Flowrate ◽  
Diffusion Absorption

Abstract Despite being identified nearly a century ago, the diffusion absorption refrigeration (DAR) cycle has received relatively little attention. One of the strongest attractions of the DAR cycle lies in the fact that it is thermally driven and does not require high value work. This makes it a prime candidate for harnessing low grade heat from solar collectors, or the waste heat from stationary generators, to produce cooling. However, to realize the benefits of the DAR cycle, there is a need to develop an improved understanding of how design parameters influence its performance. In this vein, this work developed a new parametric model that can be used to examine the performance of the DAR cycle for a range of operating conditions. The results showed that the cycle's performance was particularly sensitive to several factors: the rate of heat added and the temperature of the generator, the effectiveness of the gas and solution heat exchangers, the mass flowrate of the refrigerant and the type of the working fluid. It was shown that can deliver good performance at low generator temperatures if the refrigerant mass fraction in the strong solution is made as high as possible. Moreover, it was shown that a H2O-LiBr working pair could be useful for achieving cooling at low generator temperatures.

Experimental Analysis of a Laboratory-Scale Diesel Engine Exhaust Heat-Driven Absorption Refrigeration System as a Model for Naval Surface Ship Applications

2020 ◽  
Vol 36 (02) ◽  
pp. 152-159 ◽  
Author(s):  
Cüneyt Ezgi ◽  
Sinem Bayrak
Keyword(s):  
Diesel Engine ◽  
Experimental Analysis ◽  
Alternative Energy ◽  
Cooling Capacity ◽  
Energy Sources ◽  
Naval Academy ◽  
Absorption Refrigeration ◽  
Refrigeration System ◽  
Exhaust Heat ◽  
Absorption Refrigeration System

Decreasing industrial energy sources and major environmental problems caused by uncontrolled energy consumption have led to studies on alternative energy sources. This study presents a design and experimental analysis of an exhaust gas-driven absorption refrigeration system for the purpose of air conditioning by using the exhaust heat of a diesel engine, which is installed in the Naval Academy Mechanics Laboratory. The diesel engine is loaded with a dynamometer, and water and ammonia are used as an absorbent and refrigerant, respectively. At various diesel engine loads, cooling capacity and coefficient of performance (COP) of the absorption refrigeration system are calculated. Experimental results have indicated the cooling capacity as 1.098 kW at a maximum engine power of 4.9 HP. The highest COP value in the designed system has been calculated to be .3022 for the generator temperature of 160 C. Although the COP of refrigeration is low, the absorption refrigeration system can be provided a great cooling load from the exhaust heat of diesel engines and can be used in naval surface ships. In addition to energy efficiency of naval surface ships, infrared and acoustic signature can be minimized and a ships susceptibility can be dramatically reduced.

Performance Analysis on a Solar-Driven Air-Cooled Ejector Refrigeration System for Air-Conditioning Using Ammonia as Refrigerant

2014 ◽  
Vol 501-504 ◽  
pp. 2282-2287 ◽  
Author(s):  
Yu Hang Liao ◽  
Wei Lu ◽  
Lie Pan
Keyword(s):  
Performance Analysis ◽  
Solar Irradiance ◽  
Air Conditioning ◽  
Cooling Capacity ◽  
Climatic Conditions ◽  
Operating Conditions ◽  
Refrigeration System ◽  
Outdoor Temperature ◽  
Indoor Temperature ◽  
Changing Trend

The performance of a solar-driven air-cooled ejector refrigeration system using ammonia as refrigerant with rated cooling capacity of 10.5kW was analyzed for air-conditioning purpose. The cooling capacity of the proposed system increases with the rising of indoor temperature and enhancement of solar irradiance, while decreases with the rising of outdoor temperature. The COP has similar changing trend with that of the cooling capacity except that it increases rapidly with the enhancement of solar irradiance firstlyand then become stable by and large after solar irradiance exceeding a certain value. The cooling capacity is 6.3~52kW and the COP 0.06~0.11 under the normal operating conditions with indoor temperature over 27, outdoor temperature below 38°C and solar irradiance surpassing 500 W/m2. The proposed system can match the climatic conditions in air-conditioning season of Nanning, a typical city in hot summer and warm winter region.

scholarly journals Evaporator Frosting in Refrigerating Appliances: Fundamentals and Applications

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5991
Author(s):  
Christian J. L. Hermes ◽  
Joel Boeng ◽  
Diogo L. da Silva ◽  
Fernando T. Knabben ◽  
Andrew D. Sommers
Keyword(s):  
First Principles ◽  
Simulation Models ◽  
Cooling Capacity ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Trial And Error ◽  
Refrigeration System ◽  
Duty Cycles ◽  
Transfer Principles ◽  
Frost Layer

