scholarly journals Study of a solar air conditioning system with ejector

2020 ◽  
Vol 5 (1) ◽  
pp. 14
Author(s):  
Ghodbane Mokhtar

Air conditioning is one of the indispensable conditions of well-being in human life, so the face of this research to provide this basic necessity in remote areas and in desert places far from power grids. To achieve this goal, solar air conditioning has been adopted, where the compressor was replaced by an ejector, a parabolic trough solar collector and a small pump; this means that the solar air conditioner does not need a huge amount of electrical energy to operate. This paper is studding the thermodynamic cycles of this air conditioner as a function of changing the climatic conditions of Bouzaréah region in Algeria under several practical conditions of heat exchangers (Condenser, Evaporator and Generator). This study will allow the determination of the optical and thermal efficiency of the solar collector used as a solar thermal generator, refrigeration subsystem performance (COPEje) and system thermal ratio of the air conditioner, where the cooling load is estimated at 18 kW.

2021 ◽  
Vol 288 ◽  
pp. 01066
Author(s):  
Ahmed Al–Okbi ◽  
Yuri Vankov ◽  
Hasanen Mohammad Hussain

The process of operating an air conditioning system by hybrid energy that uses solar energy for purpose of saving electrical energy with improving the performance from modern and environmentally friendly systems. With high demand for air-conditioning systems in summer in hot regions, especially in Iraq due to high temperatures, the issue of using renewable energies becomes more attractive due to the continuous interruption of electrical energy. Air conditioners in Iraq consume more than half of the average electricity production. Therefore, saving energy leads to ensuring the reliability of electricity and reduces the consumption of fuel and gases that pollute the environment and negatively affect on the ozone layer. In the current research, the atmosphere of the city Baghdad was used to collect the solar thermal energy through a vacuum solar collector and combine it with a conventional air conditioner in order to reduce the electrical energy consumption on the compressor and increase the coefficient of performance. Several tests were conducted on the experimental device for comparing results with the conventional device and evaluating performance. The results showed that the performance with the vacuum solar collector became more efficient 8.97 instead of 4.27 than with the conventional system, and the energy consumption decreased by 52%.


Author(s):  
S. N. Osipov ◽  
A. V. Zakharenko ◽  
E. M. Shirokova

The increase of average outdoor temperatures and their fluctuations over the past 20 years (as evidenced by the records of summer temperatures in our country) has significantly increased the need for air conditioning premises where people are present for a long time, especially when they are crowded (shops, entertainment halls, classrooms, etc.). The air conditioning process is quite energy-intensive, but the growth of well-being in many republics of the former USSR, as well as the increasing complexity of the physiological adaptation of the human body to rising outdoor temperatures make it possible (and at the same time necessary) to implement these systems on a large scale. It is important to take into account that electricity prices are currently maintained at a high level for homeowners, and in the coming years the prices will only grow. Therefore, the development of new ways of significant increase of the energy efficiency of the indoor air conditioning process is of a great interest. One of these methods is the use of laminar (or close to them) moving layers of conditioned air in a limited area of work or rest of people. Such a zone, about 1.0‒1.2 m height from a floor in each apartment is, e.g., living rooms (bedroom) in which standard temperature conditions are created by means of simple air supplying and air intake devices. In the case of sedentary work of people, the height of such a zone of conditioned air should be increased to 1.3‒1.5 m. It has already been established that the use of laminar (or close to them) air flows allows to reduce the power consumption by two or more times due to significantly reduced heat exchange with the surrounding heated surfaces. Besides, the simplicity of such systems ought to be noted. In particular, in conditions of modern systems of control and management of air conditioning, the "duties" of consumers include only the installation on the control device of the initial data relating directly to the required parameters of the microclimate. At the same time, it should be noted that there is currently no complete scientific and technical description of aerodynamic and heat exchange processes in the air conditioning zone. Even in modern conditions for countries with a sharply continental climate (Russia, Kazakhstan, etc.), the problem is the choice of the type of air conditioner for its effective use in hot periods of summer. In general, it can be noted that all the problems of energy-efficient use of air conditioners must find a comprehensive solution.


