scholarly journals EFFECT OF AIR FLOW OBSTRUCTION IN A CONDENSING UNIT ON SPLIT AIR CONDITIONER PERFORMANCE

2020 ◽  
Vol 82 (5) ◽  
Author(s):  
Andriyanto Setyawan
Keyword(s):  
Air Conditioning ◽  
Air Flow ◽  
Cooling Capacity ◽  
Input Power ◽  
The Other ◽  
Coefficient Of Performance ◽  
Air Conditioner ◽  
Air Conditioning System ◽  
Heat Rejection ◽  
Other Hand

Obstructions of air flow in the outdoor unit could block the condenser air flow and reduce its heat rejection As a result, it could decrease the performance of a room air conditioning system. The paper presents the effects of the air flow obstruction of a condensing unit on the performance of a split-type air conditioner with refrigerant R410A. The study was conducted experimentally by employing front and side obstructions with varied distance from the condensing unit. The front obstruction of 100 cm height was applied at varied distance from 10 cm to 100 cm, while the side obstruction of the same height was applied at distance of 5, 10, and 15 cm. The presence of air flow obstructions results in the decrease of cooling capacity and coefficient of performance (COP). On the other hand, it increases the input power of the AC unit. From the experiment, it is obvious that the distance of front obstruction of 10 cm results in the reduction of cooling capacity by 46% and COP by 56%. It is also revealed that the distance of the front obstruction of 50 cm or more has no significant effect for the performance of the air conditioning unit. In addition, the side obstructions have the less significant effect than that of the front obstruction.

Enhancing Air Conditioning Performance Using TiO2 Nanoparticles in Compressor Lubricant

2015 ◽  
Vol 1125 ◽  
pp. 556-560 ◽  
Author(s):  
Sumeru ◽  
Triaji P. Pramudantoro ◽  
Farid Nasir Ani ◽  
Henry Nasution
Keyword(s):  
Air Conditioning ◽  
High Pressures ◽  
Cooling Capacity ◽  
Input Power ◽  
Air Conditioner ◽  
Vapor Compression ◽  
Air Conditioning System ◽  
Air Conditioners ◽  
Vapor Compression Refrigeration Cycle ◽  
Vapor Compression Refrigeration

Most air conditioners utilize vapor compression refrigeration cycle in their operation. In this cycle, the compressor is deployed to circulate the refrigerant from low to high pressures. Lubrication is an important aspect in the compressor to lubricate internal parts. Due to their remarkable properties in the thermo-physical and heat transfer capabilities, nanoparticles have prospect to be applied in the refrigeration and air conditioning system. The reliability and solubility nanoparticle of TiO2 in refrigeration systems have been investigated by several by several researchers. By introducing TiO2 nanoparticle in the lubricant, the friction coefficient and input power of the compressor can be decreased. An air conditioner with cooling capacity of 2.5 kW is utilized in the experiment. Five different concentrations of nanoparticle in the lubricant, viz.: 0.1, 0.2, 0.4, 0.5 and 0.6 gram of TiO2 in one liter of lubricant were mixed using a magnetic stirrer. After 10 days, TiO2 nanoparticles in the lubricant were observed its solubility. Furthermore, based on their solubility, TiO2 nanoparticle with concentration of 0.2 g/L was selected in the experiments. The results show that the air conditioner using R290 with TiO2 nanoparticle in the lubricants works normally and the input power of the air conditioner decreases about 3.1% and the cooling capacity and the COP increase about 5.1% and 8.4%, respectively, compared to the system without nanoparticle in the lubricant.

scholarly journals Thermal Performance Analysis of Low-GWP Refrigerants in Automotive Air-Conditioning System

2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Yousuf Alhendal ◽  
Abdalla Gomaa ◽  
Gamal Bedair ◽  
Abdulrahim Kalendar
Keyword(s):  
Air Conditioning ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Exergy Destruction ◽  
Air Conditioning System ◽  
Capacity Coefficient ◽  
Automotive Air Conditioning ◽  
Automotive Air Conditioning System ◽  
Compressor Power ◽  
Low Global Warming Potential

