• Title/Summary/Keyword: Total heat

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A Study on the Energy Conservation Effect of Each Energy Consumption Component In Indoor Swimming Pools (실내수영장의 에너지 소비요소별 에너지 절약효과에 관한 연구)

  • 김영돈;권규동;여명석;김광우
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.14 no.12
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    • pp.1092-1101
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    • 2002
  • The objective of this study is to develop energy saving strategies for indoor swimming pools and to estimate the effect of each energy saving strategy. For this purpose, field measurements regarding pool water heating energy, domestic hot water heating energy are conducted and a base energy consumption model is implemented using the DOE-2.1E program. The results of the study reveal that 25% of the total pool water heating energy may be saved by using night time pool covers, 27% of the total domestic hot water heating energy may be saved by using a waste water heat recovery system (effic. 60%), and of the total ventilation energy may be saved using an exhaust air heat recovery system (effic. 60%).

The Characteristics of Combustion for Living Leaves in Quercus variabilis with Monthly Seasonal Variations (굴참나무 생엽의 월별 연소특성에 관한 연구)

  • Park, Young-Ju;Oh, Jin-Youl;Lee, Si-Young;Lee, Hae-Pyeong
    • Journal of the Korean Society of Hazard Mitigation
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    • v.10 no.3
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    • pp.85-90
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    • 2010
  • In this study, we have examined the monthly combustion characteristics of Quercus variabilis, a representing Quercus Spp. in Korea, using its living leaves over the period of from June to October. As a result, we were able to identify that their moisture content was about 114%~155%. The leaves of Quercus variabilis collected in October showed the lowest moisture content and nonflaming ignition temperature. The leaves of July showed the fastest flaming ignition time of 27s while those from September showed the longest persistence of flame with 105s, and also showed the highest total heat release amount. There was a noticeable difference in each month of the above period regarding total heat release amount and total smoke release amount with a gradual increase from June to October. The maximum smoke density was a bit higher in October leaves but there was no significant monthly difference. In addition, July leaves were shown to reach the maximum value in the shortest time of 795s.

Combined Treatment of Fumaric Acid with Mild Heat to Inactivate Microorganisms on Fresh Spinach during Storage (Fumaric acid와 mild heat의 병합 처리에 따른 시금치의 저장 중 미생물 제어 효과)

  • Son, Hyeon-Jeong;Kang, Ji-Hoon;Oh, Deog-Hwan;Min, Sea Cheol;Song, Kyung Bin
    • Journal of Applied Biological Chemistry
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    • v.59 no.1
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    • pp.69-74
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    • 2016
  • The objective of this study was to examine the combined effect of fumaric acid with mild heat on the inactivation of microorganisms on spinach. Spinach leaves were inoculated with Escherichia coli O157:H7 and Listeria monocytogenes. Based on the results of single treatment of fumaric acid (0.1, 0.3, and 0.5%) or mild heat (40, 50, and $60^{\circ}C$) regarding the inactivation of the inoculated bacteria, the optimal condition for the combined treatment was suggested to be 0.5% fumaric acid and mild heat treatment at $50^{\circ}C$ for 5 min. The combined treatment of fumaric acid with mild heat caused 2.53 and 2.62 log reductions of the populations of L. monocytogenes and E. coli O157:H7, respectively. In addition, during storage of fresh spinach at $4^{\circ}C$ for 12 d, the combined treatment reduced initially the populations of total aerobic bacteria by 2.77 log CFU/g compared with the control. In particular, after 12 d of storage, the population of total aerobic bacteria for the combined treatment sample was 4.84 log CFU/g, whereas the control sample had 6.66 log CFU/g. Color and vitamin C content of spinach samples were not altered significantly by the combined treatment during storage. These results indicate that the combined treatment of fumaric acid with mild heat is an effective method to control microorganisms on spinach during storage.

