The Air-shiter is a new product possible ventilation at the same time cooling or heating with combined refrigerator and heat recovery ventilator. And a key device of this system is the air shifter. The air shifter device is to convert the outdoor air, room air, supply air and exhaust air flow. Therefore, an experimental study has been carried out to investigate the operating performance for this system. The results, it is possible to ventilate at the same time of heating by outside air above 30℃ in summer. and of heating by outside air within 3℃ in winter. The indoor discharge temperature is over 40℃, and the coefficient of performance is 3.4 in winter.
The Air-shiter is a new products possible ventilation at the same time cooling or heating with integrated refrigeration and ventilation units. and is a key component of the air shifter devices and bypass damper. The air shifter devices are to convert the outdoor air, room air, supply air and exhaust air flow. And the bypass damper is device to determine a ventilation. After research and development of these systems were as follows. It is confirmed that the Air-shiter is possible ventilation at the same time cooling or heating, and outdoor air cooling in the spring or fall.
A computational fluid flow analysis of a car has been accomplished to explain the lift characteristics according to the changes of wiper angle and car speed. The present study established the process to get the lift coefficient distribution on the whole range of a wiper operating angle. From the result of the present research, it could be seen that the lift coefficient of a wiper with the lower wiper angle had relatively smaller magnitude. On the other hand, the lift coefficient with the wiper angle near 45° was relatively larger than that with the other wiper angles. The present study also verified the usefulness of the lift coefficient that the lift distributions of various car speeds could be derived from the result of a lift coefficient distribution for only a car speed.
In this study, the structural analysis for bellows joint of high-performance that can enhance the performance of seismic isolation piping was performed. Bellows joint is that the corrugated flexible piping is connected at the both sides of elbow. An one axis of the bellows joint fixed, and the other end of the axis changes the position from 0° to 315° for the radius displacement of 500 mm. Results obtained are as follows for this case in analysing of the maximum stress and plastic strain of the bellows joint. As the location of the base isolation displacement get farther from the fixed pipe, the bellows joint is pulled, and the maximum stress and plastic deformation is increased. And so the maximum stress occurs near the bellows at both ends of the elbow. Displacement in the 135° position, a maximum stress of 837 MPa and a plastic strain of 3.00% was the highest.
The thermal conductivity for the ground heat exchanger installed in the local facilities of greenhouse area at JangSu-Gun in Jeollabuk-Do was analyzed experimentally. For measuring the thermal conductivity of the ground heat exchanger, a bore hole was punched at the size of diameter 150mm, depth 160m. And a closed-type heat exchanger of high density polyethylene at the size of diameter 40mm was installed vertically. The heated water by an electric heater was circulated through the ground heat exchanger with a pump. The inlet/outlet temperatures and the flow rates of this water are measured and the thermal conductivity was calculated. The experimental results were as follows. The inlet/outlet temperatures of the ground heat exchanger were increased rapidly until 7 hours, then they were increased gently and the difference of inlet/outlet temperature was maintained at about 4.5℃. The thermal conductivity calculated by the line source theory was 2.207W/mK.
The flow rate analysis for sanitary fixtures has been studied to determine the water supply piping system and size. The study has been carried out to analyze for a various water supply pressure and piping size theoretically. Also, the study has been carried out to analyze for a various water supply piping system experimentally. The water supply pressure is varied from 0.01MPa to 0.07MPa, and the piping size is varied from 6mm to 15mm. The water supply piping systems are one-to-one, all-loop-type, and bathroom-loop-type water supply piping system. The results indicate that the piping size is able to supply water fully in case of smaller than 15mm if the water supply pressure keep an necessary minimum pressure. And the gap of flow rate is very little for the various water supply piping systems
The paper concerns numerical study of fully developed laminar flow of a Newtonian water and non-Newtonian fluids, 0.2% aqueous of sodium carboxymethyl cellulose(CMC) solution in eccentric annuli with combined bulk axial flow and inner cylinder rotation. Pressure losses and skin friction coefficients have been measured when the inner cylinder rotates at the speed of 0～200 rpm. A numerical analysis considered mainly the effects of annular eccentricity and inner cylinder rotation. The present analysis has demonstrated the importance of the drill pipe rotation and eccentricity. In eccentricity of 0.7 of a Newtonian water, the flow field is recirculation dominated and unexpected behavior is observed. it generates a strong rotation directed layer, that two opposing effects act to create two local peaks of the axial velocity. The influences of rotation, radius ratio and working fluid on the annular flow field are investigated.
Recently, A N2 gas generator has become a very popular issue in application to semiconductor production process. An experimental study has been carried out to investigate the production performance as a N2 purity and production of N2 gas generator. The N2 gas generator used a small size system with two adsorption towers and an air compressor as flow rate 20 m3/h. The N2 gas generator system size is width 2270 mm, length 850 mm and height 2135mm. An experimental data has been measured as the variation of a adsorption temperature, adsorption pressure and adsorption time. The results indicate that the N2 gas production increase in case of decreasing adsorption temperature, increasing adsorption pressure and decreasing adsorption time. The N2 purity is highest value of 99.93% when the governor orifice diameter is 0.5 mm.
Recently, ice-on-coil type ice storage system has become a very popular issue in application to electric powered air conditioning systems. An experimental study has been carried out to investigate the ice making characteristics of an ice-on-coil type ice storage system. The ice storage system used two rectangular tank, one is 900 ℓ with a thermal capacity 3,300 kcal/h and the other is 3,000 ℓ with a thermal capacity 9,900 kcal/h. An experimental data has been measured as the variation of a ice making time. The results indicate that the ice making rate increase due to variation of ice making time gradually, and is high in case of the smaller refrigerant coil from 5 hour but larger refrigerant coil after this.
The paper concerns an experimental and numerical study of fully developed laminar flow of a Newtonian, water and non-Newtonian fluids, 0.2% aqueous of sodium carboxymethyl cellulose(CMC) solution in concentric and eccentric annuli with combined bulk axial flow and inner cylinder rotation. Pressure losses and skin friction coefficients have been measured when the inner cylinder rotates at the speed of 0～300 rpm. The influences of rotation, radius ratio and working fluid on the annular flow field are investigated.
A study of temperature profiles in mixing zone of AHU(air handling unit) can contribute greatly to enhance performance of AHU system, so the study on the temperature distribution between RA(return air) and OA(outdoor air) is important to analyze the mixing characteristics in a mixing zone of AHU. Accordingly, the temperature profiles during RA(return air) and OA(outdoor air) supply process into mixing zone of AHU with an air mixer are studied numerically. The effect of air mixer, OA temperature and RA/OA flow rate are studied in detail. In this study, the results show that the mixing effect is all high for installed the air mixer. The more OA flow rate decrease, the more mixing effect is high.