• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2011년도 제36회 춘계학술대회논문집
• /
• pp.127-129
• /
• 2011

빌딩에서 쾌적한 환경을 유지하기 위해 온도제어가 필요하다. 온도를 제어하기 위해서 적정 온도를 유지시켜주는 매체인 상변화물질을 이용할 수 있다. 상변화물질은 고유의 상변화온도가 있고 상변화물질은 열을 얻고/방출할 때 녹거나/굳게 된다. 이러한 장점이 있으므로 상변화물질은 공기-상변화물질 열교환기에 적용할 수 있다. 본 연구에서는 시스템 성능에 만족하도록 공기-상변화물질 열교환기를 설계하였고 열교환기의 성능을 연구하기 위해서 실험을 수행한다.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2010년도 추계학술대회 초록집
• /
• pp.95-95
• /
• 2010

In recent, there are tremendous requirements to improve the fuel economy of vehicle. For satisfaction of requirements, Hybrid Electric Vehicle or other technologies are suggested and implemented. However, it should be noted that almost 35% energy loss is occurred in the shape of exhaust gas as ever. For increase the efficiency of vehicle, it is certain that the exhaust gas energy should be recover, and generate energy. In previous studies, the technologies such as turbo-compound, thermoelectric and rankine cycle are suggested to recover the exhaust heat energy in vehicle. But, they focus on the conventional vehicle or parallel Hybrid Electric Vehicle. Series Hybrid Electric Vehicle has advantage that the engine and drive shaft are de-coupled. It means that the engine can be operated in high efficiency area regardless with vehicle states. Therefore, if rankine cycle is applied to series hybrid electric vehicle, operating condition of that becomes almost steady. So, in this study, theoretical analysis on the efficiency of rankine cycle applied to series hybrid electric city bus is carried and the energy recovered from exhaust gas during vehicle drive cycle is calculated.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1998년도 가을 학술발표회 논문집(I)
• /
• pp.66-71
• /
• 1998

Recently, it has been increased to construct massive concrete structures, like under-ground structure, offshore structure etc., ie. concrete construction have become larger and higher and are demanding lower heat concrete to prevent thermal cracking. It has been progressed to replace cements with fly-ash and slag to lower heat of hydration, but it is hard to control quality of the mineral admixtures in stage of adjusting of real construction. Application of low heat portland(Belite Rich) cement for the mass concrete is the best solution to satisfied those requirements. Here are explained the basic properties of fresh concrete as well as hardened concrete of using low heat portland cement(LHPC). Also, we compare the results of adiabatic temperature rise test using LHPC and OPC.

• 한국압력기기공학회 논문집
• /
• 제11권1호
• /
• pp.33-38
• /
• 2015

The effects of post weld heat treatment(PWHT) on the mechanical properties of 2.25Cr-1Mo steels were investigated. As the PWHT temperature or holding time increased, the strength of low alloy steels progressively decreased due to softening process. After the conventional PWHT, the strength was larger than the minimum value of materials specification. The Charpy impact energy was hardly affected by the conventional PWHT. The trend of mechanical properties was analyzed in terms of tempering parameter. Most materials replaced from a power plant met the requirements of materials specification except for one heat. Same heat of materials with low impact energy were attributed to the voids formed during casting process.

• 설비공학논문집
• /
• 제3권4호
• /
• pp.231-240
• /
• 1991

A design method has been developed for a Stirling engine with a tubular heater and cooler and a screen type regenerator. This paper provides a design procedure to determine the thermodynamic states and the geometric configurations of the Stirling engine for residential heat pumps. The major design is concerned with the working spaces, i.e. compression and expansion spaces and the heat exchangers such as the heater, the cooler and the regenerator. The Schmidt analysis has been employed to obtain the mass flow rates and heat transfer requirements of the system. The performance analysis of a model Stirling engine was performed by Martini-Weiss program to prove the validity of this design method. The results obtained indicate that this design method is valid for the Stirling engine conceptual design and performance analysis.