The Maximum Power Condition of the Endo-reversible Cycles (내적가역 사이클의 최대출력 조건)

  • 정평석;김수연;김중엽;류제욱
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.1
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    • pp.172-181
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    • 1993
  • Pseudo-Brayton cycle is defined as an ideal Brayton cycle admitting the difference between heat capacities of working fluid during heating and cooling processes. The endo-pseudo-Brayton cycle which is a pseudo-Brayton cycle with heat transfer processes is analyzed with the consideration of maximum power conditions and the results were compared with those of the endo-Carnot cycle and endo-Brayton cycle. As results, the maximum power is an extremum with respect to the cycle temperature and the flow heat capacities of heating and cooling processes. At the maximum power condition, the heat capacity of the cold side is smaller than that of heat sink flow. And the heat capacity of endo-Brayton cycle is always between those of heat source and sink flows and those of the working fluids of pseudo-Brayton cycle. There is another optimization problem to decide the distribution of heat transfer capacity to the hot and cold side heat exchangers. The ratios of the capacies of the endo-Brayton and the endo-pseudo-Braton cycles at the maximum power condition are just unity. With the same heat source and sink flows and with the same total heat transfer caqpacities, the maximum power output of the Carnot cycle is the least as expected, but the differences among them were small if the heat transfer capacity is not so large. The thermal efficiencies of the endo-Brayton and endo-Carnot cycle were proved to be 1-.root.(T$_{7}$/T$_{1}$) but it is not applicable to the pseudo-Brayton case, instead it depends on comparative sizes of heat capacities of the heat source and sink flow.w.

Thermal Performance Analysis of Hybrid heat Supply System for Zero Carbon Green Home (제로카본 그린홈 구현을 위한 하이브리드 열공급 시스템의 열성능 분석)

  • Joo, Hong-Jin;Lee, Kyoung-Ho;Kwak, Hee-Youl
    • Journal of the Korean Solar Energy Society
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    • v.32 no.6
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    • pp.53-59
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    • 2012
  • This study was carried out to evaluate thermal performance of the renewable hybrid heat supply system with solar thermal system and wood pellet boiler for Zero Carbon Green home of apartment houses. The hybrid heat supply system was set up at Korea Institute Energy Research in 2011. The system was comprised of the wood pellet boiler unit with heat capacity designed as 20,000kcal/hr, a $0.15m^3$ hot water storage tank for space heating, a evacuated tubular solar collector $3.74m^2$ of aperture area at the $20^{\circ}$ install angle, a $0.3m^3$ hot water storage tank. Thermal performance tests for one-house of apartment house were carried out by hot water load and heating load in winter season through the hybrid heat supply system. As a result, hot water energy supplied by the hybrid heat supply system was 11kWh in a day. Solar thermal energy portion was 2.99kWh which is 27% of the total hot water energy supply. wood pellet boiler supply portion was 8.017kWh which is 73% of the total hot water energy supply.

Gastric Fluid and Heat Stress Response of Listeria monocytogenes Inoculated on Frankfurters Formulated with 10%, 20%, and 30% Fat Content

  • Kim, Hack-Youn;Kim, Cheon-Jei;Han, Sung Gu;Lee, Sunah;Choi, Kyoung-Hee;Yoon, Yohan
    • Food Science of Animal Resources
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    • v.34 no.1
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    • pp.20-25
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    • 2014
  • This study evaluated the effects of frankfurter fat content on Listeria monocytogenes resistance to heat stress and gastric fluid, and the Caco-2 cell invasion efficiency of the pathogen. A 10-strain mixture of L. monocytogenes was inoculated on frankfurters formulated with 10%, 20%, and 30% fat content (10%: F10, 20%: F20, 30%: F30) and stored at $10^{\circ}C$ for 30 d. The samples were analyzed for L. monocytogenes resistance to heat stress and a simulated gastric fluid challenge. The total bacteria and L. monocytogenes survival rates were measured on tryptic soy agar plus 0.6% yeast extract and Palcam agar, respectively. L. monocytogenes colonies inoculated on F10, F20, and F30 samples were used for a Caco-2 cell invasion assay. In general, no obvious differences were observed between the survival rates of total bacteria and L. monocytogenes grown on different fat contents under heat stress and gastric fluid challenge. However, L. monocytogenes obtained from the F30 samples had a significantly higher Caco-2 cell invasion efficiency than those in the F10 and F20 samples (p<0.05). These results indicate that although high fat content in food may not be related to L. monocytogenes resistance to heat stress and gastric fluid, it may increase the Caco-2 cell invasion efficiency of the pathogen.

