• New & Renewable Energy
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• v.5 no.4
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• pp.3-8
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• 2009

This global case study pursues diversification and intensification for an application system of the national wind atlas which has been developed to support national strategy building and promotion of wind energy dissemination. We chose nine counties' national wind atlas and compared their map area, extraction height, temporal and spatial resolutions, download services, etc. to derive a best practice for the Korea wind atlas application system. Therefore, the web service content is designed to offer high-resolution height information of which covers wind turbine rotor sweeping area and time-series dataset which can be downloaded for further analysis by users. It is anticipated that the system and web service would contribute greatly to wind energy policy making, business and research sectors.

• Journal of the Korean Solar Energy Society
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• v.35 no.1
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• pp.81-87
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• 2015

Recently, in order to prevent increasing energy usages in the international community, many countries have attempted to develop the innovative renewable energy systems. Among the renewable energy systems, Ground source heat pump(GSHP) system which supply the heating, cooling and hot water in the building has been attracted by its stability of heat production and high efficiency. However, the initial drilling costs become very expensive and the construction period takes longer the other systems, because GSHP system needs more than 100 m depth drilling. In this study, in order to reduce initial costs of the GSHP, the building integrated geothermal system using the horizontal heat exchanger was developed. The heating and cooling load in the standard housing model was calculated by a simulation and the system design capacity in the high-rise apartment was decided by the total load. Based on the system design capacity, the high-rise apartments were applied to a BIGS and vertical GSHP system and there are analyzed about initial costs. In the result, the initial cost of BIGS could reduce 24% of the initial cost of the vertical GSHP system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.3
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• pp.279-286
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• 2006

The present study concerns the annual performance evaluation of a hybrid-renewable energy system with geothermal and solar heat sources for hot water, heating and cooling of the residential buildings. The hybrid energy system consists of ground source heat pump of 2 RT for cooling, solar collectors of $4.8m^2$, storage tank of 250 liters and gas fired backup boiler of 11.6 kW. The averaged coefficients of performance of geothermal heat pump system during cooling and heating seasons are measured as 4.1 and 3.5, respectively. Also solar fraction for hot water is measured as 35 percent. Overall, the results shows that the hybrid-renewable energy system satisfactorily operated under all climatic conditions.

• Journal of Internet Computing and Services
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• v.22 no.6
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• pp.17-24
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• 2021

The use of renewable energy sources for power generation has been steadily increasing. Power generation using renewable energy has the advantage of not generating carbon but has the disadvantage of high volatility depending on the weather. This volatility makes stable power supply difficult. Curtailment is occurring to address volatility. Various facilities are operated together to solve the loss caused by the curtailment. The existing SCADA must be modified for turbine control reflecting the conditions of various facilities. However, since it is difficult to modify SCADA, a modular control system is required. In this study, we propose Modular Control System Based on Closed-Loop Control for Wind Farms. Since the control logic can be changed without modifying SCADA, it is easy to respond to changes. The developed modular control system was evaluated as a lab test and confirmed to operate smoothly. Through future research, the experiment will be conducted by applying a modular control system to the actual wind farm.

• Solar Energy
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• v.11 no.2
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• pp.70-76
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• 1991

Electrochemical reaction utilizing the semiconducting photoanodes can be applied to the photoelectrolysis of water to produce hydrogen. In this preliminary experiment, $TiO_2$ photoanodes were prepared by sintering anatase-$TiO_2$ powder at $1,250^{\circ}C$ and thermal oxidizing titanium plate at $850^{\circ}C$ in air and oxygen, respectively. Their surface structures were observed by XRD and optical microscope. I-E characteristics of thermally oxidized $TiO_2$ photoanode were also investigated under illuminated and dark conditions using 1 N and 0.1 N NaOH electrolyte solutions.

• Smart Media Journal
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• v.3 no.1
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• pp.22-27
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• 2014

Recently, domestic energy environment is facing new challenges owing to the depletion of fossil fuel such as oil. Renewable energy resources including solar and wind energy are attracting more interests than ever before. However, solar power system is costly in comparison with the conventional power generation systems and also the energy density is low. Furthermore, large area is required in order to install solar power system. Generally, performance of solar power system is affected by weather conditions and alignment of sun and the solar cell modules. In this study, a new type of sun tracking system for solar power system is proposed. To verify the feasibility of the proposed system, actual implementation of prototype system and experiments are carried out.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.5
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• pp.82-91
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• 2014

The combined generator system by integrating several renewable energy sources can share the electrical infrastructure and therefore have the advantage of constructing not only the transmission system but also the power conversion system. Among the various combined renewable system, the wind power and wave power has a high possibility of future growth due to the economic feasibility in offshore environment. This kind of large-scale combined systems might be follow the determination by the transmission system operator's directions and control the output profile by focusing at PCC. However, both renewable energies are depend on the unpredictable environmental variation; it is needed to do the compensation devices. In this paper, the ESS compensation plan is proposed to do output determination of the combined generator system by paying attention to active power of utility grid with the analysis of the controllable elements of the wind and wave power generator. The improvement of the new application technique of the combined system is confirmed through using the PSCAD/EMTDC. The entire simulation process was designed by adopting the active power control according to the reference signal of TSO.

• Journal of the Korea Organic Resources Recycling Association
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• v.22 no.1
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• pp.20-26
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• 2014

Interest in renewable fuel of recent has increased. Among them, From next year the government announced that it would enforce the RFS. Interest associated with it are concentrated. The RFS, for manufacturers of transportation fuels such as a vehicle, you are a renewable fuel a certain percentage of the fuel supplied. In other words, it refers to a system of mandatory to supply by mixing biofuels. Already in Europe, America and other developed countries to diversify energy sources and subjected Additionally there since ancient times for its rural development by introducing the RFS takes effect coming. Further and inspect to deal with climate change, which is performed via the RFS. Some even are represented by five axis of the sustainability of the RFS.

• New & Renewable Energy
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• v.7 no.3
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• pp.74-82
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• 2011

Because concern on the problem of the limited energy is growing and the wind energy is considered as one of the biggest solutions, the researches on the wind energy and turbine are accomplished vigorously. The simulation tools on the non-linear characteristics of wind turbine system are various and it could describe the non-linear characteristics well but, the tool and methodology to apply non-linear control theory rarely exist. In this paper, the application procedure of sliding mode control theory to 2-DOF non-linear wind turbine system is suggested and the application results of it are also shown as compared with a torque loop control theory.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.19-21
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• 2008

Renewable energy resources such as wind, wave, solar, micro hydro, tidal and biomass etc. are becoming importance stage by stage because of considering effect of the environment. Solar energy is one of the most successful sources of renewable energy for the production of electrical energy following wind energy. And, the solar/photovoltaic cell generators can not make two-state model as conventional generators, but should be modeled as multi-state model due to solar radiation random variation. The method of obtaining reliability evaluation index of solar cell generators is different from the conventional generators. This paper presents a basic study on reliability evaluation of power system considering solar cell generators with multi-states.