• International Journal of Aerospace System Engineering
• /
• v.9 no.2
• /
• pp.1-9
• /
• 2022

The NEA release mechanism is used to provide restraint and release functions with low shock for critical deployment operations on solar arrays after launch. The GK3 solar array consists of 2 wings and 6 hold down points per panel. The NEA SSD9103S1 is a part of the GK3 solar array hold-down and release mechanism. Each NEA unit is equipped with two Z-diodes which provide power to a NEA unit connected in series after actuation of the fuse wire. This paper presents the hot firing test results of a quadrature NEA SSD9103S1 configuration. One output powers a maximum of 4 NEA SSD9103S1 units simultaneously. The necessary actuation pulse duration has been determined to meet margin requirement for thermal energy of minimum 4. Actuation thermal energy difference is about 6.6% between each half of two fired serial NEAs. Thermal energy margin at worst case is minimum 5.9 in case of an actuation pulse duration of 500 ms. Two series Zener impedance depend on current applied has been characterized by an additional actuation after all fuse wires are open circuit. Total number of actuation commands to the GK3 NEA unit reduce drastically from 24 in case of single NEA configuration down to 8 in case of parallel and quadrature NEA configurations. It can be accommodated by the existing HP2U Pyro design without any impact.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2021.10a
• /
• pp.572-573
• /
• 2021

By optimizing the development of IoT-type thermal image-based photovoltaic fault detection equipment and interworking with drones using a drone with an intelligent path movement function, real-time analysis of the acquired image data facilitates fault reading of solar power plants. , design a system that can read out the failure of a solar panel using the image subtraction analysis technique and the presentation of the basic technology that can improve the power generation rate of the solar power plant and make an efficient maintenance model.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.35 no.12
• /
• pp.1383-1389
• /
• 2011

The current study focuses on the consistent analysis of heat transfer in multichannel volumetric solar receivers used for concentrating solar power. Changes in the properties of the absorbing material and channel dimensions are considered in an optical model based on the Monte Carlo ray-tracing method and in a one-dimensional heat transfer model that includes conduction, convection, and radiation. The optical model results show that most of the solar radiation energy is absorbed within a very small channel length of around 15 mm because of the large length-to-radius ratio. Classification of radiation losses reveals that at low absorptivity, increased reflection losses cause reduction of the receiver efficiency, notwithstanding the decrease in the emission loss. As the average temperature increases because of the large channel radius or small mass flow rate, both emission and reflection losses increase but the effect of emission losses prevails.

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.05a
• /
• pp.190-193
• /
• 2008

The heat transfer characteristics of molten salt storage system for the solar thermal power generation were investigated. Temperature profiles and the heat transfer coefficients during the storage and discharge stage were obtained with the steam as the heat transfer fluid. Two kinds of inorganic salt were employed as the storage materials and coil type of heat exchanger were installed in both tanks to provide the heat transfer surfaces during the storage and discharge stage. The effects of steam flow rates, flow direction of steam in the storage tank and the initial temperature of storage and discharge tank on the heat transfer were tested.

• 한국태양에너지학회:학술대회논문집
• /
• 2008.11a
• /
• pp.232-237
• /
• 2008

The integration of PV modules into building facades or roof could raise their temperature that results in the reduction of PV system's electrical power generation. Hot air can be extracted from the space between PV modules and building envelope, and used for heating in buildings. The extraction of hot air from the space will enhance the performance of BIPV systems. The solar collector utilizing these two aspects is called PV/T(photovoltaic/thermal) solar collector. This research is about the development of solar roof system with PV/T collector to apply into buildings. A test cell experiment was performed with the PVT roof installed: It found that the hot air supply from the PVT air collector contributed to increase the heating efficiency by 2 times and the electrical efficiency by about 8%.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.35 no.4
• /
• pp.366-371
• /
• 2022

