History of Thermal Energy Storage
Current day solar heating dates back to 1940 when M.I.T. built their experimental "Solar Energy House #1" in Cambridge, MA. A huge tank in the basement stored enough energy to keep the occupants comfortable in the winter. This project was funded by a gift by Godfrey Cabot to the Massachusetts Institute of Technology for Solar energy studies in 1938.
A system using glass plate collectors and a pebble bed for energy storage was built in 1959 in Denver Colorado. After 18 years of monitoring the system was essentially maintenance free and its performance had degraded to 78% of the original design. The degradation was attributed to glass breakage inside the collectors which is a problem that does not occur in modern day vacuum tube collectors. This project provides evidence that a well designed and well built system can operate reliably over many years with very little maintenance.
The TES system is widely used in Europe and is expected to be the standard by 2030.
What is Thermal Energy Storage?
Thermal Energy Storage (TES) also known as a 'thermal store' uses a storage tank designed to retain heat deposited during the hot summer months for use during colder winter weather. The heat is typically captured using solar collectors, although other energy sources are sometime used separately or in parallel based on climatic conditions. The water stored in the tank can reach temperatures in excess of 185°. It is easy to see that there is an ample supply of BTU's stored that can provide heat and hot water to the building through many cloudy and cold days. The volume of storage will determine the heating load supplied to meet or augment the heating requirements of the building.
Using solar collectors and well insulated tanks, the thermal mass is brought to operating temperature in the summer from the solar collectors and used for heat in the winter months. The target temperature of the thermal mass in the underground tanks is 180° F. The tanks are sized to meet part or all of the heating requirements whether it is residential or commercial. In turn, this will determine how many collectors are required.
THERMAL RESERVE and Thermal Solar Storage
A thermal storage heating system works by capturing and storing the sun’s energy in the summer and reusing it as the source of heat in the winter. The transfer and storage medium is water, thereby making the systems environmentally friendly. The stored energy provides for a continuous source of heat all winter long. The collectors continue to work all winter, although the replenishment rate is less. A Thermal Storage System (TES) is a proven technology and is in use in many parts of the world.
A Thermal Reserve system includes vacuum tube solar collectors, a control system and storage tanks. The system is flexible and integrates well into an existing building or makes an excellent choice for new construction.