• Title/Summary/Keyword: Indoor Air Flow

Search Result 270, Processing Time 0.03 seconds

A Study on Characteristics of Indoor- Air-Quality in Interior Space Equipped with System Air-Conditioner (시스템 에어컨 설치 공간의 실내공기질 특성에 관한 연구)

  • Lee, Sang-Won;Kim, Jong-Min;Yeum, Seung-Won;Cho, Dae-Gun;Choi, Jae-Boong;Kim, Seok-Woo
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.20 no.5
    • /
    • pp.304-313
    • /
    • 2008
  • This paper investigates the indoor-air-quality (IAQ) characteristics of the interior space equipped with system air-conditioner. The behaviors of individual variables such as temperature, humidity and concentration of carbon dioxide ($CO_2$) that influence on IAQ of the interior space were characterized under various cooling conditions by numerical and experimental studies. The numerical analysis predicting the temperature behavior of the interior space was conducted, and its results showed a good agreement with the experimental ones. The $CO_2$ concentration and humidity were measured and their time dependent behaviors were monitored and analyzed. From the results, it was found that there existed the differences of the time-dependent behaviors of IAQ variables according to the locations. In addition, it is demonstrated that the large discharge angle of $45^{\circ}$ made the temperature profile more irregular and the high discharge flow of 5.34 m/s produced similar temperature profiles at three different sensing locations. Finally, the humidity of interior space was less sensitive to the changes of the air cooling conditions than the case of temperature and the $CO_2$ concentration increase mainly depended on the number of individuals inside the space.

Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013 (설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.26 no.12
    • /
    • pp.605-619
    • /
    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.

Predicted Air Flow Around Objects Using the Discrete Vortex Method

  • Kim, Tae-Hyeung
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.9 no.E
    • /
    • pp.347-357
    • /
    • 1993
  • The Lagrangian grid-free numerical method, the discrete vortex method, was applied to solve the Navier-Stokes euqations. This method avoids the introduction of numerical viscosity swamping the real physical viscosity at high Reynolds number, unlike Eulerian method, e.g. finite difference and element methods. The boundary integral equation method for the potential flow solution was included to make the discrete vortex method more feasible for complex geometries. The fast adaptive multipole expansion method was incorporated to reduce the computational time from $O(N^2)$ to O(N) for the computations of vortex-vortex interactions. The test problems were air flow around one circular cylinder and two circular cylinders in tandem with various gaps. The numerical results were in excellent gareement with the experimental and other computational results. The applicabilty of the method was discussed with the indoor and the outdoor air pollution problems, especially the contaminant transport in the recirculation regions.

  • PDF

An Experimental Study for the Improvement of Ventilation Conditions and Effectiveness in the Manufacturing Industry by Increasing the Mixing Factor (K-Factor) (혼합계수(K-Factor) 증가에 따른 사업장의 환기 조건 및 효율 개선에 관한 연구)

  • Lee, Yun-ho;Lee, Seokwon;Lee, Kyoungho;Kim, Hyunwook
    • Journal of Korean Society of Occupational and Environmental Hygiene
    • /
    • v.29 no.3
    • /
    • pp.343-350
    • /
    • 2019
  • Objectives: This study aims to identify whether ventilation conditions and their effectiveness can be significantly improved in an experimental chamber by increasing the mixing factor (K-Factor). Methods: In a chamber with a volume of $1m^3$, air velocity was measured at six different points with four roof fans in the upper part of the chamber being operated in order. The impact of the ventilation conditions was analyzed when the flow rates were increasing and the first inlet of the chamber was either open or closed. Smoke patterns were also observed at four corner points where ventilation was limited. Kruskal Wallis and Mann-Whitney tests were performed to compare air velocities measured in the chamber. Results: The air velocities measured at only the third point increased significantly from $0.03{\pm}0.03m/s$ (door open) and $0.05{\pm}0.06m/s$ (door closed) with two fans, $0.08{\pm}0.08m/s$ with three fans, and $0.09{\pm}0.09m/s$ with four fans operating (p<0.05). However, air velocities at the four corner points did not significantly increase. Smoke patters also showed that the open inlet of the chamber had no effect on improvement of ventilation conditions and effectiveness. Conclusions: In this study, the air velocities at six points in the chamber did not significantly increase despite the increase in the mixing factor and flow rates of ventilation in the controlled environment. Therefore, the inflow of outdoor air throughout an open inlet and installation of a forced ventilation system can potentially increase the indoor air velocity and improve ventilation condition without an increase in the mixing factor.

