• Title/Summary/Keyword: Fuel Consumption Characteristics

Search Result 504, Processing Time 0.03 seconds

Effect of Growing Part Following Local Heating for Cherry Tomato on Temperature Distribution of Crop and Fuel Consumption (방울토마토 생장부 추종 국소난방이 군락 온도분포 및 연료소비에 미치는 영향)

  • Kwon, Jin Kyung;Kang, Geum Chun;Moon, Jong Pil;Lee, Tae Seok;Lee, Su Jang
    • Journal of Bio-Environment Control
    • /
    • v.24 no.3
    • /
    • pp.217-225
    • /
    • 2015
  • Local heating system providing hot air locally to growing parts including shoot apex and flower cluster which were temperature-sensitive organs of cherry tomato was developed to reduce energy consumption for greenhouse heating without decline of crop growth. Growing part following local heating system was composed of double duct distributer which connected inner and outer ducts with hot air heater and winder which moved ducts up and down following growing parts with plant growth. Growing part local heating system was compared with conventional bottom duct heating system with respect to distributions of air and leaf surface temperatures according to height, growth characteristics and energy consumption. By growing part local heating, air temperature around growing part was maintained $0.9{\sim}2.0^{\circ}C$ higher than that of lower part of crop and leaf surface temperature was also stratified according to height. Investigations on crop growth characteristics and crop yield showed no statistically significant difference except for plant height between bottom duct heating and growing part local heating. As a result, the growing part local heating system consumed 23.7% less heating energy than the bottom duct heating system without decrease of crop yield.

Analysis of Heating Characteristics of Multi-Layered Insulation Curtain with Silica Aerogel in Greenhouses (실리카 에어로겔을 이용한 다겹보온커튼의 온실 난방 특성 분석)

  • Jin, Byung-Ok;Kim, Hyung-Kweon;Ryou, Young-Sun;Lee, Tae-Seok;Kim, Young-Hwa;Oh, Sung-Sik;Kang, Geum-Choon
    • Journal of Bio-Environment Control
    • /
    • v.29 no.4
    • /
    • pp.320-325
    • /
    • 2020
  • This study aimed to analyze thermo-keeping and economic feasibility by utilizing silica aerogel, which has been attracting attention as a new material, complementing the disadvantages of the conventional multi-layered thermal screen, and producing and installing multi-layered thermal screen. The multi-layered thermal screen used in the experiment was produced in two combinations using a non-woven fabric containing silica aerogel and measured and compared the temperature and fuel consumption changes due to differences in practice with the multi-layered thermal screen being sold and used on the market. Experimental results show that the temperature and relative humidity changes due to the differences of the multi-layered thermal screens in the single-span greenhouse and the multi-span greenhouse were small but remained almost the same temperature and relative humidity. It is judged that this shows that the multi-layered thermal screen using silica aerogel is not inferior to the conventional multi-layered thermal screen. As a result of a comparative analysis of heating energy, the aerogel-based multi-layered thermal screen reduced fuel consumption by about 15% in the single-span greenhouse and about 20% in the multi-span greenhouse compared to the conventional multi-layered thermal screen. It is clear that heating energy is saved as a greenhouse size and duration increase. It was found that the silica aerogel-based multi-layered screen was more breathable and warmer than the conventional multi-layered thermal screen, but It was found that the multi-layered screen used in the multi-span greenhouse was heavier and stiff compared with the conventional multi-layered thermal screen, indicating less workability and operability. Therefore, improvements were applied to the multi-layered screens used in the single-span greenhouses. It was confirmed that the replacement of internal insulation materials reduced thickness and improved stiffness so that there could be sufficient possibility for farmers to use.

Comparison of Combustion Characteristics On the Basis of the Dilution Ratio in Diesel Engines with LPL EGR (저압 EGR을 적용한 디젤엔진의 희석비에 따른 연소 특성 비교)

  • Lim, Gi-Hun;Park, Jun-Hyuk;Choi, Young;Lee, Sun-Youp;Kim, Yong-Min
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.35 no.5
    • /
    • pp.525-531
    • /
    • 2011
  • Exhaust gas recirculation (EGR) is more effective than selective catalytic reduction (SCR) or lean $NO_x$ trap (LNT) for the reduction of $NO_x$ emissions in diesel engines. A large amount of EGR gas is necessary to satisfy the stringent regulations on $NO_x$ emissions. Low pressure loop (LPL) EGR is almost independent of the variable geometry turbocharger (VGT) at a specific boost pressure, so LPL EGR is better than conventional high pressure loop (HPL) EGR in terms of EGR supply. We compare the influence of HPL EGR and LPL EGR on the combustion characteristics at a constant boost pressure in a diesel engine. The dilution ratio was employed as an independent parameter to analyze the effect of the dilution of the intake charge for each EGR loop. At the same level of $NO_x$ emissions, the fuel consumption and smoke opacity were slightly lower for LPL EGR than for HPL EGR.

