scholarly journals Design and Analysis of a Thermoelectric Air-conditioning System

Author(s):  
A. Anthony Adeyanju ◽  
K. Manohar

Thermoelectric devices use the Peltier effect which creates a heat flux between the junctions of two different types of materials. The thermoelectric module also referred to as a heat pump transfers heat from one side to the other when a DC current is applied. This study carried out the theoretical and experimental analysis of a thermoelectric air conditioning system. A prototype thermoelectric air conditioner of 286 W cooling capacity was built and a testing enclosure made from plywood and Styrofoam was also constructed in order to validate the theoretical result with an experimentation. It was discovered that thermoelectric air conditioning took 4 minutes to reach its desired temperature of 22℃ whereas the standard air conditioning system (Refrigeration Cycle) took 20 minutes to cool to a room temperature. Economically it was also discovered that thermoelectric air conditioning system is 50% cheaper than the refrigeration cycle air conditioning systems. The thermoelectric air conditioner has cheaper maintenance and greater estimated life span of 7 years more than the refrigeration air conditioner. This is because the air conditioner that operates on the refrigeration cycle uses a rotating compressor while the thermoelectric air conditioner uses thermometric module.

2018 ◽  
Vol 197 ◽  
pp. 08013
Author(s):  
Enang Suma Arifianto ◽  
Ega Taqwali Berman ◽  
Mutaufiq Mutaufiq

The purpose of this research is to know the improvement of car air conditioner system performance using an ejector. The study was conducted on a car engine with power 100 PS (74 kW) @ 5000 rpm. The test procedure is carried out under two conditions: the normal refrigeration cycle mode and the refrigeration cycle mode with the ejector. The working fluid used in the refrigeration cycle is R-134a. Performance data was measured on engine revolutions ranging from 1500 - 3000 rpm. Finally, the results showed that ejector usage on AC system generates an increase in the refrigeration effect and coefficient of performance (COP) of 25% and 22%, respectively. This has implications to better cooling capacity and compressor work that is lighter.


2014 ◽  
Vol 672-674 ◽  
pp. 54-60 ◽  
Author(s):  
Ting Xiang Jin ◽  
Xiao Feng Xu

As coal, oil, natural gas and other non-renewable energy consumption and increasing energy demand, the utilization of solar energy as a new energy is greatly enhanced. In this work, a grid connected photovoltaic solar air conditioning system is designed, mainly comprised of solar panel, controller, inverter, room air conditioner and other parts. Air conditioning systems rely mainly on solar photovoltaic power; achieve the effect of energy conservation and environmental protection. The experimental result indicates that the system can achieve stable operation and the utilization of solar energy driving air conditioning system to save electricity. This air conditioning system is compared with the ordinary air conditioning system, SEER can increase 10.6 ~ 29.4%, HSPF can increase 6.25 ~ 18.5%.


Author(s):  
Akira Kaneko ◽  
Masafumi Katsuta ◽  
Takahiro Oshiro ◽  
Sangchul Bae ◽  
Shunji Komatsu ◽  
...  

In previous research, we have been focusing on the performance of the each element heat transfer and hydraulic performance of refrigeration cycle. Experimental investigations have been repeated several times, and finally, we have substantial database including the effect of lubricant oil. Moreover, the maldistribution of two-phase in an evaporator can be also predicted from the experimental database. Under these circumstances, this study is intended to effectively put the construction of an automotive CO2 air conditioning system into practical design use through the simulation using the above-mentioned database. This paper describes the refrigeration cycle performance prediction of each element (e.g., an evaporator, a gas-cooler, and so on) by a simulation using substantial database and various available correlations proposed by us and several other researchers. In the performance prediction model of heat exchangers, local heat transfer and flow characteristics are considered and, in addition, the effects of lubricant oil on heat transfer and pressure drop are duly considered. The comparison is also made between simulation results and bench test results using a real automotive air conditioning system. Finally, the developed simulation method can predict the cooling capacity successfully within ±10% for A/C system simulation. By incorporating the lubricant oil effect, the simulation results are improved to ±5% and ±15% for the cooling capacity and pressure drop for evaporator simulation, respectively.


2019 ◽  
pp. 49-53
Author(s):  
Євген Іванович Трушляков ◽  
Микола Іванович Радченко ◽  
Андрій Миколайович Радченко ◽  
Сергій Георгійович Фордуй ◽  
Сергій Анатолійович Кантор ◽  
...  

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.


2019 ◽  
Vol 25 (12) ◽  
pp. 1-14
Author(s):  
Rafah Hussain ◽  
Issam Mohammed Ali

Reducing global warming potential (GWP) of refrigerants is needed to the decrease of ozone-depleting of refrigeration systems leakages. Refrigerant R1234yf is now used to substitute R134a inside mobile air conditioning systems. Thermodynamic properties of R1234yf are similar to R134a. Also, it has a very low GWP of 4, compared to 1430 for R134a, making it a proper choice for future automobile refrigerants. The purpose of this research is to represent the main operating and performance differences between R1234yf and R134a. Experimental analysis was carried out on the automotive air conditioning system (AACS) with 3 kW nominal capacity, to test and compare the performance of R134a with R1234yf. Experiments were accomplished for both refrigerants in almost the same working conditions and procedure with a range of ambient temperature varied from 26oC to 50oC. Parameters studied were ambient temperature, type of refrigerant in the system at compressor speed 1450 rpm, and internal thermal loads of passenger room. The performance characteristics of the system, including COP and cooling capacity, were studied by changing different parameters. The results show that COP of R134a is higher than R1234yf by 12.6%, while the refrigeration effect of R134a is higher than R1234yf by 25%. This shows that R1234yf is a suitable and good candidate for drop-in replacement of R134a in AACS.


