• 제목/요약/키워드: hot air heating

검색결과 332건 처리시간 0.028초

국내 기상조건하 주거용 건물 가스 보일러의 부분부하 특성과 에너지 사용량 분석 (Analysis of the Part Load Ratio Characteristics and Gas Energy Consumption of a Hot Water Boiler in a Residential Building under Korean Climatic Conditions)

  • 유병호;서병모;문진우;이광호
    • 설비공학논문집
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    • 제27권9호
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    • pp.455-462
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    • 2015
  • Residential buildings account for a significant portion of the total building-energy usage in Korea, and a variety of research studies on the domestic boiler have therefore been carried out; however, most of these studies examined the boiler itself, whereby the part-load ratio characteristics and the corresponding gas-energy consumption patterns were not analyzed. In this study, the part-load ratio and operating characteristics of a domestic gas boiler were analyzed within a residential building equipped with a radiant floor-heating system; in addition, the energy consumption between condensing and conventional boilers was comparatively analyzed. Our results show that significant portions of the total operating hours, heating load, and energy consumption are in the part-load ratio range of 0 through 40%, whereby the energy consumption was significantly affected by the boiler efficiency under low part-load conditions. These results indicate that the part-load operation of a boiler is an important factor in residential buildings; furthermore, replacing a conventional boiler with a condensing boiler can reduce annual gas-energy usage by more than 20%.

사무소건물의 용도 및 측정기간에 따른 에너지 소비 특성 (Characteristics of Energy Consumption in an Office Building located in Seoul)

  • 박병윤;정광섭
    • 설비공학논문집
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    • 제17권1호
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    • pp.82-87
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    • 2005
  • The purpose of this study is to suggest the characteristics and actual state of energy consumption by the analysis of energy consumption data in an office building. This study examines and analyzes daily and monthly energy consumption of an office building located in Seoul, Korea regarding type of load and business classification within a building. The results are as follows. 1) Energy consumption of office building for each type of load show similar consumption patterns, regardless of seasons such as cooling period and heating period. 2) Out of all annual energy consumption, consumption for lighting took about $43\;\%,$ general electric Power about $23\;\%,$ emergency power $25\;\%,$ computer center $5\;\%$ and cooling power $4\;\%,$ showing that the consumption for lighting was highest, and the percentage of energy consumption for cooling power for operation of cooling facilities took the lowest percentage. 3) Annual gas consumption used for heating and hot water supply were $38,\;36\;\%$ for officetel and office respectively, and $26\;\%$ for arcade. 4) Electricity consumptions used for cooling power for each use of building, office and officetel recorded in July and August of cooling seasons. Even though it shows different patterns for each month, energy consumption showed unique pattern throughout the cooling seasons.

판형열교환기의 운전 및 설계변수에 따른 파울링 특성에 관한 연구 (The Fouling Characteristics of Plate Heat Exchangers with Geometric and Operating Parameters)

  • 전재명;이응찬;강훈;김용찬
    • 설비공학논문집
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    • 제26권4호
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    • pp.163-168
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    • 2014
  • The plate heat exchanger has been widely used in water heating systems due to high efficiency, simple structure, and easy maintenance. However, the studies on the effects of fouling on the heat transfer performance under various operation and maintenance conditions are very limited in the open literature. The objective of this study is to investigate the effects of fouling with calcium carbonate ($CaCO_3$) on the heat transfer characteristics of the plate heat exchanger under various operating and geometric conditions. The heat transfer coefficient and pressure drop in the plate heat exchangers were measured under accelerated fouling conditions with $CaCO_3$ by varying geometric and operational parameters. The fouling resistance increased with the decrease in the flow rate, and the increase in the chevron angle and the concentration.

