• Journal of Bio-Environment Control
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• v.11 no.2
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• pp.81-87
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• 2002

This study was conducted to investigate the cooling efficiency and growth of tomatoes by root zone cooling device using a pad-box and cultivated system. The structure of the root zone cooling system using a pad-box was four piece of pads bonded an the side and a fan set at the bottom. Cool wind was generated by the outside air which was punched at intervals of 10 cm along three rows. Cold wind flowed to the root zone in the culture medium. The root zone cooling efficiency of cold wind generation by using a pad-box flowing through a wet-pad was determined. Major characteristic of this cuttural system consist of bed filled with a perlite medium and a ventilation pipe using PVC. The cold wind generation by a pad box (CWP) was compared to that of cold wind generation by a radiator (CWR), cold water circulation using a XL-pipe (CWX) and the control (non-cooling). When the temperature of water supplied was 16.2-18.4$^{\circ}C$, temperatures in the medium were 20.5~23.2$^{\circ}C$ for CWP 22.7~24.2$^{\circ}C$ for CWR, 22.8~24.27$^{\circ}C$ for CWX and 23.1~-29.6$^{\circ}C$ for the control. The results show that the cold wind temperature using the pad-box was lower by 1~2$^{\circ}C$ than that of cold water circulation in the XL-pipe and lower by 5~6$^{\circ}C$ than that of the control. Growth such as leaf length, leaf width, fresh weight and dry weight, was greater in three root zone cooling methods than in the control. Root activity was higher in the rat zone cooling methods than in the control. However, there was no significant difference among root zone cooling methods.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.129-129
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• 2017

태양광 발전으로 생산된 전력으로 냉방기나 난방기를 직접 구동하는 경우에 냉방을 위해서는 7,8,9월 집광량이 많아야 하고, 난방을 위해서는 12,1,2월에 집광량이 많아야 한다. 하지만 일반적으로 사용되는 집광판은 평판형의 고정식이 대부분으로 필요에 따라서 집광량을 변동시키는 것이 불가능하다. 따라서 전력부하가 가장 큰 시기에 집량광이 가장 많아지도록 설치되어야 한다. 본 연구에서는 최적의 집광판 설치조건을 구명하기 위하여 집광판의 설치 각도에 따른 년중 일사량을 예측하기 위한 모델을 개발하고 계산된 일사량과 기상청에서 실측한 일사량을 비교하였다. 분석 대상은 대전(북위 36도 22분)으로 하였다. 년간 최대 일사량을 확보할 수 있는 집광판 설치각은 $36^{\circ}$로 분석되었다. 반면에 월별로 최대 일사량을 확보하기 위한 집광판 설치각도는 1월에 $57^{\circ}$, 2월에 $48^{\circ}$, 3월에 $36^{\circ}$, 4월에 $24^{\circ}$, 5월에 $15^{\circ}$, 6월에 $12^{\circ}$, 7월에 $15^{\circ}$, 8월에 $24^{\circ}$, 9월에 $36^{\circ}$, 10월에 $45^{\circ}$, 11월에 $57^{\circ}$, 12월에 $60^{\circ}$로 예측되었다. 한편 냉방부하가 많은 6.7.8.9월에 최대 일사량을 확보하기 위한 집광판 설치각도는 $21^{\circ}$로 예측되었다. 이상의 결과로 볼 때 태양광 발전을 위한 집광판은 전력부하와 용처에 따라 적정한 설치각도를 결정하는 것이 중요한 것으로 판단되었고, 본 연구에서 개발된 예측모델이 이러한 작업에 유효하게 사용될 수 있을 것으로 판단되었다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.6
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• pp.65-70
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• 2020

In this paper, to establish a high-efficiency air-conditioning and heating system, we developed a simultaneous air-conditioning and heating system that can do both air-conditioning and heating at the same time. It was applied to hybrid plant plants to enable automation of complex farms. For this purpose, the heat exchanger, which functions as a condenser during heating, was required to function as an evaporator during cooling so that air conditioning and heating could be implemented simultaneously. For experiments, the simultaneous air conditioning system for heating and cooling was produced and applied to the plant factories in the farms so that plants could be grown, stored, and dried. As a result, a single system was able to control the temperature environment of agricultural products with an energy-saving system that simultaneously resolves heating and cooling. Therefore, efficient crop management was possible by implementing an air conditioning system that did not require installing air conditioners and boilers at the same time.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.6
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• pp.566-573
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• 2004

