• Journal of the Korean Solar Energy Society
• /
• v.33 no.6
• /
• pp.12-18
• /
• 2013

Domestic solar hot water system can be divided into a passive type and an active type. In a passive type the storage tank is horizontally mounted immediately above the solar collectors. No pumping is required as the hot water naturally rises into the storage tank from the collectors through thermo-siphon flow. While, in an active type the storage tank is ground- or floor-mounted and is below the level of the collectors; a circulating pump moves water or heat transfer fluid between the storage tank and the collectors. We installed two types solar hot water systems consisting of the same storage tank and collectors at the same place, and were measured and compared typical operating characteristics under the same external conditions. In particular, the daily system performance was presented through the stirring test after the sunset. The results show that the amount of solar radiation obtained for an active type were less than a passive type on a cloudy day, because the operation of the circulation pump stops frequently took place on that day. However, on a sunny day, depending on the stable operation of the circulation pump, the amount of solar radiation obtained for an active type were increased than a passive type.

• Journal of the Korean Solar Energy Society
• /
• v.27 no.1
• /
• pp.55-61
• /
• 2007

This paper describes the procedure and calculation results of basic design and transient variation of performance of 1 MWe large scale solar thermal power plant (STPP) by using the commercial software of THERMOFLEX and TRNSYS, respectively. In order to simulate the transient variation of STPP, the results of basic design are necessary. The design standard of the STPP is 1 MWe generation with solar only at high DNI condition and then 0.6 MWe output power for 1 hour using stored energy when the DNI becomes lower unable to operate normally. The results of basic design show the important design data of flow rates, water/steam conditions at each equipments and the estimated efficiency of STPP. In addition, dynamic simulation results of STPP are predicted and plotted for one year and three different days weather data of Daejeon.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
• /
• v.14 no.3
• /
• pp.1-7
• /
• 2018

In this paper, we designed a seasonal geothermal storage system and studied the applicability in the alluvial aquifer. We conducted a basic survey to apply this system to greenhouses actually operated in the Geum river basin alluvial aquifer. After choosing a potential area through electrical resistivity survey, the system parameters were set using drilling survey and pumping test result. We installed a system based on the factors, and operated for about 9 months. As a result, high temperature water(injection temperature $30^{\circ}C$) was stored at 22.5 Mcal ($1,609m^3$) for 3 months in cooling operation and 125 Mcal ($16,960m^3$) of low temperature water (injection temperature $7^{\circ}C$) were stored for 6 months in the remaining heating operation.

• Journal of Hydrogen and New Energy
• /
• v.2 no.1
• /
• pp.77-82
• /
• 1990

To investigate the effect of strains heat effect and thermal energy on the intrinsic degradation of $LaNi_5$, the changes of P-C-Isotherm curves under the condition of mainly applied one of the above factors were investigated. The revesible hydrogen storage capacity decreased by means of the hydrogenation at high temperature without cyclings or pressure induced cyclings with low thermal energy. The degree of degradation was more severe as the heat of hydrogenation reaction increased. Thus the intrinsic degradation of $LaNi_5$ depended upon lattice strain as well as thermal energy.

• Journal of the Korean Solar Energy Society
• /
• v.28 no.1
• /
• pp.75-81
• /
• 2008

Thermal performance of passive solar Trombe wall system which is applied on the south wall of KIER Zero energy Solar House has been monitored for 6 months of heating season. Based upon the long-term measurement results, extensive statistical analysis was conducted to investigate temperature profiler and heat flow pattern in Trombe wall system under actual operating condition. Heat flow characteristics depending on the time variation of day and month was clearly revealed. Heat gain and loss on the inner surface of the Trombe wall was calculated base upon measured temperature data. Those results would be utilized to improve the efficiency of new type solar storage wall system.

