• Journal of the Korean Society of Industry Convergence
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• v.24 no.4_2
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• pp.467-474
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• 2021

The renewable energy is known as eco-friendly energy to reduce the use of fossil fuel and decrease the environmental pollution due to exhaust gas. Targets of solar collector in domestic are usually acquisitions of hot water and hot air. System of air-heating collector is one of the technologies for obtaining hot air in cases of especially heating room and drying agricultural product. The purpose of this study is to investigate the characteristics of thermal flow such as relative pressure, velocity, outlet temperature and buoyancy effect in air-heating collector using solar heat. The flow field of air-heating collector was simulated using ANSYS-CFX program and the behaviour of hot air was evaluated with SST turbulence model. As the results, The streamline in air-heating collector showed several circular shapes in case of condition of buoyancy. Temperature difference in cross section of outlet of air-heating collector did not almost show in cases of buoyancy and small inlet velocity. Furthermore merit of air-heating collector was not observed in cases of inlet velocities. Even though it was useful to select condition of buoyancy for obtaining high temperature, however, it was confirmed that the trade off between high temperature of room and rapid injection of hot air to room could be needed through this numerical analysis.

• Journal of the Korean housing association
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• v.6 no.1
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• pp.31-37
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• 1995

The purpose of this study is to analyse the distribution of thermal sensation response and thermal environment condition in convective heating space. The contents of this study are as follows: 1)the spatial distributions of thermal conditions are measured 2)the thermal sensation vote of residents is taken in order to investigate the relation between thermal condition and human thermal sensation in sedentary condition 3)to analyse the distribution of subject's thermal sensation vote and thermal environment condition by two methods-regression method and graph method.

• Journal of the Korean housing association
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• v.6 no.2
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• pp.51-55
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• 1995

This study presents a real neutral floor surface temperature in floor panel heating system(Ondol). The Ondol heating system can keep the constant temperature. However, the actual temperature when a person sits on a floor can be different from the surface temparature of a floor it self. The contents of this study are as follows : 1) measuring the spatial distributions of thermal conditions 2) the thermal sensation vote of residents is taken in order to investigate the relation between thermal condition and human thermal sensation in sedentary condition 3) estimating the neutral floor surface temperatures by measuring floor surface temperatures.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.578-583
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• 2008

Korea which has change of clear season is using unique heater by the name of On-dol being invented since ancient times. Floor-heating device has no radiator, and generates no noise and dust. It can obtain satisfied heating sense than other heating system in low room temperature. And also it is a pleasant system that equals bottom and top temperature in a room. The purpose of this study is to develop the Floor-heating device using pulsating heat pipe. It propose floor-heating device using pulsating heat pipe of the dry process which alternative polyethylene pipe(low XL pipe) that is used widely to existent floor heating system and produce pilot Experiment and analyzed operation condition and performance of most suitable. In this study, main purpose is to develop floor-heating system using pulsating heat pipe by finding an optimum working condition according to changing ratio and evaluating a performance.

• Journal of Welding and Joining
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• v.8 no.4
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• pp.20-26
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• 1990

In this study, to make research on its optimum condition in friction weld when the heating pressure is change during 1.6 to 3.0 $kgf/mm^2$, the experiment was performed with metal bearing under various condition; 1600 r.p.m spindile speed, 0.6 $kgf/mm^2$ preheating pressure, upset pressure 2.6 $kgf/mm^2$, 0.5 seconds preheating time, 1.7 seconds heating time, water and air was ejected 6 $kgf/mm^2$ into the bushing. On the basis of the experimental results, the following conclusion are drawn; 1) At the area of weld interface, the heardness is shown the maximum value and heat-affected zone about 0.5mm both sides. 2) Bending strength is shown the optimum heating pressure 2.4 kgf/mm. 3) With the approach of the flash, Sn is increased only 2 mm in A-alloy structure.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.403-407
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• 2005

Objective of the research is to demonstrate solar thermal space and ground heating system which is integrated to a greenhouse culture facility for reducing heating cost, increasing the value of product by environment control, and developing advanced culture technology by deploying solar thermal system. Field test for the demonstration was carried out in horticulture complex in Jeju Island. Medium scale solar hot water system was installed in a ground heating culture facility. Reliability and economic aspect of the system which was operated complementary with thermal storage and solar hot water generation were analyzed by investigating collector efficiency, operation performance, and control features. Short term day test on element performance and Long term test of the whole system were carried out. Optimum operating condition and its characteristics were closely investigated by changing the control condition based on the temperature difference which is the most important operating parameter. For establishing more reliable and optimal design data regarding system scale and operation condition, continuous operation and monitoring on the system need to be further carried out. However, it is expected that, in high-insolation areas where large-scale ground storage is adaptable, solar system demonstrated in the research could be economically competitive and promisingly disseminate over various application areas.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.422-426
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• 2003

