• Title/Summary/Keyword: 간접열

Search Result 208, Processing Time 0.028 seconds

Development of thermal-drying system and equipment for sewage/waste water sludge ($\cdot$폐수 슬러지 열건조 시스템 및 장치개발 <연속감압식 간접 열건조 시스템>)

  • 허병수;신용한;김태훈;장당엽;안영철
    • Environmental engineer
    • /
    • s.182
    • /
    • pp.62-67
    • /
    • 2001
  • 본 연구에서는 기존의 로터리 방식이나 플래시 방식 등의 직접열에 의한 건조방식이 2차 공해 유발 및 폭발이나 화재의 위험을 항상 내포하는 등 여러 가지 단점이 있으므로 이러한 문제점을 연속 감압식 간접열 방식의 건조장치를 개발하여 근원적으로 해결하고자 하였다. 본 연구의 목표는 50kg/hr용량의 연속 감압식 간접열 방식의 디스크 건조장치를 개발하여 건조효율을 70$\%$ 이상 향상시키며(기존의 제품은 50$\%$

  • PDF

A Study on the Conditions of Drying Efficiency for Conveyor-Belt-Type Dryers Employing Continuous Decompression Indirect Heating Method (연속 감압-간접열 방식의 벨트형 건조장치를 이용한 건조효율 연구)

  • Ha, Sang-An;Kim, Dong-Kyun;Wang, Jei-Pil
    • Resources Recycling
    • /
    • v.24 no.6
    • /
    • pp.54-60
    • /
    • 2015
  • The objective of this study is to develop a belt-type dryer with a capacity of 1 ton/day, thereby improving drying efficiency by more than 70% and reducing the size of dryers by more than 50%, and thus making dryers smaller and lighter to reduce the installation and operation costs by more than 20%. We identified structural improvements by analyzing existing dryers employing indirect heating and verified the superior drying performance of the proposed method through some basic experiments. Furthermore, we verified the improvements in the heat transfer and drying characteristics as we conducted the experiments at reduced pressure.

A Study on Intrinsic Noise of Capacitively Coupled Active Electrode (용량성 결합 능동 전극의 내부 잡음 분석)

  • Lim, Yong-Gyu
    • Journal of the Institute of Convergence Signal Processing
    • /
    • v.13 no.1
    • /
    • pp.44-49
    • /
    • 2012
  • The indirect-contact ECG measurement is a newly developed method for unconstrained and nonconscious measurement in daily Life. This study is the first step to reducing the large background noise appearing in indirect-contact ECG. This study built the thermal noise model of capacitively coupled active electrode which is used in indirect-contact ECG. The results show that the level of thermal noise estimated by the thermal noise model is much the same as that of actual background noise for the capacitively coupled active electrode alone. By applying the actual electrical properties of a sample cotton cloth to the thermal noise model, the theoretical level of thermal noise in the indirect-contact ECG was estimated. The results also show that the level of op-amp's intrinsic noise is so small that it can be negligible in comparison with thermal noise of resistors. The relationship between the level of thermal noise and the resistance of the bias resistor was derived, and it is the base for the further study how to choice the optimal resistance for the bias resistor.

Study on Performance Prediction and Energy Saving of Indirect Evaporative Cooling System (간접식 증발냉각장치의 성능예측과 에너지절약에 관한 연구)

  • Yoo, Seong Yeon;Kim, Tae Ho;Kim, Myung Ho
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.39 no.9
    • /
    • pp.743-749
    • /
    • 2015
  • The purpose of this study is to predict the performance of an indirect evaporative cooling system, and to evaluate its energy saving effect when applied to the exhaust heat recovery system of an air-handling unit. We derive the performance correlation of the indirect evaporative cooling system using a plastic heat exchanger based on experimental data obtained in various conditions. We predict the variations in the performance of the system for various return and outdoor air conditioning systems using the obtained correlation. We also analyze the energy saving of the system realized by the exhaust heat recovery using the typical meteorological data for several cities in Korea. The average utilization rate of the sensible cooling system for the exhaust heat recovery is 44.3% during summer, while that of the evaporative cooling system is 96.7%. The energy saving of the evaporative cooling system is much higher compared to the sensible cooling system, and was about 3.89 times the value obtained in Seoul.

