• Resources Recycling
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• v.32 no.2
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• pp.43-51
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• 2023

In this research, through LCA analysis, the environmental impact of automotive engine manufacturing and re-manufacturing was analyzed from the perspective of the entire process, and the greenhouse gas reduction effect was calculated based on this. The amount of greenhouse gas emitted from the process of acquiring and manufacturing raw materials for automotive engines is about 3,473 kg for new manufacturing and 872 kg for re-manufacturing. Thus, the amount of greenhouse gas reduction by engaging in re-manufacturing is about 2,601 kg; the analysis shows a reduction effect in each part of the entire process except for the processing stage. As a result of the LCA weighted analysis, the environmental impact of new product manufacturing was found to be 1.07E+03 Eco-point, and it was 2.67E+02 Eco-point for re-manufacturing. The share of GWP(Global Warming Potential) among the six major impact categories(Abiotic Depletion Potential, Acidification Potential, Eutrophication Potential, Global Warming Potential, Ozone-layer Depletion Potential, Photochemical Oxidant Creation Potential) as high at 99.72%(new manufacturing) and 99.68%(re-manufacturing).

• Environmental and Resource Economics Review
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• v.9 no.5
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• pp.853-876
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• 2000

The purpose of this paper is to come up with the measures for sustainable development of the agricultural sector in store for the strengthened U.N. Framework Convention on Climate Change. We analyze the spillover effects of Methane and Nitrous Oxides taxes (carbon tax) on the Korean agricultural sector. Unlike the other sectors, the agricultural sector has a unique characteristic generating greenhouse gas in the process of production itself even without consuming much fossil fuel. In order to estimate the impacts of those taxes, non-linear optimization method has been used with various assumed scenarios. The production effect, income and' price effect, and greenhouse gas emission reduction effect in the agricultural sector have been estimated through this method. The empirical results show that the paddy sector has a bigger tax effect than the livestock sector. In the paddy sector, the carbon tax has more impacts in the suburban areas than in the rural areas, while the swine farming section in the livestock sector has a conspicuous income effect in the midst of low greenhouse gas emission effect. These results allude us to apply graded tax rates to the crop, the livestock, and the region of different kind. Even if the agricultural sector has a less tax effect when compared with other industrial sectors, an environmental tax might be an effective measure to prevent global warming.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.277-284
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• 2018

For the main variables to be selected by the designer for the heating and cooling load calculation in greenhouses, in order to evaluate the effect of these design values on the heating and cooling load, the simulations were carried out by varying the respective design values. Based on these results, we proposed the design values which should pay special attention to selection. The design values which have the greatest effect on the heating load were the overall heat transfer coefficient of the covering material and the design outdoor temperature was next. The effect of the design values according to the number of spans showed little difference. In the case of the single-span greenhouse, the effect of the design values related to the underground heat transfer can not be ignored. However, in the case of the multi-span greenhouse, the effect of the design values related to the underground heat transfer and the infiltration rate were insignificant. The design values which have the greatest effect on the cooling load were the solar radiation into the greenhouse and the evapotranspiration coefficient, followed by the indoor and outdoor temperature difference and the ventilation rate. The effect of the design values showed a great difference between the single-span greenhouse and the multi-span greenhouse, but there was almost no difference according to the number of spans. The effect of the overall heat transfer coefficient of the covering material was negligible in both the single-span greenhouse and the multi-span greenhouse. However, the effect of the indoor and outdoor temperature difference and the ventilation rate on the cooling load was not negligible. Especially, it is considered that the effect is larger in multi-span greenhouse.

