• 한국태양에너지학회 논문집
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• 제24권3호
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• pp.39-46
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• 2004

In this paper, thermodynamic design data for heating of double-effect absorption system using LiCl-water for evaporator heating source of sofar energy are investigated for the water-LiCl pair and a comparative study of the water-LiCl pair with the water-LiBr pair is given used for the computer simulation. The computer simulation is based on mass, material and heat balance equations for each part of the system. Coefficients of performance and flow ratios for effects of different operating temperatures are investigated. It is found that the heating COP is higher for the water -LiCl pair than for the water-LiBr pair, and FR is lower for the water-LiCl pair than for the water LiBr pair.

• 한국기계가공학회지
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• 제18권2호
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• pp.108-113
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• 2019

Due to the special structure of the car seat, the heating and cooling module must be installed in a limited area resulting in difficulty in regards to achieving optimal cooling and heating efficiency. In order to solve these problems, this paper establishes a new structure for heating and cooling modules, verifies the structural feasibility of the thermoelectric module for cooling and heating the seat through fluid simulations, and verifies the proper design of the mechanical components of the thermoelectric module.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.630-633
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• 2008

Geothermal heat pump systems use the earth as a heat source in heating mode and a heat sink in cooling mode. These systems can be used for heating or cooling systems in farm facilities such as greenhouses for protected horticulture, cattle sheds, mushroom house and etc. A horizontal type means that a geothermal heat exchanger is laid in the trench buried in 1.2 to 1.8 m depth. Because a horizontal type has advantages of low installation, operation and maintenance costs compared to a vertical type, it is easy to be adopted to agriculture. In this study, to heat and cool farm facilities and obtain basic data for practical application of horizontal geothermal heat pump system in agriculture, a horizontal geothermal heat pump system of 10 RT was installed in greenhouse. Heating and cooling performance of this system was estimated. The horizontal geothermal heat pump used in this study had heating COP of 4.57 at soil temperature of $14^{\circ}C$ with depth of 1.75m and heating COP of 3.75 at soil temperature of $7^{\circ}C$ with the same depth. The cooling COP was 2.7 at ground temperature at 1.75m depth of $25.5^{\circ}C$ and 2.0 at the temperature of $33.5^{\circ}C$.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.226-229
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• 2006

Process design has been performed for the warm hydroforming of light weight alloy tubes. For the heating of tubes, specially designed induction heating system has been adopted to ensure rapid heating of tubes. The induction heating system uses 30kHz frequency induction coil in order to concentrate the energy in the tube and prevent the energy loss. But the induced heat by the integrated heating system, consisting of induction coil, tube, pressure oil and dies, was normally not equally distributed over the length and circumference of the tube specimen, and consequent temperature distribution was non-uniform. So additional heating element has been inserted into the inside of the tube to maintain the forming temperature and reduce temperature drop due to heat loss to the molds. And for that heat loss, a heat insulation system has also been installed. The drop in flow stress at elevated temperatures results in lower internal pressure for hydroforming and lower clamping forces. The proposed warm hydroforming process has been successfully implemented when applying 6061 aluminum extruded tubes.

• 설비공학논문집
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• 제23권8호
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• pp.571-579
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• 2011

Heat pump systems for commercial building with variable refrigerant flow(VRF) are expanding a market due to high energy efficiency, lower maintenance cost and easy installation comparing with the conventional heat pump with the constant refrigerant flow. In general, heat pump systems degrade the energy efficiency in the extremely low temperature regions. In this study, VRF heat pump system with refrigerant heating is experimentally investigated to overcome the low heating performance in the extremely low temperature regions. VRF heat pump system with refrigerant heating is found out the sufficient heating performance in the -25 degree temperature condition comparing with the conventional heat pump system and is obtained more than 2,500 kPa high pressure in the evaporator at low temperature.

• 설비공학논문집
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• 제15권7호
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• pp.551-556
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• 2003

The present study concerns an experiment on the heating characteristics of a system air-conditioner (A/C) using PWM method or inverter method at low temperature con-ditions. The compressors used are digital scroll type and BLDC inverter type. Under the low outside temperature condition, -5$^{\circ}C$, -1$0^{\circ}C$, -15$^{\circ}C$, heating capacities and COPs are mea-sured by the psychometric calorimeter using air enthalpy method. Also, outlet air temperatures at heating operation mode are measured at -5$^{\circ}C$, -1$0^{\circ}C$ and -15$^{\circ}C$. Experimental results show that COPs of the system A/C using a PWM method are more effective than those of the inverter method at heating operation mode. Although the heater is on, COPs of PWM method are similar to those of BLDC inverter method. Moreover, the heating capacities of PWM method at -5$^{\circ}C$, -1$0^{\circ}C$ and -15$^{\circ}C$ are larger about 10~20% and outlet air tempe-rature at -15$^{\circ}C$ is larger about 10%, compared to the inverter method.

