• Journal of the Korean Solar Energy Society
• /
• v.26 no.3
• /
• pp.71-78
• /
• 2006

Thermodynamic irreversibility analysis of an air-to-water heat pump system is analyzed in this study. This analysis shows the distribution of irreversibilities(true losses in thermodynamic sense) through the system components and informs us of a potential improvements with the irreversibility factor decreases. The results show that the largest irreversibilities occur in the motor-compressor unit. The remaining irreversibilities are distributed relatively uniformly through the other parts including utilization system. The increase of performance can be attained through either the improvement of adiabatic efficiency of motor-compressor unit(${\eta}_{mc}$) or the reduction of temperature difference(${\Delta}T$). With the decrease of utilization temperature($T_u$) COPH also increases but the exergetic efficiency decreases. The increase of COPH of about 0.05 can be accomplished with 1K decrease of ${\Delta}T$ or $T_u$.

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.10a
• /
• pp.91-93
• /
• 2008

A Buoyant Hybrid Power Generation System (BHPGS) described in this paper, is a conceptual approach to a hybrid solar-wind power generation in the near sea. The primary purpose of the BHPGS is given to improve utilization of solar cell modules. Main components of the BHPGS include a solar cell module, buoyant object, power generator, and support assembly including weight. Components such a generator controller, DC/AC converter, etc., are not configured in the current BHPGS because they can easily be purchased as a commercial-off-the-shelf product. In addition, some of the BHPGS applications are discussed.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.13 no.1
• /
• pp.35-44
• /
• 2018

Korea government aims to generate 20 percent of its electricity with clean, renewable energy by 2030, while reducing its reliance on fossil fuel and nuclear power plants. Technically, solar energy has resource potential that far exceeds the entire global energy demand. Solar energy industry has experienced phenomenal growth in recent years due to both technological improvements resulting in cost reductions and government policies for renewable energy development and utilization. Even though solar power generation has several advantages over other forms of electricity generation, the major problem is the requirement of land which is scarcely available in the local site and its cost. This study analyzes the available capacity of landing and floating solar plants for the case of chonnam province in korea. The results of design capacity show about 7.5GW for landing and 1.5GW for floating solar power plant. Also, with a purpose to comprehend intention-behaviour gap about acceptance of solar community, the solutions are suggested.

• 한국태양에너지학회:학술대회논문집
• /
• 2009.04a
• /
• pp.31-36
• /
• 2009

There have been many solar tracking systems developed for the high accuracy in solar tracking. One of the key components of any motion control system is software. LabVIEW offers an ideal combination of flexibility, ease-of-use and well-integration with other I/O pieces for developing solar tracking system. Real-time solar positions which vary with GPS's data are used simultaneously to control the solar tracker by a chain of operating modes between the open and closed loops. This paper introduces a step by step procedure for the fabrication and performance assessment of a precision solar tracking system. The system developed in this study consists of motion controllers, motor drives, step-motors, feedback devices and application. CRD sensors are applied for the solar tracking system which play a primary role in poor conditions for tracking due to a gear backlash and a strong wind. Mini-dish was used as a concentrator for collecting sun light. The solar position data, in terms of azimuth and elevation, sunrise and sunset times was compared with those of KASI(Korea Astronomy & Space Science Institute). The results presented in this paper demonstrate the accuracy of the present system in solar tracking and utilization.

• Journal of the Korean Institute of Educational Facilities
• /
• v.20 no.2
• /
• pp.25-32
• /
• 2013

The purpose of this study is to analyze the state-of-the-art solar energy system design cases among LEED(Leadership in Energy and Environmental Design) certified school projects and to explore the feasibilities for their applications in domestic school design. Investigating the sold wattages in some kinds of buildings, the wattages per an educational facility is the second-largest after that per an industrial facility. That shows that our attention should be actively directed to the utilization of New and Renewable Energy in school facilities. Therefore photovoltaics systems, lighting systems and solarthermal facilities of solar energy systems were analyzed in the LEED cases. Findings demonstrate that applications of solar energy systems in K-12 educational facilities have been executed more than those in higher educational facilities. However, K-12 educational facilities and higher educational facilities by private funds are not categorized as Green Buildings by Support for Making Green Buildings Act. That fact is needed to be amended. Besides that, design developments are needed for building integrated photovoltaics systems and solarthermal facilities in domestic educational facilities.