국내 태양열 냉난방시스템 겸용 설치사례

  • Yun, Jang-Su;Jo, Jang-Hyeon
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
    • /
    • v.40 no.5
    • /
    • pp.18-24
    • /
    • 2011
  • 태양열 집열기에서 생산된 열원을 축열한 축열조의 온수를 겨울에는 직,간접 열교환을 통하여 난방을 실현하고 축열조의 여름에는 흡수식 냉동기 발생기(Generator)에 공급하여 흡수식 냉동기를 가동하고 냉동기에서 생산된 저온의 냉수로 냉방을 실현하는 태양열 냉난방 겸용시스템에 대한 설치 사례를 소개하고자 한다.

  • PDF

Performance Comparison between Indirect Evaporative Cooler and Regenerative Evaporative Cooler made of Plastic/Paper (플라스틱/종이 재질의 간접 증발 소자와 재생 증발 소자 성능 비교)

  • Kim, Nae-Hyun
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.17 no.1
    • /
    • pp.88-98
    • /
    • 2016
  • The Korean summer is hot and humid, and air-conditioners consume considerable amounts of electricity. In such cases, the simultaneous use of indirect evaporative coolers may help reduce the sensible heat and save electricity. In this study, heat transfer and pressure drop characteristics of indirect or regenerative evaporative coolers made from plastic/paper are investigated. The results showed that heat and mass transfer model based on the ${\epsilon}-NTU$ method predicted the indirect evaporation efficiencies, cooling capacities and pressure drops adequately. Both for indirect or regenerative evaporative cooler, the indirect evaporation efficiency increased with increasing dry channel inlet temperature or relative humidity. The indirect evaporation efficiency of the regenerative evaporative cooler was larger than that of the indirect evaporative cooler.

Optimization Process Models of Gas Combined Cycle CHP Using Renewable Energy Hybrid System in Industrial Complex (산업단지 내 CHP Hybrid System 최적화 모델에 관한 연구)

  • Oh, Kwang Min;Kim, Lae Hyun
    • Journal of Energy Engineering
    • /
    • v.28 no.3
    • /
    • pp.65-79
    • /
    • 2019
  • The study attempted to estimate the optimal facility capacity by combining renewable energy sources that can be connected with gas CHP in industrial complexes. In particular, we reviewed industrial complexes subject to energy use plan from 2013 to 2016. Although the regional designation was excluded, Sejong industrial complex, which has a fuel usage of 38 thousand TOE annually and a high heat density of $92.6Gcal/km^2{\cdot}h$, was selected for research. And we analyzed the optimal operation model of CHP Hybrid System linking fuel cell and photovoltaic power generation using HOMER Pro, a renewable energy hybrid system economic analysis program. In addition, in order to improve the reliability of the research by analyzing not only the heat demand but also the heat demand patterns for the dominant sectors in the thermal energy, the main supply energy source of CHP, the economic benefits were added to compare the relative benefits. As a result, the total indirect heat demand of Sejong industrial complex under construction was 378,282 Gcal per year, of which paper industry accounted for 77.7%, which is 293,754 Gcal per year. For the entire industrial complex indirect heat demand, a single CHP has an optimal capacity of 30,000 kW. In this case, CHP shares 275,707 Gcal and 72.8% of heat production, while peak load boiler PLB shares 103,240 Gcal and 27.2%. In the CHP, fuel cell, and photovoltaic combinations, the optimum capacity is 30,000 kW, 5,000 kW, and 1,980 kW, respectively. At this time, CHP shared 275,940 Gcal, 72.8%, fuel cell 12,390 Gcal, 3.3%, and PLB 90,620 Gcal, 23.9%. The CHP capacity was not reduced because an uneconomical alternative was found that required excessive operation of the PLB for insufficient heat production resulting from the CHP capacity reduction. On the other hand, in terms of indirect heat demand for the paper industry, which is the dominant industry, the optimal capacity of CHP, fuel cell, and photovoltaic combination is 25,000 kW, 5,000 kW, and 2,000 kW. The heat production was analyzed to be CHP 225,053 Gcal, 76.5%, fuel cell 11,215 Gcal, 3.8%, PLB 58,012 Gcal, 19.7%. However, the economic analysis results of the current electricity market and gas market confirm that the return on investment is impossible. However, we confirmed that the CHP Hybrid System, which combines CHP, fuel cell, and solar power, can improve management conditions of about KRW 9.3 billion annually for a single CHP system.

