• Title/Summary/Keyword: Air Conditioner

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A Study on the Comparison of Thermal Comport Performance Indices for Cooling Loads in the Classroom (학교건물에서 냉방부하에 따른 열적 쾌적성 평가지표 비교 연구)

  • Noh, Kwang-Chul;Oh, Myung-Do
    • 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.

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Program Development for Detecting Charged Refrigerant Amount in System Air-Conditioner using Fuzzy Algorithm (퍼지 알고리즘을 이용한 시스템 에어컨의 냉매충전량 감지 프로그램 개발)

  • Tae S. J.;Choi C. S.;Kim H. M.;Cho K.;Moon J. M.;Kim J. Y.;Kwon H. J.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.18 no.2
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    • pp.172-179
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    • 2006
  • This study developed a program for detecting charged refrigerant amount in system air-conditioner. System air-conditioner is an air-conditioning system with multiple indoor units. Due to the complexity of the system, it is more difficult to detect the refrigerant amount charged in the system air-conditioner than in a general single air-conditioner. Experiments were performed for a 6 HP outdoor unit with 3 indoor units in a psychrometric calorimeter. The experimental amount of the charged refrigerant was ranged from $60\%\;to\;140\%\;with\;10\%$ increasement. Fuzzy algorithm was employed for detecting the charged refrigerant amount in the system air-conditioner. The experimental data were used for curve-fitting for the general ranges of indoor and outdoor temperature conditions. Membership function was determined for the whole ranges of experimentally measured data and rule-bases were defined for each charged refrigerant amount. Developed program successfully predicted the measured data within $10\%$ resolution range.

Refrigerant Amount Detection Technology for System Air-Conditioner Using Design of Experiment (실험계획법을 이용한 시스템에어컨의 냉매량검지 기술개발)

  • Lee, Soo-Young;Takeichi, Hisashi;Tae, Sang-Jin;Yoon, Baek
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.22 no.1
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    • pp.26-32
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    • 2010
  • This paper is suggesting a new technology for refrigerant amount detection of a system air-conditioner installed under various installation conditions. System air-conditioner was introduced to domestic market first in 2000. It consists of one or a series of outdoor units and a number of indoor units connected with single pipe line to the outdoor unit. The system can vary the capacity from 2.0 kW to 186 kW. For the system Installed under long and high-elevated condition, about 100 kg of refrigerant is charged in the whole system. In this paper, the new technology RAD (Refrigerant Amount Detection) with edge technology of refrigerant cycle control and measurement of a system air conditioner was developed and investigated for its application for the various installation conditions.

Comparison of the PMV and $CO_2$ Concentration, Energy Consumption Characteristics of Central Air-Conditioning System and System Air-Conditioner with Ventilation System for Large Space (중형공간에서 중앙공조방식과 시스템에어컨 방식에 따른 PMV와 $CO_2$농도, 에너지소비량 비교)

  • Sung, Sang-Chul;Noh, Kwang-Chul;Chin, Sim-Won;Oh, Myung-Do
    • Proceedings of the SAREK Conference
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    • 2008.11a
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    • pp.298-303
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    • 2008
  • PMV, $CO_2$ and the energy consumption performance were numerically investigated in a large space with air-conditioning systems of four type. The numerical results showed that thermal comforts in the occupied zone are nearly similar in three systems except 3-way wall type system air-conditioner with ventilation system installed 2.2m height from the bottom. In case of 3-way wall type system air-conditioner the energy consumption for cooling loads was reduced about 25.5% compared to other air-conditioning systems. From the viewpoint of IAQ, it was turned out that system air-conditioner with ventilation system became worse about 20% compared to central air-conditioning systems for cooling load. The PMV, $CO_2$ concentration and energy consumption of all systems for heating loads were similar in a large space considered.

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Transient Vibration Identification and Reduction of a Centrifugal Fan for a Wall-installed Air-conditioner (벽걸이에어컨의 원심홴에 대한 과도진동 규명 및 저감)

  • Kim, Minsung;Lim, Jonghyuk;Chung, Jintai
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.26 no.4
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    • pp.383-390
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    • 2016
  • In this paper, experiment and dynamics simulations were carried out to identify and reduce the out-of-plane vibration that occurs in a centrifugal fan of an air conditioner installed to a wall. In a wall-installed air conditioner, large space between a case and heat exchanger is often required for the fan to avoid the collision with the case and exchanger. This large space hinders the slim design of the air conditioner even if air conditioner market demands a slim air conditioner. In the present study, in order to determine the cause of the vibration in the centrifugal fan, the out-of-plane vibration and the physical properties were investigated, and the dynamic characteristics of the centrifugal fan were obtained by experiments. Based on these experiments, a dynamic simulation model was established to determine the cause of the out-of-plane vibration of the centrifugal fan. It was found that the main factor of out-of-plane vibration in the centrifugal fan is the axial misalignment between the centrifugal fan and the motor shaft.

