Performance Of Air Conditioning Unit Research Articles

Enhancing the Air Conditioning Unit Performance via Energy Storage of Different Inorganic Phase Change Materials with Hybrid Nanoparticles

Air conditioning unit performance, coupled with new configurations of phase change material as thermal energy storage, is investigated in hot climates. During the daytime, the warm exterior air temperature is cooled when flowing over the phase change material structure that was previously solidified by the night ambient air. A theoretical transient model is constructed and solved numerically for the proposed design in plate and cylinder configurations. This model is studied at different inlet hot ambient air temperatures and phase change material types (SP24E and SP26E) without and with inclusion of hybrid nanoparticles. The results affirm that the discharging and charging duration for the cylinder is minimal compared to the plate configuration. Raising the inflow air temperature lowers the exit air temperature and air conditioning coefficient of performance and power-saving but shortens the cooling time. Using phase change material with a relatively low melting temperature increases the melting time and exit air temperature but reduces the charging time. Mixing hybrid nanoparticles with phase change material has a short-term positive influence on air conditioning performance. The maximum power saving for 2 h of working is 16.4% for the cylinder, while for 10 h of working, it is 6.4% for the plate.

Improving the performance of air conditioning unit by using a hybrid technique

An Air Conditioning Unit with magnetic field and different tubes was designed, fabricated and evaluated in this study. The Effect of magnetic field and different types of tubes on the performance of Air Conditioning was studied experimentally. A testing system of Air Conditioning Unit was developed as the test rig. The modified tubes as a straight tube before the condenser and after the evaporator were replaced by a finned bended tube with five bends and a coil finned tube with five turns. The experimental results for the temperature of refrigerant and the coefficient of performance for an air conditioning unit were presented. Changing the tubes and introducing electric charging has a significant effect on the performance of the unit. The electric charging has a positive effect of the performance of the system. The electric charging enhanced the performance by 76% in case of bent tube and by 177% in case of coil tube. The bent pipe increases the refrigerant temperature between 50% and 200%, while the coil pipe increases the temperature between 18 % and 190 %.• This method increases the refrigerant temperature for Air Conditioning system.• This method provides simple technical testing of Air Conditioning Unit with magnetic field and different tubes• This method can be useful to enhance the performance of Air Conditioning Unit.

Performance of Air Conditioning Unit under Constant Outdoor Wet-Bulb Temperature and Varied Dry-Bulb Temperature

An experiment has been carried out for examining the performance of an air conditioning unit under constant outdoor wet-bulb temperature and varied dry-bulb temperature. During the experiment, the wet-bulb temperature of the compartment for outdoor unit was maintained at 22℃ and the dry-bulb temperature was varied from 24℃ to 36℃. The increase of outdoor air temperature results in the increase of supply air temperature, discharge temperature, suction temperature, and liquid line temperature. These cause the degradation of the air conditioner performance. An increase of power consumption by 1.4% and decrease of cooling capacity by 0.8% were observed for each 1℃ increase of outdoor air temperature. As a result, the energy efficiency ratio drops by 2% for each 1℃ increase of outdoor air temperature.

An Investigation of Using Michrochannel Condenser to ‎Improve the Performance of Air Conditioning Unit

In the recent years, many researches have been focused towards the new technology in heat exchangers. Besides, the economy of manufacturing takes up a great attention of scientific works. Through this work the use of microchannel condenser achieves increase in energy. The study was conducted on two air conditioning units utilize R-22 as a refrigerant and having different cooling capacities 3516 W and 5274 W. The results showed that the use of microchannel condenser achieves increase in Energy Efficiency Ratio (EER) which reflected on the total efficiency of the device and reduce energy cost. The obtained results indicated that, the use of microchannel condenser led to increase in EER by (4.3:11.3%) for the first unit and and (9.5:29%) for the second one compared with that unit use FTC. Also, the use of MChC led to decrease the pressure drop by (20%:30%) while the convective heat transfer coefficient is improved by (61.6:84.1%).

Parametric study on the effect of using cold thermal storage energy of phase change material on the performance of air-conditioning unit

