The Calorifier is a device that supplies hot water to the crew for showering and cooking. In particular, problems such as hot water not coming out when a trainee and a crew member take a shower at the same time may occur due to a malfunction of the temperature control valve that controls the temperature. In particular, when the hot water usage time is almost constant, such as a training ship, a high calorific value is required. When there is no dissatisfaction with the use of hot water, satisfaction with the educational environment is improved. Therefore, in this study, a solenoid temperature control valve is applied to increase satisfaction with hot water use, and a mechanical time switch is applied to the hot water circulating water pump to save energy.

Small-sized heater is usually used to make the hot water in resting place, factory, household affairs and so on. One of methods to obtain hot water in short time is known as using instantaneous electric water heater. In this study, numerical analysis for small-sized hot water heater with straight double tube-type was tried to achieve the basic design data. This study aims to investigate the characteristics of thermal flow, for instance, such as pressure difference, outlet mean temperature and velocity, due to clearance. As the clearance is decreased, outlet mean temperature and pressure difference(Pmax.-Pmin.) are increased. Therefore appropriate relations between area of heat source and pressure difference should be set up. Further small-sized hot water heater in this study must be equipped with electric device capable of heating over 90℃.

본 연구에서는 ‘설향’ 딸기의 관부를 부분 난방하고 양액을 온수로 공급하면서 관행 재배 방식에 비해 온실 공간 온도를 낮게 관리하는 딸기 부분 난방 시험을 수행하였다. 정식 후 11월까지는 특별한 처리가 없어 대조구, 시험구 모두 온실 내 환 경이 유사하게 관리되었으며 관부 난방 및 온수 양액을 공급 하기 시작한 12월부터는 야간의 온실 온도, 관부 온도 및 베드 온도가 차이를 보였다. 12월의 온실 야간 평균 온습도는 대조구 7.1℃, 87.2%, 시험구 5.7℃, 88.7%로 시험구의 온도가 낮았으나 관부 난방을 수행함으로써 시험구 온실의 관부 및 베드의 온도를 9.3℃, 12.7℃로 유지하였고, 대조구 온실의 관부 및 베드 온도 7.9℃, 10.8℃보다 높게 관리할 수 있었다. 시험기간 내에서 시험구 온실의 딸기 관부 및 베드 온도는 대조구에 비해 모두 약 2.0℃ 가량 높게 유지되는 것으로 나타났다. 주간에는 온수 양액을 공급함으로써 지하수를 이용했을 때보 다 평균 8.7℃ 높은 온도 양액을 공급할 수 있었고 이로 인해 베드 온도도 약 5.0℃ 가량 높게 나타났다. 시험구에서는 시험 기간 동안 온실 난방, 관부 난방 및 온수 양액 공급에 총 9,475.7×10 3 kcal의 에너지를 소비하였고 대조구에서는 온실 공간 난방에 총 16,847×10 3 kcal의 에너지를 소비하여 시험구에서 대조구 대비 약 43.8%의 에너지 절감 효과를 확인할 수 있었다. 시험구에서 딸기 관부의 온도를 높게 관리함으로써 작물의 생육을 촉진시킬 수 있었고 그로 인해 정식 후 초세가 대조구에 비해 좋지 않았던 시험구의 딸기가 25주 후에는 대조구와 생육적인 면에서 큰 차이가 없는 것으로 나타났다. 딸기의 수확량은 초세가 좋았던 대조구에서 1화방의 수확량이 시험구에 비해 많았으나 2화방, 3화방에서는 관부의 온도를 높게 관리한 시험구의 수확량이 더 많았다. 3월 말까지의 주당 수확량은 시험구 412.7g/plant, 대조구 393.3g/plant로 유의미한 차이는 없었으나 시험구가 대조구에 비해 4.9% 많이 나온 것으로 보아 딸기의 온도 민감부인 관부의 온도를 높게 관리하는 것이 딸기 생육과 생산성에 영향을 미치는 것으로 판단된다.

