• Journal of Power System Engineering
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• v.12 no.4
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• pp.32-38
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• 2008

The improvement of cooling ability for the air conditioner is the most efficient method of application of its system. Therefore, this study has been investigated the improvement of cooling ability for the air conditioner using automotive by attached of a thermoelectric module. According to the result of test, capacity of the thermoelectric module make temperature range from $-75^{\circ}C$ to $+300^{\circ}C$ possible to cooling and exothermic. In addtion to, the reduction effect of energy revealed and the effect of liquid hammer remained with safety by attached the thermoelectric module. It was found that the air conditioner system by attached thermoelectric module have better cooling ability than the air conditioner system of existing vehicle.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.3
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• pp.87-93
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• 2008

The $CO_2$ air conditioning system installed in fuel cell vehicles could be used either for stack cooling or for cabin cooling, and thus was used for the stack cooling when additional stack heat release was required over a fixed radiator capacity for high power generation. This study investigated the performance of the stack cooling system using $CO_2$ air conditioner at various operating conditions. Also, the heat releasing effectiveness and mutual interference were analyzed for the stack cooling system using an air conditioner and compared with the conventional radiator cooling system with/without cabin cooling. The heat release of the stack cooling system with the aid of $CO_2$ air conditioner increased up to 36% more than that of the conventional radiator cooling system with cabin cooling. Furthermore, the heat release of the stack cooling system using $CO_2$ air conditioner increased more by 7% than that of the conventional radiator cooling system without cabin cooling.

• Journal of Biosystems Engineering
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• v.36 no.5
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• pp.319-325
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• 2011

This study was conducted to figure out the diagnosis basis of cooling performance depending on water amount in the refrigerant of air conditioner, which can be estimated by the temperatures and pressures along the refrigerant circulation line. A car air conditioner of SONATA III (Hyundai motor Co., Korea) was tested at maximum cooling condition at the engine speed of 1500 rpm in the room controlled at 33~$35^{\circ}C$ air temperature and 55~57% relative humidity conditionally. Measured variables were temperature differences between inlet and outlet pipe surfaces of the compressor, condenser, receive drier and evaporator; and high pressure and low pressure in the refrigerant circulation line; and temperature difference between inlet and outlet air of the cooling vent of evaporator. In this study, changes of the water amount in the refrigerant were correlated to the temperatures and pressure changes and also water amount caused poor cooling performance. As water amount increased in the refrigerant in the air conditioner, the performance of the cooling or the heat transfer became worse. Temporal variations of the surface temperature of the evaporator outlet pipe and the low-side pressure showed various patterns that could estimate the water amount. When the water amount caused bad cooling performance, the patterns of the temperature of the evaporator outlet pipe indicated irregular fluctuation greater than $5^{\circ}C$. When the diagnosis system is using just external sensors of the low-side pressure and the temperatures of inlet and outlet air of cooling vent of the evaporator, the precise pattern of bad cooling performance caused by excess water amount in the cooling line was irregular pressure fluctuation, 25 kPa under 120 kPa, and temperature, $12^{\circ}C$ and less.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.11
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• pp.943-956
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• 2003

A numerical program has been developed for the simulation of automotive engine cooling system. The program determines the mass flow rate of engine coolant circulating the engine cooling system and radiator cooling air when the engine speed is adopted by appropriate empirical correlation. The program used the method of thermal balance at individual element through the model for radiator component in radiator analysis. This study has developed the program that predicts the coolant mass flow rate, inlet and outlet temperatures of each component in the engine cooling system (engine, transmission, radiator and oil cooler) in its state of thermal equilibrium. This study also combined the individual programs and united into the total performance analysis program of the engine cooling system operating at a constant vehicle speed. An air conditioner system is also included in this engine cooling system so that the condenser of the air conditioner faces the radiator. The effect of air conditioner to the cooling performance, e.g., radiator inlet temperature, of the radiator and engine system was examined. This study could make standards of design of radiator capacity using heat rejection with respect to the mass flow rate of cooling air. This study is intended to predict the performance of each component at design step or to simulate the system when specification of the component is modified, and to analyze the performance of the total vehicle engine cooling system.

