• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.11 no.5
• /
• pp.598-604
• /
• 1999

The thermal performance of cooling towers is affected by the temperature of inlet water, wet bulb temperature of entering air add water-air flow rate. In this study, the effects of these variables are simulated using NTU-method and experimentally investigated for the counter-flow cooling towers. The simulation program to evaluate these variables which affect the performance of cooling tower was developed. The maximum errors between the results of simulations and experiments were 3.8% under the standard design conditions and 5.4% under the other conditions. The performance was increased up to 46~50% as the water loading was increased from $6.8m^3$/$hr\cdot m^2$ to $15.9m^3$/$hr\cdot m^2$. The range was reduced up to 56~42% when the wet bulb temperature of the entering air was increased from $22^{\circ}C\; to\; 29^{\circ}C.$

• Journal of Bio-Environment Control
• /
• v.29 no.3
• /
• pp.259-264
• /
• 2020

In this study, the humidity control effect of a counter-flow ventilator was analyzed in a greenhouse with high relative humidity at night in the winter season. A case of the counter-flow ventilator was 0.96 × 0.65× 0.82(W × D × H, m) and there were heat transfer element and two fans for air supply and exhaust in the counter-flow ventilator. Two counter-flow ventilators were used in this study and the setting humidity of the ventilators was 80%. The temperature and relative humidity at night(18:00-8:00) in the greenhouse were measured. In a greenhouse without a counter-flow ventilator, the average temperature and humidity was 14.9℃, 82.8%, respectively. When the counter-flow ventilator was operated, the corresponding averages were 15.1℃, 79.9%. The independent sample t test of monthly temperature and relative humidity showed no difference in temperature, and a significant difference in relative humidity with 1% of the significance level. Therefore, using the counter-flow ventilator helps to control relative humidity in greenhouse and increase yield.. And further research considering the pros and cons of using the counter-flow ventilator is needed.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.3
• /
• pp.802-807
• /
• 2010

The high efficient and cooling system is very important to the control panels of electrical distributors, and Industrial automated system including computer. Also, it can be used widely in various industrial systems such as industrial robots, numerically controlled machining center, and so on. The cooling method which flowing gasses were forced to circulate by compulsion was adapted in this study. then development of counter flow type of cooling system for effective panel cooling. In the present study, fin assembly was developed for this cooling system. As results, the developed system has the improvements of cooling performances and radiant heat ratio. Its increasing of airflow mass is about 20%, and radiation rate of heating is twice or more as high as the conventional system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.14 no.3
• /
• pp.191-198
• /
• 2002

Cooling tower design procedure was set up using conventional Merkel theory, The design data could be different depending on the characteristic curve that the engineer chose. It reveals that the consistent and reasonable criteria are required based on the exact information of the cooling tower Performance. In this study, an off-design performance analysis program for a counterflow-type cooling tower was developed and verified by comparing with experimental data. Also, the off-design performance with various operating conditions was analyzed.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.9 no.1
• /
• pp.84-93
• /
• 2001

The aim of this study is to provide fundamental informations that make it possible to use a cool stream and a hot stream simultaneously. We changed the pressure of compressed air that flows into a tube, the inner diameter of orifice that a cold stream exits, and the mass flow rate ratio. And in each case, we measured the temperature of a cold stream and a hot stream in each exit of a tube. Also we measured the axial temperature distribution and the radial temperature distribution in internal space of a tube. From the study, following conclusive remarks can be made. Average flow rate that flows into a tube is in proportion to square root of inlet pressure. As inlet pressure increases axial and radial temperature distribution in the inner space of vortex-tube increase. As mass flow rate ratio change, separation point moves.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.10 no.4
• /
• pp.69-76
• /
• 2002