본 연구는 난방온실의 온도분포 균일화를 위한 기초자료 제공을 목적으로 온수난방 방식의 토마토 재배 온실 에서 난방실험을 통하여 난방배관의 표면온도와 실내기온 사이의 상관관계를 분석하고, 난방배관의 열전달특성 분석과 난방배관 배치의 개선을 통하여 난방배관 표면온도의 편차를 줄이고 균일도를 향상시키기 위한 방안을 도출하였다. 서로 다른 두 온실의 온도분포를 분석하여 최대편차와 균일도를 검토한 결과, 온수의 유량이 많고 난방배관의 길이가 짧게 배치된 온실의 온도편차가 작고, 균일도는 높은 것으로 나타났다. 또한 순환팬을 가동한 경우에 온도편차는 작아지고 균일도가 개선되는 것을 확 인할 수 있었다. 난방배관의 표면온도와 실내기온 사이의 상관관계를 분석한 결과, 두 온실 모두에서 유의적인 (p<0.01) 정적 상관관계가 있는 것으로 나타났다. 온수난방 온실에서 실내기온의 분포는 난방배관 표면온도의 분포에 영향을 받는다는 것을 확인할 수 있었고, 온도편차 가 최소화 되도록 난방배관을 배치함으로써 실내기온 분포의 균일도를 개선할 수 있는 것으로 판단되었다. 난방 배관의 열전달 특성을 분석한 결과 배관의 길이가 길어 지면 온도편차는 커지고, 관내의 유속이 빨라지면 온도 편차는 작아지는 것으로 나타났다. 따라서 지선배관의 길이가 짧아지도록 난방배관을 배치하고, 관내의 유속을 제어함으로써 온실의 온도분포와 환경의 균일성을 개선 할 수 있을 것으로 판단되었다. 국내 온실에서 가장 많 이 사용하고 있는 튜브레일(40A) 방식의 온수난방시스 템에서 하나의 지선배관에서의 온도편차를 3oC 이내로 조절하기 위해서는 관내의 유속이 0.2, 0.4, 0.6, 0.8, 1.0m·s-1일 때 난방배관의 길이는 각각 40, 80, 120, 160, 200m 이내로 제한해야 하는 것으로 분석되었다.

정확도 높고, 실용적으로 손쉽게 사용될 수 있는 온수양생 방법을 표준화하고 이를 통한 콘크리트 압축강도 예측방법을 제시하고자 변수 실험을 진행하였다. 전양생 시간, 온수양생 온도, 온수양생 시간에 대한 변수실험을 통해 18시간 전양생 시간, 70℃ 온수양생 온도, 24시간 온수양생시간의 온수양생시험 표준 조건을 제시하였다. 온수양생시험 표준 조건에 대한 추가적인 배합시험을 통해 콘크리트의 압축강도를 조기에 산정할 수 있는 선형 추정식을 산정하였고, 압축강도 추정식의 높은 신뢰도를 확인하였다. 또한, 혼화재 종류 및 혼화재 치환율 변수에 대한 온수양생시험을 통해 온수양생을 통한 콘크리트 압축강도 조기 추정방법은 시멘트 종류, 혼화재 종류 및 치환율, 골재의 종류가 동일한 배합에 대해서만 그 적용이 가능하다는 결론을 도출하였다.

The purpose of this study is to provide basic data for setting environmental design standards for domestic greenhouses. We conducted experiments on thermal environment measurement at two commercial greenhouses where hot water heating system is adopted. We analyzed heat transfer characteristics of hot water heating pipes and heat emission per unit length of heating pipes was presented. The average air temperature in two greenhouses was controlled to 16.3oC and 14.6oC during the experiment, respectively. The average water temperature in heating pipes was 52.3oC and 45.0oC, respectively. Experimental results showed that natural convection heat transfer coefficient of heating pipe surface was in the range of 5.71~7.49W/m2 oC. When the flow rate in heating pipe was 0.5m/s or more, temperature difference between hot water and pipe surface was not large. Based on this, overall heat transfer coefficient of heating pipe was derived as form of laminar natural convection heat transfer coefficient in the horizontal cylinder. By modifying the equation of overall heat transfer coefficient, a formula for calculating the heat emission per unit length of hot water heating pipe was developed, which uses pipe size and temperature difference between hot water and indoor air as input variables. The results of this study were compared with domestic and foreign data, and it was found to be closest to JGHA data. The data of NAAS, BALLS and ASHRAE were judged to be too large. Therefore, in order to set up environmental design standards for domestic greenhouses, it is necessary to fully examine those data through further experiments.

