• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.167-171
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• 2009

We conducted performance test of a 350 kW class wood pellet boiler installed at a dormitory whose total area is $1,354\;m^2$. The maximum heating capacity of the boiler is 350 kW(300,000 kcal/kg). The wood pellet boiler consists of 3 parts; boiler, hot water storage tank and wood pellet storage tank. In testing the boiler, we shut off hot water utility supply and open up floor heating water system in order to measure exact value of the heating output of the wood pellet boiler. To determine the efficiency and heating output of the wood pellet boiler, we measured mass flow rate of wood pellet, the lower heating value(LHV) of the wood pellet, mass flow rate and temperature of water for floor heating and so on. We measured the mass flow rate of fuel, wood pellet with respect to rotational speed of auger, wood pellet feeding screw. We also measured the flue gas concentration of the wood pellet boiler by using a gas analyser. The result shows that the efficiency of the wood pellet boiler is 80.6% based on lower heating value at 124 kW of heating output. At this condition, O2 concentration of the flue gas is 6.0%, CO and NOx concentrations are 85 and 102 ppm.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.103.1-103.1
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• 2010

Recently domestic wood pellet boilers are installed in rural and forestry houses. The fuel price per lower heating value of wood pellet is about 20 % lower than that of heating oil on July 2010. In spite of lower price of wood pellet, a few user of wood pellet boiler complain expensive fuel cost. One of this reason is inaccurate or improper air-fuel ratio setting of wood pellet boiler. O2 concentration of flue gas of domestic wood pellet boiler is about 9.7 % and there are few domestic wood pellet boiler which can control air-fuel ratio automatically. We tested a domestic wood pellet boiler in changing boiler thermal output and air-fuel ratio. The nominal boiler thermal output is 25 kW (21 500 kcal/h). We measured thermal efficiency and flue gas concentrations such as CO and NOx at each boiler thermal load with various air-fuel ratio. The results show that if air flow rate is the same as full load and part load, thermal efficiency of part load of 40 % drops about 7.7 %p compared to boiler full load case.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.3
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• pp.251-260
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• 2014

Biomass burning is one of the significant emission source of PM and CO, but a few studies are reported in Korea. Air pollutants emission from biomass burning such as wood stove and boiler, and wood-pellet stove and boiler were estimated in this study. Activity levels related to biomass burning such as fuel types, amount of fuel loading, and location and temporal variation were investigated by field survey over Korea. Fuel loadings were 14.9 kg/day for wood stove, 31.3 kg/day for wood boiler, 12.8 kg/day for wood-pellet stove, 32.5 kg/day for wood-pellet boiler during the season of active use. These were mostly burned in winter season from october to april of next year. Estimated annual emissions from wood stove & boiler were CO 76,677, $NO_x$ 710, $SO_x$ 70, VOC 20,941, TSP 6,605, PM10 2,921, PM2.5 1,851, and NH3 7 ton/yr, respectively. Emissions from wood-pellet stove and boiler were CO 32,798, $NO_x$ 1,830, $SO_x$ 25, VOCs 5,673, TSP 629, PM10 457, PM2.5 344, and $NH_3$ 2 ton/yr, respectively. When the emission estimates are compared with total emissions of the national emission inventory (CAPSS: Clean Air Policy Support System), Those occupy 12.5%, 2.8% of total national emission for CO and PM10, respectively. These results show wood and wood-pellet burning appliances were one of the major source of air pollution in Korea. In future, these types of heaters need to be regulated to reduce air pollution, especially in suburb area.

• Journal of Forest and Environmental Science
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• v.23 no.2
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• pp.79-85
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• 2007

This survey was carried out to investigate the utilization situation of fire-wood boiler by the questionnaire and personal interview on rural and mountain households of Gangwon province from 1998 to 2005. The questionnaire include 7 questions on installation, 7 questions on fuel, 3 questions on use, and 3 questions on improvement. Each question was analyzed by percentage to investigate the use situation. This survey indicated that the general problems in use of fire-wood boiler are fuel purchase, collection and transportation, that the development of the household heating boiler using wood-based forming fuel which is cheap, small volume, easy handling, convenient purchase and high heat efficiency could be an alternative to improve the problems and that the continuous expansion of the supply of fire-wood boiler can prevent the devastation of forest through the regulation of imprudent fuel supply. Although the financial aid plan on the installation of fire-wood boiler is in active, many petty households in rural and mountain areas lose a chance to install the fire-wood boiler due to the unsatisfactory information. Thus, it will be desirable for municipal government to prepare the information plan to offer the equal chance and condition to all households in rural and mountain areas and to increase the financial aid for the continuous supply of fire-wood boiler.

• Korean Journal of Organic Agriculture
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• v.21 no.3
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• pp.335-350
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• 2013

With the efforts to development of renewable energy technologies, and increasing awareness to environmental issues, the usage of wood pallets has been increasing every year since the introduction of wood pallet technology to the domestic market. until 2009, majority usage of pellet boiler was in the residential houses. In an effort to increase the distribution of wood pellet boiler to cultivation facilities with high usage of fuels, The Ministry of Agriculture and Forestry has launched a distribution project of wood pellet boiler for fuel usage as a part of the agricultural and fishery energy efficiency projects. Although only small number of farms with a heat-culturing facility have replaced from conventional boiler to pellet boiler. Although part of reason for low usage of pallet boiler is lack of understanding and information of it, the main reasons are high initial cost and uncertainty of its cost efficiency. Also, most people from agricultural industry don't realize it's significance in terms of environmental benefit due to lack of understanding in 'resource circulation' and 'adopting to climate change'. In this study, first, we did a cost-efficiency analysis of the farm which uses a diesel boiler to grow cucumber, tomato, paprika. Then we replaced the diesel boiler to a pallet boiler and measured its cost-efficiency again. By comparing the cost-efficiency of the diesel boiler with the pellet boiler, we analyzed the economic viability of pellet boiler. Then we analyzed viability of pallet boiler usage in terms of 'resource circulation' and 'adopting to climate change'. As a result of our analysis, we have found out that under the current system of government support, the energy usage varies depends of the types crops grown and the higher the energy use, the more cost efficient it is to use the pallet boiler. Also, it is economically viable to use the pallet boiler in terms of 'resource circulation' and 'adopting to climate change'.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.3
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• pp.491-497
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• 2002