Recently many efforts have been made to develop a novel class of non-fullerene electron acceptor materials for high-performance organic solar cells. In this work, anthraquinone derivatives, TMAQ and THAQ, were prepared and their availability as electron acceptor materials for organic solar cells were investigated in terms of optical, thermal, electrochemical properties, and solar cell devices. Compared to TMAQ, a significant bathochromic shift of absorption band was observed for THAQ owing to intramolecular hydrogen-bond-assisted CT interactions. Thanks to the fused aromatic ring structure and benzoquinone unit, both TMAQ and THAQ exhibited a high thermal stability and an efficient electron reduction process. In particular, the intramolecular O-H---O=C hydrogen bond of THAQ plays an important role in improving the thermal stability and electron reduction properties. In the P3HT:acceptor solar cell system, THAQ-based devices had more than ca. 6 times higher power conversion efficiency than TMAQ -based devices. These results serve as a guide for developing high-efficient anthraquinone-based electron acceptor materials.

• Journal of the Korean Solar Energy Society
• /
• v.32 no.3
• /
• pp.11-18
• /
• 2012

To expect accurately the maximum power of solar cell module under various installation conditions, it is required to know the performance characteristics like temperature dependence. Today, the PV (photovoltaic) market in Korea has been growing. Also BIPV (building integrated photovoltaic) systems are diversified and become popular. But thermal dependence of PV module is little known to customers and system installers. In IEC 61215,a regulation for testing the crystalline silicon solar cell module, the testing method is specified for modules. However there is limitation for testing the module with diverse application examples. In extreme installation method, there is no air flow between rear side of module and ambient, and it can induce temperature increase. In this paper, we studied the roof type installation of PV module on the surface of one-axis tracker system. We measured temperature on every component of PV module and compared to open-rack structure. As a result, we provide the foundation that explains temperature characteristics and NOCT (nominal operation cell temperature) difference. The detail description will be specified as the following paper.

• Journal of Aerospace System Engineering
• /
• v.16 no.5
• /
• pp.86-93
• /
• 2022

Generally, a deployable solar panel is used primarily to achieve sufficient power output to perform the mission. However, temperature distribution on the antenna reflector may increase due to the shading effect induced by the presence of the deployable solar panels. Appropriate thermal design is critical to minimize the thermal deformation of the mesh antenna reflector in harsh on-orbit thermal environments to ensure remote frequency (RF) performance. In this paper, we proposed a dual-surface primary reflector consisting of a mesh antenna and a flexible fabric membrane sheet. This design strategy can contribute to thermal stabilization by using a flexible solar panel on the rear side of membrane sheet to reduce the temperature distribution caused by the deployable solar panel. The effectiveness of the mesh antenna design strategy investigates through on-orbit thermal analysis.

• Journal of the Korean Solar Energy Society
• /
• v.24 no.4
• /
• pp.11-18
• /
• 2004

A solar concentrator, named KIERDISH II, was built at KIER in order to investigate the feasibility of high temperature solar energy application system. The constructed concentrator is a dish type solar concentrator with a focal length of 4.68m and a diameter of 7.9m. To successfully operate KIERDISH II, optimal design of the absorber is very important and flux density distribution has to be known. The focal flux density distribution on the receiver was measured. We have observed the shape and size of flux images and evaluated percent power within radius. Flux density distribution is usually measured by a CCD(charge coupled device) camera and a radiometer. In this paper we present a flux mapping method to estimate the characteristic features of the flux density distribution in the focal region of solar concentrator. The minimum radius of receiver is found to be 0.15m and approximately 90% of the incident radiation is intercepted by receiver aperture.

• 한국태양에너지학회:학술대회논문집
• /
• 2012.03a
• /
• pp.280-285
• /
• 2012

It is important to produce the high temperature and high pressure air for the concentrated solar power system using the combined cycle. In this paper, based on the concept of tubular receiver, we designed two types with focus on radiation loss reduction. These two receivers were tested in the KIER solar furnace of 40kW thermal capacity. Performance of the two receivers were evaluated and compared.