• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.39 no.1
• /
• pp.37-43
• /
• 2015

Evaporative cooling is a very effective way for exhaust heat recovery that uses both latent heat and sensible heat. This study investigated the performance of a heat recovery system using evaporative cooling. The experimental apparatus comprised a plastic heat exchanger, a water spray nozzle, an air blowing fan, a water circulation pump, and measuring sensors for the temperature, humidity, and flow rate. The effectiveness of the sensible heat recovery without evaporation was measured and compared with that of the total heat recovery with evaporation. The effectiveness of the sensible and total heat recoveries decreased as the air flow rate increased, and a much higher effectiveness was obtained with the counterflow arrangement in both cases. For total heat recovery, the effectiveness increased with the water flow rate, and the parallel flow arrangement was found to be more sensitive to the water flow rate than the counterflow arrangement.

• Proceedings of the Korean Society for Bio-Environment Control Conference
• /
• 1995.10a
• /
• pp.74-77
• /
• 1995

냉동기등의 냉방장치에 의한 온실의 기온하강은 주간에 과다한 일사부하로 인하여 경제적으로 불가능하기 때문에 현재 증발냉각법이 주로 이용되고 있다. 그러나 증발냉각법의 구체적인 설계기준안에 대한 국내연구는 전무한 실정이다. 따라서 본 연구는 우리나라 기상여건을 고려하여 증발냉각법을 위한 설계기준안을 제시하고자 하였다. (중략)

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
• /
• v.15 no.1
• /
• pp.67-81
• /
• 1986

냉각탑, 밀폐식냉각탑, 증발식응축기는 증발식냉각기의 분류에 속한다. 열은 증발에 의해 제거되어, 중력에 따라 유하하는 수 film으로 부터 충전물, 또는 밀폐식냉각탑, 증발식응축기의 관군상을 흐르는 공기에 전달된다. 따라서 공기측에서의 열과 물질의 이동프로세스는 기본적으로는 동일하다. 각 형식에서의 차이는 냉각되는 유체측에서의 열저항의 형태가 다르다는 점이다. 이 무저항은 냉각탑에서는 아주 작으나 다른 두 경우에 있어서는 계산상 고려하지 않으면 안된다. 이 논문은 이들 세 형식에 대해 통일된 이론을 적용할 수 있다는 것을 보여주기 위한 것이다. 그러므로 열 및 물질이동저항의 계산을 위한 식에 대해 논의하고 있다. 또한 복잡성을 피하기 위해, Merkel의 근사식을 공기측의 열 및 물질이동계산에 이용하였다.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.39 no.9
• /
• pp.743-749
• /
• 2015

The purpose of this study is to predict the performance of an indirect evaporative cooling system, and to evaluate its energy saving effect when applied to the exhaust heat recovery system of an air-handling unit. We derive the performance correlation of the indirect evaporative cooling system using a plastic heat exchanger based on experimental data obtained in various conditions. We predict the variations in the performance of the system for various return and outdoor air conditioning systems using the obtained correlation. We also analyze the energy saving of the system realized by the exhaust heat recovery using the typical meteorological data for several cities in Korea. The average utilization rate of the sensible cooling system for the exhaust heat recovery is 44.3% during summer, while that of the evaporative cooling system is 96.7%. The energy saving of the evaporative cooling system is much higher compared to the sensible cooling system, and was about 3.89 times the value obtained in Seoul.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.11
• /
• pp.892-897
• /
• 2020

Previous plastic heat exchangers are expensive because the mold must be newly manufactured depending on the air conditioning space. On the other hand, danpla is so thin that the heat exchange performance is excellent. Moreover, danpla can be used easily in ventilation systems in view of fabrication. This study proposes correlations for the cooling performance of an indirect evaporative cooling system. The experimental apparatus consisted of a heat exchanger, spray nozzle, fan, thermostat, pump, and measuring sensors for temperature, humidity, and airflow rate. The results showed that the effectiveness decreased gradually as the airflow rate increased. In addition, there was an optimal condition in terms of effectiveness. The performance prediction correlations were determined using the experimental data from various conditions. The proposed correlations showed performance accuracies within 4 % error.