Inverse Model Toolkit을 이용한 리모델링 건축물의 에너지 성능평가 사례 (A Case Study on Energy Performance Analysis of Retrofitted Building Using Inverse Model Toolkit)

  • 권경우;이석주;박준석
    • 설비공학논문집
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    • 제26권8호
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    • pp.394-400
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    • 2014
  • Several models and methods have been developed to verify the improvement of energy performance in retrofit buildings. The verification is important to confirm the effectiveness of new technologies or retrofits. Inverse model toolkit proposed by ASHRAE evaluates the changes of the energy performance of retrofit buildings by using actual energy consumption data. In this study, the inverse model toolkit was used to analyze heating and cooling energy performance of an office building. Analyzed coefficients of correlation of actual energy consumption with estimated energy consumption was above 0.92 and well fitted. It was confirmed that energy consumption of natural gas decreased by 43.4% and also that electricity decreased by 13.8%, after the retrofit of the case building. For the energy usage, cooling energy was increased by 7.4%, heating energy was decreased by 42.3%, hot water and cooking were increased by 3.4%, lighting and electronics were decreased by 19.3%, and the total energy was decreased by 18.9%.

Performance Analysis of Sensible and Latent Energy Recovery System for Thermally Controlled Facility

  • Park, Byung-Kyu;Kim, Moo-Geun;Kim, Geun-Oh
    • International Journal of Air-Conditioning and Refrigeration
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    • 제9권4호
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    • pp.17-26
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    • 2001
  • Simulation was conducted using TRNSYS to evaluate the thermal performance of a facility. This facility has a condensing-type heat exchanger which is able to recover the latent energy for the purpose of reducing the heating energy in winter. The boiler and chiller are selected based on the annual peak loads and controlled to maintain the facility at the set temperature of 14~$17^\circ{C}$. Supplied energy by the boiler and recovered energy by the heat exchanger were calculated as a function of number of pass through heat exchanger, kind of fuel and hot water velocity. Simulation results show that about 20% of the total heating load can be recovered by the heat exchanger and the amount of latent heat is increasing with the number of pass. This means that the efficiency of the waste energy recovery system can be increased by using a condensing-type heat exchanger rather than a traditional sensible heat exchanger.

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태양열 난방 시스템에 적용되는 축열조의 성층화에 관한 연구 (A Study on Thermally Stratied Hot Water Storage Tank in A Solar Heating System)

  • 홍희기;김효경
    • 대한설비공학회지:설비저널
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    • 제15권1호
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    • pp.87-96
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    • 1986
  • An experiment on the devices that enchance the stratification of storage tanks in a solar heat ins system has been carried out. The benefits of thermal stratification in sensible heat storage are to increase the system performance such as the collector efficiency or the fraction of the total load supplied by solar energy. Using the diffuser and the distributor as the stratification enchancement device, the expeliments were perfomed in the different condition of diameter and material of the distributor. As a result of experiments, there exists the diameter of distributor in which the stratification is made maximum under certain design and operation condition. Also it was identified that the kind of distributor material influenced the degree of stratification. Comparing the experimental result to the computational results calculated under the same conditions, the node number N(stratification index) was determined. The results of computer simulation that was performed about the actual solar heating system in Seoul for 24 hours show the relative advantage of stratified over well-mixed storage and the significant improvements in system performance.

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설비공학 분야의 최근 연구 동향 : 2016년 학회지 논문에 대한 종합적 고찰 (Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2016)

  • 이대영;김사량;김현정;김동선;박준석;임병찬
    • 설비공학논문집
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    • 제29권6호
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    • pp.327-340
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    • 2017
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. 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 flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (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 of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.

가열 및 건조방법이 새우의 극성지방질 조성에 미치는 영향 (Effects of Cooking and Drying Methods on the Polar Lipids Composition of Shrimp)

