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 Evaporative Cooling Options for Building Air-Conditioning: A Comprehensive Study for Climatic Conditions of Multan (Pakistan)

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3061 ◽  
Author(s):  
Shazia Noor ◽  
Hadeed Ashraf ◽  
Muhammad Sultan ◽  
Zahid Mahmood Khan
Keyword(s):  
Thermal Comfort ◽  
Co2 Emissions ◽  
Air Conditioning ◽  
Evaporative Cooling ◽  
Cooling Capacity ◽  
Climatic Conditions ◽  
Maximum Temperature ◽  
Human Thermal Comfort ◽  
Work Input ◽  
System Configurations

This study provides comprehensive details of evaporative cooling options for building air-conditioning (AC) in Multan (Pakistan). Standalone evaporative cooling and standalone vapor compression AC (VCAC) systems are commonly used in Pakistan. Therefore, seven AC system configurations comprising of direct evaporative cooling (DEC), indirect evaporative cooling (IEC), VCAC, and their possible combinations, are explored for the climatic conditions of Multan. The study aims to explore the optimum AC system configuration for the building AC from the viewpoints of cooling capacity, system performance, energy consumption, and CO2 emissions. A simulation model was designed in DesignBuilder and simulated using EnergyPlus in order to optimize the applicability of the proposed systems. The standalone VCAC and hybrid IEC-VCAC & IEC-DEC-VCAC system configurations could achieve the desired human thermal comfort. The standalone DEC resulted in a maximum COP of 4.5, whereas, it was 2.1 in case of the hybrid IEC-DEC-VCAC system. The hybrid IEC-DEC-VCAC system achieved maximum temperature gradient (21 °C) and relatively less CO2 emissions as compared to standalone VCAC. In addition, it provided maximum cooling capacity (184 kW for work input of 100 kW), which is 85% higher than the standalone DEC system. Furthermore, it achieved neutral to slightly cool human thermal comfort i.e., 0 to −1 predicted mean vote and 30% of predicted percentage dissatisfied. Thus, the study concludes the hybrid IEC-DEC-VCAC as an optimum configuration for building AC in Multan.

Analysis of the Behavior of an Air Conditioning System Based on the Solar Energy Natural Regulation in Amazonian Climatic Conditions

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Elson C. Santos ◽  
Emanuel N. Macêdo ◽  
Marcos A. B. Galhardo ◽  
Thiago Oliveira Costa ◽  
André Felipe P. Costa ◽  
...  
Keyword(s):  
Direct Current ◽  
Air Conditioning ◽  
Cooling Capacity ◽  
Climatic Conditions ◽  
Power Modeling ◽  
Frequency Converters ◽  
Industrial Buildings ◽  
Air Conditioning Systems ◽  
Solar Resource ◽  
Installed Capacity

Abstract Air conditioning systems (ACSs) represent one of the main demands for electricity in residential, commercial, and industrial buildings. The use of a photovoltaic air conditioning unit (PVACU) represents an attractive application to this demand for reasons such as environmental concerns and the match between diurnal cooling load and solar resource. A PVACU consists of a photovoltaic generator (PVG) that supply an ACS through direct current to direct current and frequency converters, without energy storage. This system considers the natural adjustment of the ACS cooling capacity according to the PVG power. Modeling the ACS, the PVG, and the thermal load (TL) makes possible to evaluate PVACU performance. For this, a small library’s TL and an ACS supplied by a PVG were used as case study. The PVG installed capacity assumes values of 700, 1000, and 1400 Wp. The simulation results show that the PVACU with a 1400 Wp PVG would be sufficient to regulate internal temperature within international comfort standards in the range of 20 °C to 24 °C. According to the data obtained in the simulations, it was possible to conclude that the PVACU has a large potential to be used in air conditioning of other environments in regions with Amazonian climatic conditions.

scholarly journals Performance Analysis of Vapour Compression Refrigeration System using HC Refrigerant Mixtures for Water Chiller

2019 ◽  
Vol 8 (9) ◽  
pp. 2513-2517
Keyword(s):  
Global Warming ◽  
Performance Analysis ◽  
Ozone Depletion ◽  
Operating Conditions ◽  
Superior Performance ◽  
Refrigeration System ◽  
Refrigerant Mixture ◽  
Refrigerant Mixtures ◽  
Vapour Compression ◽  
Hfc Refrigerant