• 한국시뮬레이션학회논문지
• /
• 제27권2호
• /
• pp.25-33
• /
• 2018

군용 장비 개발 시 운용자가 안정적인 환경에서 운용할 수 있도록 온도조건을 고려하여 설계하여야 한다. 각종 군용 장비를 보관하는 쉘터는 다양한 환경에서 운용되고 있다. 시험장비 및 수리부속품의 저장온도 및 운용 요구조건은 $-32^{\circ}C{\sim}50^{\circ}C$로 쉘터 내부는 저장온도 및 운용 요구조건을 충족할 수 있도록 설계되어야 한다. 본 연구에서는 MIL-STD-810G의 기준을 고려하여 고온 및 태양열 조건에서 군에서 운용중인 2.5톤의 군용쉘터의 열해석을 수행하였다. 열해석은 열저항 및 열회로개념을 활용하여 적용하였으며 해석결과를 검증하기 위해 실제 제작된 군용쉘터에 대한 태양열 시험을 실시하여 결과를 비교하여 제시하였다.

• 대한안전경영과학회지
• /
• 제17권4호
• /
• pp.113-121
• /
• 2015

This study aims to examine the risk of electrical fire in places where electric heat wires are used. In general, the use of electric heating wires is becoming more common and prevalent in a bid to prevent increasing damage caused by freezing and bursting in residential water pipes, factory pipes and irrigation pipes in vinyl greenhouse and a variety of heat wire products are available in market with legal safety requirements imposed on them. However, the widespread use of anti-freezing burst heat wire products has caused increasing incidents of fire, which often fail to be incorporated into statistics due to quick onsite extinguishing and insignificant damage although damage is gradually on the rise. Against this backdrop, this study aims to look into the possibility of ignition caused by electric heat wires and the mechanism of how it turns into catching fire through overheat and short circuit tests for anti-freezing burst electrical heat wires (hereinafter called the 'heat wire') and expects to serve as the basis for further observations and analyses on the cause of fire and the process of ignition in a scientific manner.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회A
• /
• pp.1176-1180
• /
• 2008

This paper represents a study on design hypothesis to improve properties of a product. The functional requirements and function structure of various technical products are analysed. From the above analysis we could formulate one hypothesis. This hypothesis also satisfies basic rules clarity, simplicity and safety that are required in all design cases. The hypothesis says that functional requirements is refined to improve and if there are components which have the same function, they can be integrated into one component and improved. A one-handed faucet was developed by applying the above hypothesis to a two-handed faucet. The design of heat exchange tester was be improved successfully through the hypothesis.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
• /
• pp.303-308
• /
• 2001

Recently, concrete structures have become larger and higher and are demanding high performance concrete with lower heat to prevent thermal cracking, far greater workability, high strength and durability, Application of low heat portland(Type IV) cement for the high performance concrete is the best solution to satisfied those requirements. Here are explained the effect on the properties of high flowing concrete using low heat portland cement by material and mixing variations. Variables for sensitivity test were selected items like finess modulus of aggregates, particle size of limestone powder, unit water, superplasticizer, viscosity agent and concrete temperature. The results of this study were be applied to slurry wall of #215 and #216 of underground LNG tank in Inchon.

• 한국압력기기공학회 논문집
• /
• 제12권1호
• /
• pp.85-92
• /
• 2016

The operating temperature of VHTR components is much higher than that of conventional PWR due to high core outlet temperature of VHTR. Material requirements and technical issues of VHTR reactor components which are mainly dominated by high temperature service condition were discussed. The codification effort for high temperature material and design methodology are explained. The design class for VHTR components are classified as class A or B according to the recent ASME high temperature reactor design code. A separation of thermal boundary and pressure boundary is used for VHTR components as an elevated design solution. Key design characteristics for reactor pressure vessel, control rod, reactor internals, graphite reflector, circulator and intermediate heat exchanger were analysed. Thermo-mechanical analysis of the process heat exchanger, which was manufactured for test, is presented as an analysis example.