The aim of this study is to provide fundamental informations that make it possible to use a cool stream and a hot stream simultaneously. We changed the pressure of compressed air that flows into a tube, the inner diameter of orifice that a cold stream exits, and the mass flow rate ratio. And in each case, we measured the temperature of a cold stream and a hot stream in each exit of a tube. Also we measured the axial and the radial temperature distribution in internal spare of a tube. From the study, fellowing conclusive remarks 7an be made. First, As the number of nozzles increase, separation point move into the hot exit. Second, When we use guide vane type nozzle, the axial temperature distribution constant over the 0.75 of air mass flow rate radio. Third, When we use Spiral type nozzle, axial and radial temperature distribution in the inner space is higher than another nozzle. Fourth, Axial and radial temperature distribution in the inner space vortex-tube is determined by separation point. And separation point is moved by changing of air mass flow rate ratio. At last, A heating apparatus is possible far vortex-tube to use.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2005.11a
• /
• pp.236-237
• /
• 2005

An experimental study on the Hybrid Cooling Tower has been done having a rated capacity of 3RT. Counter flow type fill, cross flow type fill and hybrid-type fill which is combined with two type fills as previously stated having a height of 0.3m have been used in the 0.8m${\times}$0.4m${\times}$1.9m dimensional tower respectively. The heat exchanger is consisting of 2 or 3 rows. The relevant temperatures and the velocities were selected based on the typical Korean weather for the year round operation of the tower. The cooling capacity of the tower is explained with respect to varying air inlet velocities, wet-bulb temperatures, and air to cooling water volume flow rate ratio (L/G ratio). The capacity of the hybrid-type fill was much superior to other fills, but hybrid-type fill shows higher pressure drop.

• Proceedings of the SAREK Conference
• /
• 2005.11a
• /
• pp.359-364
• /
• 2005

In dehumidification evaporation cooling system. the regeneratie evaporative cooler(REC) makes an important role to reduce the sensible cooling load in the system through evaporative cooling, By this reason, many studies about increasing the cooling capacity of the REC were undertook. In this paper, we analyzed the cooling characteristics of the REC due to the structures of the REC and determined the best structure for the REC's effectiveness and cooling capacity. From the study. we could obtain some important results: at first. corrugated type has the benefit to expand the channel width of the REC, But because the type has some weak points about the size and weight. there is almost no benefit to improve the performance of the REC. Through these reasons. we decided that finned type is the best structure to improve the performance of the REC.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.10 no.5
• /
• pp.535-549
• /
• 1998

A numerical study for performance analysis of a counterflow type forced draft tower and natural draft cooling tower has been performed based on the method using the finite volume method with non-orthogonal body fitted and non-staggered grid system. For solving the coupling problem between water and air, air enthalpy balance, moisture fraction balance, water enthalpy balance, and water mass balance equations are solved with Navier-Stoke’s equations simultaneously. For the effect of turbulence, the standard k-$\varepsilon$ turbulent model is implied in this analysis. The predicted result of the present analysis is compared with the experimental data and the commercial software result to validate the present study, The predicted results show good agreement with the experimental data and the commercial software result. To investigate the influence of the cooling tower design parameters such as approach, range and wet bulb temperature, parametric studies are also peformed.

• Journal of the Korean Society of Industry Convergence
• /
• v.25 no.4_2
• /
• pp.565-572
• /
• 2022

The white plume from the cooling tower can be generated by mixing between discharging hot and humid air and cold air outside. This causes various problems such as icing, traffic disturbances, and fire factors in the vicinity, moreover it can also damage the image of a company. Various methods can be used to prevent white plume, one of them is to install a heat exchanger at the outlet of the cooling tower so that the heat exchanger transfers as much heat as possible to lower the temperature. Therefore the air flow path in the cooling tower should be optimized. Installation of the filler can be used to make the air flow better, thus we investigate the effect of filler on the air flow using CFD method. The pressure and velocity profile in the cooling tower could be acquired by the calculations. The filler made the velocity of the air entering the heat exchanger uniform this was because high flow resistance of the filler suppresses the generation of eddy in the cooling tower. But the total air pressure drop increased about 2 times with filler because the pressure drop by the filler accounted for about 60% of the total pressure drop.