• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.27 no.6
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• pp.513-522
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• 1998

우리나라의 여름 기후는 고온 다습한 특징을 갖고 있다. 고온 다습한 지역에서는 습도가 쾌적성을 결정하는데 중요한 요소가 되기 때문에, 습도가 높으면 온도가 그다지 높지 않더라도 쉽게 무더위를 느낀다. 이러한 계절적 특성을 없애 쾌적한 생활을 영위하기 위하여 생활의 질적 향상과 더불어 공조장치의 수요가 매년 두드러지게 증가하고 있다. 특히, 실내의 경우에는 공조장치 중 대표적인 에어컨(air conditioner)으로 냉방을 행함으로써 고온 다습한 여름철의 거주공간을 개선하고 있다. 그러나 고온 다습한 환경하에서의 과다한 에어컨 사용은 인체의 온열 환경적 측면에서 오히려 불리하다. 왜냐 하면, 에어컨에서는 여름철에 잠열(latent heat)을 고려해야 함에도 불구하고 단지 현열비(sensible heat factor)로 취출온도를 결정하고 있기 때문이다. 그 결과, 실내가 과다하게 냉각되어 재실자에게 불쾌감은 물론, 심지어 냉방병도 초래할 수가 있다.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.195-202
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• 2010

Cooling air-conditioning of APC (Agricultural Products processing Center) workplace is important to improve the working environment in the summer season. As existing cooling systems for air-conditioning of whole workplace are inefficient because of their high equipment operating costs, relatively inexpensive cooling system is required. The objectives of this study were to simulate the thermal flow fields in APC workplace having the positive and negative pressure type fan and pad systems and spot cooling system by using CFD software (FLUENT, 6.2) and estimate the cooling effectiveness of respective cooling systems. The results showed that the negative pressure type fan and pad system was inappropriate for the present APC workplace because of excessive outside air influx from open gateway and the positive pressure type fan and pad system created relatively low temperature field but non-uniform velocity field at worker positions. The spot cooling system could supply cool air to worker positions with relatively constant air velocity and temperature.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1999.11a
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• pp.164-168
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• 1999

온실은 동절기 난방을 주목적으로 설비되어 년중 작물재배 시는 하절기 온실내부 온도가 필요이상으로 상승하여 실내온도가 35-4$0^{\circ}C$ 정도로 올라가는데 이러한 상태에서의 온도는 많은 작물의 생육적온을 벗어난 온도로서 고온장해를 나타낸다. 이 같은 문제점을 해결하기 위해 몇 가지 냉방방법이 알려져 있는데 에어컨 등과 같은 냉방장치를 이용한 기계적 냉각방식과 수분증발을 통한 증발식 냉각방식으로 대별되며 이중 기계적인 냉방방식은 설비나 유지관리 면에서 비용이 많이 들어 비경제적이고, 증발냉각 방식중에서도 Fan and Pad 법이 가장 효과가 좋은 것으로 알려져 있으나 이역시 설치 및 유지비가 많이 들고, vep의 탈부착이 어려워 고정시켜놓을 경우 동계 광투과에 방해가 되는 등의 문제가 많다. (중략)

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.349-354
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• 2013

This study examined a technique for cooling root zone aimed at lowering substrate temperature for sweet pepper (Capsicum annum L. 'Orange glory') cultivation in coir substrate hydroponics during hot season, from the $16^{th}$ of July to $15^{th}$ of October in 2012. The root zone cooling technique was applied by using an air duct (${\varnothing}12$ cm, hole size 0.1 mm) to blow cool air between two slabs during night (5p.m. to 3a.m.). Between the $23^{rd}$ of July and $31^{st}$ of August (hot temperature period), average daily substrate temperature was $24.7^{\circ}C$ under the root zone cooling, whereas it was $28.2^{\circ}C$ under condition of no cooling (control). In sunny day (600~700 W $m^{-2}{\cdot}s^{-1}$), average substrate temperatures during the day (6a.m. to 8p.m.) and night (8p.m. to 6a.m.) were lower about $1.7^{\circ}C$ and $3.3^{\circ}C$, respectively, under the cooling treatment, compared to that of control. The degree of temperature reduction in the substrate was averagely $0.5^{\circ}C$ per hour under the cooling treatment during 6p.m. to 8p.m.; however, there was no decrease in the temperature under the control. The temperature difference between the cooling and control treatments was $1.3^{\circ}C$ and $0.6^{\circ}C$ in the upper and lower part of the slab, respectively. During the hot temperature period, about 32.5% reduction in the substrate temperature was observed under the cooling treatment, compared to the control. Photosynthesis, transpiration rate, and leaf water potential of plants grown under the cooling treatment were significantly higher than those under the control. The first flowering date in the cooling was faster about 4 days than in the control. Also, the number of fruits was significantly higher than that in the control. No differences in plant height, stem thickness, number of internode, and leaf width were found between the plants grown under the cooling and control, except for the leaf length with a shorter length under the cooling treatment. However, root zone cooling influenced negligibly on eliminating delay in fruiting caused by excessively higher air temperature (> $28^{\circ}C$), although the substrate temperature was reduced by $3^{\circ}C$ to $5.6^{\circ}C$. These results suggest that the technique of lowering substrate temperature by using air-duct blow needs to be incorporated into the lowering growing temperature system for growth and fruit set of health paprika.