Properties of Cement Matrix Using Vegetable Activated Carbon (식물성 활성탄을 활용한 시멘트 경화체의 특성)

  • Lee, Jae-Hoon;Park, Chae-Wool;Lee, Sang-Soo
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2020.06a
    • /
    • pp.138-139
    • /
    • 2020
  • With the rapid progress of industrialization, indoor air quality is a very important factor for modern people who spend most of their day indoors. The recent issue of fine dust and radon on the portal site's popularity search shows that interest in indoor air quality has increased. Fine dust causes respiratory diseases, and radon causes severe lung cancer. The new material was tested using plant activated carbon, palm activated carbon and bamboo activated carbon. Both palm activated carbon and bamboo activated carbon are porous materials and generate smooth physical adsorption. As a result of the experiment, both the activated carbon tends to gradually decrease in strength and fluidity as the replacement ratio increases. The reason for this is that both activated carbons have the property of absorbing moisture, so it is judged that the strength is lowered by absorbing moisture necessary for curing. In the case of fluidity, it is judged that the fluidity is reduced by absorbing the moisture required for the flow. In the future, if the problem of the color of the finished cured body is compensated, it will be possible to manufacture a functional finishing board to replace the existing interior finishing material.

  • PDF

A Study on the Indoor Comfort Control By Smart Comfort Algorithm (스마트 쾌적 알고리즘을 적용한 실내 쾌적 제어에 대한 연구)

  • Yoon, Seok-Am;Lee, Jeong-Il
    • Journal of IKEEE
    • /
    • v.19 no.4
    • /
    • pp.603-609
    • /
    • 2015
  • Thermal comfort is one of the fundamental aspects of indoor environmental quality and it is strongly related to occupant satisfaction and energy used in building. In this paper, we proposes smart comfort algorithm that save energy and provide a pleasant and comfortable environment for workers by the indoor comfort conditions(Predictive Mean Vote) detection and controlling the temperature and humidity, air flow. Simulation results, heating and cooling control of the thermal comfort control can be compared with the existing general air conditioners reduces the power of 0.5kW and indoor comfort can be maintained. Also, It showed a 49.2% improvement in the light by lighting control algorithm.

A Study on the Safety Consciousness of Resident for the Environmental Factors in Apartments (공동주택 환경요인에 대한 거주자의 안전의식 조사 연구)

  • Park, Hyeon-Ku;Song, Hyuk;Go, Seong-Seok
    • Journal of the Korean Society of Safety
    • /
    • v.20 no.4 s.72
    • /
    • pp.106-113
    • /
    • 2005
  • The housing is a human's basic space and the comfort and the safety are the most basic conditions. According to the flow of age for Well-Being since the 21th, the suppliers and the users of apartment are making best effort now for the embossment of green environmental quality of apartment, and outstretch their hands for marketing strategic purposes in a side of indoor and outdoor environment with distinctive elements. But these supply and use are on progress competitively with the simple distinction, it is thought that indoor and outdoor environment are must be promoted according to the survey of residents' consciousness. So this study aims to provide basic materials with residents for the promotion of comfortable dwelling environment by solving the basic safety problem and also aims to survey and analyze the residents' safety consciousness in object of physical and non-physical environmental quality of indoor and outdoor of apartment by analyzing indoor air quality pollution, the feeling of being victimize caused by air pollution and safety consciousness according to physical environment elements.