• 한국태양에너지학회:학술대회논문집
• /
• 2012.03a
• /
• pp.248-254
• /
• 2012

In the situation of expanding domestic solar power supply business long-term performance modeling of a proposed solar-cooling and cleaning system to increase electromotive force and light transmission is carried out to test the effectiveness of the system. To test the effectiveness of the system, the data which comparing the solar power planet installing the system to not installing at the same time is used. A difference between the utilization factor of each comparison group were recorded. Approximately from one year to two years Field Test was performed, Result of apply to cooling/cleaning technology, Each of plant by From least 7 percent up to 16 percent utilization factor increased, and the cooling / cleaning is output through improved as a result of the determined.

• 한국태양에너지학회:학술대회논문집
• /
• 2008.04a
• /
• pp.269-274
• /
• 2008

Nowaday, The Sustainable Development about global environment is the most important subject. In urban environment, a variety of the nature energy utilization such as the solar energy are the most efficient solution to solve this issue. One of these efficient, solutions, a photovoltaic system using sunlight has been introduced to the building with an advantage such as cost-effective, safe for using and good for environment friendly in light with energy utilization. Recently, many of the apartment housings are built in domestic country. The apartment buildings have been constructed since early of 1970's. now apartment is taking over 50% out of entire housing in korea. The apartment housing applying to a photovoltaic system has been extensively studied in the foreign country but our county runs short. So, It was necessary to technical development of PV application which is suitable in Korean house culture. The objective of this study is to develop the building integrated PV application method for apartment building.

• Journal of Energy Engineering
• /
• v.20 no.4
• /
• pp.353-357
• /
• 2011

An embedded two-axis solar tracking system was developed by using AVR micro controller for enhancing solar energy utilization. The system consists of an Atmega128 micro controller, two step motors, two step drive modules, CdS sensors, GPS module and other accessories needed for functional stability. This system is controlled by both an astronomical method and an optical method. Initial operation is performed by the result from the astronomical method, which is followed by the fine controlled operation using the signals from Cds sensors. The GPS sensor generates UTC, longitude and latitude data where the solar tracker is installed. A database of solar altitude, azimuth, and sunrise and sunset times is provided by UART (Universal Asynchronous Receiver/Transmitter).

• 한국태양에너지학회:학술대회논문집
• /
• 2012.03a
• /
• pp.364-369
• /
• 2012

The development of solar thermal energy used adsorption desalination technology have been examined as a viable option for supplying clean energy. In this study, the modelling of the main devices for solar thermal energy used and adsorption desalination system was introduced. Silica gel type adsorption desalination system is considered to be a promising low-temperature heat utilization system. The design is divided into three parts. First, the evaporator for the vaporization of the tap water is designed, and then the reactor for the adsorption and release of the steam is designed, followed by the condenser for the condensation of the fresh water is designed. In addition, new features based on the energy balance are also included to design absorption desalination system. In this basic research, One-bed(reactor) adsorption desalination plant that employ a low-temperature solar thermal energy was proposed and experimentally studied. The specific water yield is measured experimentally with respect to the time controlling parameters such as heat source temperatures, coolant temperatures, system switching and half-cycle operational times. Desalination is processes that permeate our daily lives, but It requires substantial energy input, powered either from electricity or from thermal input. From the environmental and sustainability perspecives, innovative thermodynamic cycles are needed to produce the above-mentioned useful effects at a lower specific energy input. This article describes the development of adsorption cycles for the production of desalting effects. We want that this adsorption system can be driven by low temperature heat sources at 60 to $80^{\circ}C$, such as renewable, solar thermal energy.

• Journal of the Korean Solar Energy Society
• /
• v.37 no.2
• /
• pp.59-66
• /
• 2017

This paper compares the output power of different types of small Stirling engines in conjunction with the utilization of low grade thermal energy. A series of experimental measurements were performed to assess the output power of each engine under different conditions of the temperature difference between the hot and cold ends as well as applied weight. Results are presented in terms of torque and output power per heat transfer area. Among tested, the MM-7 engine produced the highest power of 4.455mW ($321mW/m^2$) under a temperature difference of $40^{\circ}C$.