In the present study, a new wood boiler was developed through the performance test. The efficiency of the boiler was obtained up to about 63.7%, which is 67% higher than that of conventional wood boiler, about 38.2%. The structure of the new boiler is more complicated than the conventional boiler. The passage of combustion gas is sufficiently long to exchange heat well with heating water. Therefore, the obtained efficiency is so high, and the temperature of exhaust gas was lower than 200$^{\circ}C$, which is as low as that of light oil boiler. The composition of exhaust gas was measured, and the CO gas concentration was obtained more than 3000 ppm. So, it seems that more study is needed to lower the concentration of CO gas.

• Journal of Applied Reliability
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• v.12 no.1
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• pp.35-46
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• 2012

Wood pellet is one of biomass energy fuels, which is produced by compressing woody biomass such as sawdust, planer shavings, and whole-tree removal or tree tops and branches leftover after logging into cylindrical form. Latterly much attention has been paid to wood pellet boiler which is suitable for use at various scales in domestic and industrial furnaces for heat production to replace conventional fossil fuel energy sources since the use of wood pellet that is carbon neutral can alleviate global warming. This study presents the result of developing a high efficiency wood pellet boiler with 55MJ/h capacity. Efficiency has been improved by using a rotating disk burner with a shorter screw feeder. Special attention has been paid to the improvement of the safety of the wood pellet boiler from backfire by adopting a double protecting system composed of a shutter and an air curtain. The result shows that the efficiencies of the wood pellet boiler are 97.2% and 89.2% based on lower and higher heating values, respectively, at 15.1kW of heating output.

• Journal of Energy Engineering
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• v.23 no.3
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• pp.211-220
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• 2014

This study reports the formation characteristics of tar, ash and clinker due to a wood pellet grade and the performance analysis of wood pellet boiler in terms of the moisture contents change of the wood pellet. Tar was accumulated on the heating surface according to combustion of wood pellet, the ash was yielded on the floor of combustion chamber in a wood pellet boiler and the clinker was solidified at the burner due to combustion of the 3rd grade wood pellet. Especially, the moisture contents is important factor to define the grade. Wood of logging residues has a non-uniform moisture contents after the field process, yields of tar, ash and clinker are increased in case of combustion due to the high ash contents. For these reasons, emission of harmful compounds in the exhaust gas, decrease of boiler efficiency and the system operating errors are observed. In the performance analysis of wood pellet boiler in terms of the moisture contents change of the 1st grade wood pellet, the boiler efficiency was reduced by 27.08% with 6.6% moisture contents increase. The optimum moisture contents of wood pellet is needed to improve the boiler performance and efficiency.

• Korean Journal of Organic Agriculture
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• v.22 no.2
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• pp.255-268
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• 2014

We are now currently facing serious climate changes such as super typhoon, flood, intense heat, severe cold, super hurricane, drought, desertification, destruction of ecosystem, marine pollution, reduction of food production, destruction of tropical forests, exhaustion of water resources, climate refugees, etc. All of the above mainly derive from greenhouse gas exhaustion. Such harmful consequence might directly affect mankind's sustainable development. If we keep using resources that emits greenhouse gases, the global temperature will rise about $3.2^{\circ}C$ by year 2050. In case of $3^{\circ}C$ rise in temperature, it will result in abnormal climate which will bring about severe property damage. Moreover, 20~50% of the ecosystem will become extinct. As Korea's economy increasingly expands, so do our energy consumption rises. And because of the consequences that can be driven by increasing rate of resource use, not just Korea itself, but also the whole world should seriously concern about greenhouse gases. Although agricultural division only takes up about 3.2% of total greenhouse gas emission, the ministry of Agriculture, Food and Rural Affairs are taking voluntary actions to gradually reduce $CO_2$ and so does each and every related organizations. In order to reduce $CO_2$, introduction of new and renewable energy in farm house warming is crucial. In other words, implementing wood-pellet boiler and geothermal heat boiler can largly reduce $CO_2$ emission compared to diesel boiler. More importantly, not only wood-pellet and geothermal heat is pollution-free but they also have economic advantages some-what. In this thesis, the economic advantage and sustainablity will be introduced and proved through comparing practical analysis of surveyed farm house under structure employing wood-pellet boiler and geothermal heat boiler with Agriculture-Economic Statistic of 2012 who uses diesel boiler.

• Journal of Applied Reliability
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• v.13 no.1
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• pp.31-44
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• 2013

Recently, due to the high rise of energy costs and environmental problem issues, much attention has been paid to wood pellets. Wood pellets are produced by compressing woody biomass into cylindrical form. Wood pellets are suitable for use at various scales in industrial furnaces for heat production to replace conventional fossil fuel energy sources since the use of wood pellet that is carbon neutral can alleviate global warming. This study presents the result of developing two industrial wood pellet boilers with high safety having capacities of 290kW and 440kW. Efficiency has been improved by using a rotating screw bar grate burner. Special attention has been paid to the improvement of the safety of the wood pellet boilers from backfire by adopting a triple protecting system composed of a rotary feeder, an air curtain, and a backfire protecting DC-fan.