• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.1
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• pp.36-42
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• 2007

The latest cars give much importance in the role of HVAC system that controls the environment of the area for passengers more than just basic capability In this study, we drew the automobile interior as three dimension and arranged a method of numerical analysis on HVAC environment in the automobile interior displaying air current distribution and temperature distribution through simulation of the automobile interior on the ventilation volume and outlet area, The aim of this study is to develop the estimated method for HVAC environment in the automobile interior. Results of numerical analysis, to cool automobile interior needs more considerations if thinking cheerful surroundings of automobile interior air but the more magnitude of outlet is small, the more cooling capability is excellent and realistic countermeasures about a realistic geometry and boundary condition.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.3
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• pp.228-234
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• 2007

Opening an ancient tomb interior can deal fair damage for preservation in long period because of high moisture. In this study, a duct-type HVAC system was installed to preserve an ancient tomb and temperature and humidity was measured to analyze heat environment. Armhole was measured to search whether an ancient tomb receives effects of vibration caused by a duct-type HVAC system. According to the measured data, temperature in an ancient tomb is kept adaptively in conservation regardless of a duct-type HVAC system installation when it rains in summer. The other side, humidity is kept adaptively in conservation when installed duct-type HVAC system. But when it is in natural state, a lot of humidity by dew condensation phenomena. So it needs a duct-type system for an ancient tomb conservation. In the case of vibration, measurement value of 3 satisfy control but Germanic DIN 4150 does not satisfy. Therefore, equip must be such that it can prevent vibration for safety.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.9
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• pp.979-988
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• 2014

Recently, the interest in the thermal comfort is ever increasing as the time people stay in the automobile is gradually increasing. So far, however, the cooling performance of the HVAC(heating and ventilation air conditioning) system is evaluated by thermal environment criteria such as indoor air velocity and temperature, not by a thermal comfort index. Furthermore, the precise criteria has not been established yet when the thermal comfort for the automobile is evaluated using numerical analysis. In this study, the numerical analysis of automobile indoor thermal comfort according to various parameters such as HVAC operating mode, airflow, passenger boarding conditions is performed during the HVAC system's initial operating time(20 minutes). The solar ray tracing model and S2S radiation model are used and validated to simulate an external heat source. Based on this study, an evaluation model which can predict the thermal comfort index for the combination of the above parameters is presented.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.1
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• pp.23-28
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• 2012

In the present work, numerical analyses of air flow in HVAC duct have been carried out for enhancement of cooling/heating performance. For the analyses, three-dimensional Reynolds-averaged Navier-Stokes equations have been solved with the shear stress transport turbulence model. The numerical results were validated in comparison with the experimental data. Based on the numerical results, the HVAC duct was designed to reduce the pressure loss. The modified duct geometry shows largely reduced pressure drop in comparison with the reference geometry. And, through modified duct shape, the performance of air conditioning has been enhanced.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1272-1276
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• 2009

The purpose of this study is to introduce wasted heat recovery heat exchanger for different kind of material in HVAC systems in field. For the purpose of estimating the large volume rotary heat exchanger and cross flow plate heat exchanger in heat recovery ventilator.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.6 s.249
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• pp.728-733
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• 2006

The reduction of the Vehicle interior noise has been the main interest of NVH engineers. The driver's perception on the vehicle noise is affected largely by psychoacoustic characteristic of the noise as well as the SPL. In particular, the HVAC sound among the vehicle interior noise has been reflected sensitively in the side of psychology. In previous study, we have developed to verify identification of source for the vehicle HVAC system through multiple-dimensional spectral analysis. Also we carried out objective assessments on the vehicle HVAC noises and subjective assessments have been already performed with 30 subjects. In this study, the linear regression models were obtained for the subjective evaluation and the sound quality metrics. The regression procedure also allows you to produce diagnostic statistics to evaluate the regression estimates including appropriation and accuracy. Appropriation of regression model is necessary to $R^2$ value and F-value. And testing for regression model is necessary to independence, homoscedesticity and normality. Also we selected optimum layout of damping material using Taguchi method. As a result of application, sound quality is improved more quietly, powerfully, even though costly, and smoothly.

• The Journal of the Acoustical Society of Korea
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• v.8 no.1
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• pp.59-66
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• 1989

This study aims to provide the basic data useful in assessing indoor-noise and designing sound devices in office buildings of HVAC system. The measurements of HVAC noise were carried out in office room and mechanical room. The performance of absorptive chamber and side branch was also estimated in the office buildings which have HVAC noise problems. The results of experiments show that the NR value of indoor HVAC noise is rather higher than that of ISO recommendations at the frequencies below 500Hz. In addition, the results indicated that the absorptive chamber attenuates noise over broad band frequencies and side branch reduces noise at the special resonant frequency.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.7
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• pp.363-370
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• 2013

HVAC&R systems are the most energy consuming building services, representing approximately half of the final energy use in the building sector. Despite their significant energy use, there is a lack of a consistent and homogeneous framework to efficiently guide research. This research is about the energy consumptions of HVAC&R systems, with the aim of establishing a common idea for the analysis of building energy efficiency. Our approach deals with the concept of an HVAC&R set that is composed of subsystems. A matrix combination evaluation is examined, and a total of 960 sets can be implemented in a large scale office building. A method as a tool for energy evaluations of HVAC&R systems, and HEET as a energy simulation program, were developed.

• International Journal of Air-Conditioning and Refrigeration
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• v.14 no.4
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• pp.138-146
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• 2006

Recently, a technology based on the proportional integral (PI) control have grown rapidly owing to the needs for the robust capacity of the controllers from industrial building sectors. However, PI controller generally requires tuning of gains for optimal control when the outside weather condition changes. The present study presents the possibility of reinforcement learning (RL) control algorithm with PI controller adapted in the HVAC system. The optimal design criteria of RL controller was proposed in the environment chamber experiment and a theoretical analysis was also conducted using TRNSYS program.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.537-540
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• 2008

A numerical study has been carried out on the optimization of an air cleaning system which was installed in a heating, ventilation and air conditioning system (HVAC) system of subway station for particle removal. Required particle removal efficiencies of three different air cleaning systems were calculated from ventilation rate, and indoor/outdoor concentration of PM10. Mass balance equations of PM10 were used to solve the required particle removal efficiencies. Fibrous filter was considered as an air cleaning system. Calculations were carried out about two different places which were waiting area and platform of subway station, respectively. This study proposed optimized design and operation condition of each air cleaning system.