Collapse Analysis of Ultimate Strength Considering the Heat Affected Zone of an Aluminum Stiffened Plate in a Catamaran (카타마란 알루미늄 보강판의 열영향부 효과를 고려한 최종강도 붕괴 해석)

  • Kim, Sung-Jun;Seo, Kwang-Cheol;Park, Joo-Shin
    • Journal of the Korean Society of Marine Environment & Safety
    • /
    • v.26 no.5
    • /
    • pp.542-550
    • /
    • 2020
  • The use of high-strength aluminum alloys for ships and of shore structures has many benefits compared to carbon steels. Recently, high-strength aluminum alloys have been widely used in onshore and of shore industries, and they are widely used for the side shell structures of special-purpose ships. Their use in box girders of bridge structures and in the topside of fixed platforms is also becoming more widespread. Use of aluminum material can reduce fuel consumption by reducing the weight of the composite material through a weight composition ratio of 1/3 compared to carbon steel. The characteristics of the stress strain relationship of an aluminum structure are quite different from those of a steel structure, because of the influence of the welding[process heat affected zone (HAZ). The HAZ of aluminum is much wider than that of steel owing to its higher heat conductivity. In this study, by considering the HAZ generated by metal insert gas (MIG) welding, the buckling and final strength characteristics of an aluminum reinforcing plate against longitudinal compression loads were analyzed. MIG welding reduces both the buckling and ultimate strength, and the energy dissipation rate after initial yielding is high in the range of the HAZ being 15 mm, and then the difference is small when HAZ being 25 mm or more. Therefore, it is important to review and analyze the influence of the HAZ to estimate the structural behavior of the stiffened plate to which the aluminum alloy material is applied.

A Study on the Gradation Effect of the Property of Roller Compacted Concrete Pavement (골재 입도분포가 도로포장용 롤러전압 콘크리트에 미치는 영향 연구)

  • Song, Si Hoon;Lee, Seung Woo
    • International Journal of Highway Engineering
    • /
    • v.17 no.3
    • /
    • pp.49-58
    • /
    • 2015
  • PURPOSES : The use of environmentally friendly construction methods has been recently encouraged to reduce fuel consumption and the effects of global warming. For this purpose, the roller compacted concrete pavement (RCCP) construction method has been developed. RCCP is more environmentally friendly and economically efficient than general concrete by reducing the amount of CO2 generated through the application of a smaller amount of cement. RCCP has a number of advantages such as an easy construction method, low cost, high structural hydration performance, and aggregate interlocking. However, mix design standards and construction guidelines of RCCP are required for domestic application. In addition, a study on aggregate selection, which has an effect on the characteristics of RCCP, is necessary owing to a limited number of researches. Thus, the aggregate effect on the performance of RCCP in securing the required strength and workability was evaluated in consideration of domestic construction. METHODS : Sand and coarse aggregates of both 19mm and 13mm in maximum size were used in this study. Four types of aggregate gradations (s/a = 30%, 58%, and 70% for the sand and coarse aggregate of 19mm in maximum size, and s/a = 50% for a combination of the three types of aggregates) were set up to investigate the effects of the PCA band on the RCC characteristics. The conditions of s/a = 30% and 70% were evaluated to check the gradation effect outside of the recommended band. The conditions of s/a = 58% and 50% were used because they are the optimum combination of the two and three types of aggregates, respectively. RCCP gradation band was suggested gradation with a proper construction method of RCCP by synthetically comparing and analyzing the correlation of optimum water content, maximum dry density, and strength of requirements through its consistency and compaction test. RESULTS : The lower and upper limit lines are insufficient to secure a relatively strong development and workability compared to an aggregate gradation in the RCCP gradation band region. On the other hand, the line in the RCCP gradation band and the 0.45 power curve in the RCCP gradation band region were satisfactory, ensuring the required strength and workability. CONCLUSIONS : The suitable aggregate gradation on RCCP process should meet the RCCP gradation band area; however, fine particles passing through a #60 sieve do not need to be within the recommended gradation band because the influence of this region on such fine particles is small.

