• 제목/요약/키워드: Hot air heater

검색결과 105건 처리시간 0.037초

자연순환형 태양열온수기 동파방지기술 (Freeze Protection for Passive Solar Water Heating System)

  • 김종현;홍희기;정재동
    • 설비공학논문집
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    • 제23권5호
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    • pp.327-333
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    • 2011
  • In the present work, a new freeze protection method has been proposed for a natural circulation system of solar water heater. Though electrothermal wire is popularly used for the purpose, there are freezing troubles by wire cut-off and shortage of excessive electric power consumption. In the experimental device, hot water in storage tank was used to heat the outlet pipe from the tank if the pipe surface temperature falls lower than a set point. The cold water pipe to the storage tank was installed to directly contact the hot water pipe surface temperature rose by transferred heat.

전기 및 연료전지자동차용 DPH 난방장치개발연구 (Heat Transfer Characteristics of DPH(Dual Pack Heater) in Electric and Fuel Cell(FC) Car)

  • 노홍구;임경빈;노종호;이영기;고준빈
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2009년도 하계학술발표대회 논문집
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    • pp.1262-1266
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    • 2009
  • The study aims to analyzed and identify the heat transfer characteristics of heating unit for car using experimental method in order to design DPH. The temperature comparison processes were done with various experimental conditions. In addition, the optimal conditions of DPH design were proposed as field test in real car, hot air flow, transient situation.

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탄소중립 확보를 위한 친환경 동절기 대체 열원 성능 검증 (Performance Verification of Curing Method in Cold-Weather with Using Energy Saving Electronic Heater for achieving Korean Carbon Neutra)

  • 조만기;김상균;홍성민;박종훈
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2021년도 가을 학술논문 발표대회
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    • pp.192-193
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    • 2021
  • Recently, the need to strengthen the Air Environment Conservation Act and secure alternative heat sources during the winter by carbon neutrality policies has been raised. Accordingly, winter construction, which has safety and quality measures, is emerging as an essential factor. It is believed that eco-friendly tropical type electric hot air heaters will be able to solve most of the problems of winter construction at construction sites, especially prevention of suffocation and fire accidents. In addition, as a result of on-site performance verification, it has secured more than the same performance as the existing curing method, and the curing technology can create an eco-friendly and pleasant working environment while considering safety and construction.

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저온 외기조건에서 케스케이드 급탕열펌프의 성능특성에 관한 해석적 연구 (Numerical Study of the Performance Characteristics of a Cascade Heat Pump Water Heater at Low Ambient Temperatures)

  • 송재현;정해원;박재우;강훈;김용찬
    • 설비공학논문집
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    • 제25권5호
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    • pp.225-232
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    • 2013
  • Heat pump systems have been widely adopted in buildings for cooling and heating, due to their higher energy efficiency. Recently, the demand for hot water supply from the heat pump system has been increasing. To increase the water supply temperature with higher system efficiency and reliability, a heat pump water heater adopting cascade cycle was investigated in this study. The cascade heat pump water heater consisted of a low-stage cycle using R410A, and a high-stage cycle using R134a. A simulation program for the cascade heat pump water heater was developed, and verified by comparison with experimental data. The performance of the cascade heat pump water heater was optimized, by varying the compressor rotating speeds of the low- and high-stage cycles. At low ambient temperatures, the performance of the cascade cycle was compared with that of the single-stage cycle. The system efficiency of the cascade cycle was higher than that of the single-stage cycle, showing a lower compression ratio and compressor discharge temperature.

보온터널 난방을 위한 온수난방용 코일튜브 열교환기의 열전달 특성 (Heat Transfer Characteristics of Coil Tube Heat Exchanger for Hot Water Heating of Greenhouse Thermal Tunnel)

  • 유영선;강금춘;김영중;백이;강연구;이형모
    • Journal of Biosystems Engineering
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    • 제31권5호
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    • pp.430-435
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    • 2006
  • Greenhouse horticulture in South Korea covered about 52,000 ha in 2005. Greenhouse area of about 12,000 ha has been heated during winter season with heating cost of $20{\sim}40%$ of total Production cost. Farmers engaged in greenhouse horticulture were changed into aged people. Therefore the laborsaving of working process and the saving of greenhouse heating cost should be accomplished simultaneously to increase income of greenhouse horticulture. The best method for saving of greenhouse heating cost is to install thermal tunnels into greenhouse. Then hot air heaters using fossil fuel should be changed into hot water heaters. In other words air heating using forced convection should be changed into natural convection system. In this research coil tube made of flexible PE pipe was designed as hot water heat exchanger and its heat exchanging characteristics were analyzed. This new heat exchanger has been adopted as a natural convection system for hot water heating of greenhouse horticulture.

