본 연구에서는 서로 다른 열전달 특성을 가진 탄소섬유 전기발열체와 경유온풍난방기가 온실 내부의 온습도, 에너지소비, 작물생육 등에 미치는 영향을 분석하기 위해 오이 재배 단동온실에 대한 난방 비교시험을 수행하였다. 전기발열체 온실에서 난방용량이 온실 환경과 난방기 운전에 미치는 영향을 분석하기 위해 온실에 6, 9, 16kW의 전력을 각각 공급한 결과 전기발열체 ON-OFF 주기는 각각 9, 11, 15회로 비례하여 증가하였으며 온실 내부 평균온도는 각각 15.2, 15.3, 15.6oC, 평균상대습도는 84, 81, 76%로 나타나 난방 용량이 클수록 온실내부 온도는 높고, 상대습도는 낮게 나타났다. 또한 6, 9kW 가동 시 하부온도가 상부보다 0.1oC 높았으며 16kW 가동 시는 상부 평균온도가 하부보다 0.2oC 높았다. 전기발 열체와 경유온풍난방기의 비교 시험에서는 난방 시 온실 상부와 하부의 온도차가 전기발열체 온실이 0.1~0.2oC로 경유온풍난방기 온실의 0.5~0.6oC보다 작았으며, 온실 상류와 하류의 온도차는 전기발열체 온실이 0~0.1oC로 경 유온풍난방기 온실의 1.3~1.4oC보다 작아 정밀한 온도관리가 가능하였다. 난방기간 동안 사용한 에너지사용량은 경유온풍난방기 온실이 경유 867L를, 전기발열체 온실이 전력량 8,959kWh를 사용하였으며, 난방비용은 각각 607 천원과 403천원이 소요되어 전기발열체 온실에서 약 34%의 비용절감 효과가 있었다. 전기발열체 온실의 경우 상대적으로 군락 상하부의 환경관리가 균일하여 초장을 비롯한 전반적 생육상황이 경유온풍난방기 온실보다 좋았으나 통계적으로 유의한 차이는 없었으며, 수확량 역시 전기발열체 온실의 작물군락 하부 온도가 경유온풍 난방기 온실보다 1.3oC 더 높게 관리되어 4.3% 증수효과가 있었으나 통계적으로 유의한 차이는 없었다. 원예 시설의 최적 난방 관리를 위해서는 각 난방기의 열전달 특성에 기초하여 난방기 용량, 배치, 열분배 방법에 대한 설계가 요구되며, 전열선 형태의 난방기 역시 작물형상 및 재배방법을 고려하여 전열선의 개수, 위치, 방열 온도 등에 대한 설계가 필요한 것으로 판단되었다.

In the industrial field, various type of fuel have been used for product processing facilities. Recent for 10 years, the usage of natural gas (NG) was gradually increased. Because it has many merits; clean fuel, no transportation, storage facility and so on. There are common safety concept that strict explosion protection approaches are needed for facilities where explosive materials such as flammable liquid, vapor and gases exist. But some has an optimistic point of view that the lighter than air gases such as NG disperse rapidly, hence do not form explosion environment upon release into the atmosphere, many parts has a conventional safety point of view that those gases are also inflammable gases, hence can form explosion environment although the extent is limited and present. In this paper, the heating equipments (Hot Oil Heater) was reviewed and some risk management measures were proposed. These measures include hazardous area classification and explosion-proof provisions of electric apparatus, an early gas leak detection and isolation, ventilation system reliability, emergency response plan and training and so on. This study calculates Hazardous Area Classification using the hypothetical volume in the KS C IEC code.

This is fundamental study to apply the waste edible-oil utilization technology using cooking oil. Especially, this study was carried out to apply a hot air heater using the waste edible-oil. This waste edible-oil hot air heater was a fuel supply equipment, a combustion and a indirect heat exchanger. waste edible-oil hot air heater was remodeled and manufactured by modification of a heavy oil hot air heater of a heating capacity 40,000kcal/h, changing fuel supplying system fitted with the waste edible-oil. An experimental apparatus supplies waste edible-oil, which is heated with intake oil, into an intake fuel injection nozzle of the combustion equipment. As the result, heavy oil, light oil and waste edible-oil Caloric value were 10,000kcal/kg, 10,890 kcal/kg and 9,370 kcal/kg. The waste edible-oil hot air heater performance showed that air temperature at inlet , outlet and exhaust gas were 23℃, 59∼63℃, 280℃ respectively. heat rating and thermal efficiency showed that in hot air heater was 683,333kJ/h, 78% respectively. It was found that CO, CO2 were 13ppm, 13.1%. waste edible-oil consumption rate was 22.1ℓ/h.

This study was carried out to investigate of the combustion characteristics for the waste edible-oil and heavy oil on hot air heater. There was highly reduction in energy cost using by the hot air heater. The hot air heater to study with duct connector type, and the motor output was 2.2kW. The experimental factors for performance test, fan speed ranged from 1700 rpm to 1800rpm, and SFC, efficiency, exhaust gas emissions, and noise were measured. The results obtained were as follows; efficiency were increased to 87% at the heavy oil and was decreased to 79% on the waste edible-oil. The fuel consumption was decreased to 25L/h at the heavy oil and CO2 emissions was decreased in the case of the heavy oil