• Journal of Power System Engineering
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• v.18 no.6
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• pp.99-105
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• 2014

This paper presents a comparison of operating characteristics for industrial water cooler with variation control methods. The performance analysis regarding the characteristics of condensation capacity, evaporation capacity, compressor load, COP of an on-off type cooler, a hot gas-bypass control type cooler and an inverter control type cooler with respect to the system load is reviewed, respectively. The primary results are as following: the variation of required compressor load of an on-off type cooler with respect to load is 5%, that of hot gas-bypass type is 18% and 66% for an inverter control type cooler. As the result shows, an inverter control type yields relatively huge difference of required compressor load compared to other types of control system. In terms of partial load, COP of an inverter control type cooler presents the highest value, and is considered as the optimized type for the used of the system involving frequent partial load.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.1
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• pp.101-108
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• 2011

Understanding the exhaust gas recirculation (EGR) cooler fouling in diesel engine is important factor in the durability characteristic of a EGR system. We develope a test rig and PM feeder using carbon black to examine the effect of fouling on EGR cooler devices those were consisted of flat and shell & tube type. The EGR cooler fouling process is a complex interaction involving heat exchanger shape, boundary condition, constitutes, chemistry and operating mode. As the soot deposited to EGR cooler, these formed a thin deposit layer that was less heat exchange than the fresh status of tube enclosing the exhaust gas, resulting in lower heat exchange effectiveness in both type coolers. But these deposits caused different results in pressure drop, it is increased in flat type, but decreased in Shell & tube type of EGR cooler. A cause was estimated from a change of the flow structure and a decrease of contact area as the EGR cooler fouling.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.10
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• pp.769-775
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• 2008

In this study, the investigations on the dimpled type Exhaust Gas Recirculation (EGR) cooler have been focused on the high heat exchanger efficiency. To overcome low heat exchanger efficiency of general EGR cooler, the dimpled type EGR cooler was developed. It was ensured the improvement of the performance of the dimpled type EGR cooler related to the heat exchange based on a series of the experiment. These results were caused by the increase of thermal surface area in accordance with the dimple's one. The estimation model of the heat exchanger efficiency using the Effectiveness-NTU method was also developed in order to verify the validity of experimental result. Also, the program for the estimation of the heat exchanger efficiency on the EGR cooler with regard to the dimpled tube shape was developed. Resultantly, it was confirmed that the dimpled type EGR cooler could be served better performance than the conventional one in view of the heat exchanger efficiency.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.1
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• pp.30-36
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• 2010

The heat flowrate and pressure drop of $CO_2$ in a multi-tube-in-tube helical coil type gas cooler were investigated experimentally. The mass flowrate of $CO_2$ and coolant were varied from 0.06 to 0.075 [kg/s], respectively and the cooling pressure of gas cooler were from 8 to 10 [MPa]. The heat flowrate of $CO_2$ in the test section is increased with the increase in mass flowrate of coolant, the cooling pressure and mass flowrate of $CO_2$. The pressure drop of $CO_2$ is decreased with the decrease in mass flowrate of coolant and $CO_2$, but decreased with increase in cooling pressure of $CO_2$. The heat flowrate of $CO_2$ in the multi-tube-in-tube helical coil type gas cooler is greatly higher than that of $CO_2$ in the double pipe type gas cooler, while the pressure drop of $CO_2$ in the multi-tube-in-tube helical coil type gas cooler is greatly lower than that of $CO_2$ in the double pipe type gas cooler. Therefore, in case of the application of $CO_2$ at the multi-tube-in-tube helical coil type gas cooler, it is expected to carry out the high-efficiency, high-performance and compactness of gas cooler.

