• Journal of Energy Engineering
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• v.25 no.3
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• pp.66-72
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• 2016

In this study, a sulfonated poly(arylene ether ketone) block copolymer was prepared from hydrophilic oligomer and hydrophobic oligomer. The structure of the prepared membrane was characterized by $^1H$-NMR, FT-IR and GPC. The $M_w$(weight-average molecular weights) of the polymer was $209,700g\;mol^{-1}$ and the molecular weight distribution($M_w/M_n$) of 1.25 was obtained. The prepared membrane showed excellent thermal stability with gradual weight loss up to $200^{\circ}C$. The proton conductivity of SPAEK block copolymer reached the maximum of $9.0mS\;cm^{-1}$ at $90^{\circ}C$ under 100% relative humidity (RH). From the observed results, it is necessary to do more aggressive attempt to study the possibility of application as an ion-conductive composite electrolyte.

• Journal of Energy Engineering
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• v.11 no.1
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• pp.1-9
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• 2002

The purpose of this study is to maintain high efficiency and reasonable use of cool thermal storage systems operated in the domestic building sector. As the result of efficiency test from the five types of operated cool storage systems on the condition that COP ranges are 2.6 to 3.4 during the day time and 2.1 to 3.0 during the night time and it decreased by more than 30% of rated COP given 3.8 to 3.0. The Analysis of cool storage rate shows that only 3 (21.4%) systems out of 15 buildings hold to over 40% capacity for its total capacity. To prevent the decrease in operating efficiency, it should correct the malfunction of 3-way valve and expansion valve and the mistake of control values for schedule program and increase cooling tower capacity. In order to improve piping line, it needs bypass brine line off refrigerator, separation of chilled water line with Ice Slurry system at day and night time and speed control of chilled and warm water pumps. This study does require the more studies on improving difficulty of increasing cooling load with Ice on Coil system, waterproofing with Ice Ball system, COP drop during the night time with Ice Lens, low operating temperature during the day time with Ice Slurry and increasing of Power loss due to hot gas de-icing with Ice Harvest in the future.

• Journal of Biosystems Engineering
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• v.9 no.2
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• pp.74-80
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• 1984

Storage materials for a minimized storage system should be able to store much energy in small quantities, and to solve such a problem, salt hydrates such as CALCIUM CHLORIDE, SODIUM SULFATE, SODIUM PHOSPHATE etc. were considered as most suitable storage media in which phase change phenomena take place at low temperature. Therefore those salt hydrates were used as storage media in this study, and piped-storage tanks were manufactured vertically for the experiment. The characteristics of thermal storage media were investigated and the results are summarized as follows: 1. From the experiment of radial temperature distribution of vertical piped-storage system, the latent heat phenomenon did not occur in all storage media during heating process because of generations of heat due to the reduction in the number of water molecules. However, among those storage media CALCIUM CHLORIDE had most remarkable latent heat phenomenon during cooling process. Therefore CALCIUM CHLORIDE was considered as most suitable storage media. 2. Heat quantity transferred to the storage media was the largest in case of CALCIUM CHOLORIDE under the same conditions during heating and cooling process.

• Applied Chemistry for Engineering
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• v.21 no.5
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• pp.522-526
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• 2010

Heat storage application techniques can be categorized into the sensible heat storage and the latent heat storage according to the method of heat storage. Heat storage is the way of saving remaining heat when heating and cooling loads are light, and then using it when the heating and cooling loads are heavy. Latent heat storage is defined as the method of saving heat by using substances which have high potential heat when phase change is in the range of a certain temperature and when heat storage space is small, compared to those of sensible heat storage and it is possible that absorption and emission of heat at a certain temperature. This study is conducted to save energy when either air-conditioning or heating is operated in a building. We have tried to find out the essential properties of matter and the optimum mixing rate about cement and gypsum for building materials, which have been widely used for proper phase change materials (PCM), when thermal environment property is applied. So we obtained the result of the cooling delay effect about 19% with heat storage mortar containing 3 wt% of PCM.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1076_1077
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• 2009

‘09년 국가정책의 가장 큰 주제 중 하나는 "저탄소 녹생성장"이다. 그러나 지구온난화는 급속하게 진행되고 있어, 최근 100년동안 지구평균온도는 $0.75^{\circ}C$ 상승하였다. 이는 또 다른 환경문제를 야기하는 한편, 전력공급 측면에서 냉방부하가 점점 더 늘어나는 것을 의미한다. 그러나 다행히도 주간의 전력사용을 최소화하고 냉방할 수 있는 시스템 즉 축냉시스템이 보급되고 있으며 신재생에너지를 활용할 수 있어 산학연의 관심이 집중되고 있다. 본 고에서는 축냉시스템의 원리, 지원제도, 보급실적 및 보급효과에 대해서 분석해 보고자 한다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1136-1137
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• 2008