Study on the Drying Characteristics of Poultry Manure for Its Dryer Development (계분건조기 개발을 위한 계분의 건조특성 연구)

  • 장동일
    • Korean Journal of Poultry Science
    • /
    • v.20 no.3
    • /
    • pp.141-149
    • /
    • 1993
  • In order to develop a poultry manure dryer, a pilot dryer was designed and drying experiments were conducted to investigate the drying characteristics of poultry manure. According to the results, the pilot dryer could be operated without any air pollution problems. When poultry manure was dried from 79.2%(w.b. basis) moisture content, the final moisture content ranged from 38.7% to 57.9% depending upon the drying conditions. The drying results showed that drying rate was 189.8~198.0 kg/h and moisture evaporation rate was 124.0~125.4kg-$H_2$O/L. For this drying, electricity requirement was 9.5~19.3 Wh/kg and fuel consumption rate was 6.9~9.3 kg-$H_2$O/L with 50.2~65.1% thermal efficiency.

  • PDF

Recent Progress in Air-Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2014 (설비공학 분야의 최근 연구 동향: 2014년 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.27 no.7
    • /
    • pp.380-394
    • /
    • 2015
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2014. 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 heat and mass transfer, cooling and heating, and air-conditioning, the flow inside building rooms, and smoke control on fire. Research issues dealing with duct and pipe were reduced, but flows inside building rooms, and smoke controls were 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 thermal contact resistance measurement of metal interface, a fan coil with an oval-type heat exchanger, fouling characteristics of plate heat exchangers, effect of rib pitch in a two wall divergent channel, semi-empirical analysis in vertical mesoscale tubes, an integrated drying machine, microscale surface wrinkles, brazed plate heat exchangers, numerical analysis in printed circuit heat exchanger. In the area of pool boiling and condensing, non-uniform air flow, PCM applied thermal storage wall system, a new wavy cylindrical shape capsule, and HFC32/HFC152a mixtures on enhanced tubes, were actively studied. In the area of industrial heat exchangers, researches on solar water storage tank, effective design on the inserting part of refrigerator door gasket, impact of different boundary conditions in generating g-function, various construction of SCW type ground heat exchanger and a heat pump for closed cooling water heat recovery were performed. (3) In the field of refrigeration, various studies were carried out in the categories of refrigeration cycle, alternative refrigeration and modelling and controls including energy recoveries from industrial boilers and vehicles, improvement of dehumidification systems, novel defrost systems, fault diagnosis and optimum controls for heat pump systems. It is particularly notable that a substantial number of studies were dedicated for the development of air-conditioning and power recovery systems for electric vehicles in this year. (4) In building mechanical system research fields, seventeen 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, and renewable energies, piping in the buildings. Proposed designs, performance 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 was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the evaluation of work noise in tunnel construction and the simulation and development of a light-shelf system. The subjects of building energy were worked on the energy saving of office building applied with window blind and phase change material(PCM), a method of existing building energy simulation using energy audit data, the estimation of thermal consumption unit of apartment building and its case studies, dynamic window performance, a writing method of energy consumption report and energy estimation of apartment building using district heating system. The remained studies were related to the improvement of architectural engineering education system for plant engineering industry, estimating cooling and heating degree days for variable base temperature, a prediction method of underground temperature, the comfort control algorithm of car air conditioner, the smoke control performance evaluation of high-rise building, evaluation of thermal energy systems of bio safety laboratory and a development of measuring device of solar heat gain coefficient of fenestration system.

Operational Characteristics of a Dry Electrostatic Precipitator for Removal of Particles from Oxy Fuel Combustion (순산소 연소 배출 입자 제거용 건식 전기집진장치 운전 특성)

  • Kim, Hak-Joon;Han, Bang-Woo;Oh, Won-Seok;Hwang, Gyu-Dong;Kim, Yong-Jin;Hong, Jeong-Hee
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.34 no.1
    • /
    • pp.27-34
    • /
    • 2010
  • In a test duct with closed configuration, particle removal performance of an edge-plate type electrostatic precipitator (ESP) was evaluated at a high flow rate in $CO_2$ rich environments by changing gap distances between collection plates, concentrations of $CO_2$, particle sizes, types of electrodes, and types of power supplies. At the same experimental conditions, collection efficiency of particles with the mean particle size, 300 nm, decreased as the gap distance and $CO_2$ concentration increased because of low electrostatic force and low discharged current. In addition, as the particle size increased, the efficiency increased because of high charging rate of the large particles. With the electrode type which has higher surface area of a discharging plate and with the power supply which applied 25 kHz-pulsed DC voltages, the removal efficiency was high even in rich $CO_2$ condition due to high electrostatic force at the same power consumption.