• Journal of the Korean earth science society
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• v.42 no.6
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• pp.770-788
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• 2021

This study aimed to determine whether middle school students could understand global warming and the greenhouse effect, and explain them in terms of global radiative equilibrium. From July 13 to July 24 in 2021, 118 students in the third grade of middle school, who completed a class module on 'atmosphere and weather', participated in an online assessment consisting of multiple-choice and written answers on radiative equilibrium, the greenhouse effect, and global warming; 97 complete responses were obtained. After analysis, it was found that over half the students (61.9%) correctly described the meaning of radiative equilibrium; however, their explanations frequently contained prior knowledge or specific examples outside of the presented data. The majority of the students (92.8%) knew that the greenhouse effect occurs within Earth's atmosphere, but many (32.0%) thought of the greenhouse effect as a state in which the radiative equilibrium is broken. Less than half the students (47.4%) answered correctly that radiative equilibrium occurs on both Earth and the Moon. Most of the students (69.1%) understood that atmospheric re-radiation is the cause of the greenhouse effect, but few (39.2%) answered correctly that the amount of surface radiation emitted is greater than the amount of solar radiation absorbed by the Earth's surface. In addition, about half the students (49.5%) had a good understanding of the relationship between the increase in greenhouse gases and the absorption of atmospheric gases, and the resulting reradiation to the surface. However, when asked about greenhouse gases increases, their thoughts on surface emissions were very diverse; 14.4% said they increased, 9.3% said there was no change, 7.2% said they decreased, and 18.6% gave no response. Radiation equilibrium, the greenhouse effect, and global warming are a large semantic network connected by the balance and interaction of the Earth system. This can thus serve as a conceptual system for students to understand, apply, and interpret climate change caused by global warming. Therefore, with the current climate change crisis facing mankind, sophisticated program development and classroom experiences should be provided to encourage students to think scientifically and establish scientific concepts based on accurate understanding, with follow-up studies conducted to observe the effects.

• Journal of the Korean Institute of Rural Architecture
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• v.22 no.1
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• pp.13-20
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• 2020

As the number of plastic greenhouses has increased in Korea, the damage from typhoons and snow has also increased. Structural design codes for a disaster-resistant plastic greenhouse have been revised over the last few decades. In particular, the revised code draft in 2017 have changed in many ways compared to the 1995 code. Nevertheless, There is no study of the effect of new design code on plastic greenhouse. Therefore, this study evaluated the safety of plastic greenhouse against wind load according to 1995 and 2017 codes for type 1 houses, which is most commonly built in Jeju, through comparing the analytical results of plastic greenhouses designed by 1995 code and 2017 code draft. The results are as follows. (1) The uplift load due to the negative pressure on the roof of the plastic greenhouse increased significantly in 2017 code draft. (2) Since the existing members could not meet the design requirements, the rafters had to be replaced with members of the same cross-section as the columns. (3) Due to excessive lifting, measures were also needed to prevent lifting at the foundation of the plastic greenhouse.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.9
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• pp.1359-1363
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• 2017

In this study, the Relux program was simulated for optimum conditions of daylight and artificial light sources(LED) in the glass greenhouse. From the results of daylight simulation, the optimum design conditions for the glass greenhouse were established which were 90[o] installation angle and higher transmittance. In this case of growing lettuce in the glass greenhouse, the control method of the only artificial light source was compared that of daylight and LED. The result of illumination simulation produced a power consumption effect of 37.2[%] in the summer and 51.9[%] in the winter, respectively. From this results, we propose to suggest that we grow the lettuce in the energy saving glass greenhouse.

• Food Science and Preservation
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• v.5 no.1
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• pp.13-21
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• 1998

Korean medicinal herb extracts(KMHE) were applied to the preservation of greenhouse produce in order to prove their effectiveness. KMHE showed remarkable antimicrobial effects against Bacillus cereus, Peudomonas syringae, and Corynebacterium xerosis causing the postharvest decay of greenhouse produce. Among KMHE the extracts of Rheum palmatum L. and Coptis chinensis Franch most obviously inhibited the growth of microorganims causing the Postharvest decay of greenhouse produce, which destroyed to undetectable levels when treated with more than 500ppm of KMHE. The activities of KMHE were stable in the wide spectrum of pH and temperature. Direct visualization of microbial cells by using both transmission electron microscope and scanning electron microscope showed microbial cell membrane the function of which was destroyed by treating with the dilute solutions of KMHE. This change of cellular membrane permeability could be identified in the experiment that O-nitrophenyl-$\beta$-D-galactopyranoside(ONPG), the artificial substrate of $\beta$-galactosidase, was hydrolyzed in the presence of KMHE, indicating that the membrane was perturbed by KMHE.

