scholarly journals EVALUATION METHOD OF COP AND LATENT HEAT LOAD FOR DUCTLESS AND DUCTED AIR CONDITIONING WITH SPLIT TYPE AIR CONDITIONER

2018 ◽  
Vol 83 (749) ◽  
pp. 597-606
Author(s):  
Akinori HOSOI
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 172 ◽  
pp. 03008
Author(s):  
Rie Tasaka ◽  
Sayaka Kindaichi ◽  
Daisaku Nishina ◽  
Mitsuhiko Maeoki

Recently, the heat load for space heating in residential houses has been reduced as airtightness, and thermal insulation performance has been improving even in moderate climate regions of Japan. In such situations, the heat load can be handled by one room air-conditioner with high energy efficiency. We report the results of computational fluid dynamics (CFD) analysis of an indoor thermal environment and the airflow distribution during the space heating operation in a ductless house air conditioning system, in which heated air from a room air conditioner installed in a thermal-insulated basement space is distributed throughout the building using air inlets on the floor in each story and open-door rooms without ductworks. To determine the adequate size and position of the air inlets on the floor in this heating system, we evaluated the air circulation performance for changes in the conditions of the air inlets by CFD analysis for a standard two-storey house model in Japan. The results suggest that the air temperature distribution is markedly different in the size and position of the air inlets on the floor. Large volumes of airflow through the openings in the building resulted in maintaining the rooms at a temperature range of 17 to 24 degrees uniformly. These results also provide information for system and building designs for effective space heating and for proper usage when choosing to open or close air inlets in the operational phase.


2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Chien-Lun Weng ◽  
Lih-Jen Kau

About 7% of people’s daily time is spent in taking vehicles between office and home. Besides, with the improvement of the living standard in today’s society, people’s requirements for a comfortable environment inside the car are constantly increasing and this must rely on an effective vehicle air conditioner to maintain the comfort of the cabin environment. In general, a vehicle air conditioner uses the air-mixing mode to regulate the temperature control system. In this mode of operation, the compressor needs to work continuously, which is extremely energy consuming. The vehicle’s air conditioner is greatly affected by the inner and outer heat load, which are generated therein. Furthermore, the heat load is instantly changeable. Therefore, only when the controller can adapt to the feature of heat load, then we can find the optimal control method, thus enabling the vehicle’s air conditioner to interact with the actual heat load to supply the balanced cooling capacity and, as a result, create the most comfortable environment inside the cabin with minimum energy consumption. For this purpose, we bring up in this paper a low-energy-consumption smart vehicle air-conditioning control system to detect total heat load, which can change the vehicle’s air-conditioning capacity mode to maintain the average temperature at 25.2°C∼26.2°C and the average humidity at 46.6%∼54.4% in the cabin. When the inner heat load is stable, the rest times of the compressor can reach 16∼23 times per hour, which attains a rate of fuel saving around 21%∼28%. With the proposed architecture, the purpose of the low-energy-consumption vehicle air-conditioning system can be achieved, which, at the same time, creates a comfortable environment inside the cabin.


2015 ◽  
Vol 9 (1) ◽  
pp. 135-140
Author(s):  
Dong Zhi-Ming ◽  
Guo Li-Xia ◽  
Chang Ji-Bin ◽  
Zhou Xue-Bin

Aiming to compare the cooling effect, two types of solar-powered semiconductor air-conditioning devices were designed in different structures. According to the cooling load in an experimental room, the solar panels and battery capacity were determined for the development of a test system. In the same working condition, a comparison test was carried out to examine the cooling performance. Experimental results showed that the design of dual water-cooled cooling unit presented a higher ratio of energy efficiency, with its maximum value of 1.08. By observing the experimental data of the prototype, its comparative economic evaluation results indicated that the annualized cost of solar semiconductor airconditioning was app. 2.7 times that of air-conditioning made from an ordinary compressor.


2021 ◽  
pp. 102585
Author(s):  
Kasni Sumeru ◽  
Mohamad Firdaus Sukri ◽  
Triaji Pangripto Pramudantoro ◽  
Eddy Erham ◽  
Rizki Muliawan

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