In order to effectively utilize thermal energy, we analyzed the performance of the high efficiency latent heat storage system which can be used for greenhouse heating by using the developed phase change material. The system consists of hot water boiler, heat storage material, heat storage box, heat storage tank, circulation pump, control panel, and storage material. As a result, the latent heat and latent heat temperature of sodium acetate hydrate as latent heat storage material are 231.6 ~ 264.8kJ/kg, 54.95 ~ 55.48℃. As the number of cooling and heating increased, the latent heat temperature showed a slight change, but the latent heat decreased 33.1kJ/kg as the number of repetition increased. In the case of sodium acetate hydrate, large supercooling phenomenon was observed, and it was found that mixing of additives such as nucleating agent, thickener and supercooling agent can control the supercooling more effectively. The consumption of kerosene decreased until the temperature of the heat storage tank was raised to the set temperature by the closed circuit for 4 hours in the initial stage of the boiler operation. The heat exchange rate according to the change of the flow rate was maintained at the set temperature inside the heat storage tank after 4 hours of operation, Consumption was high. As the flow rate increased, the inlet and outlet temperature difference decreased, the heat exchange rate increased, and the heat exchange efficiency was in the range of 57.4 ~ 60.5%.

In this study, a hot water pipe and a blowing fan were combined for developing zone heating technology for cherry tomato. The concept of this system was that hot air was firstly made by hot water pipe in one layer plastic duct and then a blowing fan made the hot air formed in a duct discharge through a duct hole to a shoot apex or a flower cluster which was temperature-sensitive part of cherry tomato. This system mainly consisted of hot water boiler, thermal tank, heat radiation plastic duct with the function of moving up and down electrically depending on the height of shoot apex. Developed system was applied to the cherry tomato greenhouse located in Jangam Chungcheongnamdo from Dec. 28, 2015 to Feb. 16, 2016 and compared with conventional entire space heating system of cherry tomato greenhouse and looked into cumulative yield for the estimate of growing state and energy saving rate from the conventional consumed energy. The result showed that cumulative yield was 3% higher and consumed energy was 32% lower than those of control greenhouse. The average temperature of shoot apex zone was 0.4~1.1℃ higher and the average relative humidity of shoot apex zone was 2,2~2.3% lower than those of entire space during night time in a shoot apex zone heating greenhouse and the average temperature of shoot apex zone was 0.7~1.4℃ lower and the relative humidity of shoot apex zone was 2.9~8.3% higher than those of entire space during night time in a entire space heating greenhouse.

In this study, environmental new feeding and management system that are suitable for hot and cool water supply and floor heating system was developed and analyzed the effect for productivity and meat quality with supplying hot water in winter, the results were as follow as. HWSS was not affecting improvement with broiler productivity in initial time. Supplying hot water made the temperature inside broiler barn not go down rapidly as time went by from former term to latter term and continuous supplying hot water made boiler be adapted properly to the temperature and humidity of breeding environment that was requiring at its own growth phases. With unsaturated fatty acid / saturated fatty acids, HWSS was higher in broiler breast but CWSS was higher in the leg. With AST, ALT in blood, HWSS is higher than CWSS but with neutral lipid, protein, glucose, albumin, cholesterol, HWSS is higher than CWSS. Water circulation heating system gave an impact on meat quality and PH showed a higher in CWSS system. Also, redness and yellowness of the meat color was confirmed to be greater in HWSS. It was proved that the temperature difference of drinking water affected farm productivity, the blood and flesh quality, therefore, that could be estimated to be utilized successfully, if that should be used appropriately for productivity improvement according to the week-old of growth phase.

This study is Performance Improvement of Hot Water Panel to Energy Reducing. Hot Water Panel is two kinds of Wet and Dry Type. This panels are very important to reduce energy saving, for example TOE, energy savings. The effecting elements to performance improvement of hot water panel are panel characteristics and manufactured types. This study used dry type of hot water. The dry type acquired 56% energy saving comparison to wet type.