• 설비공학논문집
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• 제29권9호
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• pp.463-471
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• 2017

According to the Korea industrial standard of air conditioning systems (KS C 9306), cooling and heating loads for buildings can be calculated by using maximum and minimum temperature in BIN data. Cooling and heating loads can be determined by building set temperature and ambient temperature. Cooling and heating system capacity of buildings can be normally designed according to determined heating and cooling loads. Cooling and heating system capacity can be reduced by updated BIN data, applying TAC (Technical Advisory Committee) values. In this study, updated BIN data have been analyzed using ambient temperature of 19 areas in Korea for the last 10 years (2005~2014) provided by KMA (Korea Meteorological Administration). Building cooling and heating loads have been calculated following TAC based BIN data. As a result, designed system capacity decreased depending on applying TAC. Those were reduced as 7.1% ($100m^2$ building), 8.7% ($1,000m^2$ building) in cooling capacity, 11.7% in heating capacity when TAC 2.5% applied. And also, it is expected system initial and operating cost by decreasing system capacity.

• 한국태양에너지학회 논문집
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• 제33권2호
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• pp.70-77
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• 2013

Recently the radiant panel heating and cooling system has been regarded as an alternative of low temperature heating and high temperature cooling by applying the renewable energy sources to the heating and cooling of buildings. Especially this system can be used as HVAC system alternatives in super high-rise buildings for energy saving and thermal comfort. Also it can be possible to reduce the plenum space because the minimum ventilation air will be supplied into the space. This study focused on the evaluation the basic characteristics of thermal output in prefabricated steel wall panel system for radiant heating and cooling. In order to evaluate the thermal output according to both various supply water temperatures and supply water flow rates, three-dimensional dynamic heat transfer analysis was performed. As results, for the heating mode, thermal output increased by 26% with the supply temperature increasing by $5^{\circ}C$. The surface temperature of panels range within $1{\sim}3^{\circ}C$. For the cooling mode, thermal output decreased by 18.2% with the supply temperature increasing by $2^{\circ}C$. The surface temperature of panels range within $0.5{\sim}1^{\circ}C$ and it was shown the even temperature distribution.

• 한국건축시공학회지
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• 제10권2호
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• pp.97-104
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• 2010

본 연구에서는 전열해석 프로그램인 피지벨(PHYSIBEL)을 사용하여 블라인드 내장형 창호시스템의 일사차단성능 및 단열성능에 따른 에너지 성능을 평가하였다. 피지벨 해석시 창호별 구성 재료의 열적특성과 해석조건을 결정하기 위해서 Mock-up시험을 실시하였으며, 컴퓨터 시뮬레이션을 통한 결과를 바탕으로 공동주택 기준층 1개 세대(33평형)를 대상으로 연간에너지 소비특성, 연간전열량, 연간 냉난방 비용을 분석하였다. 실험결과, 연간전열량은 일반 창호시스템 대비 블라인드 내장형 창호시스템에서 블라인드를 올린 경우 냉방시 10%, 난방시 11% 절감할 수 있으며, 블라인드를 내린 경우 냉방시 25%, 난방시 30%정도를 절감할 수 있는 것으로 나타났다. 블라인드 내장형 창호시스템의 냉 난방 부하 절감량은 일반 창호시스템에 비해 냉방시 283.3KWh, 난방시 76.3KWh 로 냉 난방 에너지 절감효과는 단위세대당 359.6KWh 절감시킬 수 있는 것으로 나타났으며, 이것은 단위세대당 연간 에너지원단위(TOE) 약 0.078toe, 이산화탄소톤($tCO_2$) $0.16tCO_2$을 절감시킬 수 있어 온실가스 저감에도 유리할 것으로 판단된다. 또한, 블라인드 내장형 창호시스템의 냉 난방비용 절감액은 일반창호시스템과 비교하여 연간 냉방비용 10만원, 난방비용 5만원으로 연간 냉 난방 비용을 약 15만원 정도 절감시킬 수 있는 것으로 나타났다.

• 한국해양공학회지
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• 제17권1호
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• pp.80-85
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• 2003

In this study, we developed an analysis method of plate forming by induction heating, verifying the effectiveness of the present method through a series of experiments. The phenomena of the induction heating involves a 3D transient problem, coupled with electromagnetic, heat transfer, and elastoplastic large deformation analyses. To solve the problem, or present an appropriate model and an integrated system. Using the present analysis model, or can estimate the plate deformation in heating without experiments and simulate the plate bending process of induction heating.