The energy and exergy of low-global warming potential (GWP) refrigerants were investigated experimentally and theoretically. Refrigerants with a modest GWP100 of  ≤ 150 can be sufficient for bringing down emissions which were concerned for the automotive air-conditioning system. Three types of low-GWP refrigerants, R152a, R1234yf, and R1234ze(E), were examined with particular reference to the current high-GWP of R134a. The effect of different evaporating and condensing temperatures in addition to compressor speed was considered. The purpose was to bring a clear view of the performance characteristics of possible environment friendly alternatives of R134a. The analysis was carried out with compressor power, cooling capacity, coefficient of performance, exergy destruction, and exergy efficiency. It was noted that the total exergy destruction of R1234yf was reduced by 15% compared to that of R134a. The refrigerant R1234ze(E) has the highest energetic and exergetic performance compared with the other investigated refrigerants.

scholarly journals Investigation on the improvement of car air conditioning system performance using an ejector

2018 ◽  
Vol 197 ◽  
pp. 08013
Author(s):  
Enang Suma Arifianto ◽  
Ega Taqwali Berman ◽  
Mutaufiq Mutaufiq
Keyword(s):  
System Performance ◽  
Test Procedure ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Air Conditioner ◽  
Air Conditioning System ◽  
Compressor Work ◽  
R 134A

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.

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

2020 ◽  
pp. 1-11
Author(s):  
A. Anthony Adeyanju ◽  
K. Manohar
Keyword(s):  
Air Conditioning ◽  
Thermoelectric Module ◽  
Cooling Capacity ◽  
Peltier Effect ◽  
Refrigeration Cycle ◽  
Air Conditioner ◽  
Air Conditioning System ◽  
Thermoelectric Air Conditioner ◽  
Air Conditioning Systems ◽  
Dc Current

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.

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 Energy Saving in Split Air Conditioner using Evaporative Cooling Pad at the ODU

2019 ◽  
Vol 9 (1) ◽  
pp. 1858-1862
Keyword(s):  
Power Consumption ◽  
Performance Improvement ◽  
Air Conditioning ◽  
Evaporative Cooling ◽  
Cooling Capacity ◽  
Air Conditioner ◽  
Optimum Thickness ◽  
Outdoor Air ◽  
Air Conditioning System ◽  
Overall Performance

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.

Experimental analysis of the low-GWP refrigerant R1234yf as a drop-in replacement for R134a in a typical mobile air conditioning system

2012 ◽  
Vol 226 (11) ◽  
pp. 2713-2725 ◽  
Author(s):  
Yu Zhao ◽  
Zhaogang Qi ◽  
Jiangping Chen ◽  
Baixing Xu ◽  
Bin He
Keyword(s):  
Working Conditions ◽  
Air Conditioning ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Laminated Plate ◽  
Improve Performance ◽  
Air Conditioning System ◽  
Expansion Valve ◽  
Variable Displacement ◽  
Valve Opening

This study investigated the performance of a typical mobile air conditioning system using R134a and R1234yf as the working fluids under different working conditions. The system is composed of a microchannel parallel flow condenser, a laminated plate evaporator, a variable displacement compressor, and a thermal expansion valve. The different working cycles of each refrigerant were comprehensively compared. The optimum refrigerant charge amount of the R1234yf system was approximately 95% of the R134a system during drop-in tests. The performance of the R134a system was a little higher than that of the R1234yf system. The cooling capacity and system coefficient of performance of the R134a system were 12.4% and 9% larger, respectively. This result is mainly because of the thermophysical property differences between the two refrigerants and the improper expansion valve opening of R1234yf. Analysis on the whole cycle revealed that the R1234yf system could obtain a higher evaporating pressure and a larger superheat and subcooling. Redesigning the expansion valve for R1234yf could improve performance of the system.

THE PERFORMANCE OF CONDENSER UNDER DIFFERENT VEHICLE SPEEDS

2013 ◽  
Vol 21 (02) ◽  
pp. 1350013 ◽  
Author(s):  
CHIH-CHIU SHEN ◽  
JAU-HUAI LU
Keyword(s):  
Electric Vehicle ◽  
Electric Vehicles ◽  
Air Conditioning ◽  
High Efficiency ◽  
Cooling Capacity ◽  
Vehicle Speed ◽  
Air Conditioner ◽  
Electric Motors ◽  
No Emission ◽  
Air Conditioning System

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.

