• KIEAE Journal
• /
• 제10권4호
• /
• pp.45-50
• /
• 2010

This study for middle school facilities is second following the study of the energy consumption of primary school facilities. There is not on the analysis of the current energy usage for middle school facilities in nations to set goals of energy reduction. Therefore, The purpose of this study is to present various analysis result of energy consumption which is a statistical analysis of domestic middle school facilities in South Korea. As a consequence, each average energy consumption at the domestic middle school facilities analyzed as following after changing as unit 'kWh' only for comparison with every energy source. It represents that the energy consumption of electric power was 183.7MWh(70.2%), gas consumption for heating was 46.5MWh(17.8%), oil consumption was 26.5MWh(10.1%), district energy was 5.1MWh(1.9%). This result describes that consumption of electric power was large greatly and it reflects the expectation that it will climb the demand regarding this energy in the future. In additionally, it analyzed average energy consumption with $74.4kWh/m^2$ by the unit area of air-conditioning and the district which has large energy consumption was Seoul with $91.6kWh/m^2$.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
• /
• 제14권1호
• /
• pp.8-15
• /
• 2018

The purpose of this study was to analyze the energy consumption according to the HVAC systems in 122 elementary schools. To do this, we classified schools according to the HVAC systems. Selected schools were classified to the following groups by the HVAC equipments: EHP, EHP and GHP together and GHP. In addition we divided schools by the number of classes. The main results are as follow: 1) Annual average energy consumption at schools was about 300~900(kWh/students), $30{\sim}50(kWh/m^2)$, 9,000~29,000((kWh/class) 2) The smaller schools, the higher the energy consumption per class; energy usage of 10~19 classes's schools were approximately 3 times higher than 40 classes's schools. 3) Schools where the EHP was installed had the lowest energy costs and energy usage. The difference in energy costs was lower than the difference in energy usage because of the fuel price and the ratio of energy sources.

• Journal of Ceramic Processing Research
• /
• 제20권1호
• /
• pp.48-53
• /
• 2019

Carbon fiber reinforced SiC composites (C/SiC) have high-temperature stability and excellent thermal shock resistance, and are currently being applied in extreme environments, for example, as aerospace propulsion parts or in high-performance brake systems. However, their low thermal conductivity, compared to metallic materials, are an obstacle to energy efficiency improvements via utilization of regenerative cooling systems. In order to solve this problem, the present study investigated the bonding strength between carbon fiber and matrix material within ceramic matrix composite (CMC) materials, demonstrating the relation between the microstructure and bonding, and showing that the mechanical properties and thermal conductivity may be improved by treatment of the carbon fibers. When fiber surface was treated with a nitric acid solution, the observed segment crack areas within the subsequently generated CMC increased from 6 to 10%; moreover, it was possible to enhance the thermal conductivity from 10.5 to 14 W/m·K, via the same approach. However, fiber surface treatment tends to cause mechanical damage of the final composite material by fiber etching.

• International Journal of Computer Science & Network Security
• /
• 제24권4호
• /
• pp.87-106
• /
• 2024

Vehicle-to-Home (V2H) and Home Centralized Photovoltaic (HCPV) systems can address various energy storage issues and enhance demand response programs. Renewable energy, such as solar energy and wind turbines, address the energy gap. However, no energy management system is currently available to regulate the uncertainty of renewable energy sources, electric vehicles, and appliance consumption within a smart microgrid. Therefore, this study investigated the impact of solar photovoltaic (PV) panels, electric vehicles, and Micro-Grid (MG) storage on maximum solar radiation hours. Several Deep Learning (DL) algorithms were applied to account for the uncertainty. Moreover, a Reinforcement Learning HCPV (RL-HCPV) algorithm was created for efficient real-time energy scheduling decisions. The proposed algorithm managed the energy demand between PV solar energy generation and vehicle energy storage. RL-HCPV was modeled according to several constraints to meet household electricity demands in sunny and cloudy weather. Simulations demonstrated how the proposed RL-HCPV system could efficiently handle the demand response and how V2H can help to smooth the appliance load profile and reduce power consumption costs with sustainable power generation. The results demonstrated the advantages of utilizing RL and V2H as potential storage technology for smart buildings.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• 제28권10호
• /
• pp.27-36
• /
• 2014

