• 한국태양에너지학회 논문집
• /
• 제37권5호
• /
• pp.39-47
• /
• 2017

In a hot water system using solar energy, solar heat is not simply collected by the heat collecting plate, but by heat exchange between the solar collector (flat or vacuum type) and the hot water storage tank. Therefore, the amount of collected solar energy depends on the hot water usage patterns that determine the temperature of the thermal storage tank. Also, if the temperature of the hot water stored in the storage tank exceeds the dangerous temperature during the summer, the heat must be released for safety. If the temperature of the hot water in the storage tank is low, it is necessary to heat by the auxiliary heat source. In this study, three buildings are defined as hotel, swimming pool, and school facilities. And we calculated the released heat energy, auxiliary heat source, and pure storage heat energy based on different hot water usage patterns and installation angle of the solar collectors.

• 설비공학논문집
• /
• 제6권3호
• /
• pp.315-324
• /
• 1994

The energy recovery efficiency(ERE) of an aquifer thermal energy storage system was calculated using curvilinear coordinate. The results of the calculation were compared with the experimental results, and agreed within 11% of the discrepancy. The variation of ERE was investigated as a function of the underground water natural velocity, the amount of the stored energy, and period of the energy recovery. The slower the natural velocity and shorter the recovery period, the higher ERE was yielded. Also it was found that increase in the amount of energy storage yields higher ERE, and carries out less influential ERE to the natural velocity. Reiterative usage of the aquifer as a thermal storage tends to gradually increase ERE. The result of this study implements that the aquifer thermal energy storage system is suitable for large cooling/heating loads, such as district cooling/heating.

• 설비공학논문집
• /
• 제24권10호
• /
• pp.733-738
• /
• 2012

It is important issue to reduce the electric energy to save the operating cost of HVAC system. Even if electrical energy is the clean energy, it is difficult and takes high cost for storage of electricity. These cause the high peak load of electric energy for HVAC in summer season. In korea, government impose the electric charge with several grade for the purpose of cut-off the peak load of electricity. Government has a policy to support to design and install the heat/ice storage system using midnight electricity. In this study, analysis of cooling load and operating characteristics for ice storage system are performed. And, also economical efficiency is compared between ordinary charge system of electricity and midnight rate charge of electricity. The systematic and economical supports are needed for expansion of usage of energy saving equipments.

• 설비공학논문집
• /
• 제26권6호
• /
• pp.247-256
• /
• 2014

The regulations to reduce energy consumption and carbon dioxide emission in building sectors are being developed and promoted all over the world. However, in Korea, as balcony extension of the apartments has been legally allowed, it became prevalent and resulted in excessive energy consumption. This study derived the possibility of PCM application to the thermal storage wall system through theoretical consideration and investigated the problems occurring when the balcony space has been extended to the diverted space. In addition, this study aims at the possibility of verifying the installation and confirming the cooling energy reduction effect, by conducting measuring tests with the actual installation of PCM applied thermal storage wall system. As a result of theoretical consideration, it is determined that the disadvantages with the existing thermal storage wall system can be complemented by applying PCM, and this study suggests the PCM applied Thermal Storage Wall System. The study was conducted on 1/6 of a miniature inner room of a domestic apartment with 84 $m^2$ of exclusive area. From the results of actual measurements, it is confirmed that the balcony extension structure can gain 11.3% of more calories than the existing balcony structure, resulting in the increase in cooling energy usage. It is determined that the installation of the PCM applied Thermal Storage Wall System may gain 25.2% of less calories to reduce cooling energy usage.