Urinary PAH Metabolites as Biomarkers of Environmental PAHs Exposure (환경성 PAHs 노출과 생체지표 연구)

  • Lee, Kyoung-Ho;Li, Zhung-Min;Cho, Soo-Hun;Kwon, Ho-Jang;Kang, Dae-Hee
    • Toxicological Research
    • /
    • v.23 no.1
    • /
    • pp.39-46
    • /
    • 2007
  • The aim of the study was to see if there is any differences in urinary 1-hydroxypyrene glucuronide (1-OHPG) and 2-naphthol levels in children ($8{\sim}14$ years old) and their mothers ($30{\sim}46$ years old) living three cities in South Korea (Seoul, Incheon and Pohang) and three in China (Changchun, Datong and Kunming), where the levels of air pollution varies. The factors related with urinary biomarkers levels were also evaluated. The study subjects consisted of 118 Korean (60 children and 58 their mothers) and 120 Chinese (60 children and 60 their mothers). Urinary 1-OHPG was measured by synchronous fluorescence spectroscopy after immuno-affinity purification using monoclonal antibody 8E11 and urinary 2-naphthol concentrations were determined by HPLC with fluorescence detector. Information on recent consumption of diet containing high PAHs, environmental tobacco smoke (ETS), type of cooking and heating fuels, and other life-style characteristics were collected by self-administered questionnaire. The arithmetic mean of urinary 1-OHPG levels (n = 120, $mean{\pm}SD$, $6.77{\pm}7.96{\mu}mol/mol$ creatinine) in Chinese were 10 fold higher than those in Korean (n = 118, $0.62{\pm}0.61{\mu}mol/mol$ creatinine) (P < 0.01). Urinary 2-naphthol levels in Chinese (n = 119, $59.50{\pm}82.29{\mu}g/g$ creatinine) were significantly higher than those in Korean (n = 117, $25.09{\pm}46.56{\mu}g/g$ creatinine) (P < 0.01). Urinary 1-OHPG and 2-naphthol levels were significantly higher in children living the polluted cities in China (Datong and Chanchun, respectively). Multiple linear regression analysis indicated that living in factory area (vs. residential area) and use of coal stove as heating fuel were significant predictors for urinary 1-OHPG (overall model $R^2$= 0.46, n = 204). And ETS was predictor for urinary 2-naphthol levels in Korean ($R^2$ = 0.36, n = 46). These results indicated that urinary 1-OHPG and 2-naphthol levels were related with different ambient particulate air pollution, type of heating fuels and ETS.

Applicability of Various Biomasses to Pulverized Coal Power Plants in Terms of their Grindability (다양한 바이오매스의 분쇄도 실험을 통한 미분탄 화력발전 적용가능성 연구)

  • Kang, Byeol;Lee, Yongwoon;Ryu, Changkook;Yang, Won
    • Clean Technology
    • /
    • v.23 no.1
    • /
    • pp.73-79
    • /
    • 2017
  • Recently usage of biomass is increased in pulverized coal power plants for reduction of $CO_2$ emission. Many problems arise when thermal share of the biomass is increased, and milling of the biomasses is one of the most important problems due to their low grindability when existing coal pulverizer is used. Grindability of coal can be measured through the HGI (Hardgrove grindability index) equipment as a standard, but method of measuring biomass grindability has not been established yet. In this study, grinding experiment of coal and biomass was performed using a lab-scale ball mill. One type of coal (Adaro coal) and six biomasses (wood pellet (WP), empty fruit bunch (EFB), palm kernel shell (PKS), walnut shell (WS), torrefied wood chip (TBC) and torrefied wood pellet (TWP)) were used in the experiment. Particle size distributions of the fuels were measured after being milled in various pulverization times. Pulverization characteristics were evaluated by portion of particles under the diameter of $75{\mu}m$. As a result, about 70% of the TBC and TWP were observed to be pulverized to sizes of under $75{\mu}m$, which implies that they can be used as alternative biomass fuels without modification of the existing mill. Other biomass was observed to have low grindability compared with torrefied biomass. Power consumption of the mill for various fuels was measured as well, and the results show that lower power was consumed for torrefied biomasses. This result can be used for characterization of biomass as an alternative fuel for pulverized coal power plants.