• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2022.11a
• /
• pp.160-161
• /
• 2022

Hydrogen is bridge fuel with high energy content and environmentally friendly to satisfy the stringent IMO regulation relating to greenhouse gas (GHG) emissions. There is growing interest in hydrogen in numerous nations and regions illustrated by an extensive range of research and development in technology. Regarding maritime applications, researchers have recognized the utilization of hydrogen as a fuel for fuel cells, a device that converts the chemical energy of the fuel to electrical energy. Solid oxide fuel cell (SOFC), with high working temperature, is easy to combine with the waste heat recovery cycles/devices to increase output power and thermodynamic performances as well. Furthermore, the cold energy from liquid hydrogen supplied to SOFC can also be used to generate more power. In this study, we proposed a SOFC integrated system with the idea of combining the waste heat recovery from the SOFC exhaust stream and cold energy utilization from LH₂. The designation is aimed to target small-scale vessel which uses electric propulsion for short distances voyage.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.26 no.2
• /
• pp.72-78
• /
• 2014

In a cold chain, the refrigerator is also employed for defrosting, by using an electric heater, which consumes 15% of the power for the system operation. In this study, the condensation heat of the refrigerant was suggested as the heat source of defrosting heat, instead of that from an electric defrost heater. The heat for defrosting was stored to a phase change material (PCM, NMP : $52^{\circ}C$) in thermal storage, and was periodically supplied to the evaporator by a circulation loop of brine. As a result, a defrost time by the PCM was obtained that was less than or equal to that by the electric heater. Moreover, power consumption during defrosting was saved by up to 99% of that of the electric heater.

• Transactions of the Korean hydrogen and new energy society
• /
• v.31 no.2
• /
• pp.234-241
• /
• 2020

This paper presents a thermodynamic performance analysis of a combined cycle consisting of regenerative organic Rankine cycle (ORC) and liquefied natural gas (LNG) Rankine cycle to recover low-grade heat source and the cold energy of LNG. The mathematical models are developed and the system performances are analyzed in the aspect of thermodynamics. The effects of the turbine inlet pressure and the working fluid on the system performance such as the mass flow rates, heat transfers at heat exchangers, power productions at turbines, and thermal efficiency are systematically investigated. The results show that the thermodynamic performance of ORC such as net power production and thermal efficiency can be significantly improved by the regenerative ORC and the LNG cold energy.

• The Journal of the Korea Contents Association
• /
• v.22 no.8
• /
• pp.671-680
• /
• 2022

This study evaluated the consistency between the web-based and paper-based mibyeong and cold-heat pattern questionnaire, the Korean medicine-based tool for diagnosing and classifying health status. First, a web-based survey was conducted on 72 ordinary people; subsequently, a paper-based survey was conducted after a certain time interval. The equivalence between the web-based and paper-based surveys was evaluated on the basis of the consistency between scores using the Intraclass Correlation Coefficient (ICC) and Bland-Altman methodology. The mibyeong questionnaire showed high reliability for the web-based and paper-based surveys (ICC=0.95, 95% CI 0.92 - 0.97), and the cold-heat pattern questionnaire showed high reliability for both cold syndrome (ICC=0.98, 95% CI 0.96 - 0.99) and heat syndrome (ICC=0.9, 95% CI 0.83 - 0.93). The difference in average scores between the two survey methods was -0.25 for the mibyeong survey, -0.17 for the cold syndrome, and 0.11 for the heat syndrome, showing a similar pattern. Among the respondents, 84% showed positive satisfaction with the web-based survey, and 80% preferred the web-based survey. Overall, this study confirmed the reliability and feasibility of the web-based survey methods for the mibyeong and cold-heat pattern questionnaire. This could be a useful tool for the follow-up of subjects in long-term cohort studies.

• The Journal of Korean Medicine
• /
• v.27 no.2 s.66
• /
• pp.134-144
• /
• 2006

Tongue diagnosis is an important diagnostic method in traditional Oriental medicine. It has been especially accepted that quantitative analysis of tongue images allows the accurate diagnosis of the exterior-interior and cold-heat patterns of a patient. However, to ensure stable and reliable results, the color reproduction of such images must first be error-tree. Moreover, tongue diagnosis is much influenced by the surrounding illumination and subjective color recognition, so it has to be performed objectively and quantitatively using a digital diagnostic machine. In this study, 457 tongue images of outpatients were collected using the Digital Tongue Inspection System. Through statistical analysis, the result shows that the heat and cold patterns can be distinguished clearly based on the hue value of the tongue images. The average hue value (1.00) of the tongue's image in the cold pattern is higher than that in the heat pattern (0.99).