• 한국전자통신학회논문지
• /
• 제11권1호
• /
• pp.53-58
• /
• 2016

지구 온난화, 고유가 그리고 심각한 전력난 문제를 해소하기 위해, 가정용 전기요금 누진제 적용과 함께 산업용 전기요금의 지속적인 상승이 이루어지고 있어 에너지 이용 효율을 크게 개선할 수 있는 에너지 저장 시스템을 스마트 그리드에 적용하기 위한 노력들이 새롭게 시도되고 있다. 본 연구에서는 에너지 저장 장치로 활용될 수 있는 리튬이온 전지의 구성 및 동작원리, 에너지 저장 시스템의 전력계통 적용 분야, 배터리 에너지 컨버터 기술, 그리고 적용사례를 연구함으로서 에너지 저장 시스템을 전력계통에 적용하는 데 필요한 기반 기술을 확립한다.

• 설비공학논문집
• /
• 제27권3호
• /
• pp.123-127
• /
• 2015

Thermochemical heat storage is a cutting-edge technology which can balance the energy usage between supplies and demands. Recent studies have suggested that thermochemical heat storage has significant advantages, compared to other storage methods such as latent heat storage or sensible heat storage. Nevertheless, ongoing research and development studies showed that the thermochemical heat storage has some serious problems. To bring the thermochemical heat storage method into market, we introduce experimental setup with composite material using perlite that supports calcium chloride sorbent. Also, to compare thermal properties with composite material, we used pure thermochemical material. Then, we found that the composite material has higher heat storage density by mass than pure calcium chloride. Moreover, it can be easily regenerated, which was impossible in the pure thermochemical materials.

• 공업화학
• /
• 제30권3호
• /
• pp.290-296
• /
• 2019

리튬이온배터리는 여러 에너지저장시스템 중 가장 관심을 받고 있는 장치이다. 특히, 분산형 전력공급원으로서의 신재생에너지 수요의 증가, 안정적인 전력의 수급, 전기자동차의 보급의 확대에 따라 에너지저장장치의 사용은 증가하고 있다. 최근, 에너지저장장치로서 리튬이온배터리의 사용량의 증가에 따른 폐리튬이온배터리의 재활용, 복원 기술은 사회, 경제적으로 중요한 연구분야이다. 본 총설에서는 최근 폐리튬이온배터리 성능진단, 재활용 또는 복원 기술과 발전가능성에 대하여 기술하고자 한다.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2009년도 하계학술발표대회 논문집
• /
• pp.1288-1293
• /
• 2009

The TES (Thermal Energy Storage) cooling system utilizing cheaper off-peak electricity has been applied just for building air-conditioning currently and causes limitation of usage rate and inefficiency of national resources utilization. In this regard, more says the necessity to apply TES system in industrial cooling system which is longer using period and wider usage. In this study, we will approve the technical and economical improvement in efficiency of industrial cooling system applied TES system by utilizing cheaper off-peak electricity and it will attribute the promotion of TES system and stabilization of supply and demand of electric power by proving the necessity to develop more efficient industrial cooling system by combining TES system.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1992년도 하계학술대회 논문집 B
• /
• pp.1052-1054
• /
• 1992

The conventional serial UPS using battery energy storage unit is almost universally used. Despite its common usage, the conventional UPS has a number of disadvantages which may be effectively overcome by the application of flywheel energy storage unit. This paper proposes a new type of parallel processing UPS using flywheel energy storage unit, which has the feature of high power, long life, and high efficiency.

• 한국정밀공학회지
• /
• 제22권6호
• /
• pp.199-206
• /
• 2005

In this work, a theoretical investigation on the energy harvesting is undertaken using one of potential smart materials; piezoelectric material. The energy equations fur both square and circular types of the piezoelectric material are derived, and the energy generated from two commercially available Products: $PZT (Lead/Zirconium/Titanium: Pb(Zr,\;Ti)O_3)$ and PVDF (polyvinylidene fluoride) are investigated in terms of the thickness and area. In addition, a finite element analysis (FEA) is undertaken to obtain the generated energy due to the uniform pressure applied on the surface of the piezoelectric materials. A comparative work between the theory and the FEA is made followed by the brief discussion on the usage of the harvested energy for Bio MEMS.