Comparison of the cooling performance is provided between the desiccant cool-ing systems incorporating a direct evaporative cooler and a regenerative evaporative cooler, respectively. Cycle simulation is conducted, and the cooling capacity and COP are evaluated at various temperature and humidity conditions. The COP of the system with a regenerative evaporative cooler and the regeneration temperature of 6$0^{\circ}C$ is evaluated 0.65 at the outdoor air condition of 35$^{\circ}C$ and 40% RH. This value is found about 3.4 times larger than that of the system with a direct evaporative cooler. Furthermore, incorporating a regenerative evaporative cooler eliminates the need for deep dehumidification in a desiccant dehumidifier that is necessary to achieve low air temperature in the system with a direct evaporative cooler. Subsequently, the regenerative evaporative cooler enables the use of low temperature heat source to regenerate the dehumidifier permitting the desiccant cooling system more beneficial compared with other thermal driven air conditioners.

• Journal of Energy Engineering
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• v.3 no.1
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• pp.44-53
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• 1994

STELF 기술의 핵심의 되는 IMPEX 블록의 잔류 공급률, 겉보기 밀도, 흑연의 혼합비 등 여러 가지 주요 변수가 블록의 특성에 미치는 영향을 조사하여 실제 반응기를 설계하는데 필요한 자료를 구하였다. 대표적인 염들에 대하여 물질전달 및 열전달 문제를 일으키지 않는 영역에서 최소의 부피를 갖는 값들을 계산하였고, 각각의 물질이 갖는 특정 전도도에서의 최대 냉방 및 난방 에너지 밀도를 계산하였다. 이로부터 얻은 값들을 8시간 동안 사용할 수 있는 6kW 냉방용 반응기 설계에 적용하여 본 결과 SrCL2-8/1 NH3가 최적의 염임을 확인하였다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.8
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• pp.780-786
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• 2001

For the compressor speed control of a multi-type air conditioning system, a fuzzy control algorithm was developed. The sum of zone temperature errors and its derivative were used as input variables, and the compressor speed was selected as the output variable. To test the effectiveness of the control algorithm, one outdoor environmental chamber and four indoor environmental chambers were used. In the chambers the zone temperature step change test and the indoor unit change over test were performed. Test results showed that, for the control of compressor speed, the fuzzy control algorithm was more effective than the conventional proportional control algorithm for the energy conservation.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.469-473
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• 2005

Capacities of a tandom-type air-conditioner may be modulated by turning on/off multiple compressors and adjusting positions of a electronic expansion valve. In this study. control algorithms for compressors and a electronic expansion valve were developed by using fuzzy’ logics. There algorithms were implemented in a test lab and proved to be effective for the control of indoor air temperature and superheat temperature.

• Journal of Energy Engineering
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• v.4 no.1
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• pp.67-75
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• 1995

50 kW 냉방용 화학열펌프에 관한 전산설계를 하기 위하여 반응기 모사용 부프로그램을 작성하였으며 전체 시스템을 위하여 상용모사기인 ASPEN PLUS를 이용하였다. 반응물로 각각 SrCl2-8/1 NH3 그리고 MnCl2-6/2 NH3를 사용하는 두 시스템에 대하여 비교 연구하였으며, 조작조건에 따라 시스템 설계치의 변화를 관찰하였다. 이로부터 향후 실용화될 화학열펌프 시스템에 대한 기본 설계자료를 제시할 수 있었다. SrCl2-8/1 NH3를 반응물로 한 경우 반응기의 UA는 6,868.2 J/(s·K), 출력은 95.2 kW이었고, 제한 성능 계수는 0.40이었다. MnCl2-6/2 NH3의 경우 UA는 1,569.7 J/(s·K), 출력은 109.0 kW이었으며 제한 성능계수는 0.34이었다. 이로부터 SrCl2-8/1 NH3을 반응물로 한 시스템이 MnCl2-6/2 NH3를 사용한 시스템보다 유리함을 알 수 있었다.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.675-680
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• 2006

Capacities of a tandem-type air-conditioner may be modulated by turning on and off of multiple compressors, and adjusting the position of a electronic expansion valve. In this study, control algorithms for compressors and a electronic expansion valve were developed by using fuzzy logics. The pressure control algorithm was also developed for the safe operation of compressors. There algorithms were implemented in a test lab and proved to be effective for the control of indoor air temperature and superheat temperature,

• Proceedings of the SAREK Conference
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• 2007.06a
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• pp.67-67
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• 2007