• Journal of Bio-Environment Control
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• v.24 no.3
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• pp.243-251
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• 2015

This study aimed to determine the effects of root zone cooling using air duct on air temperature distribution and root zone and leaf temperatures of sweet pepper (Capsicum annum L. 'Veyron') grown on coir substrate hydroponic system in a greenhouse. When the air duct was laid at the passage adjacent the slab, the direction of air blowing was upstream at $45^{\circ}$. The cooling temperature was set at $20^{\circ}C$ for day and $18^{\circ}C$ for night. For cooing timing treatments, the cooling air was applied at all day (All-day), only night time (5 p.m. to 1 a.m.; Night), or no cooling (Control). The air temperature inside the greenhouse at a height of 40 and 80cm above the floor, and substrate and leaf temperatures, fruit characteristics, and fruit ratio were measured. Under the All-day treatment, the air temperature was decreased about $4.4{\sim}5.1^{\circ}C$ at the height of 40cm and $2.1{\sim}3.1^{\circ}C$ at the height of 80cm. Under the Night treatment, the air temperature was decreased about $3.4{\sim}3.8^{\circ}C$ at the height of 40cm and $2.2{\sim}2.7^{\circ}C$ at the height of 80cm. The daily average temperature in the substrate was in the order of the Control ($27.7^{\circ}C$) > Night ($24.1^{\circ}C$) > All-day ($22.8^{\circ}C$) treatment. Cooling the passage with either upstream blowing at $45^{\circ}$ or horizontal blowing at $180^{\circ}$ was effective in lowering the air temperature at a height of 50cm; however, no difference at a height of 100cm. Cooling the passage with perpendicular direction at $90^{\circ}$ was effective in lowering the air temperature at the height between 100 and 200cm above the floor; however, no effect on the temperature at the height of 50cm. A greater decrease in leaf temperature was found at 7 p.m. than that at 9. a.m. under both All-day and Night treatments. Fresh weight partitioning of fruit was in the order of the All-day (48.6%) > Night (45.6%) > Control (24.4%) treatment. A higher fruit production was observed under the All-day treatment, in which the accumulated average temperature was the lowest, and it may have been led to a higher proportion of photosynthate distributed to fruit than other treatments.

• Journal of Bio-Environment Control
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• v.9 no.1
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• pp.1-10
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• 2000

This study was performed to find an efficient method to overcome extremely high temperature in greenhouses during summer season. The actual utilization of greenhouses during hot summer season showed that about 21.6％ of the investigated greenhouse farms were in fallow state, and most of greenhouse farms were cultivated under the very inferior environment. Thermal environment of greenhouses according to the evaporative cooling method and several assistant cooling methods such as ventilation, shading screen, roof sprinkling were examined. As the each assistant cooling method was used, about 74.8％, 25.9％, and 58.2％ of temperatures measured at intervals of ten minutes between ten and seventeen o'clock were above 35$^{\circ}C$. When shading screen and evaporative cooling system were operated, most greenhouse air temperatures were maintained below 35$^{\circ}C$, and showed a drop of 3.8~4.2$^{\circ}C$ as compared with naturally ventilated greenhouse.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2001.11a
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• pp.59-62
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• 2001

여름철 온실내 고온 문제를 해결하기 위해 이용되는 자연환기형 포그냉방은 환기가 충분치 못할 경우 온실 내부의 습도가 증가하여 증발 효율이 떨어지는 문제가 발생한다. 제습장치를 이용하여 온실 내부의 상대습도를 낮추면 증발 냉각 효율을 높일 수 있을 것으로 생각된다. 본 연구에서는 제습장치를 이용한 포그냉방 온실에 대한 CFD 모델을 개발하여 온실의 열환경 및 수분 환경을 분석하고자 한다. (중략)

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1995.10a
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• pp.103-106
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• 1995

최근 시설재배 면적이 급증하고 있는 것에 부응하여 시설을 이용한 작물의 주년안정생산에 관한 연구가 활성화되고 있다. 그러나 여름철의 고온극복과 냉방에 관한 연구는 아직까지도 많은 어려움을 겪고 있다. 우리나라와 같이 사계절이 뚜렷한 기후여건에서는 겨울철의 난방 및 보온에 못지 않게 여름철의 냉방 및 고온극복 대책이 주년안정생산에 있어서 빼놓을 수 없는 중요한 과제가 아닐 수 없다. (중략)

• Journal of Bio-Environment Control
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• v.32 no.1
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• pp.15-22
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• 2023

Roses are one of the most produced flower species in the world, and cut roses are produced in the greenhouses all year round. Recently, due to the increase in the temperature in the greenhouses in summer, the quality of cut roses is seriously deteriorated, such as shortening the stem length. This study was conducted to investigate the effects of the growing seasons on the qualities of cut roses and also to test the effect of cooling at night in high temperature season on the cut flower qualities of roses. Comparing the qualities and yields of cut roses for each season, the major cut flower qualities such as flower stem length, stem diameter and fresh weight were statistically significantly decreased in roses ('Pink Beauty' and 'Pink Shine') produced in summer. The yields didn't show a statistically significant difference in both cultivars. Investigating the cut flower qualities, the flower stem length increased by 15% for 'Pink Beauty', 11% for 'Ararat', and 12% for 'Pink Shine' when treated with cooling at night in warm season than the untreated control. In addition, when treated with cooling at night in warm season, the fresh weight of all three cultivars increased by 20-30% statistically significantly than conventionally cultivated control. It is expected that cooling at night in warm season will be helpful to improve the cut flower quality deterioration in summer.

• KOREAN POULTRY JOURNAL
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• v.40 no.6 s.464
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• pp.111-113
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• 2008