Network analysis applications in energy management systems play a key role in the economic and reliable operation of power systems. In order to provide operators with useful network information, the accurate results of topology processing, state estimation, power flow, and contingency analysis must be simulated. This paper proposes a validation methodology of network analysis applications in energy management systems. The energy management systems was checked to ensure that it meets the originally specified functions based on the proposed methodology. In addition, the performance of state estimation is evaluated with the reference of the proposed methodology. The proposed methodology is being conducted by energy management systems and the Korean power systems have been utilized for the test systems.

• Journal of Power Electronics
• /
• 제10권3호
• /
• pp.320-327
• /
• 2010

In this paper, multiple offshore wave energy converters with different output characteristics are connected to one power distribution substation. The connection between the power take-off of the different wave energy converters and the electrical power transmission system is presented in order to investigate whether multiple wave energy converters can augment energy yield and improve network integration capabilities. Moreover, the model of an array of wave energy converters is developed with the goal of analyzing the effects of the offshore wave farm on the electrical network to which it is connected. It is also developed to ensure that the electricity generated by the array is sufficiently controllable, and of a quality that can be integrate into the electricity supply network without unduly increasing the cost of connection, production or delivery.

• International Journal of Fluid Machinery and Systems
• /
• 제10권3호
• /
• pp.209-217
• /
• 2017

The paper presents two novel concepts of increasing the energy storage capacity at pumped storage power plants, both existing and new projects. The concepts utilize compressed air as a working medium to displace water from a volume originally not available for storage. The concepts are likely to give additional storage volume at a low cost, however, much development and many investigations are needed before the concepts can be shown to be technical and economical feasible solutions for energy storage. The concepts are disclosed so that researchers and utilities can start those investigations, hopefully helping the green transition by providing highly valuable energy storage for a future renewable energy having a much higher share of renewable energies than the current systems.

• Journal of Advanced Information Technology and Convergence
• /
• 제10권1호
• /
• pp.57-69
• /
• 2020

In general, many IoT devices, including smart phones, use LTE, Wi-Fi, and Bluetooth, and these communication modules generate a lot of energy consumption during periodic data transmission. This paper proposes a method of the data transmission mode change for improving energy efficiency in various communication environments that mobile devices may encounter. We propose an algorithm for setting the mode considering energy efficiency, data transmission performance and cost when the mobile device transmits data, and transmitting the data in an optimized manner according to the state of the mobile device. The proposed algorithm is implemented through experiments on energy efficiency for each communication module, and the scenario is used to verify how efficiently the proposed algorithm uses energy.

• Progress in Superconductivity and Cryogenics
• /
• 제10권2호
• /
• pp.27-29
• /
• 2008

Superconducting RF cavities are being considered for accelerating a proton beam at 700 MHz in the linac of the Proton Engineering Frontier Project (PEFP) and its post-project. Dumbbell fabrication is a mid-process for manufacturing an elliptical superconducting RF cavity. During the dumbbell fabrication, control of the dumbbell length and the $TM010\;{\pi}$ mode frequencies is necessary to build up a desired cavity. A new formula with a perturbation measurement method is used to measure and calculate the frequencies of the individual half-cells of a PEFP low-beta dumbbell, and to tune the frequency and length of the half-cells. In this article, the tuning method and results of the PEFP low-beta dumbbells have been presented.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• 제30권1호
• /
• pp.10-16
• /
• 2018

The climate of summer in Korea is quite hot and humid. Many studies have been carried out to reduce the energy required for operating a dehumidifier. The dehumidifier is mainly connected to the cooling system since it operates in the summer. Conventional dehumidification methods often require additional cooling and energy for dehumidification. In this study, a system for increasing the efficiency by applying a membrane was analyzed. Its energy saving effect was analyzed when it was applied to residential buildings. Economic efficiency was also evaluated. As a result of this study, 9.0% energy savings were achieved for residential buildings. The investment recovery period was 28.9 years. Such long investment recovery period was because the initial investment cost was excessive and annual energy saving only appeared in the summer.