초록 ▼

□ 과제명 : 시설원예 난방기기의 효율적 운용기술 연구
▶ 연구목적 :
○ 온실내 태양잉여열을 열원으로 하는 고효율 온실 난방시스템 개발
○ 히트펌프/온풍난방기 병용 온실용 하이브리드 난방 기술 개발

▶ 주요연구내용 :
○ 1세부과제명 : 온실내 잉여 에너지를 활용한 난방시스템 효율향상 연구
- 겨울철 환기로 버리는 온실 태양잉여열과 외부공기열을 축열하여 난방온수 생산
※ 겨울철 주간에 적정 온실온도 유지를 위해 환기로 버리는 태양잉여열은 계절별로 난방부하의 20~100%에 달하는 활용가

□ 과제명 : 시설원예 난방기기의 효율적 운용기술 연구
▶ 연구목적 :
○ 온실내 태양잉여열을 열원으로 하는 고효율 온실 난방시스템 개발
○ 히트펌프/온풍난방기 병용 온실용 하이브리드 난방 기술 개발

▶ 주요연구내용 :
○ 1세부과제명 : 온실내 잉여 에너지를 활용한 난방시스템 효율향상 연구
- 겨울철 환기로 버리는 온실 태양잉여열과 외부공기열을 축열하여 난방온수 생산
※ 겨울철 주간에 적정 온실온도 유지를 위해 환기로 버리는 태양잉여열은 계절별로 난방부하의 20~100%에 달하는 활용가능 에너지원
- 기존 공기열 히트펌프 대비 성능 32% 향상, 지열히트펌프 대비 설치비 40% 절감
※ 경유온풍난방기 대비 난방비 80% 절감, CO2 배출량 42% 저감

○ 2세부과제명 : 원예시설 난방기기의 하이브리드 운용기술 연구
- 공기열 히트펌프와 경유온풍난방기의 하이브리드식 최적제어시스템 개발
- 온풍난방기 병용 공기열 히트펌의 성능저하에 대한 최적 보상 가능
- 관행 공기열 히트펌프 - 경유온풍난방기 운전대비 난방비 35% 절감

Abstract ▼

○ Study on improvement of heating system efficiency using surplus energy in greenhouse
A greenhouse heating system to improve air source heat pump performance using inside and outside air of greenhouse as a heat source selectively was developed. In this system, thermal storage modes divided into

○ Study on improvement of heating system efficiency using surplus energy in greenhouse
A greenhouse heating system to improve air source heat pump performance using inside and outside air of greenhouse as a heat source selectively was developed. In this system, thermal storage modes divided into the inside circulation mode using surplus solar heat discharged outside of greenhouse to maintain the greenhouse temperature properly and the outside circulation mode using greenhouse outside air heat. The thermal storage modes were designed to be switched mutually according to greenhouse inside temperature set in advance. Six temperature values were input to control the heat pump operating, thermal storage mode switching and greenhouse heating automatically. Prototype heating system was tested in a plastic greenhouse without crop to investigate the operating characteristics, and the results showed that the inside circulation mode began at about 11:00 and lasted for about 210 minutes and inside greenhouse temperature was maintained between 20∼28℃ in spite of non-ventilation. System heating COP of the inside circulation mode in daytime was 3.35, which was 36% and 25% higher than that of the outside circulation modes in the nighttime and daytime respectively. Improved field test model with heat pump of 70kW in closed room and thermal storage tank of 20 tons under splitting temperature control was designed and installed in a plastic greenhouse of rose cultivation. According to the results of the field test, the system heating COP of the inside circulation mode using surplus solar heat in daytime was 3.0∼4.5 higher than that of 2.5∼2.9 of the outside circulation mode using greenhouse outside air heat in night time. Average system heating COP of field test model was estimated at about 3.1 which was 32% higher than that of conventional air to water heat pump with thermal storage. Installation cost of present system was about 15% higher than that of conventional air to water heat pump, but about 40% lower than that of vertical closed-loop ground source heat pump. Heating cost and carbon dioxide emission of present system were estimated to be 20% and 58% respectively compared to conventional light oil hot air heater.

○ Study on hybrid operation technology of heater used for horticultural facility
Recently, Air source heat pump supply is expanding due to lower installation and cheaper agricultural electricity costs. Hence farmers can easily use that for saving greenhouse heating costs. However it is necessary to develop technology of compensating air source heat pump defect for using that efficiently. Heat pump inefficiency at low outdoor temperature should be solved firstly. As an method of solving above problem, it is necessary to combine air to air heat pump and diesel heater customarily used for heating. In this study, hybrid type operating technology for combining them were developed in optimal algorithm which were determining time for turing on diesel heater depending on indoor temperature of greenhouse. Optimal hybrid operational rule was summarized as follow as ; Firstly, heat pump get turned on temperature below setting point in advance and then diesel heater get turned on 2∼3 celsius degree lower than setting temperature. Secondly, diesel heater could be get off after raising the optimal temperature based on heating burden rates calculation before reaching setting temperature in advance and then heat pump could be get off on setting temperature point. Main goal of developed idea was that making the heat pump running time longer so that hybrid heating system can get better efficiency in saving heating cost. As a result of heating experiments of field application, heating cost saving rate was 54% in conditions of heating burden rates of 70% heat pump and 30% diesel heater comparing with diesel heater’s running cost and the greenhouse temperature was controlling at the range 0∼1 celsius degree lower than setting temperature point.