2019 ◽  
Vol 11 (7) ◽  
pp. 2045 ◽  
Author(s):  
Néstor Santillán-Soto ◽  
O. García-Cueto ◽  
Alejandro Lambert-Arista ◽  
Sara Ojeda-Benítez ◽  
Samantha Cruz-Sotelo

This paper presents a hypothetical and comparative performance of a 5 ton air conditioner (AC) operating in two zones in different urban microclimates for 25 days. One site represents a type of homogeneous planned urbanism and the other is a traditional heterogeneous zone. Air temperature data was collected and then processed using a linear regression model included in the operating manual of the AC in order to obtain their energy consumption. Results indicate that for an area with 500 homes, a traditional urban complex requires 12,350 kWh of electrical energy more than a planned zone (1.89%). This extra energy amounts up to $1180 and adds 9191 kg of CO2 to the atmosphere. The increased energy consumption has implications that increase the cost and environmental aspects of two urban microclimates, so that urbanization without planning is less friendly to the environment. In this sense, this study highlights the effects of urban microclimates on domestic electricity consumption from air conditioning. In addition, for a city with an arid desert climate, the variation in electricity consumption is associated with changes in the urban mosaic. The results found represent scientific evidence that can be used as a reference to establish public policies that could be incorporated into the local construction regulations, oriented to reduce the energy consumption associated with the use of air conditioning equipment.


2020 ◽  
Vol 48 (3) ◽  
pp. 134-142
Author(s):  
M. M. Sodnompilova

Verbal restrictions common among the Turko-Mongol peoples of Inner Asia and Siberia are analyzed on the basis of folkloric and ethnographic sources. Their principal forms are silence, circumlocution, and whisper. The socio-cultural context of these restrictions is reconstructed. They are seen in various domains of culture, in particular relating to social norms, and are believed to refl ect fear of human life and the well-being of man and society in the communication with nature represented by deities and spirits. This is a natural reaction that has evolved under the harsh environmental and climatic conditions of Inner Asia. The sa me concerns, extending to social communication, have regulated interpersonal interactions. In a nomadic culture, verbal restrictions stem from the importance of the ritual function of language and a specifi c attitude toward spoken language, which, over the centuries, was the principal means of information storage and transfer, cognition and adaptation. This concept of speech affected the emergence of the principal behavioral stereotypes. The rigid norms of behavior account for the importance of the nonverbal context of the nomadic culture— the high informative potential of the entire space inhabited by the nomads, and the rich symbolism of their material culture, traditional outfi t, and dwelling.


2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Ali Al-Alili ◽  
Yunho Hwang ◽  
Reinhard Radermacher

Solar air conditioners (A/Cs) have attracted much attention in research, but their performance and cost have to be optimized in order to become a real alternative to conventional A/C systems. In this study, a hybrid solar A/C is simulated using the transient systems simulation program(trnsys), which is coupled with matlab in order to carry out the optimization study. The trnsys model is experimentally validated prior to the optimization study. Two optimization problems are formulated with the following design variables: solar collector area, solar collector mass flow rate, solar thermal energy storage volume, and solar electrical energy storage size. The genetic algorithm (GA) is selected to solve the single-objective optimization problem and find the global optimum design for the lowest electrical consumption. To optimize the two objective functions simultaneously, energy consumption and total cost (TC), a multi-objective genetic algorithm (MOGA) is used to find the Pareto curve within the design variables' bounds while satisfying the constraints. The overall cost of the optimized solar A/C design is also compared to a standard vapor compression cycle (VCC). The results show that coupling trnsys and matlab expands trnsys optimization capability in solving more complex optimization problems. The results also show that the optimized solar hybrid A/C is not very competitive when the electricity prices are low and no governmental support is provided.