교토의정서가 발효된 2005년 이후 온실가스를 감축해야 한다는 요구가 급속도로 증대되고 있다. 더군다나 유류가격이 상승하여 '08. 5월 현재 배럴당 130달러를 육박하고 있으며, 몇몇 경제학자들은 올해 말에 150달러를 상회하는 것이 어렵지 않다고 추측하고 있다. 에너지에 대한 관심이 집중되는 가운데, 관련업계는 태양광, 풍력 등 신재생에너지 개발에 힘을 쏟고 있다. 본 고에서는 신재생에너지를 활용하여 온실가스를 줄일 수 있는 지열원 히트펌프시스템의 적용사례와 축냉설비 보급지원 효과를 분석해 보고자 한다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.1 no.1
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• pp.55-63
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• 1989

A one dimensional analytic model for the prediction of the stratification coefficient of a liquid-based solar heating system is developed. The stratification coefficient, $K_s$, is defined as the ratio of the actual useful energy gain to the energy gain that would be achieved if there were no thermal stratification in the storage tank. Previous studies incorporated only collector-side effects, but in this study both the collector and load-side effects are included for the overall performance evaluation.

• Journal of the KSME
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• v.33 no.2
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• pp.183-190
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• 1993

에너지 문제에 현명하게 대처하기 위해선 폐열과 심야전력을 활용한 축열시스템의 저변확대가 시급하다. 특히 우리나라와 같이 냉난방으로 인한 계절별 전력 수요폭이 심한 나라에서는 공조용 축열 시스템 개발이 필요하다. 현재 우리나라에 보급되고 있는 것은 빙축열 시스템이 대부분인데 지역과 조건 그리고 용량에따라 좀더 다양한 시스템 선택이 필요하다. 그리고 에너지의 축출 방법에 있어서도 전체 공조 시스템의 특성과 효율을 특히 고려해야 할 것이다. 축열 시스템의 핵심은 무엇보다도 축열조의 소형화(compact)와 축열 효율이다. 즉 되도록 작은 크기의 축열조 로써 최대한 많은 에너지를 저장하며 또한 최대한 많은 에너지를 회수하는 것이다. 일반적으로 축열조에 열을 저장 그리고 축출하는 과정에는 에너지(useful energy)의 손실이 생기게 된다. 이는 열전달 과정 중에 시스템 내의 엔트로피의 증가로 생기는 필연적인 손실로 이것을 최소로 하는 설계 기술이 필요하다.

• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2088-2095
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• 2023

The safety of nuclear installations is largely determined by the tightness of fuel elements cladding. As the Fukushima nuclear accident showed, the main task in case of loss of power supply is to ensure reliable removal of residual heat release from spent fuel pool (SFP) with irradiated fuel assemblies (IFAs). The paper presents the results of calculated-experimental studies and thermal-hydraulic modeling of temperature storage modes of IFAs in SFP. Experimental studies of SFP's temperature regime and calculated evaluation of residual heat removal due to the thermal conductivity of building structures surrounding the SFP were performed. To ensure the safe operation of research reactors, it's necessary to know the IFA's residual heat power (RHP) in the reactor and SFP, which is determined depending on the operating time of fuel assemblies (FAs) and the IFAs calculated holding time. The FAs operating time depends on the reactor energy output. The IFAs calculated holding time is determined by the fuel burnup, U-235 mass in the fuel, and reactor utilization factor. The IFAs fuel burnup was calculated using the MCU-PTR program. Also presented are the RHP's calculation results using some of the empirical dependencies. The concept of a passive heat removal system (PHRS) based on thermosyphon's operating principle was proposed.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.167-168
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• 2017

This paper investigates to identify an optimal for analysis of battery behavior in system-level applications such as Battery Energy Storage Systems in Smart Grid infrastructures and Electrical vehicles. At system level applications, it is mandatory to check model for meaningful equivalency and practical ability for extension from unit cell to Battery stack. The investigation of current battery models in relation to their suitability for study and analysis of system level applications of battery helpful for identification of optimal model and it also provides an intuition and direction to develop the most suitable model, if such models are not available already.