Results 1 - 10 of 305
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[en] Solar water heating implementation has as effect greenhouse gas emission reduction. Romanian solar collector market and solar technologies implementation are not yet developed because the market is dominated by high cost equipment. Due to this, the author deduces that the use of simpler technologies, with lower technical performances, but inferior capital cost, will induce higher solar energy penetration into the market. One of the cheapest solutions for solar water heating is Integrated Collector Storage Solar Water Heaters technology. The author purpose an analytical method for technical and economical solar collector's performance assessment. Technical performances of the solar collectors will be compared for different types of ICSSWH's. Systems calculation will be done analytically. The starting point of the estimation is the heat balance on solar collector's boundary. Using heat transfer equation, energy fluxes and equipment efficiencies during collection and store time can be calculated. Technical performances for market existing solar collectors will be reminded. The paper conclusions are valuable for solar hot water design. (author)
[en] A relationship for calculating coolant mass mean temperature integrated over the channel length of radiation-absorbing heat-exchange panels of flat solar collectors is presented. The results of calculation are presented in the form of graphic relationships between the integral mean and arithmetical mean values of mass mean temperatures of the coolant and its flow rate. (author)
[en] This report is concerning with basic questions in use of solar electropanels and their output characteristics. The charge characteristics of buffer accumulators are shown too. The conditions of they optimal matching with DC-AC-DC converts are pointed. Pulse converts represent like most effective solution in proposed improved realization of that unit. (authors)
[en] Solar water heater is the most employed solar energy system. This system is in utmost efficiency if it is installed in optimal slope and direction's and this subject depends as different parameters such as geographical location. This study examines the way of attaining optimum slope and direction for evacuated solar collector and their relation to geographical location of their installation. As examining this type of Evacuated Solar Collector in different geographical locations and during the year is difficult for example because of environmental conditions, changing amount of radiation and etc. At the begging of the study evacuated solar collector has been examined in fixed day and in a fixed geographical location in different slope and direction and then. After comparing the result are assuring from the behavior of these evacuated solar collector, with the help of related controlling formulas. Evacuated solar collector has been examined during the whole year. The results of this study demonstrated that Hay and Davies's Anisotropic Sky models efficiently describe thermal behavior of evacuated solar collector. This model demonstrated that the optimum annual and seasons slope is related to the latitude of installation place and for evacuated solar collector, optimum annual slope is equal to the latitude.
[en] A brand new no-contact method of determining the average working-surface temperature of plate-type radiation-absorbing thermal exchange panels (RATEPs) of flat solar collectors (FSCs) for heating a heat-transfer fluid (HTF) is suggested on the basis of the results of thermal tests in full-scale quasistationary conditions. (authors)
[en] The response of the photovoltaic (PV) panel temperature is dynamic with respect to the changes in the incoming solar radiation. During periods of rapidly changing conditions, a steady state model of the operating temperature cannot be justified because the response time of the PV panel temperature becomes significant due to its large thermal mass. Therefore, it is of interest to determine the thermal response time of the PV panel. Previous attempts to determine the thermal response time have used indoor measurements, controlling the wind flow over the surface of the panel with fans or conducting the experiments in darkness to avoid radiative heat loss effects. In real operating conditions, the effective PV panel temperature is subjected to randomly varying ambient temperature and fluctuating wind speeds and directions; parameters that are not replicated in controlled, indoor experiments. A new thermal model is proposed that incorporates atmospheric conditions; effects of PV panel material composition and mounting structure. Experimental results are presented which verify the thermal behaviour of a photovoltaic panel for low to strong winds.
[en] Putting the finishing touches to a low cost geothermal System for use in buildings, linking geothermal energy with solar panels, seeking new viable sources in France and overseas... moving from very low intensity geothermal energy to high intensity, these are a few examples of research currently being undertaken at BRGM (France's national Bureau for Geological and Mining Research). (author)
[en] This paper reports the design, characterization and implementation of a fiber Bragg grating (FBG) temperature sensor in a power electronic inverter which has a high electromagnetic interference (EMI) radiation. The performance and characteristics of the sensor are investigated by monitoring the temperature variation of the insulated gate bipolar transistor (IGBT) in photovoltaic (PV) arrays inverter. The thermal expansion of the optical fiber is enhanced by mounting the FBG sensor to a metal sheet. Due to this enhancement, the FBG temperature sensor recorded an improvement in terms of linearity and sensitivity. A comparison is made between the performance of the enhanced FBG sensor and a thermocouple in a high EMI environment, and the results show that the FBG sensor performs better. (authors)
[en] In the paper the methods of measuring thermal parameters of photovoltaic panels - transient thermal impedance and the absorption factor of light-radiation are presented. The manner of realising these methods is described and the results of measurements of the considered thermal parameters of selected photovoltaic panels are presented. The influence of such selected factors as a type of the investigated panel and its mounting manner on transient thermal impedance of the considered panels is also discussed. (paper)
[en] Solar thermal utilization, especially the application of solar water heater technology, has developed rapidly in China in recent decades. Manufacturing and marketing developments have been especially strong in provinces such as Zhejiang, Shandong and Jiangsu. This paper takes Zhejiang, a relatively affluent province, as a case study area to assess the performance of solar water heater utilization in China. The study will focus on institutional setting, economic and technological performance, energy performance, and environmental and social impact. Results show that China has greatly increased solar water heater utilization, which has brought China great economic, environmental and social benefits. However, China is confronted with malfeasant market competition, technical flaws in solar water heater products and social conflict concerning solar water heater installation. For further development of the solar water heater, China should clarify the compulsory installation policy and include solar water heaters into the current 'Home Appliances Going to the Countryside' project; most of the widely used vacuum tube products should be replaced by flat plate products, and the technology improvement should focus on anti-freezing and water saving; the resources of solar water heater market should be consolidated and most of the OEM manufacturers should evolve to ODM and OBM enterprises. (author)