The effect on the pain reaction, instrumental A.D.L and R.O.M, quality of life apply to local heat and muscle-joint exercise in elderly with osteoarthritis (퇴행성관절염 노인환자의 온열요법 및 근관절운동이 통증반응, ROM, 일상활동기능장애, QOL에 미치는 효과)

  • Ryu, Jea-Mon;Choi, Ji-Won
    • Journal of Korean Physical Therapy Science
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    • v.11 no.4
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    • pp.11-19
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    • 2004
  • Muscle stiffness, pain discomfort in daily activities are cardinal symtoms on arthritis. To reduce these symtoms, a nonequivalent one-group pre & posttest experiment was carried out at a rural community health post area in kwangju province during eight weeks(from 25th of January to 20th of March, 2002) The subjects were sixteen old (60-80) with osteoarthritis. And to reduce the level of pain, discomfort in daily living and to increase that of life satisfaction, 25-30minutes of muscle-joint exercise followed by 25-30minutes of local heat therapy were done three times a week. The total experimental period extended at 12 weeks and the total 36 times it executed 1. The retrogression characteristic osteoarthritis elderly with local heat and a muscle joint exercise was the telegram which it receives and after receiving, the score of the paindaily activity function appeared to the lead, there was a difference which considers statistically, this constriction was supported.(Z=4.947, p<0.0001) 2. The retrogression characteristic osteoarthritis elderly with local heat and a muscle joint exercise was the telegram which it receives and after receiving, the score of daily activity function appeared lowly, there was a difference which considers statistically, this construction was supported.(Z=2.7226, p<0.0279) 3. The retrogression characteristic osteoarthritis elderly with local heat and a muscle joint exercise was the telegram which it receives and after receiving, there was not a difference where the quality of life considers statistically, this construction was rejected.(Z=-1.2087, p>0.2171)

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Developing Liquid Cooling Garments to Alleviate Heat Strain of Workers in Summer and Exploring Effective Cooling Temperature and Body Regions (여름철 작업자들의 고체온증 예방을 위한 액체냉각복 개발 및 효과적인 냉각온도와 인체 냉각부위 탐색)

  • Jung, Jae-Yeon;Kang, Juho;Seol, Seonhong;Lee, Joo-Young
    • The Korean Fashion and Textile Research Journal
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    • v.22 no.2
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    • pp.250-260
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    • 2020
  • The purpose of the present study was to explore the most effective body region and cooling temperature to alleviate heat strain of workers in hot environments. We developed liquid cooling hood, vest, sleeves and socks and applied the water temperatures of 10, 15, 20, and 25℃ through the liquid cooling garments in a hot and humid environment (33℃ air temperature and 70% RH air humidity). A healthy young male participated in a total of 16 experimental trials (four cooling garments × four cooling temperatures) with the following protocol: 10-min rest, 40-min exercise on a treadmill and 10-min recovery. The results showed that rectal temperature, mean skin temperature, and ratings of perceived exertion during exercise; heart rate and diastolic blood pressure during recovery; and total sweat rate were lower for the vest condition than other garment conditions(p < .05). However, there was no differences in mean skin temperature among the four cooling garments when we compared the values converted by covering area(%BSA). When we classified the results by cooling temperature, there were no consistent differences in thermoregulatory and cardiovascular responses among the four temperatures, but 25℃ water temperature was evaluated as being the most ineffective cooling temperature in terms of subjective responses. In conclusion, the results indicated that wearing cooling vest with < 20℃ cooling temperature can alleviate heat strain of workers in hot and humid environments. If the peripheral body regions are cooled with liquid cooling garments, larger cooling area with lower cooling temperature than 10℃ would be effective to reduce heat strain of workers. Further studies with a vaild number of subjects are required.