• Proceedings of the Korean Society for Bio-Environment Control Conference
• /
• 1998.05a
• /
• pp.11-15
• /
• 1998

증발냉각시스템의 원리는 물이 수증기로 상태변화할 때 필요한 기화열을 주변으로부터 공급받으면서 공기의 온도가 감소하는 것이다. 이것은 덥고 건조한 지역에서는 매우 효과적이지만 상대습도가 높은 지역에서는 냉방효과가 낮다. 따라서 국내의 모든지역에 증발냉각시스템의 적용이 적합한지는 의문이다. (중략)

• Journal of Bio-Environment Control
• /
• v.7 no.4
• /
• pp.283-289
• /
• 1998

The adaptability of an evaporative cooling system to hot summer climate in greenhouses was comprehensively judged by fuzzy theory, based on the 20 years(1975~1994) weather data of nine representative regions in Korea. As uses the evaporative cooling system for greenhouses during summer in Korea, the inside air temperature of most regions except the southwest coastal areas, the south coastal areas, and Cheju island can be basically controlled below 32.5$^{\circ}C$, and ventilating air can be cooled 5$^{\circ}C$ and more. The analyzed results in this paper are on the basis of good ventilation system. When the evaporative cooling system is applied, the ventilation system which has good air flow organization is needed. Although the summer climate in Korea is high temperature and humidity, evaporative cooling systems are suitable for farm buildings in most regions. This facts better meet the needs of cooling for greenhouse in summer and provides a scientific basis for spreading the evaporative cooling system It is proposed that the further research is needed about the application of evaporative cooling system to greenhouses.

• Journal of Bio-Environment Control
• /
• v.7 no.3
• /
• pp.237-245
• /
• 1998

Greenhouse crop production under critical summer climate In Korea has considerable difficulties because of high temperature and relative humidity. In this study, some water pipes were tested as a means of the dehumidification and increment of evaporative cooling efficiency. As a result of heat transfer characteristic analysis, overall heat transfer coefficient of copper pipe was larger than steel pipe, and estimated values were smaller than measured values. The condensed quantities of vapor were not significantly different between copper pipe and steel pipe, however dehumidifying effect by the water pipes was significantly large. It was estimated based on the results that the evaporative cooling system by the water pipe will be able to increase the evaporative cooling efficiency of about 48%, and decrease the temperature of about 1.3$^{\circ}C$.

• Journal of the Korean GEO-environmental Society
• /
• v.23 no.4
• /
• pp.11-20
• /
• 2022

In order to acquire hydraulic characteristics for unsaturated layers, water retention tests were performed and compared by using the evaporation method, volumetric pressure plate extractor (VPPE) and chilled-mirror dew point method. The evaporation and chilled-mirror method are currently developed experimental technology and measure the water retention curve of unsaturated soils quickly and accurately. In the evaporation and VPPE method, the water retention has been measured and compared until 100kPa matric suction and consequently the result of the evaporation method could be verified. In the chilled-mirror method, the water retention has been measured until high level of matric suction and the overall shape of water retention curves could be obtained. As a result of water retention tests, the representative water retention curves were obtained and the applicability of each test method was discussed. Using both the evaporation and chilled-mirror methods, the soil water retention curve can be acquired reasonably for the whole range of matric suction.

• Journal of Bio-Environment Control
• /
• v.19 no.4
• /
• pp.183-188
• /
• 2010

It is necessary to develop an efficient and affordable cooling technology and apply the practical system to rural farmhouse, control to adequate growth environment by adjusting temperature of root zone. A study on managing medium temperature of the hydroponics for strawberry cultivation was conducted and feasible evaporative cooling system for the media cooling were as follows: Characteristics of temperature drop were investigated for the evaporative cooling devices using microporous film duct, felt mulching on media surface, and water permeable sheet in culture tank. The evaporative device with water permeable sheet in culture tank was the most efficient and economic on media cooling system.