2011 ◽  
Vol 19 (02) ◽  
pp. 131-140
Author(s):  
QUBO LI ◽  
DEMISS A. AMIBE ◽  
NORBERT MÜLLER

An air conditioning system using water as refrigerant (R718) that compresses water vapor with multistage stage variable speed axial compressor with intercooling between stages by water injection is considered. Four stage compression with flash intercooling resulted in 50% improvement of coefficient of performance (COP) at full load compared to conventional refrigerants like R134a. The energy efficiency of an air conditioning unit is specified by seasonal energy efficiency ratio (SEER). SEER is defined as the ratio of cooling output of an air conditioner measured and electrical energy consumption as per AHRI 210/240 during cooling season. The SEER is computed after determining the evaporator cooling capacity and the electrical energy demand of the compressor at each bin temperature using assumed compressor isentropic efficiency, mechanical efficiency and electrical efficiency and multiplying by the weight of each bin temperature to determine the total for the cooling season. As a result of multistage compression, best part load performance of water as a refrigerant and operation of compressor near design point at part load due to variable speed drive, 50%–60% improvement in SEER is obtained compared to the best available in the market using conventional refrigerants such as R134a with single stage compression.


2019 ◽  
pp. 9-14
Author(s):  
Євген Іванович Трушляков ◽  
Андрій Миколайович Радченко ◽  
Микола Іванович Радченко ◽  
Сергій Анатолійович Кантор ◽  
Веніамін Сергійович Ткаченко

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.


2020 ◽  
Vol 4 (2) ◽  
pp. 123-132
Author(s):  
Farzana Iqbal ◽  
◽  
Muhammad Imran ◽  

We are all aware of environmental benefits of trees. They provide shelter and food for animals, purify the air of pollution and regulate the temperature.Trees play a critical role in the quality of human life as well as the environmental well-being of our communities. Quran also has numerous passages that describe the lush gardens and trees. Allah created trees, plants and fruits not only for their known vital benefits as food, they are also a source of delight to eyes.During battle , Muslims are required to avoid cutting down trees.Hadith from Prophet Muhammad that relate the importance of trees and plants in islam.Islam Not only hands over the list of do’s and don’ts but also convince mankind with wisdom.Even a man of ordinary prudence can understand easily from Hadith that Hazrat Muhammad ﷺnot only instructed us to plant trees but also the most significant aspect. He gave us vision to save the environment 14 centuries ago. He has connected the plantation with social responsibility and piousness. Trees can control the temperature cool the environment absorb carbon dioxide and clean the air act as natural air conditioner, control noise, prevent soil erosion etc. Such key environmental benefits are also proven by science. Holy Prophet Muhammad ﷺ gave us vision so if we conduct according to that vision, environment problems can be controlled easily.


Author(s):  
Demiss A. Amibe ◽  
Qubo Li ◽  
Norbert Mu¨ller

An air conditioning system using water as refrigerant (R718) that compresses water vapor with multistage stage variable speed axial compressor with intercooling between stages by water injection is considered. Four stage compression with flash intercooling resulted in 50% improvement of coefficient of performance (COP) at full load compared to conventional refrigerants like R134a. The energy-efficiency of an air conditioning unit is specified by seasonal energy efficiency ratio (SEER). SEER is defined as the ratio of cooling output of an air conditioner measured and electrical energy consumption as per AHRI 210/240 during cooling season. The SEER is computed after determining the evaporator cooling capacity and the electrical energy demand of the compressor at each bin temperature using assumed compressor isentropic efficiency, mechanical efficiency and electrical efficiency and multiplying by the weight of each bin temperature to determine the total for the cooling season. As a result of multistage compression, best part load performance of water as a refrigerant and operation of compressor near design point at part load due to variable speed drive, 50–60% improvement in SEER is obtained compared to the best available in the market using conventional refrigerants such as R134a with single stage compression.


2020 ◽  
Vol 38 (7A) ◽  
pp. 984-991
Author(s):  
Krar M. Kuder ◽  
Hashim A. Hussein ◽  
Ali H. Numan

The present research paper is on photovoltaic air conditioning system using the direct drive method. The experimental system setup arranged in Iraq at Al-taje site at longitude 44.34 and latitude 33.432 during the summer season inside a room. The proposed off-grid system consists of an array of photovoltaic, battery used to store power, PWM (pulse width modulation) charge controller, and DC air cooler. During the examination of the system, proven success of this new type(dc air conditioner ) of client urges Iraq warm conditions as an alternative type used instead of the prevailing types of air conditioners (AC air conditioner )in Iraq which consume large amounts of electrical energy and gets a cooling system for the room full working on solar energy.                                                                                                                


Sign in / Sign up

Export Citation Format

Share Document