  • 김현구;조길석;신효선
    • 한국식품과학회지
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    • 제21권1호
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    • pp.25-30
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    • 1989
  • 가열처리 및 건조방법이 새우의 극성지방질에 미치는 영향을 밝히고자하였다. 새우중의 당지방질의 주요성분은 esterified steryl glycoside, monogalactosyl diglyceride 및 steryl glycoside 이었으며, 열풍건조한 것은 동결건조한 것보다 esterified steryl glycoside 함량은 유의적으로 많은 반면에 monogalactosyl diglyceride 함량은 적었다. 새우중의 인지방질의 주요성분은 phosphatidyl enthanolamine, phosphatidyl choline phosphatidic acid, phosphatidyl inositol, phosphatidyl serine 이었으며, phosphatidic acid 함량은 가열처리 하지 않고 열풍건조한 것은 8.3%, 동결건조한 것은 5.9%로서 전자가 후자보다 유의적으로 많았고, phosphatidyl ethanolamine 함량은 마이크로파 처리 할 경우 동결건조한 것은 열풍건조한 것보다 그 함량이 많은 반면에 phosphatidyl choline함량은 적었다. 생새우의 당 및 인지방질 획분의 주요 지방산은 pentadecanoic acid palmitic acid oleic acid, nervonic acid 및 eicosapentaenoic acid 이었다.

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식용유지의 가열시 와송 추출물이 산화안정성에 미치는 영향 (Effect of Wa-song(Orostachys japonicus A. Berger) Extract on the Oxidative Stability of Edible Oil During its Heating)

  • 이수정;신정혜;서종권;성낙주
    • 한국식품위생안전성학회지
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    • 제24권1호
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    • pp.12-18
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    • 2009
  • 열풍건조 및 동결건조된 와송의 열수추출물을 대두유 및 돈지에 0.1, 0.5 및 1.0 g/100 mL의 농도로 첨가하고 $180^{\circ}C$에서 가열하는 동안 유지의 산화 안정성을 측정하였다. 유지의 색도는 가열시간이 경과될수록 증가되었으며, HWE 첨가구에서 색도가 다소 높았다. 아니시딘가는 가열시간이 경과될수록 유의적으로 증가되었으나, 48시간 가열 후 0.5 및 1.0 g/100 mL의 HWE 첨가구, 1.0 g/100 mL의 FWE 첨가구를 제외하면 모든 실험구에서 대조구보다 낮았다. 돈지에서는 시료의 첨가량에 관계없이 모든 실험구에서 대조구보다 낮았다. 산가는 가열시간이 길어짐에 따라 유의적으로 증가하였으나, 대두유에서 시료의 첨가량에 따른 유의차는 없었으며, 가열 48시간 이후 HWE 첨가구가 FWE 첨가구에 비해 다소 낮았다. 과산화물가도 HWE 첨가구가 FWE 첨가구보다 낮았다. TBA가는 대두유에서 가열 24시간 이후에 대조구보다 낮았으며, 돈지에서는 가열전기간 동안 대조구보다 낮았다. 따라서 와송 열풍건조시료는 동결건조 시료에 비해 항산화능이 우수하며, 돈지의 가열시 산화안정성에 효과가 있을 것으로 생각되었다.

Design and Exergy Analysis for a Combined Cycle of Liquid/Solid $CO_2$ Production and Gas Turbine using LNG Cold/Hot Energy

  • Lee, Geun-Sik
    • International Journal of Air-Conditioning and Refrigeration
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    • 제15권1호
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    • pp.34-45
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    • 2007
  • In order to reduce the compression power and to use the overall energy contained in LNG effectively, a combined cycle is devised and simulated. The combined cycle is composed of two cycles; one is an open cycle of liquid/solid carbon dioxide production cycle utilizing LNG cold energy in $CO_2$ condenser and the other is a closed cycle gas turbine which supplies power to the $CO_2$ cycle, utilizes LNG cold energy for lowering the compressor inlet temperature, and uses the heating value of LNG at the burner. The power consumed for the $CO_2$ cycle is investigated in terms of a solid $CO_2$ production ratio. The present study shows that much reduction in both $CO_2$ compression power (only 35% of the power used in conventional dry ice production cycle) and $CO_2$ condenser pressure could be achieved by utilizing LNG cold energy and that high cycle efficiency (55.3% at maximum power condition) in the gas turbine could be accomplished with the adoption of compressor inlet cooling and regenerator. Exergy analysis shows that irreversibility in the combined cycle increases linearly as a solid $CO_2$ production ratio increases and most of the irreversibility occurs in the condenser and the heat exchanger for compressor inlet cooling. Hence, incoming LNG cold energy to the above components should be used more effectively.