This paper presents a study on a new technique of using thermal energy storage of phase change material system with conventional air-conditioning unit to increase its cooling performance. The technique is based on integrating plates of phase change material with the condenser of the air-conditioning unit. The phase change material plates use its cold storage energy during the night time to increase the cooling performance of the unit during the daytime. The air is used to transfer the cold storage energy from the phase change material plates to the air-conditioning unit during the daytime. The study is performed during charging the phase change material with cold storage energy at night and discharging this energy to the air-conditioning unit at daytime. A theoretical transient model for the phase change material with air heat exchanger is constructed and a numerical solution of the theoretical model is presented. The numerical solution of the theoretical model is validated with an experimental work. The effect of the phase change material plates configurations and the inlet velocity and temperature of the air inlet to the phase change material plates on the charging and discharging process is carried out. Also, the effect of these parameters on the air-conditioning unit performance is presented. The results show that the longer and thinner phase change material plates configuration has the lower charging and discharging time. The discharging time and the outlet cold air temperature from the phase change material plates are decreased with increasing inlet air velocity and temperature. The charging time is decreased with decreasing inlet air temperature and rising inlet velocity. The maximum increase of the coefficient of performance of the air-conditioning unit with phase change material for the different configurations compared to the conventional one for inlet air temperature 35 °C, is 14%, 13% and 12% for inlet air velocity 0.96 m/s, 1.2 m/s and 1.44 m/s respectively. The discharging and charging time and the outlet cold air temperature from the phase change material plates are decreased with increasing inlet air velocity and temperature respectively. Also, at inlet air temperature 45 °C, and velocity 1.44 m/s, the maximum useful cooling power per kg of the phase change material is 46, 50, 54, 55, and 67 W for the configurations 2, 5, 4, 1 and 3 respectively. The results illustrate that, at air inlet velocity 0.96 m/s, the maximum percentage of the saved power per ton refrigeration for each kg phase change material with respect to conventional AC unit is about 11.6%, 6.7% and 5.4% for inlet air temperature 45 °C, 40 °C and 35 °C respectively.

Effect of a double-row liquid–vapor separation condenser on an air-conditioning unit performance

A double-row liquid–vapor separation condenser (DLSC) is presented, and its optimal pass scheme is obtained by numerical calculation and is applied to an air conditioning unit. The thermodynamic performance of the air conditioning unit with the DLSC is tested experimentally. The pressure drop and the heat transfer uniformity of the DLSC and the cooling capacity and energy efficiency ratio (EER) of the air conditioning unit are analyzed. Results indicate that the pressure drop of the DLSC is much smaller than that of the original condenser, and the two-phase heat transfer uniformity of the DLSC is better than that of the original condenser. Overall, the DLSC can improve the cooling capacity and the EER of the air conditioning system.

An experimental work on the effect of using new technique of thermal energy storage of phase change material on the performance of air conditioning unit

An experimental work on using a new technique of thermal energy storage system with conventional air conditioning (AC) unit to raise its performance is presented. The technique is based on integrating plates of phase change material (PCM) with the condenser of the AC unit. The PCM plates use their cold storage energy during the night to increase the cooling performance of the AC unit during the next daytime. An experimental test rig for the PCM thermal storage plates is constructed in two configurations; horizontal and vertical plates. The experimental study is performed during the discharging of the charged cold storage energy at night to the AC unit at day. The effect of the PCM plates configurations and the velocity and temperature of the air inlet to the PCM plates on the discharging process and AC unit performance is presented. The results show that the coefficient of performance (COP) of the AC unit with PCM plates is greater than its COP without using PCM plates. At the initial period of the process, the outlet air temperature from the vertical PCM plates is smaller than that of the horizontal plates and after a certain period, the situation is reversed. Using PCM plates heat exchanger decreases the condenser pressure and increasing the evaporator cooling capacity. At inlet air velocity and temperature 0.96 m/s and 45 °C, using vertical and horizontal PCM plates decreases the consumed power of the AC unit by about 9.8% and 11.2%, respectively compared with AC unit without PCM plates.

Development of an open-loop ground source cooling system for space air conditioning system in hot climate like Indonesia

Ground source cooling system (GSCS) is promising technology to serve cooling demands of buildings. This study presents a development of an open-loop GSCS for space air conditioning at Hasanuddin University Gowa campus. Experimental study was carried-out by pumping water from well of 57 m depth and flowing the water over a heat exchanger to cool refrigerant of air conditioning (AC) unit. The performance of AC unit was investigated under actual operation with various water flowrates. The temperatures of inlet and outlet water in the heat exchanger were also measured. The system operated from 11:00 until 18:00 o’clock local time with 3 (three) flowrates such as 3.6; 6.5 and 14.3 L/min respectively. In the low flowrate, the temperature of outlet water is approximately 37 °C. However, the compressor power is also increase significantly. The coefficient of performances (COPs) of the system in average are 2.9 in the low flowrate and 3.4 in the high flowrate. Also. the result shows that the utilization of GSCS is appropriated for cooling buildings in the hot climate like Indonesia.

