• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.4
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• pp.113-122
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• 2018

Thermal stress of pigs causes decreased feed consumption and weight gain rate, immunosuppression, reproductive disorders, and increased mortality. The concept of the temperature-humidity index (THI) has been widely used to evaluate the degree of thermal stress of pigs. However, use of this concept is strongly restricted for animals living in the enclosed facilities. In this study, Building Energy Simulation (BES) technique was used to realize the energy flow among outside weather conditions, building materials, and animals. Especially, mechanisms of sensible and latent heat generation from pigs according to surrounding air temperature and their weight were designed to accurately evaluate the THI values inside the pig house. The THI values computed by the BES model were compared to those calculated by method of the report (NIAS, 2016), the model of this study predicted the start date of heat stress about 9~76 days earlier compared to the NIAS model. Results of the BES model also showed higher frequencies of the THI above the THI threshold for pigs, indicating that conventional model has a possibility of underestimating the degree of heat stress of pigs.

• Korean Chemical Engineering Research
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• v.53 no.5
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• pp.590-596
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• 2015

Estimating potential of $CO_2$ emission reduction of non-capture $CO_2$ utilization (NCCU) technology was evaluated. NCCU is sodium bicarbonate production technology through the carbonation reaction of $CO_2$ contained in the flue gas. For the estimating the $CO_2$ emission reduction, process simulation using process simulator (PRO/II) based on a chemical plant which could handle $CO_2$ of 100 tons per day was performed, Also for the estimation of the indirect $CO_2$ reduction, the solvay process which is a conventional technology for the production of sodium carbonate/sodium bicarbonate, was studied. The results of the analysis showed that in case of the solvay process, overall $CO_2$ emission was estimated as 48,862 ton per year based on the energy consumption for the production of $NaHCO_3$ ($7.4GJ/tNaHCO_3$). While for the NCCU technology, the direct $CO_2$ reduction through the $CO_2$ carbonation was estimated as 36,500 ton per year and the indirect $CO_2$ reduction through the lower energy consumption was 46,885 ton per year which lead to 83,385 ton per year in total. From these results, it could be concluded that sodium bicarbonate production technology through the carbonation reaction of $CO_2$ contained in the flue was energy efficient and could be one of the promising technology for the low $CO_2$ emission technology.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.2
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• pp.75-84
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• 2018

Thermal stress of livestock has been issued due to recent climate change trends and this causes reproductive disorders, decreased feed consumption, immunosuppression, and increased mortality of animals. Concept of THI has been widely used to quantitatively evaluate the degree of thermal stress for animals, however use of this concept is restricted for animals living in the enclosed facilities such as mechanically ventilated broiler houses. In this study, time-based internal energy flow and variation trends of temperature and humidity were analyzed based on BES technique. Local weather data, insulation characteristics of building materials, heat and moisture generation rate from broilers according to age, algorithm of ventilation operation were adopted for boundary condition of the model to accurately compute THI values inside the mechanically ventilated broiler house. From the BES computation, excess frequency of THI threshold in Jeju city was highest on the assumption that air conditioning equipments were not installed. When general raising density ($39kg\;m^{-2}$) was adopted, total 2,191 hours were exceeded. Excess hours of THI threshold were strongly related to the cumulative air temperature ($R^2=0.87$).

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.2
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• pp.221-233
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• 2016

In order to estimate the performance of a conical cutter depending on the insert size, this study measured forces acting on conical cutters with different cutter spacings, penetration depths and skew angles using slim and heavy conical cutters. When cutter spacings ranged from 12 to 27 mm, the deviations of mean cutter forces with cutter depths appeared smaller compared to other cutter spacings. When skew angle is $0^{\circ}$, the optimal S/d ratio was obtained in the range of 4 to 4.5 for which specific energy of cutting was minimized. It were usually found in the range of 1 to 5. However, when skew angle is $6^{\circ}$, the optimal S/d ratio was obtained in the range of 1 to 3. The simple comparison results shows that the performance of slim cutter was superior to that of heavy cutter, but the use of heavy cutter can be effective, considering the cutter consumption and cutter damage when the strength of the ground is high enough.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.2
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• pp.92-104
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• 2017

Previous management for speed in road traffic system was aimed only to the improvement of mobility and safety. However, consideration for the aspect of environment and energy consumption efficiency was valued less than the former ones. Nevertheless, economical damage scope caused by climate change has been increasing and it is estimated that environmental value will be increased because of the change of external circumstances. In addition, policy for reducing carbon emission in transportation system was assessed as insufficient in improving the condition of traffic road since it only focused on the transition of private vehicle into public transportation and development of eco-friendly car. Now it is the time to prepare for the adaptation strategy and precaution for the increased number of private vehicle in Korea. For this, paradigm shift in traffic operation which includes the policy not only about the mobility but also about caring environment would be needed. It is needed to be able to monitor the actual amount of greenhouse gas in real time to reduce the amount of emitted greenhouse gas in the aspect of traffic management. In this research, a methodology which can build on-line greenhouse gas emission monitoring system by using real time traffic data and predicting the circumstance in next 5 minutes was suggested.