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2008.05a
• /
• pp.57-60
• /
• 2008

This study investigated the results of insulation heat curing method using double layer bubble sheet in slab concrete and mass concrete in cold weather environment. First of all, when double bubble sheets are applied, it was shown that slab concrete was protected from early freezing by remaining between 6 and 15℃ even in case outside temperature drops -9℃ below zero until the 2nd day from piling, and in the case of mass concrete, with the maximum temperature difference between the center and surface less than 4℃, crack occurrence index was close to 2 and no hydration heat crack occurred by internal constraint. The insulation heat preservation curing method using the double bubble sheet applied in this field prevented early freezing owing to stable curing temperature management, deterring concrete strength development delay at low temperature, and obtained the needed strength. Also, it was proven that the method is highly effective and economic for cold weather concrete quality maintenance through curing cost reduction like construction period shortening and labor cost reduction, etc by reducing the process of temporary equipment installation and disassembling.

• The Korean Journal of Community Living Science
• /
• v.17 no.2
• /
• pp.49-60
• /
• 2006

It was measured the energy expenditure in each season, the cold tolerance in winter and the heat tolerance in summer. Farmers' adaptability to the change of environment was compared with those of city-dwellers such as indoor workers and street cleaners to determine the effect of living environment, especially living temperature, on the health of human body. It turned out that farmers had experienced wide range of temperature that was higher in summer and lower in winter than indoor workers. Farmers and street cleaners showed seasonal adaptation in energy expenditure, which was high in winter and low in summer. However, indoor workers did not show seasonal changes. Energy expenditure had an inverse correlation with the temperature in work place where subjects spend the longer time in a day except in female indoor workers in Seoul. And It was proved that farmers and street cleaners had stronger cold tolerance and heat tolerance than indoor workers.

• Proceedings of the KSME Conference
• /
• 2007.05b
• /
• pp.1864-1869
• /
• 2007

In this study, we compare thermal performance between four different types of cold plates for humanoid robot cooling. Two commercially available cold plates made of copper have different dimensions and internal flow paths: One has $20{\times}20$ $mm^2$ base area with micro-channels and the other has $62.5{\times}62.5$ $mm^2$ base area with 85 round pin-fins. And two different types of cold plates of $20{\times}20$ $mm^2$ base area with 7 mm high are made of PC (polycarbonate), which aims to reduce the weight of cooling system. All cold plates are mounted on a $20{\times}20$ $mm^2$ copper block with two cartridge heaters of 30 $W/cm^2$. The overall heat transfer coefficient and thermal resistances for the liquid-cooled cold plates are obtained. The copper cold plate with micro-channels showed the best performance. Polycarbonate cold plates display fairly good thermal performance with more reduced system weight.

• Journal of Acupuncture Research
• /
• v.23 no.5
• /
• pp.31-37
• /
• 2006

Objectives & Methods : We investigated the cases for which spleen tonifying Sa-Am acupuncture was applied in ${\ulcorner}$Sa-Am-chim-gu-jeong-jeon(舍巖鍼灸正傳)${\lrcorner}$ and classified them according to the concepts of cold-heat & deficiency-excess for a better understanding of the application of spleen tonifying Sa-Am acupuncture. Results : 1. Tonification of Spleen Sa-Am acupuncture can be used to treat heat syndromes such as deficient fire caused by collapse of the spleen qi, stagnation of evil qi or spleen yin deficiency, by way of tonifying spleen qi, activating the flow of qi and blood or harmonizing spleen yin and yang. 2. Tonification of Spleen Sa-Am acupuncture can be used to treat cold syndromes such as weakness of spleen yang by way of promoting fire to generate earth, strengthening spleen yang and raising the clear yang. 3. Tonification of Spleen Sa-Am acupuncture can be used to treat deficiency syndromes such as malnutrition or poor appetite caused by spleen deficiency by way of tonifying spleen qi. 4. Tonification of Spleen Sa-Am acupuncture can be used to treat excess syndromes such as stagnation of qi and blood, abdominal mass or toxication by way of tonifying spleen qi and promoting the flow of qi and blood.

• Transactions of the Korean hydrogen and new energy society
• /
• v.24 no.6
• /
• pp.510-517
• /
• 2013

The ammonia-water based power generation cycle utilizing liquefied natural gas (LNG) as its heat sink has attracted much attention, since the ammonia-water cycle has many thermodynamic advantages in conversion of low-grade heat source in the form of sensible energy and LNG has a great cold energy. In this paper, we carry out thermodynamic performance analysis of a combined power generation cycle which is consisted of an ammonia-water regenerative Rankine cycle and LNG power generation cycle. LNG is able to condense the ammonia-water mixture at a very low condensing temperature in a heat exchanger, which leads to an increased power output. Based on the thermodynamic models, the effects of the key parameters such as source temperature, ammonia concentration and turbine inlet pressure on the characteristics of system are throughly investigated. The results show that the thermodynamic performance of the ammonia-water power generation cycle can be improved by the LNG cold energy and there exist an optimum ammonia concentration to reach the maximum system net work production.