Coupling effects of demand-side improvements ensemble on energy performance to monetary implications for UAE economy

An apparent transformation of energy trade in developing countries such as the UAE directly impacts and influences the global energy dynamics. UAE is the largest global exporter of fossil fuel for energy generation and it is therefore a necessity to analyze the regional in-house energy market as a first from the demand-side improvement perspective. Due to the arid climatic nature of the country, we performed simulations on air-conditioning unit performance, for the largest emirate of Abu Dhabi, using a convoluted parametric effect of coefficient-of-performance and set-point temperature to understand the long-term impact on energy operation and its monetary implications to the UAE economy. The targeted sectors included commercial and residential as leading energy hungry consumers. An assessment of the present situation to optimally determined using DesignBuilder and EnergyPlus, indicated clear change in energy generation, consumption and greenhouse gas emission reduction. The effects were forecasted using long-range energy alternatives planning simulation tool to predict the national wealth savings and to assist in governmental policy making until 2030 as per the Abu Dhabi Vision. The savings amounted to millions of dirhams per sector based on the unique upfront tariff & subsidy structure of the UAE and an emission reduction of approximately 2500 thousand metric tons of CO2 equivalent per sector by 2030 as per the Abu Dhabi Vision 2030.

Design of Air Conditioning Unit Performance Test Bench for Rail Vehicles

Based on the methods and standards related to both domestic and overseas air conditioning unit performance testing, a new air conditioning unit performance test bench for measuring refrigerating capacity has been developed. The test bench, which includes removable exterior environment simulation room and interior environment simulation room, applies air enthalpy method to measure refrigerating capacity of air conditioning unit. The experiment result shows that exterior environment simulation room can save 50% construction cost by using removable room. Its room temperature has high accuracy and stability by using hot air of air conditioning unit and exterior air, which can save 50%-60% energy consumption. The accuracy of testing Bench is less than 4%, which is better than the national standard GB/T 19842-2005.

차륜형 대공포 냉방장치 성능개선 연구

과거의 무기체계는 체계의 목적과 비용 등의 문제로 운용환경에 대한 관심이 부족하였으며, 특히 냉방장치가 미탑제된 체계가 많이 개발되었다. 근래 개발되는 무기체계는 고도의 정밀조준 및 고감도 시스템으로 진화함에 따라 무기체계를 효과적으로 제어하기 위하여 운용자의 운용환경도 중요한 요소로 대두되고 있다. 현재의 무기개발자들은 대부분 통합형 환경제어장치를 장착하도록 설계하고 있다. 본 연구에서는 장갑차량의 운용환경 및 설계조건을 바탕으로 한국군의 운용환경에 적합한 냉방기 및 냉방부하를 검토하고 시제품의 냉방성능 시험결과가 목표성능에 미달되어 이에 대해 개선내용 및 검토결과를 기술하였다

Air conditioning in the region of Madrid, Spain: An approach to electricity consumption, economics and CO2 emissions

An understanding of electricity consumption due to residential air conditioning (AC) may improve production and environmental impact strategy design. This article reports on a study of peak and seasonal electricity consumption for residential air conditioning in the region of Madrid, Spain. Consumption was assessed by simulating the operation of AC units at the outdoor summer temperature characteristics of central Spain. AC unit performance when operating under part load conditions in keeping with weather conditions was also studied to find cooling demand and energy efficiency. Likewise final electricity consumption was computed and used to calculate energy costs and greenhouse gas emissions (GHGs). Cooling demand, when family holidays outside the region were factored into the calculations, came to 1.46 × 10 9 kWh. Associated seasonal electricity demand was 617 × 10 6 kWh and seasonal performance of AC units around 2.4. Electricity consumption in the whole region was observed to peak on 30 June 2008 at 5.44 × 10 6 kW, being the load attributable to residential AC 1.79 × 10 6 kW, resulting about 33% of the total peak consumption. The seasonal cost per household was about €156 and the total equivalent warming impact was 572 × 10 3 t CO 2 . The method proposed can be adapted for use in other regions. ► The residential demand of AC in the Region of Madrid is studied including the effect of family seasonal holidays. ► A simulation of the air-cooled mechanical compression cycle was performed and several results were obtained such as a seasonal COP of 2.4. ► Some air-cooled AC apparatus marketed were studied and a “Commercial COP” was obtained. ► Electricity consumption and equivalent CO 2 emissions were also assessed and the seasonal COP was compared with commercial COP. ► Finally, influence of residential AC on electricity consumption of the whole region is analyzed, including also consumption peaks.

Solid-State Controller for Air Conditioning Units

It is essential to maintain the condensing temperature of air-cooled air conditioning systems at certain minimum levels when operating during cold weather. Recent advances in solid-state technology have opened up new approaches to controlling condensing temperatures at any desired minimum level. The solid-state control system described uses an SCR with a unijunction transistor firing circuit to control directly the power to the specially designed fan motors. In designing such a control system, consideration has to be given to matching properly the solid-state control, fan motor, and the temperature sensing device with the air conditioning unit performance characteristics to obtain the desired reliability and stability.