• 한국신재생에너지학회:학술대회논문집
• /
• 2006.11a
• /
• pp.176-179
• /
• 2006

This paper describes the procedure of the basic design and transient variation of performance for a 1MWe large scale solar thermal power plant system (STPPS) by using the commercial software tool of TRNSYS. In order to simulate the transient variation of STPPS's performance, the basic design of STPPS are preceded by using the THERMOFLEX, Three different days of DNI weather data of Daejeon in 2005 are used to calculate the performance. For a high DNI data values, the general ing power of 1.1 MWe and flow rate of 1.4kg/s at $804W/m^2$ are good agreement with the basic design value of 1.0 MWe, 1.36 kg/s at $800 /m^2$. Using the other weather data of low and sudden decreasing DNI values, the results show that the output power and flow rate follow well the DNI variation. Based on the results, it is allowed to use the Program to estimate the performance of STPPS for variety of DNI data.

• Journal of Biosystems Engineering
• /
• v.15 no.2
• /
• pp.123-133
• /
• 1990

Thermal performance of a solar heating plastic greenhouse designed for a hydroponic system was studied. The system was constructed with the air-water heat exchanger and thermal storage tank that were combined with hydroponic water beds. Experiments were carried out to investigate the daily average heat stored and released in thermal storage tank, average solar energy collection efficiency, average coefficient of performance, average oil reduction factor of thermal storage system, and the heat transfer coefficient during the nighttime in plastic greenhouse. The results obtained in the present study are summarized as follows. 1. Daily average heat stored in thermal storage tank and released from the thermal storage tank was 1,259 and $797KJ/m^2$ day, respectively. 2. The average solar energy collection efficiency of thermal storage tank was 0.125 during the experiment period. And the average coefficient of performance of thermal storage system in plastic greenhouse was 3.6. 3. The average oil reduction factor of thermal storage system and the heat transfer coefficient during the nighttime in plastic greenhouse were found to be 0.52 and $4.3W/m^2\;hr\;^{\circ}C$, respectively.

• KOREAN POULTRY JOURNAL
• /
• v.23 no.9 s.263
• /
• pp.116-118
• /
• 1991

탄수화물은 자연계에 널리 분포되어 있고 특히 식물계에 많이 분포되어 있으며 동물의 영양소로써 매우 중요한 물질이다. 앞에서 언급한 바와 같이 가축의 체내에서 에너지원으로 이용될 수 있는 영양소는 지방, 탄수화물, 단백질이 있다. 이 세가지 영양소 중에서 탄수화물은 가장 경제적이고 풍부한 에너지 공급원이다. 탄수화물은 식물체내에서 엽록소의 작용에 의하여 태양열을 이용하여 $CO{_2}$와$H{_2}O$로부터 합성된다. 동물은 식물이 합성한 탄수화물을 이용하는 것인데 식물체내에 존재하는 탄수화물을 모두 동물이 이용하는 것이 아니고 어떤 것은 동물이 이용할 수 있으나 어떤 것은 이용할 수 없다. 동물이 쉽게 이용할 수 있는 형태의 탄수화물은 주로 전분(starch)으로 구성되어 있으며 식물의 세포질에 포함되어 있으며 식물 자체의 에너지 공급 또는 에너지 저장의 기능을 수행하고 있다. 한편 동물이 쉽게 이용할 수 없는 형태의 탄수화물은 주로 섬유소(cellulose)가 대부분을 이루고 있으며 식물의 세포막의 주성분이고 식물체의 형태를 지탱하는 역할을 하고 있다.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.17 no.5
• /
• pp.825-832
• /
• 2022

In this paper, we discuss the design and implementation of predictive and diagnostic models for realizing intelligent predictive models by collecting and storing the power output of agricultural photovoltaic power generation systems. Our model predicts the amount of photovoltaic power generation using RNN, LSTM, and GRU models, which are recurrent neural network techniques specialized for time series data, and compares and analyzes each model with different hyperparameters, and evaluates the performance. As a result, the MSE and RMSE indicators of all three models were very close to 0, and the R2 indicator showed performance close to 1. Through this, it can be seen that the proposed prediction model is a suitable model for predicting the amount of photovoltaic power generation, and using this prediction, it was shown that it can be utilized as an intelligent and efficient O&M function in an agricultural photovoltaic system.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.13 no.5
• /
• pp.1093-1100
• /
• 2018

Fast progress in miniaturization and reducing power consumption of semiconductors for wearable devices makes it possible to develop extremely small wearable systems for various application services. This results recent wearable applications to be powered from extremely low-power energy harvesters based on solar, piezo, and TENG sources. In most cases, the harvesters generate power in non-linear manner. Therefore, we implemented and experimented the device platforms to utilize natural frequency of around 3Hz. We also designed two-stage power storages and high efficiency conversion platform to consider such non-linear power harvesting sources. The experiment showed power generation of about 4.67mW/min from these non-linear sources with provision of stable energy storages.

• Journal of the Korean Solar Energy Society
• /
• v.27 no.1
• /
• pp.55-61
• /
• 2007

This paper describes the procedure and calculation results of basic design and transient variation of performance of 1 MWe large scale solar thermal power plant (STPP) by using the commercial software of THERMOFLEX and TRNSYS, respectively. In order to simulate the transient variation of STPP, the results of basic design are necessary. The design standard of the STPP is 1 MWe generation with solar only at high DNI condition and then 0.6 MWe output power for 1 hour using stored energy when the DNI becomes lower unable to operate normally. The results of basic design show the important design data of flow rates, water/steam conditions at each equipments and the estimated efficiency of STPP. In addition, dynamic simulation results of STPP are predicted and plotted for one year and three different days weather data of Daejeon.

