855,658 research outputs found

    Solar Water Heating: Using the Sun's Energy to Heat Water

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    Key facts: - Solar water heating systems use the sun's energy to provide hot water, space heating, and air conditioning. - More than 1.5 million homes and businesses currently use solar water heating in the United States, representing a capacity of over 1,000 megawatts (MW) of thermal energy generation. Another 400 MW is likely to be installed over the next 3-5 years, according to the US Department of Energy. - Assuming that 40 percent of existing homes in the United States have sufficient access to sunlight, 29 million solar water-heating systems could be installed. Solar water heaters can operate in any climate. Performance varies depending on how much solar energy is available at the site, as well as how cold the water coming into the system is. The colder the water, the more efficiently the system operates. - Solar water heaters reduce the need for conventional water heating by about two-thirds and pay for their installation within 4 to 8 years with electricity or natural gas savings. Compared to those with electric water heaters, Florida homeowners with solar water heaters save 50 to 85 percent on their water heating bills, according to the Florida Solar Energy Center

    Solar Energy Resource Potential in Alaska

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    Solar energy applications are receiving attention in Alaska as in much of the rest of the country. Solar energy possibilities for Alaska include domestic water heating, hot-water or hot-air collection for space heating, and the use of passive solar heating in residential or commercial buildings. As a first analysis, this study concentrated on applying solar energy to domestic hot-water heating needs (not space heating) in Alaska, and an analysis of solar hot-water heating economics was performed using the F-CHART solar energy simulation computer program. Results indicate that solar energy cannot compete economically with oil-heated domestic hot water at any of the five study locations in Alaska, but that it may be economical in comparison with electrically heated hot water if solar collector systems can be purchased and installed for 20to20 to 25 per square foot.This work was made possible by a grant from the Solar Planning Office, West, 3333 Quebec, Denver, Colorado. It was performed as the Alaskan response to a western regional solar energy planning grant from the U. S. Department of Energy. The authors wish to acknowledge the support and cooperation of the Alaska State Department of Commerce, Division of Energy and Power Development, through whose efforts the grant was made available, especially Clarissa Quinlan, Grant Peterson, and Don Markle

    An innovative design and evaluation of a stratified hot water storage system - the Water Snake

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    The increase in energy prices and the demand to reduce carbon emission is attracting the attention to the implementation of diverse heating technologies such as heat pumps, solar energy, gas boilers, CHP and electric heaters. Heating applications for integrated technologies include district heating, domestic small scale applications and commercial large scale buildings. Thermal storage is likely to become key to energy efficient heating. A stratified hot water tank will play an important role in the integration of several heating technologies that operate efficiently at different level of temperatures with reduced implementation cost. This paper describes the concept and the assessment of the ‘Water Snake’, a novel low cost concept of a stratified hot water tank. The results show that the new concept could provide efficient stratification at a very low cost using this invention

    Freeze protection in gasholders

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    In cold weather, the water seals of gasholders need protection from freezing to avoid compromising the seal. These holders have a large reservoir of "tank water" at the base which is below ground. At present freeze-protection is achieved by external heating of the seal water which is in a slotted channel called a cup. Electrical heating or circulation of heated tank water to the cup are examples of systems presently used. The tank water has a large thermal capacity and National Grid wishes to investigate whether circulation of the tank water without external heating could provide sufficient energy input to avoid freezing. Only tanks in which the tank water is below ground are investigated in the report. The soil temperature under the reservoir at depth of 10m and lower is almost constant

    Comparative performance of twenty-three types of flat plate solar energy collectors

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    Report compares efficiencies of 23 solar collectors for four different purposes: operating a Rankine-cycle engine, heating or absorption air conditioning, heating hot water, and heating a swimming pool

    Relevance of Tidal Heating on Large TNOs

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    We examine the relevance of tidal heating for large Trans-Neptunian Objects, with a focus on its potential to melt and maintain layers of subsurface liquid water. Depending on their past orbital evolution, tidal heating may be an important part of the heat budget for a number of discovered and hypothetical TNO systems and may enable formation of, and increased access to, subsurface liquid water. Tidal heating induced by the process of despinning is found to be particularly able to compete with heating due to radionuclide decay in a number of different scenarios. In cases where radiogenic heating alone may establish subsurface conditions for liquid water, we focus on the extent by which tidal activity lifts the depth of such conditions closer to the surface. While it is common for strong tidal heating and long lived tides to be mutually exclusive, we find this is not always the case, and highlight when these two traits occur together.Comment: Submitted to Icaru

    Performance of coloured solar collectors

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    The use of solar collectors with coloured absorbers for water heating is an area of particular interest when considering their integration with buildings. By matching the absorber colour with that of the roof or façade of the building, it is possible to achieve an architecturally and visually pleasing result. Despite the potential for the use of coloured absorbers very little work has been undertaken in the field. In this study, the thermal performance of a series of coloured, ranging from white to black, water heating solar collectors is examined. Subsequently, the annual solar fraction for typical water heating systems with coloured absorbers is calculated. The results show that coloured solar collector absorbers can make noticeable contributions to heating loads. Furthermore, although their thermal efficiency is lower than highly developed selective coating absorbers, they offer the advantage of sensitive integration with buildings
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