• Environmental and Resource Economics Review
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• v.24 no.3
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• pp.463-488
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• 2015

A more detailed design of offset system is needed according to the emission trading system started in 2015. This study aims to estimate the supply of potential offset that can be secured by expanding high-efficiency household electric appliances. The target commodities for analysis are three different householding electric appliances: TV, washing machine, electric fan, refrigerator and air conditioner. By using the ARDL model, we estimated the coefficients of diffusion of these high-efficiency appliances from 2016 to 2022. Then, the potential supply of offset was drawn by calculating the amount of electricity saving by efficiency improvement and by applying the rates of carbon exchange. Supposing that the electricity savings rates of high-efficiency appliances are each 10% and 20%, the accumulated carbon decrement in 2022 was respectively $361,899CO_2t$ and $723,797CO_2t$. The appliance that showed the biggest carbon decrement was air conditioner, and the second biggest was refrigerator and the next was TV, followed by washing machine, electric fan.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.10
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• pp.1028-1033
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• 2008

Sequential quick crushing and alkali hydrolysis(SeCAH), as a pretreatment for foodwaste, incorporating mechanical crushing and alkali hydrolysis was proposed and investigated in this study. Focuses were placed on the improvement of biodegradability of foodwaste and the estimation of potential inhibitors for anaerobic digestion. The solubility of the pretreated foodwaste by SeCAH was increased 2.5 times rather than mechanical crushing. Considering solubility improvement and energy consumption, 2,000 rpm of crushing strength and 5$\sim$10 sec of crushing time are recommended. After SeCAH, the fraction of large organic particles(>2.36 mm) of foodwaste was sharply decreased from 88.0% to 29.0%, otherwise the fraction of small particles(<75 $\mu$m) was greatly increased from 10.5% to 40.7%. Ammouinum, potassium and sulfate were estimated as potential inhibitors for anaerobic digestion and their concentrations in pig slurry were 3331.3 mg/L, 4256.5 mg/L and 1017.5 mg/L, respectively.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.4
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• pp.717-727
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• 2017

Researches on the emissions of greenhouse gases in the construction industry, which accounts for 40% of raw materials, 30% of energy consumption, and 30% of $CO_2$ emissions in the entire industry, are mainly focused on studies of LCA. However, it is assessed that $CO_2$ emissions are higher in construction sequence than in operation sequence. Also, it is considered that construction machinery using fossil fuel is a main factor causing environmental load in construction sequence. Therefore, this study analyzes the workload and engine RPM characteristics of the excavator which is the second largest number of registered construction machinery in Korea and the highest utilization rate in actual construction site. The excavator is divided into non-load states and load states where power is transmitted to the excavator. The exhaust gas is analyzed by a direct measurement method using PEMS equipment. $CO_2$ emissions are estimated by analyzing the relationship between RPM and exhaust emission characteristics according to the actual driving conditions. Additionally, we analyze the difference between $CO_2$ emissions of construction machine calculated by this study and $CO_2$ emissions calculated by using carbon emission coefficient.

• Journal of Climate Change Research
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• v.2 no.1
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• pp.15-32
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• 2011

Due to greenhouse gas increased by human activities, abnormal climate changes are continuously occurring everywhere in the world and internationally people make efforts to reduce the emission of greenhouse gas. Our country also is making endeavors to realize low carbon society on the foundation of the green growth and for this low carbon consumption pattern settlement through green life is necessary. Therefore for the nationals the offering of the information on greenhouse gas emission that is reduced through the change to low carbon life is required. In this study the objects are beef and wine whose weight of import is high among the beverages and foods consumed in the country and we calculated the food mileage and emission of carbon dioxide of the domestic and foreign product beef and wine and estimated the potential amount that can be reduced when replacing the imported products with domestic products. As the year 2007 being standard if we replace 10% of imported beef with domestic products it is possible to reduce 14,000 tons of carbon dioxide per year and on one day out of a year if we replace imported beef with domestic beef the reduction of 384 tons of carbon dioxide is appeared to be possible. In the same standard year if we replace 10% of imported wine with domestic product we can reduce 1,396 tons and on one day out of a year if we replace imported wine with domestic wine reduction of 38 tons of carbon per year appeared to be possible. Through active promotion and expansion of variety of domestic foods and beverages in the real life of the nationals the consumption pattern of natural low carbon life should be achieved and offering of more systematized greenhouse gas emission DB is thought to be necessary.

• Journal of Bio-Environment Control
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• v.29 no.2
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• pp.161-170
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• 2020

There is systematic spatial variations in environmental properties due to sensitive reaction to external conditions at plastic greenhouse occupied 99.2% of domestic agricultural facilities. In order to construct 3 dimensional distribution of temperature, relative humidity, CO₂ and illuminance, measurement matrix as 3 by 3 by 5 in direction of width, height and length, respectively, dividing indoor space of greenhouse was designed and tested at experimental site. Linear regression analysis was conducted to evaluate optimal estimation method in terms with horizontal and vertical variations. Even though sole measurement point for temperature and relative humidity could be feasible to assess indoor condition, multiple measurement matrix is inevitably required to improve spatial precision at certain time domain such as period of sunrise and sunset. In case with CO₂, multiple measurement matrix could not successfully improve the spatial predictability during a whole experimental period. In case with illuminance, prediction performance was getting smaller after a time period of sunrise due to systematic interference such as indoor structure. Thus, multiple sensing methodology was proposed in direction of length at higher height than growing bed, which could compensate estimation error in spatial domain. Appropriate measurement matrix could be constructed considering the transition of stability in indoor environmental properties due to external variations. As a result, optimal measurement matrix should be carefully designed considering flexibility of construction relevant with the type of property, indoor structure, the purpose of crop and the period of growth. For an instance, partial cooling and heating system to save a consumption of energy supplement could be successfully accomplished by the deployment of multiple measurement matrix.