Depending on the living styles, the types of energy consumed by households have changed, and the consumption has increased rapidly. Consequently, those have led to environmental issues, such as exhaustion of energy and the climate changes. As one of solutions to such issues, energy efficiency can be approached. Therefore, in this study, the gas water heater(115S type Rheem products) that made in Germany and obtain hot water using gas as a heat source is selected. a 1.0㎥ water tank with a 6kW electronic heater is installed and a water temperature and pressure is maintain constantly also thermometer is injected. Two of gas meter, one of pressure regulator and three of time measurement devices are installed in a combustion facility and fuelling facility with a magnet valve so it can observe and record combustion reactions. Quantity of hot water that heated by boiler is recorded using a quantity measurement tank, and have been heated by the boiler have been to record and measure the amount and utilized the data acquired through measurement of all factors that are applied to acquire hot water in order to calculate the use rate of final energy. In conclusion, this researcher drew the economic strong points of the hot water generated by gas.Key

The area of greenhouse heating is 21,202 ha which becomes 42% among the total greenhouse area. As heating fuel, diesel or oil is usually used by 60%, and the heating cost takes 30 to 40% percentage at the greenhouse running. In this study, the pellet fuel heater was developed to replace oil for reducing the burden of greenhouse heating cost. The pellet fuel heater was composed of a conveying grate stoker, which could control temperature precisely like the diesel heater. Diesel and pellet were used for the greenhouse heating, whose calorific values are 9,200 and 3,898 kcal/kg, respectively. As the heating cost due to the saving effect of pellet fuel heater compared with diesel, greenhouse heating cost was reduced by 44% with pellet

Experimental hot-water heating system was consisted of power supply equipment, a hot water storage tank, circulating pump, fan coil unit and a plastic flexible hose. This heating system was manufactured by an electric heater of a power capacity 6kw/h and light-oil hot air heater in control the heating capacity was 5,000kcal/h. As the result, temperature difference due to hot-water heating system and hot air heater in greenhouse showed that air temperature at experimental greenhouse, and comparison greenhouse were 14.8℃, 13.4℃ respectively. It was found that root-zone temperature of experimental plot and control were 22℃, 15℃. Root-zone temperature in the experimental plot was 7℃ higher than that in control. The inlet-outlet water temperature difference of 2℃ and 3℃ corresponded to the difference of the heat exchange of about 3,132kcal/h, 4,916kcal/h, the heat exchange effciency ranged from 54~88% generally. Under the experimental condition, equation heat change(Y) and correlation could be represented as follows : Y = -282.92ｘ2 + 2963.9ｘ -1688.6, R2 = 0.9081. it is suggested to applicate energy of root-zone warming system where energy from the groundwater is extracted and transferred to the water

본 연구는 길이 15 m, 폭 5.6 m, 동고 2.9 m인 단동 비닐 온실 2동을 대상으로 실험구와 대조구로 나누어 실시하였다. 시스템은 전기히터를 이용한 온수가온기로서 온수저장조와 순환펌프, 팬코일유닛으로 구성하였다. 폐회로시스템의 온수배관을 통하여 온수가 순환되도록 하였으며 팬코일유닛을 통해 온실내부를 난방 하도록 하였다. 연구결과를 요약하면 다음과 같다. 실험기간 동안 순환유량은 26L/min 정도의 범위에 있었고, 평균유속은 2.0m/s 정도였다. 유출입수의 평균 온도차는 60±2℃ 이었다. 근권부 온도를 측정한 결과 처리구에는 22℃, 대조구에서는 15℃로 나타나 처리구 근권부 온도가 약 7℃ 높게 유지되었다. 입출구 온도차에 따른 열교환량은 온도차가 2℃일 경우 시간당 열교환량은 3,132kcal이고, 3.4℃일 경우 4,916kcal로서 열교환방정식은 y=-282.92X2+2963.9X-1688.6, R2=0.9081로 상관관계가 매우 높은 것으로 나타났으며 열교환효율은 54~88%로 온도차가 클수록 열교환효율은 높게 나타났다.

In this study, expedite curing period at curing temperature being 40, 60, 80℃ similar to strength of standard 28days curing temperature to confirm methods and applicability of early estimation of strength by warm water curing. Also, checked the effect related to different conditions such as using various kinds of material, differentiating quantity of material, with or without fiber mixing at same rate of water-bonding material. Existing method proposed by KS and JIS to estimate strength of 28 days standard curing temperature curing for 7days at 40℃ is not relevant because it takes so long to estimate strength. Already known method of estimating strength of 28days standard curing temperature curing for 3days in 60℃ warm water, too, is not relevant to apply 3day cycle of super high-rise. It also had the problem which didn’t consider fiber mixed concrete. According to the result of experiment, traits and rate of strength revelation were different relating to the kinds and quantity of bonding material. Strength value of mix without fiber was higher than that of mix with fiber, but without any relation to that, over 96% of similar confidence level with strength of 28 days standard curing temperature was shown in 7 days at 40℃, 3 days at 60℃, 2days at 80℃. Confidence level of estimation method of 2 days at 80℃ was similar to those of estimation methods of 4 days at 40℃, 3 days at 60℃, so it(2 days at 80℃) is regarded as the most relevant method because it’s possible to estimate strength fastly. As a result it can be said that early quality control of recently increasing super high-rise may be possible through estimation method of 2 days at 80℃.