• Journal of the KSME
• /
• v.44 no.1
• /
• pp.27-27
• /
• 2004

미국 국방부 소속 육군차량사업부(National A Automotive Center)는 대체에너지를 이용한 군용 차량 개발을 위해 Michigan 주 Rochester Hills에 위치한 E Energy Conversion Devices(ECD) 사와 일부 기술 개발 에 대한 기술 제휴를 한다고 발표했다. 국방부는 태양전 지와 수소를 연료로 사용하는 대체에너지 차량을 개발하 기 위해 ECD에 1단계 연구에 필요한 연구비를 지원했다. 이번 연구에는 연료전지를사용한차량개발을위해 5 500,$\omega$0달러가 투자되는데, Texaco Ovollic Hydrogen S Systems(TOHC)의 고체 휴대용 수소 연료와 채충천 (refueling) 시스탬이 주요 개발 목표로 설정됐다. ECD의 역할은 최근 개발된 Toyota Prius에 시범 적으로 장착된 저압 고체형 수소 저장 시스템의 기술을 군용 차량에 알맞게 전환시키는 것이다. TOHC와 ECD가 개발한 고체형 수소 보관 시스댐은 고압을 요구하는 연료전지 차량의 수소 저 장 시스템이 갖고 있는 많은 문제점들을 해결할 수 있을 것으로 기대되는 연료전지를 이용한 엔진 개발 중 최신 기술이다. 특히 전투 상황에서 차량이 폭발하기 쉬운 수소 저장 탱크를 장착한 채 전 장으로간다는 것은적에게 노출 될 경우자살과마찬가지인 치명적인 피해를 입을수 있다. 이 프로젝트의 개요를 살펴보면, 수소 저장 시스템은 적어도 약 lOkg의 수소를 적은 용적 내에 낮은 압력에서 안전하게 고체 상태로 저장할 수 있다. 이 고체 저장 용기는 하루에 두 번 1.7kg의 수소를 10분 이내에 재급유할 수 있다. 수소는대부분고압가스형태나저온액체 형태로보관된다. 기체나액체 형태의 수소는 연료전 지에 사용되기에는 적합하지 않은 점이 많다. Ovonie 수소 저장 방법은 수소를 저압 고체 형태 ( (metal hydride)로 보관하는 방법으로, 고압 기체나 저온 액체가 갖고 있는 많은 문제점들을 해결 할수있다. 그림을 참조하면 고체 형태의 수소 보관 방법이 다른 보관 방법에 비교해 단위 체적당 최고 6배 많은수소질량을보관할수 있다. 이 고체 형태의 보관방법은수소가적절한합금과평형 압력 이 상의 환경에 놓일 경우 합금에 홉착되는 현상을 이용하고 있다. 수소를 흡수한 합금은 새로운 특성 을 가진 metal hydride로 변하게 된다. 이 과정 에서 열이 부산물로 발생한다. 반대로 수소를 metal hydride로부터 분리시키기 위해서는 합금을 가열해야 한다.

• Journal of Internet of Things and Convergence
• /
• v.10 no.2
• /
• pp.125-130
• /
• 2024

With the rapid growth of mobility technology, the industrial sector is demanding storage devices that can reliably process data from various equipment and sensors in vehicles. NAND flash memory is being utilized as a storage device in mobility environments because it has the advantages of low power and fast data processing speed as well as strong external shock resistance. However, flash memory is characterized by data corruption due to long-term exposure to high temperatures. Therefore, a dedicated system for temperature management is required in mobility environments where high temperature exposure due to weather or external heat sources such as solar radiation is frequent. This paper designs a dedicated temperature management system for managing storage device temperature in a mobility environment. The designed temperature management system is a hybrid of traditional air cooling and water cooling technologies. The cooling method is designed to operate adaptively according to the temperature of the storage device, and it is designed not to operate when the temperature step is low to improve energy efficiency. Finally, experiments were conducted to analyze the temperature difference between each cooling method and different heat dissipation materials, proving that the temperature management policy is effective in maintaining performance.

• Solar Energy
• /
• v.17 no.1
• /
• pp.103-111
• /
• 1997

The purpose of this research is the study of characteristics of heat transfer in a heat pipe controlled by solenoid valve. A solenoid valve located to the adiabatic section between evaporator and condenser of heat pipe was used to control the valve action for effective energy transfer of the industrial exchanger machine. By the results presented in this study temperature difference between evaporator and condenser increases with increasing the temperature frequency and with decreasing the temperature amplitude. When inclination angle and flow rate of cooling water increases, the temperature amplitude is reached to the steady state rapidly with increasing the temperature frequncy.

• Solar Energy
• /
• v.14 no.2
• /
• pp.3-16
• /
• 1994

The major objectives of the study are to suggest the optimal basic design conditions for the horizontal storage tank system. For this purspose computer simulation has been carried out to find the characteristics of flow patterns in horizontal storage tank, and experiments have been carried out for the duration of one turnover, Experimental parameters are volume flow rate(1 LPM to 4 LPM), amount of heat generated from heat sources(0 W to 100 W), and inlet and outlet port types of the storage tank(DD type, DO type, ID type, IO type).