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.


The objective of the study is to investigate the performance improvement in a split air conditioning system using evaporative cooling pads at ODU (outdoor unit) and to determine optimum thickness and material of the cooling pad. For this purpose experiments were conducted on 0.8 TR capacity split air conditioner charged with refrigerant R-22. For comparison experiments were performed with and without evaporative cooling pad. The effect of the different cooling pad material and thickness on the overall performance of split air conditioner is experimentally found by measuring cooling capacity and the power consumption of the system including water circulation pump. From the experimental work it is found that the cellulose cooling pad gives the best results among the selected materials. Split air conditioner coupled with cellulose cooling pad of 100 mm thickness at ODU results in to 13.8% increase in overall COP, 9.5 % reduction in power consumption and 5.1 % increase in cooling capacity at 35°C DBT and 32% relative humidity outdoor air condition.


2019 ◽  
Vol 25 (7) ◽  
pp. 1-20
Author(s):  
Yasser Abdul Lateef Ghani ◽  
Abdul Hadi N. Khalifa

A time series analysis can help to observe the behavior of the system and specify the system faults. In addition, it also helps to explain the various energy flows in the system and further aid in reducing the thermodynamic losses. The intelligent supervisory LabVIEW software can monitor the incoming data from the system by using Arduino microcontroller and calculates the important parameters. Energy, exergy, and anergy analysis present in this paper to investigate the system performance as well as its components. To accomplish this, a 4-ton vertical split air conditioner based on vapor compression refrigeration cycle charged with refrigerant R-22 was modified for experimental analysis. The results showed that during 5400 secs of experimental study, the system shut down once by the software for 5 min. The volumetric and isentropic efficiencies of the compressor were 79.85 % and 64.48 % respectively. The maximum entropy generation was due to the compressor of 3.4 W/K while the maximum anergy was due to the condenser of 1.39 kW. The exergy efficiencies of the compressor, condenser, and the evaporator were 73.57, 40.18, and 47.45 % respectively. The system and Carnot COP were 2.53 and 4.9 respectively. The exergy efficiency of the air conditioning system was 48.7 %.  


2018 ◽  
Vol 931 ◽  
pp. 920-925
Author(s):  
Zohrab Melikyan ◽  
Naira Egnatosyan ◽  
Siranush Egnatosyan

Centralized air conditioning systems are widely used in buildings at present. In these conditioners, the outside air gets required temperature, humidity, purity, and other features, necessary for creating comfort microclimate in inside areas of houses, and by the help of fans and air ducts the processed air moves to all rooms of a building. As a result, the creation and maintenance of comfort conditions in buildings become complicated and expensive activity. From this point of view, it is becoming more expedient to install local air conditioners in each room instead of single central one for the whole building. For this reason new local air conditioner is developed.


2013 ◽  
Vol 21 (02) ◽  
pp. 1350013 ◽  
Author(s):  
CHIH-CHIU SHEN ◽  
JAU-HUAI LU

Due to the concern in energy shortage and environmental protection, electric vehicle is considered to be a substitute for the conventional gasoline-powered vehicles due to its characteristics of high efficiency and no emission. However, the load of air conditioning causes a serious problem for electric vehicles, especially in tropical and subtropical areas. The compressor of conventional air conditioning system is driven by engine and its speed is thus coupled to vehicle speed. In electric vehicles, the compressor is driven by electric motors and compressor speed could be decoupled to vehicle speed. This mechanism provides an opportunity to improve the energy efficiency of electric vehicle since the operation of air conditioning system may be independent of vehicle speed. The purpose of this paper is to find out the electric fan operation model as vehicle speed is varied. This paper was to establish a theoretical model for the condenser of automotive air conditioner and to conduct simulation to evaluate the effect of vehicle speed on the cooling capacity and sub-cooling of condenser. Results of simulation demonstrated that vehicle with 6 km h-1 speed has the 5°C of sub-cooling at 0.0266 kg s-1 of refrigerant flow rate and the cooling capacity was 4.93 kW. In this study, an increase of 16.6% in cooling capacity can be reached as the speed of vehicle was raised from 6 to 110 km h-1 and can promote the sub-cooling to 19.5°C. It was also found that the cooling capacity of air conditioner is extremely sensitive to vehicle speed while the vehicle is running at low speed. Furthermore, increases in the vehicle speed resulted in reduction of the length of superheat region from 17.5 to 8.5 cm. Finally, a correlation among these variables and the simulated cooling capacity was obtained in this study, enabling the relevant researchers to evaluate automotive air conditioner performance under different vehicle speeds more easily.


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