scholarly journals Experimental Thermodynamic Investigation on the Refrigerant Charge in a Transcritical CO2 Electric Bus Air Conditioning System

2021 ◽  
Vol 11 (12) ◽  
pp. 5614
Author(s):  
Haidan Wang ◽  
Shengbo Li ◽  
Yulong Song ◽  
Xiang Yin ◽  
Feng Cao ◽  
...  
Keyword(s):  
System Performance ◽  
Air Conditioning ◽  
Cooling Capacity ◽  
Exergy Efficiency ◽  
Coefficient Of Performance ◽  
Air Conditioning System ◽  
Electric Bus ◽  
Maximum Coefficient ◽  
Considerable Impact ◽  
Air Conditioning Systems

Due to its considerable impact on climate, bus air conditioning systems are being pushed to take a new and sustainable path. Electric buses relying on transcritical CO2 air conditioning units are perceived to be eco-friendly and future-proof solutions to achieving such a target. However, in order to have highly efficient air conditioning systems, the CO2 charge needs to be optimized. In this paper the energy and exergy-based analyses were performed to investigate the effect of normalized refrigerant charge on the system performance by using a test rig of a transcritical CO2 air conditioning unit for an 8 m electric bus. Results showed that the normalized refrigerant charge range of 0.248~0.336 was recommended in order to ensure the maximum coefficient of performance (COP). In addition, in sufficient charge conditions, the optimal COP, cooling capacity and exergy efficiency were 1.716, 18.97 kW and 29.79%, respectively, under the standard refrigeration condition of 35 °C/27 °C. As the ambient temperature rose from 35 °C to 40 °C, the COP, cooling capacity and exergy efficiency decreased by 16.03%, 10.90% and 12.22%, respectively. Furthermore, the exergy efficiency was found not to be sensitive to slightly insufficient charge, whereas overcharge was observed to be even beneficial to exergy efficiency under the condition of ensuring the maximum COP. In addition, insufficient refrigerant charging seriously affected the irreversible losses in the indoor and outdoor heat exchangers, whereas slight overcharge had little effect on the component exergy efficiency. Finally, the need to improve the CO2 compressor efficiency to enhance the system performance was revealed.

Design and performance analysis of a thermoelectric air-conditioning system driven by solar photovoltaic panels

2020 ◽  
pp. 095440622097616
Author(s):  
Moustafa M Aboelmaaref ◽  
Mohamed E Zayed ◽  
Ammar H Elsheikh ◽  
Ahmed A Askalany ◽  
Jun Zhao ◽  
...  
Keyword(s):  
Air Conditioning ◽  
Volume Flow Rate ◽  
Cooling Capacity ◽  
Vital Role ◽  
Input Current ◽  
Coefficient Of Performance ◽  
Thermal Loads ◽  
Air Conditioning System ◽  
Climate Conditions ◽  
Daily Average

Solar cooling technologies can play a vital role in renewable energy applications development. Thermoelectric systems have shown promising advantages over traditional refrigeration systems such as high thermal comfort, active adaptability, no moving parts, and refrigerants free. In this work, a novel thermoelectric air-conditioning system (TEACS) driven by photovoltaics (PV) is experimentally and theoretically investigated under the hot climate conditions of Sohag city (30°26′N, 42°31′E), Egypt for air conditioning of a typical small-size office room under different thermal loads. During day time, PV panels produce electricity which utilized to drive the TEACS directly and to charge batteries that store electricity to be exploited during nighttime. Moreover, a numerical model implemented in TRNSYS coupled with MATLAB software is developed to evaluate the performance of the proposed TEACS. The influences of varying the input electric current on the coefficient of performance (COP), cooling capacity, and average air room temperature are also studied. The results showed that a design point with an input current of 2.5 A for a cooling capacity of 30 W could be selected to maximize the cooling performance, in which the COP of the TEACS is found to be 2.2. Moreover, the daily average air temperature of the conditioned room was found to be 23.5, 25.5, 27.5, 28.5, and 30.5  °C for internal thermal loads of 0.0 W, 65.0 W,130.0 W, 195.0 W, and 260.0 W, respectively, at average air intake temperature of 36  °C, daily average input current of 4.28 A and air volume flow rate of 14.4 m3/h. It can be concluded that the TEACS powered by PV could be considered as a proper alternative to the traditional vapor compression systems.

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