Study on the Development for Low Noise Indoor Unit Package Air-Conditioner (저소음 패키지형 공기조화기의 실내기 개발에 관한 연구)

  • 이재효;조성철;김태헌
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.6
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    • pp.518-523
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    • 2003
  • The purpose of this study was to reduce the noise emitted from the package air-conditioner. The optimum design methods of the fans ware investigated experimentally through the analysis of noise problem caused by the conventional PAC system. New PAC system had decreased 6 dBA in overall noise level as compared with the conventional system by various technology.

Experimental Study of Performance Characteristics of Various Fin Types for Fin-Tube Heat Exchanger

  • Youn, Baek;Kim, Young-Saeng;Park, Hwan-Young;Park, Hyun-Yeon
    • International Journal of Air-Conditioning and Refrigeration
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    • v.8 no.2
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    • pp.29-38
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    • 2000
  • Air side heat transfer and pressure drop for f 9.52 fin-tube heat exchanger with various types of slit and louver fins were measured, and compared with wave-slit fin. Longitudinal and transverse tube spacings of the heat exchangers are 21.65 mm and 25mm respectively. Actual heat exchanger was tested using water, and the tests were performed for 2 row heat exchangers with 3 different fin spacings, 1.3, 1.5 and 1.7 mm. The overall performance of the enhanced fins was evaluated by comparing heat transfer coefficient with respect to fan power

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Study on Influence of Air Flow of Ceiling Type Air Conditioner on Fire Detector Response (천장형에어컨 기류가 화재감지기 작동에 미치는 영향 분석)

  • Choi, Moon-Soo;Lee, Keun-Oh
    • Fire Science and Engineering
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    • v.32 no.5
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    • pp.40-45
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    • 2018
  • This paper is an analysis of the influence of ceiling air conditioner airflow on fire detector response. In order to analyze the response characteristics of fire detector while forming air flow of a ceiling-type air conditioner, fire tests were carried out in accordance with ISO standard. This experiment was carried out in a fire test site of 10 m (width) ${\times}$ 7 m (length) ${\times}$ 4 m (height). As a result of the experiment, the response of fire detector shows a normal pattern that is delayed as the distance from the fire source is increased in the absence of the air conditioner, but it is confirmed that the pattern is not maintained in the strong air flow. When the air flow of air conditioner was strong, the response time was increased by 121% in the smoke detector and by 39% in the heat detector. In the case of ceiling type air conditioners, it is considered that the number of fire detectors should be increased, or a detector with high sensitivity should be installed for early detection of fire.

Study on Noise Reduction of an Air Conditioner through Modification of Axial Flow Fans and Shrouds (축류팬 및 슈라우드 개선을 통한 공조기 저소음화에 대한 연구)

  • Kim, Chang-Joon;Yoon, Hong-Yeol;Jung, Young-Gyu;Park, Young-Min
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.06a
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    • pp.380-387
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    • 2000
  • In this paper, a successful result of modification of an axial flow fan and a shroud for noise reduction of a window type air conditioner is presented especially in order to verify the importance of blade shape improvement and the searching for the optimal shape of shrouds. Effective ways to work out the result as mentioned above are to make the tip of the blade varied in thickness and to have special shapes. From the viewpoint of the shape in a shroud, several cases were examined and the particular value of a design parameter of the shroud was acquired to get the best noise reduction of an air conditioner. Through the application of the methods, the air conditioner became less noisy by 4.5 dB(A) in terms of air-borne noise produced only by the axial flow fan and consumed less energy by 20.9% compared to the current one.

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Performance Characteristics of a Hybrid Air-Conditioner for Telecommunication Equipment Rooms (통신기지국용 하이브리드 냉방기의 성능특성 연구)

  • Kim, Yong-Chan;Choi, Jong-Min;Kang, Hoon;Yoon, Joon-Sang;Kim, Young-Bae;Choi, Kwang-Min;Lee, Ho-Seong
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.18 no.11
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    • pp.874-880
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    • 2006
  • The power density and heat dissipation rate per unit area of the telecommunication equipment have been increased with the technology development in the footprint of telecommunication hardware. A proper heat dissipation method from the PCB module is very important to allow reliable operation of its electronic component. In this study, a hybrid air-conditioner for the telecommunication equipment room was designed to save energy and obtain system reliability. For high outdoor temperatures, the hybrid system operates in the vapor compression cycle, while, for low outdoor temperatures, the hybrid system works in the secondary fluid cooling cycle with no operation of the compressor. The performance of the hybrid air-conditioner was measured by varying outdoor and indoor temperatures. The hybrid air-conditioner yielded 50% energy saving compared with the conventional refrigeration system when the mode switch temperature was $8.3^{\circ}C$.