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, 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.