Fluid frictional hot-water system consisted of power supply equipment, a motor, fluid heater, fluid tank, circulating pump, fan, flow meter and a heat exchanger. The system had a motor of power capacity 15.2kw/h, light-oil hot air heater in control plot had the heating capacity 20,000kcal/h, by the performance test result, it could supply heat from 24.6 to 28.1 kw depending on the motor, respectively. Thermal efficiency of fluid frictional heater were 88.1% to 91.0% in the same conditions. As the result, a deviation of indoor air temperature between the treatment plot and the control plot was about 2℃. It was heating cost of the each system heater and light-oil hot air heater heating cost were 742,200won, 2,266,000won. therefore heating cost saving was 67%. Yield of tomato cultured in greenhouse with fluid frictional hot-water system was high as 4%. As a result, the fluid frictional hot-water system was 48% higher in economics than the hot air heater.

In this study, prediction of later-age compressive strength of ultra-high strength concrete, based on the accelerated strength of concrete cured in hot water was investigated. Comparing other acceleration method, hot water curing method is relatively easy and intuitive to use in the real construction site. The amount of time for evaluation of the concrete strength using the hot water curing method in KS and JIS is too long to predict the strength of the ultra-high strength concrete that are used in the tall building structure. For that reason, curing temperature of 40, 50, 60℃ 3 levels were examined to shorten the amount of time for the evaluation of the strength. When curing in warm water, different strength characteristics are verified from the experiment. In case of F3 substituting 30% fly ash in combination, because of the curing temperature sensitivity of fly ash, differences of strength expression velocity was verified according to the curing temperature at the same age. In case of B4 substituting 40% ground granulated blast furnace slag, there were no big strength expression velocity differences of the specimen cured in 3 different level of curing temperature(40, 50, 60℃). The results show reliable accuracy by regression relation between 28day strength cured by standard curing method and accelerated strength of concrete cured in warm water.(y=1x-0.0002 R2=0.9866) As a result, the feasibility of 3day-prediction was confirmed using warm water curing method with accelerated strength of concrete cured for three days in warm water.

본 연구는 온실의 난방 에너지 절감을 목적으로 온실 내부에 알루미늄 온수배관을 설치하여 난방효과에 대한 기초자료를 구축하고자 수행되었다. 그 연구결과를 요약하면 다음과 같다. 전체 실험을 포함하여 온실내의 높이별 온도편차는 4.0~7.0℃ 정도의 범위로서 그 차이가 크게 나타났다. 팬코일유니트(FCU)를 작동시킨 경우가 작동시키지 않은 경우에 비해 유출입수의 온도차가 3.3℃ 정도 크고, 소비전력량은 36.2~40.1%정도 증가하였으며, 시간당 방열량은 44.6~52.0% 정도 증가하는 것으로 나타났다. 실험기간동안 순환유량은 0.48~0.49L·s-1 정도의 범위에 있었고, 평균유속은 1.53~1.56m·s-1 정도였다. 유출입수의 평균 온도차는 6.24~11.50℃이었다. 최저 외기온 -14.0~-0.6℃ 범위에서 설정온도별 방열량은 135,930~307,150kcal 정도의 범위로서 시간당 9,610~19,630kcal·h-1 정도의 범위에 있었다. 이것은 최대난방부하의 약 23~53% 정도의 난방에너지를 공급할 수 있을 것으로 나타났다. 전체 방열량과 소비전력량은 각각 2,548,306kcal 및 3,075.7kWh이다. 화석연료인 경유로 난방할 경우, 소요되는 경유의 총 소비량은 281.6L 정도이고 비용은 321,000won인 것으로 나타났다. 농가용 전력요금을 적용하면 전력사용에 대한 총비용은 110,730won 정도로서 경유 소비 비용의 33.5% 정도로 나타났다. 실험구의 온도가 대조구보다 약 8.3~14.6℃ 정도 높게 나타났다.