Status of Light Environment in Greenhouses (온실의 광환경 실태 조사 분석)

  • 이석건;김문기
    • Proceedings of the Korean Society for Bio-Environment Control Conference
    • /
    • 1997.11a
    • /
    • pp.14-19
    • /
    • 1997
  • 식물의 광반응은 광질과 광강도에 따라 상이하며, 광은 열을 동반하게 되므로 광만을 분리하여 생각할 수 없다. 즉, 광은 식물체의 체온과 엽온을 높이고, 잎의 수증기 장력을 증가시켜 증산을 촉진하므로 기화열을 발생하는 원동력이 되기도 한다. 따라서 광은 잎속의 수분이나 기공개도 등에 영향을 주기 때문에 광합성속도에 간접적인 영향을 미치기도 한다. (중략)

  • PDF

Effects of direct and indirect bonding techniques on bond strength and microleakage after thermocycling (직접 부착법과 간접 부착법이 열순환 후 부착강도와 미세누출에 미치는 영향에 대한 연구)

  • Ozturk, Firat;Babacan, Hasan;Nalcaci, Ruhi;Kustarci, Alper
    • The korean journal of orthodontics
    • /
    • v.39 no.6
    • /
    • pp.393-401
    • /
    • 2009
  • Objective: The purpose of this study was to compare the shear bond strength (SBS) of brackets and microleakage of a tooth-adhesive-bracket complex bonded with a direct and an indirect bonding technique after thermocycling. Methods: Fifty non-carious human premolars were divided into two equal groups. In the direct bonding group a light-cured adhesive and a primer (Transbond XT) was used. In the indirect-bonding group, a light-cured adhesive (Transbond XT) and chemical-cured primer (Sondhi Rapid Set) were used. After polymerization, the teeth were kept in distilled water for 24 hours and thereafter subjected to thermal cycling (500 cycles). For the microleakage evaluation, 10 teeth from each group were further sealed with nail varnish, stained with 0.5% basic fuchsin for 24 hours, and examined under a stereomicroscope. Fifteen teeth from each group were used for SBS testing with the universal testing machine and adhesive remnant index (ARI) evaluation. Data were analyzed using the Mann-Whitney U test, Chi-square test, and Fisher's exact test. Results: There were no statistical differences on SBS and microleakage between the two bonding techniques. The indirect bonding group had a significantly lower ARI score. Bracket failures were obtained between enamel-resin interfaces. Conclusions: The type of bonding technique did not significantly affect the amount of microleakage and SBS.

A study on the room heating by solar assisted heat pump using the alternatives (대체냉매적용 태양열 열펌프시스템에 의한 난방성능분석(1))

  • 선경호;정현채
    • Proceedings of the Korea Society for Energy Engineering kosee Conference
    • /
    • 1995.05a
    • /
    • pp.94-99
    • /
    • 1995
  • 본 연구는 태양열 열펌프시스템에 의한 약 6평 규모의 실내의 난방방법으로서 간접 난방인 온수순환난방과 직접난방인 복사난방의 성능을 분석하였다. 태양열 열펌프의 최대의 열적성능을 나타낼 수 있도록 알루미늄 롤 본드형 태양열 집열기의 면적을 조절하였으며 집열효과를 극대화하기 위하여 온도감응 자동팽창밸브의 용량을 변화시켰다. 본 실험에서 적용된 태양열 열펌프 난방은 서울지방 봄 가을철의 외기온도에서 실내온도가 18~2$0^{\circ}C$로 유지되도록 설계제작되었다. 태양열 열펌프시스템에 적용된 작용유체는 온수순환 난방에는 R-12냉매. 그 대체냉매는 R-134a 및 혼합냉매, 복사난방에는 R-22냉매이었다.

  • PDF