The use of HC refrigerant mixtures has been a topic of current research in view of the concerns related to global warming and Ozone depletion problems caused by CFCs and HFCs.. The HC mixture as an alternate refrigerant has been reported to be a promising one in addressing the global warming and Ozone depletion problems. In the present work an experimental set-up is built up to test Vapour Compression Refrigeration (VCR) system with different refrigerants. The aim of this work is to investigate the performance analysis of Vapor Compression Refrigeration system with alternate refrigerants such as Hydrocarbon (HC) refrigerants mixture and compare with Hydro Fluoro Carbon (HFC) refrigerant (R134a) under the similar operating conditions. The alternate refrigerant mixture is selected in the combination of Propane (R290) and Iso-butane (R600a). The refrigeration system variables considered for the investigation of performance are evaporating temperature, condensing temperature and power consumption. The HC refrigerant mixture is observed to give superior performance compared to HFC refrigerant in terms of global warming.

scholarly journals ПІДВИЩЕННЯ ЕФЕКТИВНОСТІ СИСТЕМ КОНДИЦІЮВАННЯ ПОВІТРЯ ШЛЯХОМ РОЗПОДІЛУ ТЕПЛОВОГО НАВАНТАЖЕННЯ ЗА СТУПЕНЕВИМ ПРИНЦИПОМ

2019 ◽  
pp. 49-53
Author(s):  
Євген Іванович Трушляков ◽  
Микола Іванович Радченко ◽  
Андрій Миколайович Радченко ◽  
Сергій Георгійович Фордуй ◽  
Сергій Анатолійович Кантор ◽  
...  
Keyword(s):  
Thermal Load ◽  
Air Conditioning ◽  
Rational Design ◽  
Ambient Air ◽  
Cooling Capacity ◽  
Climatic Conditions ◽  
Outlet Temperature ◽  
Thermal Loads ◽  
Air Conditioning System ◽  
Air Conditioning Systems

Maintaining the operation of refrigeration compressors in nominal or close modes by selecting a rational design thermal load and distributing it in response to the behavior of the current thermal load according to the current climatic conditions is one of the promising reserves for improving the energy efficiency of air conditioning systems, which implementation ensures maximum or close to it in the annual cooling production according to air conditioning duties. In general case, the total range of current thermal loads of any air-conditioning system includes a range of unstable loads caused by precooling of ambient air with significant fluctuations in the cooling capacity according to current climatic conditions, and a range of relatively stable cooling capacity expended for further lowering the air temperature from a certain threshold temperature to the final outlet temperature. If a range of stable thermal load can be provided within operating a conventional compressor in a mode close to nominal, then precooling the ambient air with significant fluctuations in thermal load requires adjusting the cooling capacity by using a variable speed compressor or using the excess of heat accumulated at reduced load. Such a stage principle of cooling ensures the operation of refrigerating machines matching the behavior of current thermal loads of any air-conditioning system, whether the central air conditioning system with ambient air procession in the central air conditioner or its combination with the local indoors recirculation air conditioning systems in the air-conditioning system. in essence, as combinations of subsystems – precooling of ambient air with the regulation of cooling capacity and subsequent cooling air to the mouth of the set point temperature under relatively stable thermal load.

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.

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.

Performance analysis of a vapour compression-absorption cascaded refrigeration system with undersized evaporator and condenser

2014 ◽  
Vol 25 (4) ◽  
pp. 23-36 ◽  
Author(s):  
Vaibhav Jain ◽  
Gulshan Sachdeva Sachdeva ◽  
Surendra S Kachhwaha
Keyword(s):  
Heat Exchanger ◽  
Performance Analysis ◽  
Electricity Consumption ◽  
Electrical Energy ◽  
Cooling Capacity ◽  
Individual Performance ◽  
Refrigeration System ◽  
Percentage Decrease ◽  
Main Effect ◽  
Vapour Compression