• 한국신재생에너지학회:학술대회논문집
• /
• 2005.06a
• /
• pp.412-415
• /
• 2005

Solar thermal power generation is one of promising and well-proven ways to convert solar energy to electricity. Though it requires high initial cost for system construction and continuous efforts for maintainment. it is more positive in terms of efficiency than other solar power generation technologies. Moreover, solar thermal power generation allows additional benefits of cheap thermal storage and easy hybridization with other fossil fuel-driven power generation. Owing to these benefits, large scale solar thermal power generation technology is expected to be competitive to other commercial technologies in the near future. In this paper an overview on the solar thermal hybrid power generation technology and the state of the art in Korea were briefly introduced.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.06a
• /
• pp.688-692
• /
• 2007

Solar thermal power generation allows additional benefits of cheap thermal storage and easy hybridization with other fossil fuel-driven power generation. KIER has been performing the project for solar thermal chemical reaction hybrid power generation. The project is to build and operate the first solar thermal chemical reaction hybrid power generation system in Korea. For concentrating solar thermal energy $m^2$ dish type concentrator was adapted and a heliostat is installed for reflecting horizontal insolation to the dish concentrator. At the moment building the dish concentrator including mirror and heliostat with sun tracking system was completed and it's performance are being closely evaluated. This paper will introduce some detailed designs and construction procedures which we have experienced so far.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.37 no.10
• /
• pp.683-693
• /
• 1988

For the economical and reasonable operation of electric power system according to continual increase of electric power demand and decrease of load factor, the potential application of superconducting magnertic energy storage [SMES] with high efficiency and fast response in the electric utility is receiving attractive attension. In the light of this background, to confirm the basic principle of SMES, theoretical study, design technique and fabrication procedure for superconducting coil, current lead, cryostat, measuring and protection system of SMES are described in detail. Especially, a new design technique for superconducting coil and current lead is porposed and it was proved experimentally by the performance test of SMES which is developed for the first time in our country. At the peak operating current 200A, the maximum magnetic field amd stored energy of the coil are 3.52T and 2500J, espectively. The thermal and mechanical stability of 2500J SMES is also confirmed experimetally by its characteristics test, AC loss, protection system, charge and discharge test. The experimetal results show good characteristics of energy storage system.

• Textile Coloration and Finishing
• /
• v.19 no.1 s.92
• /
• pp.24-30
• /
• 2007

Heat storage/release system in textile is a useful tool to increase energy efficiency and enhance comfortable microclimate of clothing. Phase change materials(PCM) are used in regulating storage and release properties of thermal energy. To investigate the temperature regulating ability of fabrics with PCM microcapsule(PCMMc), Nylon fabrics were coated with PCMMc via wet processing and they were characterized by SEM, DSC and infrared thermal analyzer. Also, water moisture transpiration, water penetration resistance, peel strength and washing durability of the fabrics were assessed. The water vapor permeation and water penetration resistance decreased with increasing PCMMc content. In DSC analysis, it can be seen that the microencapsulated fabric showed both exothermic md endothermic phenomena at specific temperature. Peel strength was decreased with increasing PCMMc content.

• Journal of Hydrogen and New Energy
• /
• v.1 no.1
• /
• pp.31-39
• /
• 1989

Although it has been well known that many metal hydrides are promising to use for hydrogen storage and other applications, some difficulties still remain. Metal hydrides, particularly in powder form, have very poor thermal conductivity. The hydrogen storage alloys degrade intrinsically or extrinsically during repeated hydriding and dehydriding. Elimination of these problems is very important in the practical applications. In order to prevent degradation and to improve the thermal conductivity, the hydrogen storage characteristics of rare-earth type alloy encapsulated with Cu or Ni by means of chemical plating have been investigated. No changes has occured in hydrogen absorption capacity and equilibrium pressure even though the alloy powder is microencapsulated. The first hydrogen absorption rate of the alloy encapsulated increased considerably comparing to uncapsulated sample. In the case of encapsulating the fine powder ($>10{\mu}m$) and subsequent compacting by $8ton/cm^2$, shape of compact is maintained regardless of hydriding and dehydriding. The degree of degradation of the alloy caused by impurity gas of CO or $O_2$ was decreased prominently by encapsulation.