• Journal of Biosystems Engineering
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• v.34 no.6
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• pp.470-475
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• 2009

This study was performed to present the diagnosis basis of cooling performance deficiency according to air quantity included in refrigerant of air-conditioner by detecting the temperatures and pressures of refrigerant pipeline. The car air-conditioner of SONATA III (Hyundai motor Co., Korea) was tested by maximum cooling condition at 1500 rpm of engine speed in the room with controlled air condition at $33\sim35^{\circ}C$ and 55~57% RH. Measured variables were temperature differences between inlet and outlet pipe surface of the compressor (Tcom), condenser (Tcon), receive dryer (Trec) and evaporator (Teva), and high pressure (HP) and low pressure (LP) in the refrigerant pipeline, and temperature difference (Tcoo) between inlet and outlet air of the cooling vent of evaporator. Control variables were the refrigerant charging weight and the vacuum degree in the refrigerant pipeline before charging refrigerant. From the test, it was represented that the measuring values of (Tcom), LP and (Tcoo) were enabled to make the diagnosis of cooling performance deficiency according to quantity included in refrigerant of air-conditioner. The ranges of Tcom, LP and Tcoo to make the diagnosis of cooling performance deficiency were respectively less than $55^{\circ}C$, more than 166.7 kPa-g(1.7 kgf/$cm^2$) and less than $13.7^{\circ}C$. In the case of using only external sensors and the condition under the normal performances of air conditioner, it was considered that the ranges of LP and Tcoo to make the diagnosis of cooling performance deficiency were respectively more than 166.7 Pa and less than $12^{\circ}C$.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.6 no.1
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• pp.47-53
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• 1994

Cycle simulation of the air-conditioner was carried out using a number of candidate alternatives to R22;R32/R125/R134a(30/10/60, by mass percent), R32/R125/R134a(10/70/20), R32/R134a(25/75), R32/R134a(30/70), R32/R125(60/40), R290(propane) and R134a. In this study, we considered only the basic parts of the air-conditioner such as the compressor, the evaporator, the condenser and the capillary tube, for the purpose of analysis. The performance characteristics of alternatives considered here were examined by comparing with the case using R22 at the constant volumetric flow rate condition. The results of our analysis revealed that the use of refrigerant mixtures, R32/R134a(30/70) and R32/R125/R134a(30/10/60), was appropriate for the alternatives to R22 in view of the cooling capacity and the COP. For the case of using R134a and R290, the COP was observed to increase under the same volumetric flow rate condition, but the cooling capacity was substantially decreased. Therefore the use of R134a and R290 should be accompanied with increasing considerably the size of compressor in order to maintain the same cooling capacity of R22.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1274-1279
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• 2004

We performed the numerical study on the comparison of thermal comport performance indices for cooling loads in the classroom when the 4-way cassette air-conditioner is mounted on the ceiling. We investigated the velocity and the temperature distribution of the classroom as with respect to the variation of the air diffusion angle of the air-conditioner. Air diffusion performance index and Predicted mean vote were used for analyzing the characteristics of the thermal comport in the classroom and comparing their values each other. From the numerical results, we knew that the thermal comport is largely affected by the air diffusion angle and velocity of the air-conditioner. And we also found out that the qualitative tendency of the distribution between Air diffusion performance index and Predicted mean vote is very similar in all occupied zone.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.6
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• pp.541-548
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• 2001

The objective of this study is to analyze the possibilities and considerations for the application of the radiant floor cooling system by analyzing the problems of a conventional cooling system through field tests and thermal performance simulations of the radiant floor cooling in an apartment building. The results are as follows. (1) Problems of he conventional cooling system with PAC()packaged air conditioner)'s include draft, local discomfort, and excessive electrical peak demand. (2) According to the measurement during the cooling and intermediate seasons, the floor surface temperatures which are experienced at the time of cooling with PAC\`s and during intermediate season are similar to the temperatures for radiant floor cooling. (3) The radiant floor cooling system is applicable to apartment buildings during the cooling season, especially on hot and clear days.

• Proceedings of the SAREK Conference
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• 2004.06a
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• pp.27-27
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• 2004

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.609-614
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• 2008

The heating and cooling performance of system multi-air conditioner under high-head and long-line conditions are experimentally investigated. The maximum head and tube length were 110 m and 1000 m, respectively. The experimental system was composed of 4 outdoor units with module systems, and 13 indoor units which were joined with the mode change unit by single-tube circuit. Field tests without indoor and outdoor temperature control were performed in a general office building with 22 different working conditions. Experimental results were prepared on the p-h diagram. Also the oil level in the compressor was normally maintained at the safety zone for the system multi-air conditioner with high-head and long-line conditions.