Modern refrigerators are equipped with fan-supplied evaporators often tailor-made to mitigate the impacts of frost accretion, not only in terms of frost blocking, which depletes the cooling capacity and therefore the refrigerator coefficient of performance (COP), but also to allow optimal defrosting, thereby avoiding the undesired consequences of condensate retention and additional thermal loads. Evaporator design for frosting conditions can be done either empirically through trial-and-error approaches or using simulation models suitable to predict the distribution of the frost mass along the finned coil. Albeit the former is mandatory for robustness verification prior to product approval, it has been advocated that the latter speeds up the design process and reduces the costs of the engineering undertaking. Therefore, this article is aimed at summarizing the required foundations for the design of efficient evaporators and defrosting systems with minimized performance impacts due to frosting. The thermodynamics, and the heat and mass transfer principles involved in the frost nucleation, growth, and densification phenomena are presented. The thermophysical properties of frost, such as density and thermal conductivity, are discussed, and their relationship with refrigeration operating conditions are established. A first-principles model is presented to predict the growth of the frost layer on the evaporator surface as a function of geometric and operating conditions. The relation between the microscopic properties of frost and their macroscopic effects on the evaporator thermo-hydraulic performance is established and confirmed with experimental evidence. Furthermore, different defrost strategies are compared, and the concept of optimal defrost is formulated. Finally, the results are used to analyze the efficiency of the defrost operation based on the net cooling capacity of the refrigeration system for different duty cycles and evaporator geometries.

Effect of Hydrofluorocarbons and Hydrofluoroolefins in a Household Refrigerator as a Substitute for R134a

2019 ◽  
Vol 969 ◽  
pp. 199-204
Author(s):  
Shaik Mohammad Hasheer ◽  
Kolla Srinivas
Keyword(s):  
Cooling Capacity ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Condensation Temperature ◽  
Outlet Temperature ◽  
Refrigeration System ◽  
Volumetric Cooling ◽  
Work Done ◽  
Theoretical Results ◽  
Hfc 152A

Now a days R134a can be used in domestic refrigerators and in air conditioning of automobiles. As per Kyoto protocol the usage of R134a is restricted due to their higher GWP value. The GWP value of this refrigerant is around 1430. So in this article, thermodynamic analysis of HFC-152a, HFO refrigerants-1234ze(E) and 1234yf was done in a household refrigeration system as direct substitute to HFC-134a.The performance of the household refrigerator was compared in terms of outlet temperature of the compressor, volumetric cooling capacity (VCC), refrigeration effect, work done by the compressor and coefficient of performance (COP). The entire analysis is carried out at various operating conditions of condenser and evaporator temperatures i.e. condensation temperature of 25°C,35°C & 45°C and evaporating temperatures ranging between −20°C to 10°C.From the theoretical results, it can be concluded that R1234yf can be used as a direct substitute to R134a.

scholarly journals Análise Exergoeconômica de um sistema de trigeração de energia operando com um Ciclo Rankine Orgânico

2021 ◽  
Vol 1 (54) ◽  
pp. 20
Author(s):  
Thiago De Souza Figueredo ◽  
João Luiz De Medeiros Neto ◽  
Adriano Da Silva Marques ◽  
Carlos Antônio Cabral Dos Santos
Keyword(s):  
Steam Generator ◽  
Organic Rankine Cycle ◽  
Industrial Process ◽  
Rankine Cycle ◽  
Exergy Destruction ◽  
Absorption Refrigeration ◽  
Refrigeration System ◽  
Simple Effect ◽  
Absorption Refrigeration System ◽  
Residual Heat

<span class="fontstyle0">This work presents the results of the energetic, exergetic and exergoeconomic evaluation of a trigeneration system which is composed of an Organic Rankine Cycle (ORC), a simple effect Absorption Refrigeration System (SRA) and a boiler. The proposed system is driven by the residual heat of an industrial process. A computational code was developed on the EES (Engineering Equation Solver) platform to solve the thermodynamic and exergoeconomic equation of each equipment. The SPECO method (Specific Exergy Costing) was used for the exergoeconomic evaluation. Results indicated which equipment needs optimization in order of priority. The results show that the greatest destruction of exergy occurs in the ORC steam generator (56% of the total), followed by the condenser that presented an exergy destruction of 33%. Conversely, the pump and expander performed better, with low exergy destruction values. The results of the exergoeconomic evaluation also indicate that the steam generator and condenser from ORC need to be optimized before any other equipment, as they obtained the lowest values of the exergoeconomic factor (f</span><span class="fontstyle0">k</span><span class="fontstyle0">) and the highest values of the specific relative cost (r</span><span class="fontstyle0">k</span><span class="fontstyle0">).</span> <br /><br />

Advanced Exergetic Analysis of a Double-Effect Series Flow Absorption Refrigeration System

2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Dario Colorado-Garrido
Keyword(s):  
Second Law Of Thermodynamics ◽  
Double Effect ◽  
Exergy Destruction ◽  
Absorption Refrigeration ◽  
Pressure Generator ◽  
Exergetic Analysis ◽  
Absorption Refrigeration System ◽  
Design And Manufacture ◽  
Account Temperature ◽  
Theoretical Results

Abstract This paper contains theoretical results of an advanced exergy study of a double-effect series flow absorption refrigeration cycle. Traditional second law of thermodynamics analysis was performed and revealed the absorber as the component with the highest exergy destruction of the system. In the evaporator, ≈49.34% of the exergy destruction is avoidable and almost in it’s entirety, ≈99.12% is of endogenous nature. The highest potential for improvement of the high-pressure generator is its design and manufacture because ≈67.47% of the endogenous exergy destruction is avoidable. A parametric study was presented to discuss the sensitivity of splitting exergy destruction concepts taking into account temperature variations in the absorber and condenser temperatures and the heat source temperature.

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