Characteristics of the Flow and Heat Transfer around a Wavy Cylinder (파형 실린더 주위의 유동 및 열 전달 특성)

  • Lee, Chang-Yeol;Seo, Jang-Hoon;Hung, Pham-Anh;Yoon, Hyun-Sik;Chun, Ho-Hwan
    • Journal of the Society of Naval Architects of Korea
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    • v.46 no.1
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    • pp.1-9
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    • 2009
  • Three-dimensional characteristics of fluid flow and heat transfer around a wavy circular cylinder having sinusoidal variation in cross sectional area along the spanwise direction are numerically investigated using the immersed boundary method. The three different wavelengths of ${\pi}4$, ${\pi}3$ and ${\pi}2$ at the fixed wavy amplitude of 0.1 have been considered to investigate the effects of waviness especially on the forced convection heat transfer around a wavy cylinder when the Reynolds and Prandtl numbers are 300 and 0.71, respectively. The present computational results for a wavy cylinder are compared with those for a smooth cylinder. The time- and total surface-averaged Nusselt number for a wavy cylinder with ${\lambda}={\pi}/2$ is larger than that for a smooth cylinder, whereas that with ${\lambda}={\pi}/4$ and ${\pi}/3$ is smaller than that for a smooth cylinder. However, because the surface area exposed to heat transfer for a wavy cylinder is larger than that for a smooth cylinder, the total heat transfer rate for a wavy cylinder with different wavelengths of ${\lambda}={\pi}/4$, ${\pi}/3$ and ${\pi}/2$ is larger than that for a smooth cylinder.

A Study on the Castability of Non-precious Porcelain Metal According to Investing Method (매몰방법에 따른 도재용 비금속의 주조성에 관한 연구)

  • Lee, In-Kyu;Kim, Yong-Won
    • Journal of Technologic Dentistry
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    • v.19 no.1
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    • pp.5-12
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    • 1997
  • To examine the difference of castability of non -precious porcelain metal according to 2 type of investing method, experiments were carried out using the method of both existing investing method and the investment with spaces to the upper & lower parts of the ring. The following conclusion were obtained from the result. 1. Seperataly using the existing investment and with spaces to the upper & lower parts of the ring, 44 samples resulted in success with the former method and 52 with the latter out of 84 samples. 2. Under the existing investing method, 44 samples out of 56 total resulted in success when the temperature of the ring was $870^{\circ}C$, and all samples failed when the temperature was $800^{\circ}C$. 3. Under the investment that gives space to the ring, when casted with the temperature of the ring fixed at $870^{\circ}C$, 40 samples out of 56 and 17 samples with the temperature fixed at $800^{\circ}C$ resulted in success. 4. Under the existing investing method with the temperaure of the ring fixed at $870^{\circ}C$ and heat soaking time given an hour, 26 out of 28 samples resulted in success and 18 resulted the same with half an hour heat soaking time. 5. Using the investment that gives space to the ring, at ring temperature $870^{\circ}C$ with heat soaking time 1 hour, all of total 28 rusulted insuccess however only 12 smaples succeeded with 30 minutes heat soaking time. 6. Under the existing investing method, samples with heat soaking time 1 hour equally given at ring temperature $870^{\circ}C$, 26 samples out of 28 succeed however at $800^{\circ}C$ all samples failed. 7. In the case of ring's upper and lower parts opened ring temperature is $870^{\circ}C$ and $800^{\circ}C$ and the heat soaking time was fixed at 1 hour, all 28 samples resulted in success and at $800^{\circ}C$ 17 succeed.

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