Cu thin films of $6000{\AA}$ thickness were deposited by Electron Beam Evaporation(EBE) method on the glass. The resistivity properties and adhesion of Cu thin films were investigated by various annealing and substrate temperature. Cu thin films were annealed in the air and vacuum condition for 10 min after the deposition. The resistivity and adhesion(the force required to separate films from substrates) was measured by 4-point probe and scratch testing. The resistivity of non-annealing Cu thin films was distinguished more substrate temperature loot than substrate temperature R.T, $200^{\circ}C$. In the case of air condition annealing, as heating temperature was increased, the resistivity was decreased. In the case of vacuum condition annealing, the resistivity was increased at heating temperature $200^{\circ}C$. The best resistivity($1.72\;{\mu}{\Omega}{\cdot}cm$) of Cu thin films was obtained by the air condition heating temperature $200^{\circ}C$ at the substrate heating temperature $100^{\circ}C$. As a result of scratch testing, adhesion was increased by annealing. And maximum adhesion had 600 gf.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.5
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• pp.905-910
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• 2004

This study was carried out to observe the change of oriental melon juice quality during manufacture by heating condition and enzyme treatment. To use over-production oriental melon effectively, oriental melon juice was prepared with change of heating temperature and heating time. The heating conditions for minimum filtration time were 98.57$^{\circ}C$ and 11.29 min. The optimum conditions Predicted for separation ratio of clear solution, filtration time and browning color intensity of oriental melon juice were 98$^{\circ}C$, 13 min. In the pectin-degrading enzyme treatment test, turbidity showed minimum value in 4.40 mg％(pectin-degrading enzyme content)， 39.72 mg％ (gelatin content) and 24.09 min (treatment time)．Browning color intensity showed minimum value in 9.33 mg％ (pectin-degrading enzyme content)，44.70 mg％ (gelatin content) and 115.56 min (treatment time). The optimum conditions predicted for turbidity and browning color intensity of oriental melon concentration Juice were 6.6 mg％ (pectin-degrading enzyme content), 33.6 mg％ (gelatin content) and 70 min (treatment time).

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.246-247
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• 2017

In this study, it reviewed the effect of moisture migration in concrete with heating rate on concrete spalling. Concrete specimens with compressive strength 30MPa and 110MPa are used and its size is □100×100×h200mm. And, two kinds of heating rate are set such as IS0 834 and 1℃/min. As a result, in the concrete specimen exposed to ISO 834 standard heating condition, moisture could migrate through pore network and surface concrete pieces fall out by generating moisture clog near the surface in 110MPa concrete specimen. Meanwhile, In the case of concrete specimens exposed to 1℃/min. heating condition, it is appeared that moisture could not migrate because temperature is distributed uniformly. Therefore, surface spalling is not occurred with low heating rate. However, in the case of 110MPa concrete specimen is exploded even though it heated by low heating rate.

• Journal of the Korean Society of Safety
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• v.26 no.5
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• pp.65-72
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• 2011

The use of waste concrete can resolve the environmental pollution and shortage of natural aggregate. However, recycled aggregate includes substantial amount of cement paste. So, these aggregates are more porous, and less resistant to mechanical actions than natural aggregates. So, recently, the new manufacture processes of high quality recycled aggregates were suggested such as heating and solving to acid liquid. But the method of solving to acid liquid is not economical and produces additional environmental pollution. In this paper, for the purpose of manufacture of high quality recycled aggregates, the heating processes was added to the existing process of recycled aggregates. To find the optimum process, the experiment was performed by using the method of statistical experiment design, and the heating temperatures(4 levels : 300, 450, 600 and $750^{\circ}C$) and heating times(4 levels : 5, 20, 40, 60 minute) were main experimental variables. By the test results, the optimum manufacturing condition of coarse recycled aggregate was $600^{\circ}C$ and 40 minute, and for the fine recycled aggregate, a little heating made a satisfaction to the KS standard quality code.