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Thermal energy storage (TES) is achieved with greatly differing technologies that collectively accommodate a wide range of needs. It allows excess thermal energy to be collected for later use, hours, days or many months later, at individual building, multiuser building, district, town or even regional scale depending on the specific technology. As examples: energy demand can be balanced between day time and night time; summer heat from solar collectors can be stored interseasonally for use in winter; and cold obtained from winter air can be provided for summer air conditioning. Storage mediums include: water or ice-slush tanks ranging from small to massive, masses of native earth or bedrock accessed with heat exchangers in clusters of small-diameter boreholes (sometimes quite deep); deep aquifers contained between impermeable strata; shallow, lined pits filled with gravel and water and top-insulated; and eutectic, phase-change materials. Other sources of thermal energy for storage include heat or cold produced with heat pumps from off-peak, lower cost electric power, a practice called peak shaving; heat from combined heat and power (CHP) power plants; heat produced by renewable electrical energy that exceeds grid demand and waste heat from industrial processes. ==Solar energy storage== Most practical active solar heating systems provide storage for from a few hours to a day's worth of energy collected. There are a growing number of facilities that use seasonal thermal energy storage (STES), enabling solar energy to be stored in summer (primarily) for space heating use during winter.〔Wong B. (2011). (Drake Landing Solar Community ). Presentation at IDEA/CDEA District Energy/CHP 2011 Conference. Toronto, June 26–29, 2011.〕〔SunStor-4 Project, Marstal, Denmark. (The solar district heating system ), which has an interseasonal pit storage, is being expanded.〕〔(【引用サイトリンク】 Thermal Energy Storage in ThermalBanks )〕 The Drake Landing Solar Community in Alberta, Canada has now achieved a year-round 97% solar heating fraction, a world record and possible only by incorporating STES.〔〔Natural Resources Canada (2012). (Canadian Solar Community Sets New World Record for Energy Efficiency and Innovation ). 5 Oct 2012.〕 Molten salt is a means of storing heat at a high temperature. This is a current commercial technology used in conjunction with concentrated solar power for later use in electricity generation, to allow solar power to provide electricity on a more continuous basis. These molten salts (Potassium nitrate, Calcium nitrate, Sodium nitrate, Lithium nitrate, etc.) have the property to absorb and store the heat energy that is released to the water, to transfer energy when needed. To improve the salt properties it must be mixed in a eutectic mixture. The use of both latent heat and sensible heat are also possible with high temperature solar thermal input. Various eutectic mixtures of metals, such as Aluminium and Silicon (AlSi12) offer a high melting point suited to efficient steam generation,〔^Khare, S; Dell'Amico, M; Knight, C; McGarry, S. "Selection of materials for high temperature latent heat energy storage". Solar energy materials and solar cells, 2012.〕 while high alumina cement-based materials offer good thermal storage capabilities〔^Khare, S; Dell'Amico, M; Knight, C; McGarry, S. "Selection of materials for high temperature sensible heat energy storage". Solar energy materials and solar cells, 2013.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「thermal energy storage」の詳細全文を読む スポンサード リンク
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