In a present study, the performance of a vapour compression–absorption cascaded refrigeration system (CRS) under fouled conditions was analysed. The main effect of fouling is to decrease the effectiveness of the heat exchanger. Thus, the overall conductance (UA) of the heat exchanger is decreased. Hence, another interpretation of fouling is to reduce the effective size of the heat exchanger. In the present work, the percentage decrease in the overall conductance value (UA) of evaporator and condenser due to their fouling is varied from 0 to 50% and its consequences on various aspects of CRS are generated to ascertain any possible patterns. The detailed first law analysis reveals that for a clean evaporator and condenser, the electricity consumption is 67.5% less than vapour compression system (VCS) for the same cooling capacity. CRS is able to save only 61.3% of electrical energy when evaporator and condenser conductance is reduced by 50% due to fouling. Evaporator and condenser fouling decreased the COP and rational efficiency of the system by 4.7% and 10.5% respectively. It is also important to note that irreversibility in the evaporator and condenser is increased by 42.4% and 62.1% respectively, when their individual performance is degraded by 50% due to fouling.

Energy Saving in a Heat Pump Air-Conditioning System Using Liquid Desiccant and Membrane Contactors

2011 ◽  
Author(s):  
Stefano Bergero ◽  
Anna Chiari
Keyword(s):  
Energy Saving ◽  
Heat Pump ◽  
Hybrid System ◽  
Air Conditioning ◽  
Energy Savings ◽  
Climatic Conditions ◽  
Operating Conditions ◽  
Membrane Contactor ◽  
Traditional System ◽  
Vapour Compression

It has been demonstrated in the literature that significant energy savings can be achieved in air-conditioning through the use of so-called hybrid systems, in which a chemical dehumidification system is combined with a vapour-compression heat pump. The advantage of such systems lies in the fact that the heat pump can operate at a higher evaporation temperature than that of a traditional system in which dehumidification is achieved through condensation, thereby achieving higher coefficients of performance. The hybrid system described in the present paper operates as follows: the air supplied to the conditioned ambient is simultaneously cooled and dehumidified in an air-solution membrane contactor. The LiCl solution is cooled by means of a vapour-compression heat pump using the refrigerant KLEA 410A. The solution is regenerated in another membrane contactor by exploiting the exhaust air and the heat rejected by the condenser. A study of the steady-state behaviour of the system in summer climatic conditions was carried out, on varying some significant operating parameters, such as the thermal efficiency of the heat exchangers, the outdoor temperature and the sensible load of the conditioned room. The performances of the hybrid system were compared with those of a traditional direct-expansion air-conditioning plant; the results of the simulations reveal that, in particular operating conditions, energy saving can exceed 50%.

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 Numerical Study of Integrated Solar Photovoltaic–Thermal Module with a Refrigeration System for Air-Conditioning and Hot Water Production under the Tropical Climate Conditions of Singapore

2018 ◽  
Vol 26 (03) ◽  
pp. 1850021 ◽  
Author(s):  
Swapnil Dubey ◽  
Alison Subiantoro
Keyword(s):  
Air Conditioning ◽  
Numerical Study ◽  
Power Saving ◽  
Tropical Climate ◽  
Cooling Capacity ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Solar Photovoltaic ◽  
Refrigeration System ◽  
Climate Conditions

Thermal systems of buildings in the tropics are highly energy intensive. In this study, a novel integrated solar photovoltaic–thermal–refrigeration (PVTR) system used to produce hot water and air-conditioning in the tropical climate conditions of Singapore was analyzed. A dynamic simulation model was formulated for the analysis. Mathematical models were developed for the PV sandwich attached with a solar flat plate collector and for the main components of the refrigeration system. Thorough investigation of the electrical and thermal performances of the system were conducted through the analysis of coefficient of performance (COP), cooling capacity, water temperature and heat capacity in water heater, photovoltaic (PV) module temperature and PV efficiency. The results show that attractive electrical and thermal performance can be achieved with a maximum annual cooling COP of 9.8 and a heating COP of 11.3. The PV efficiency and power saving were 14% and 53%, respectively. The annual cooling, heating and PV energy produced were 9.7, 15.6 and 1.6[Formula: see text]MWh, respectively. The financial payback period of the system was 3.2 years and greenhouse gas (GHG) emission reduction annually was 12.6 tons of CO2 equivalents (tCO2e).

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