수평공기흡입형 온풍난방기의 온실난방효과 (Heating Effects for Inhaling Horizontal Air of Hot Air Heater in Greenhouse)

  • 장유섭;김동억;김종구;김현환;이동현;김성기
    • 한국농업기계학회:학술대회논문집
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    • 한국농업기계학회 2002년도 하계 학술대회 논문집
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    • pp.310-315
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    • 2002
  • 겨울철 저온기에 온실의 작물재배는 많은 에너지가 소요되어 저온기의 에너지비용을 최소화하는 것이 온실의 운전비용의 절감과 이용효율이 증대되어 농가소득을 높일 수 있다. 저온기에는 작물의 수확량이 적정 온도조건의 80%수준으로 최소 에너지 투입방법 기술을 개발하여 수확량을 증대시킬 필요가 있다. 기존의 난방방법인 온수보일러는 온도유지 안정성은 좋으나 시설비용이 많이 들고 온풍난방은 설치비용은 저렴하나 온도 유지안정성이 다소 떨어지는 단점이 있다. (중략)

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다공의 전열판이 내장된 공기 대 공기 전열교환기의 성능 평가 (Performance Evaluation of Air-to-Air Total Heat Transfer with Rotating Porous Plates)

  • 임태우;조동현
    • 동력기계공학회지
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    • 제11권2호
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    • pp.20-25
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    • 2007
  • The performance of air-to-air heat exchanger has been investigated with rotating porous plates newly developed in this study. With an equal interval of 18 mm, the rotating porous plates are installed inside the heat exchanger where the hot and cold airs enter at opposite ends. When flowing in opposite directions by the separating plate installed in the center of the rotating porous plates, the airs give and receive the heat each other. Dry bulb temperature is set by adjusting heat supply at heater. In order to measure the temperature distribution of the hot air side inside heat exchanger, the thermocouples are inserted between the plates. The first location of thermocouple is 10mm downstream from the inlet of heat exchanger, and succeeding ten locations are aligned at an equal interval of 18mm. From the experiment of air-to-air heat exchanger with the rotating porous plates, the heat transfer rate increased as both air flow rate and RPM of the rotating porous plate increased. It was found that the overall heat transfer coefficient increased with the increase in RPM of porous plate at the conditions of the same air flow rate.

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Analysis on the Effect of Thermal Performance with Various Load Patterns for Solar Hot Water Heating System

  • Kim, Byoung-Gi;Jang, Hwan-Young;Chung, Kyung-Taek;Suh, Jeong-Se
    • International Journal of Air-Conditioning and Refrigeration
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    • 제15권3호
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    • pp.108-113
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    • 2007
  • The performance of a solar water heater incorporating evacuated tubes was evaluated using a transient simulation program, TRNSYS. Simulations were performed for $60^{\circ}C$ of hot water load temperature and for 280 liter of daily hot water volumes and three 400 liter of storage tank volumes. Three patterns of daily hot water consumption profile were used in the present study (morning, lunch and evening). The results show that the increase in solar fraction depends on the load profile, as well as the collector efficiency coefficient. Hot water draw profile has a large effect on the performance of the SDHWS, the morning load profile has the highest solar fraction. The annual solar fraction of the system, at the weather conditions of Jinju is approximately 84% at lunch load pattern, the 280 kg of load volume, 400 kg of tank volume and the $60^{\circ}C$ of load temperature.

태양열 냉방 및 급탕 시스템의 제어 조건에 따른 열성능 (Thermal Performance of Solar Cooling & Hot-water System According to Control Condition)

  • 이호;주홍진;김상진;곽희열
    • 한국태양에너지학회:학술대회논문집
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    • 한국태양에너지학회 2008년도 추계학술발표대회 논문집
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    • pp.214-219
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    • 2008
  • This study is describes thermal performance of solar cooling and hot water for demonstration system with ETSC(Evacuated tubular solar collector) installed at Seo-gu culture center of Kwanju. Control condition for solar cooling and hot water system is changed by connection of auxiliary heater. Demonstration system was connected to central air conditioning system. Demonstration system was operated by two types. First type(A) was operated to cooling and hot water supply in that order. Second type(B) was operated to hot water supply and cooling in that order. As a result. it was indicated that the total solar energy consumption of (A) was 799 MJ and the solar energy consumption rate for the cooling and hot water supply was 70% and 30% respectively. Total solar energy consumption of (b) was 898 MJ and the solar energy consumption rate for the cooling and hot water supply was 31% and 69% respectively.

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전자유도가열용 Full-Bridge 고주파 공진형 인버터의 개발 (Development of Full-Bridge High-Frequency Resonant Inverter for Electromagnetic Induction Heating)

  • 권혁민;신대철;김용주;김기환
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2003년도 하계종합학술대회 논문집 V
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    • pp.2943-2946
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    • 2003
  • In this paper are described the indirect induction healed boiler and induction boated hot air producer using the voltage-fed series resonant high-frequency inverter which can operate in the frequency range from 20[kHz]to 50[kHz]. A specially designed induction heater, which is composed of laminated stainless assembly with many tiny holes and interconnected spot welding points between stainless plates, is inserted into the ceramic type vessel with external working coil. This working coil is connected to the inverter and turbulence fluid through this induction heater to moving fluid generates in the vessel. The operating performances of this unique appliance in next generation and its effectiveness are evaluated and discussed from a practical point of view.

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