• Journal of Advanced Marine Engineering and Technology
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• v.16 no.4
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• pp.78-87
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• 1992

The experimental study and theoretical analysis are made in order to investigate a new refrigeration system, R-22 and R-502 or R-13 cascade compressor with panel type cooler, for tuna long liner. The experimental apparatus consists with the cascade unit, 1.5 HP R-502 compressor in the first stage and 1 HP R-22 compressor in the second stage, and 3 $m^2$ cold storage room with a direct expansion panel type cooler. The main result are as follows: 1. The energy saving and C.O.P. of the R-22 and R-502 or R-22 and R-13 cascade are improved much higher than two stage compressor. 2. For the point of simplicity of design, installation, and running cost, the panel type cooler is much better than traditional hair pin coil type cooler. 3. From the experimental data and analysis, the R-22 and R-502, or R-22 and R-13 cascade compressor with panel type cooler is recommended for a new refrigeration equipment of the tuna long liner.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.7
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• pp.447-454
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• 2008

The regenerative evaporative cooler(REC) is to cool a stream of air using evaporative cooling effect without an increase in the humidity ratio. In the regenerative evaporative cooler, the air can be cooled down to a temperature lower than its inlet wet-bulb temperature. Besides the cooling performance, for practical application of the regenerative evaporative cooler, the compactness of the system is also a very important factor to be considered. In this respect, three different configurations, i.e., the flat plate type, the corrugated plate type, and the finned channel type are investigated and compared for the most compact configuration. The optimal structure of each configuration is obtained individually to minimize the volume for a given effectiveness within a limit of the pressure drop. Comparing the three optimal structures, the finned channel type is found to give the most compact structure among the considered configurations. The volume of the regenerative cooler can be reduced to 1/8 by adopting the finned channel type as compared to that of the flat plate type.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.4
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• pp.429-435
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• 2011

In this study the operational characteristics of the temperature control system between an on-offemployed cooler and a bypass type cooler is analyzed. Currently an on-off controller employed coolerwhich is the industry's leading type on the market for industrial coolers is used. The new type cooler isused a bypass controller at discharge gas. The COP of the bypass controlled cooler with discharge gas is at least 8% higher than the on-off controlled cooler. The maximum COP difference is about 20%. Based on the results, the bypass control with discharge gas shows the possible temperature control with high precision.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.5
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• pp.439-444
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• 2008

The heat capacity and pressure drop of $CO_2$ and coolant in a multi-tube type gas cooler were investigated experimentally. The main components of the refrigerant loop are a receiver, a $CO_2$ compressor, a mass flow meter, an evaporator and a multi-tube type gas cooler as a test section. The mass flowrate of $CO_2$ and coolant were varied from 0.06 to 0.075 [kg/s], respectively and the cooling pressure of gas cooler were from 8 to 10 [MPa]. The heat capacity of $CO_2$ in the test section is increased with the increment in mass flowrate of coolant, the cooling pressure and mass flowrate of $CO_2$. The pressure drop of $CO_2$ is decreased with the decrease in mass flowrate of coolant and $CO_2$, but decreased with increase in cooling pressure of $CO_2$. The heat capacity of $CO_2$ per unit heat transfer area of gas cooler is greatly high. Therefore, in case of the application of $CO_2$ at the multi-tube type gas cooler, it is expected to carry out the high-efficiency, high-performance and compactness of gas cooler.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.1
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• pp.89-99
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• 1999

The automatic design of shell & tube type oil cooler can be used in real industrial environments. Since the automatic design system is intended to be used in small companies, it is designed to be operated well under environments of CAD package in the personal computer. It has adopted GUI in design system, and has employed DCl language. Design parameters to be considered in the design stage of shell and tube type oil cooler are type of oil cooler, outer diameter, thickness, length of tube, tube arrangement, tube pitch, flow rate, inlet and outlet temperature, physical properties, premissive pressure loss on both sides, type of baffle plate, baffle plate cutting ratio, clearance between baffle plate outer diameter and shell inner diameter and clearance between baffle plate holes. As a result, the automatic design system of shell & tube type oil cooler is constructed by the environment of CAD software using LISP. We have built database of design data for various kinds of shell & tube type oil coolers. The automatic design system have been assessed and compared with existing specification of design. Good agreement with Handbook of heat exchanger and design dta of real industrial environments has been found.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.233-236
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• 2003

In this Paper, the temperature control error and cooling characteristics of inverter typ coolers are evaluated to predict application validity of coolers under heating pattern and amount The temperature control error of coolers small in 15~70% range of the max. cooling ability. At less than 15% of max. cooling ability has the inverter type cooler a basic temperature control error $\pm0.5^{\circ}C$ and acts as on/off type coolers. The inverter type cooler is unsuitable for precision temperature control under the complex heating pattern. But PID control of cooler including the heating system is an alternative for the case.