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The effect of manifold in liquid storage tank applied to solar combisystem
손효석,김철,Douglas Reindl,홍희기 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.3
There exists a return piping in solar combi-system for heating and hot water supply. When the temperature of water returning from theload is mixed with the lower side cold water of the storage tank, useful energy is reduced. This paper describes a diffuser and manifoldfor preventing this mixing and maintaining temperature stratification. Results from experiments show that manifold holes are optimum at8.5 mm in diameter with a total of 96 in number of holes at a flow rate of 0.3 lpm.
THE EFFECT OF UPPER-HEATING SYSTEM IN SOLAR WATER STORAGE TANK
손효석,권재욱,이성훈,김철,홍희기 대한설비공학회 2014 International Journal Of Air-Conditioning and Refr Vol.22 No.4
Thermal stratification in the water storage tank of solar heating system is essential to increase the collection efficiency. We previously investigated the stratification performance of side-heating system, where the hot water returning from the collector heats up the side wall of storage tank. Subsequently, we studied an evolved heating system for further improvement, where we added an upper-heating to the side-heating. Here we thoroughly examine the stratification performance of the evolved heating system using TRNSYS-based simulation. As the essential result, contrary to expectation, evolved system does not show substantial improvement of collection efficiency compared to side-heating. However, we confirm that evolved system excels in the useful energy.
손효석(Son, Hyo-Seok),홍희기(Hong, Hiki) 한국태양에너지학회 2012 한국태양에너지학회 학술대회논문집 Vol.2012 No.11
PTC solar thermal power generation system has high economical efficiency among renewable energy systems. In this study, PTC power plant installed in Chungbuk Umseong for the first time in Korea was calculated using TRNSYS. The collector efficiency is instantly 56.4% in maximum but about 30% as daily average on May.
손효석(Hyo Seok Son),홍희기(Hiki Hong) 대한설비공학회 2014 설비공학 논문집 Vol.26 No.7
Return piping is used in a solar combi-system for heating and hot water supply. When the temperature of the lower side of a storage tank is low due to hot water usage, the returned hot water after heating is mixed with the lower side cold water of the tank, and the useful energy is reduced. We studied the degree of thermal stratification in the tank, using either a diffuser or a manifold to prevent mixing. Using the diffuser, mixing starts from the bottom of the storage tank. On the other hand, the manifold has the marked effect of preventing mixing. As a result of experiments with changing the diameter and number of holes in the manifold, the optimum condition is 8.5 mm diameter and 96 holes, under the condition of 0.3 lpm.
손효석(Hyo Seok Son),홍희기(Hiki Hong) 대한설비공학회 2013 대한설비공학회 학술발표대회논문집 Vol.2013 No.6
Stratification in thermal storage tank is necessary to gain available energy in the active solar heat system. When the stratification is maintained for a long time, it represents higher available energy than non-stratified tank. Especially, if solar heat system has a return pipe line, it needs appropriate stratification enhancement device to prevent destruction of stratification. In this study, experiments were carried out on the effect of maintaining stratification by using diffuser and distributor. The experiment was performed 60 minutes in the same condition. As a result of experiments, when we installed the distributor, stratification was well maintained comparing with the diffuser. Moreover many punched distributor was shown the good degree of stratification and it was identified that there exsit flow rate range about internal distributor diameter.
손효석(H. S. Son),전형식(H. S. Chun),정희택(H. T. Chung) 한국유체기계학회 1998 유체기계 연구개발 발표회 논문집 Vol.- No.-
The pump safety related to the functions in nuclear power plants must be designed to meet load conditions considering seismic requirements. In order to satisfy both structural integrity and operability of these pumps, the initial step in the seismic qualification is to establish the resonant frequencies of the structure. Applications are made to the design of the vertical and horizontal type pump. Computational results are analyzed with respect to the dynamic characteristics and are compared to the expected design requirements.