• Journal of Biosystems Engineering
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• v.23 no.2
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• pp.147-156
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• 1998

It is desirable to use the renewable energy for the greenhouse heating in winter season, it make possible not only to save fossil fuel and conserve green environment but also to promote the quality of agricultural products and reduce the agricultural production cost. In this study the heat pump - PCM latent heat storage system has been developed to use the natural energy as much as possible for the thermal environment control of greenhouse. The coefficient of performance (COP) of the heat pump system was 3~4 with the ambient temperature ranging from 8$^{\circ}C$ to -8$^{\circ}C$, and greenhouse heating effect of the heat pump-PCM latent heat storage system on the basis of the ambient temperature was about 12-15$^{\circ}C$.

• Journal of Bio-Environment Control
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• v.27 no.1
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• pp.46-53
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• 2018

This study was conducted to determine which greenhouse provided good environmental conditions for strawberry production, and performed better at conserving energy. Temperature, RH, VPD, $CO_2$, solar radiation, yield, and fuel consumption were the parameters analyzed. The temperatures of both greenhouses were well controlled in order to provide optimal day and night temperatures for strawberry production. The air inflated double layer greenhouse had higher RH values (more than 90% at night), which led to higher disease occurrence, in comparison to the conventional double layer greenhouse. Furthermore, the air inflated double layer greenhouse had lower VPD values than the conventional double layer greenhouse. Therefore, better RH and VPD were observed in the conventional double layer greenhouse. Higher $CO_2$ concentration was observed in the air inflated double layer greenhouse while the conventional double layer greenhouse ventilated better than the air inflated greenhouse, because of its side ventilators. Moreover, higher solar radiation in the conventional double layer greenhouse resulted in higher yield, in comparison to the air inflated double layer greenhouse. Thus, we can conclude that the conventional double layer greenhouse provided a better environment for crop growth, in comparison to the air inflated double layer greenhouse. Regarding fuel consumption, the air inflated double layer greenhouse had lower fuel consumption than the conventional double layer greenhouse. Therefore, from an energy consumption point of view, we can conclude that the air inflated double layer greenhouse performed better than the conventional double layer greenhouse.

• Journal of Bio-Environment Control
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• v.28 no.3
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• pp.225-233
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• 2019

In the summer season, natural ventilation is commonly used to reduce the inside air temperature of greenhouse when it rises above the optimal level. The greenhouse shape, vent design, and position play a critical role in the effectiveness of natural ventilation. In this study, computational fluid dynamics (CFD) was employed to investigate the effect of different roof vent designs along with side vents on the buoyancy-driven natural ventilation. The boussinesq hypothesis was used to simulate the buoyancy effect to the whole computational domain. RNG K-epsilon turbulence model was utilized, and a discrete originates (DO) radiation model was used with solar ray tracing to simulate the effect of solar radiation. The CFD model was validated using the experimentally obtained greenhouse internal temperature, and the experimental and computed results agreed well. Furthermore, this model was adopted to compare the internal greenhouse air temperature and ventilation rate for seven different roof vent designs. The results revealed that the inside-to-outside air temperature differences of the greenhouse varied from 3.2 to $9.6^{\circ}C$ depending on the different studied roof vent types. Moreover, the ventilation rate was within the range from 0.33 to $0.49min^{-1}$. Our findings show that the conical type roof ventilation has minimum inside-to-outside air temperature difference of $3.2^{\circ}C$ and a maximum ventilation rate of $0.49min^{-1}$.