Assessment for Inhalation Exposure to Trihalomethanes (THMs) and Chroline and Efficiency of Ventilation for an Indoor Swimming Pool (일개 실내수영장의 공기 중 염소 및 트리할로메탄의 노출평가 및 환기 효율 평가)

  • Park, Hae-Dong;Park, Hyun-Hee;Shin, Jung-Ah;Kim, Tae-Ho
    • Journal of Environmental Health Sciences
    • /
    • v.36 no.5
    • /
    • pp.402-410
    • /
    • 2010
  • The objectives of this study were to evaluate the air quality surrounding an indoor swimming pool, to estimate the cancer risk based on the airborne exposure to trihalomethanes (THMs), and to examine the ventilation efficiency by Computational Fluid Dynamics (CFD). Chlorine and THMs were measured poolside, and in the staff room and reception area. The indoor swimming pool was modeled using the Airpak program, with ventilation drawings and actual survey data. Temperature, flow and mean age of the air were analyzed. Levels of chlorine poolside, and in the staff room, and reception area were $203\;{\mu}g/m^3$, $5\;{\mu}g/m^3$, and $10\;{\mu}g/m^3$, respectively. Chloroform was the dominant THM in all sampling sites and mean concentrations were $16.30\;{\mu}g/m^3$, $0.51\;{\mu}g/m^3$, and $0.06\;{\mu}g/m^3$ poolside, in the staff room and reception area, respectively. Bromodichloromethane and Dibromochloromethane levels were respectively estimated as $10.3\;{\mu}g/m^3$ and $1.7\;{\mu}g/m^3$ poolside, $1.3\;{\mu}g/m^3$ and $0.1\;{\mu}g/m^3$ in the staff room, and were not detected in the reception area. The cancer risks from inhalation exposure to THMs were estimated between $3.37{\times}10^{-7}$ and $1.84{\times}10^{-5}$. A short circulation phenomenon was observed from the supply air vents to the exhaust air vents located in the ceiling. A high temperature layer was formed within one meter of the ceiling, and a low temperature layer was formed under this layer due to the low velocity and high temperature of the supply air, and the improper locations of the supply air vents and exhaust air vents. The stagnation was evident at the above adult pool and the mean age of the air was 22 minutes. Disinfection by-products in the indoor swimming pool were present in higher concentrations than in the outdoor air. In order to increase the removal of pollutants, adjustment was required of the supply air volume and the supply/exhaust position.

Design of Optimal Vane Control for Ceiling Type Indoor Unit by PIV measurements (천장형 실내기의 기류 가시화를 통한 최적 제어 설계)

  • Sung Jaeyong;An Kwang Hyup;Lee Gi Seop;Choi Ho Seon;Park Seung-Chul;Lee In-Seop
    • Proceedings of the KSME Conference
    • /
    • 2002.08a
    • /
    • pp.533-536
    • /
    • 2002
  • A heating flow discharged from a 4-way ceiling type indoor unit has been investigated using a PIV(particle image velocimetry) system For the PIV measurements, an experimental model of 1/10 scale with a transparent room was devised by satisfying the Archimedes number, which is generally used in case that the forced convection has the similar magnitude as the natural convection. To optimize the heating flow, several vane angles and vane control algorithms of cross and right angle controls were considered. Regarding the vane angle, the experimental results show that it should be less than $30^{\circ}$ to avoid re-suction flows which decrease the performance of the air-conditioner. At the vane angle of $30^{\circ}$, applying open/close control gives nae to more uniform distribution of the heating flow than without control. Especially, the cross-control seems to be satisfactory for the thermal comfort.

  • PDF

Steady-State Performance Analysis of Air Conditioner with Multi-Indoor Units (복수 실내기를 가지는 에어컨의 정상상태 성능해석)

  • Hur, Hyun;Lee, Jin Wook;Jung, Eui Guk;Kim, Byung Soon
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.40 no.11
    • /
    • pp.705-715
    • /
    • 2016
  • In this study, the cycle performance of an air conditioner with multi-indoor units is analyzed and simulated. The cycle performance could be predicted through the integration of mathematical formulation for these devices. The condenser pressure is obtained by an iteration process to match the mass flow rates of the compressor and the expansion valve and the evaporator pressure is determined by an iteration process, in which the suction super heat is tracing the targeted super heat. The required software was developed by system programming. the software algorithm is extended to predict the cycle performance of an air conditioner system with multi-indoor units, and then the numerical results are compared with experimental results. This mathematical model is validated from the result of experiments conducted on 8.3kW air conditioner. The errors in capacity, electronic power, and COP are found to be within 10% in general.