Editing Trombe wall (section)

== History of passive solar systems and evolution of Trombe walls ==
In 1920s, the idea of solar heating began in Europe. In Germany, housing projects were designed to take advantage of the sun. The research and accumulated solar design experience was then spread across the Atlantic by architects such as Walter Gropius and Marcel Breuer. Apart from these early examples, heating homes with the sun made slow progress until the 1930s, when several different American architects started to explore the potential of solar heating. The pioneering work of these American architects, the influence of immigrant Europeans, and the memory of wartime fuel shortages made solar heating very popular during the initial housing boom at the end of World War II.<ref name="Lechner">{{cite book |last1=Lechner |first1=Norbert |title=Heating, Cooling, Lighting: Sustainable Design Methods for Architects |date=2008-11-24 |publisher=WILEY |isbn=978-0-470-04809-2 |pages=147–176 |edition=3rd}}</ref>

Later in the 1970s, before and after the international oil crisis of 1973, some European architectural periodicals were critical of standard construction methods and architecture of the time. They described how architects and engineers reacted to the crisis, proposing new techniques and projects in order to intervene innovatively in the built environment, using energy and natural resources more efficiently.<ref>{{cite journal |last1=Medici |first1=Piero |title=The Trombe Wall during the 1970s: technological device or architectural space? Critical inquiry on the Trombe Wall in Europe and the role of architectural magazines |journal=SPOOL |year=2018 |volume=4 |issue=2 |doi=10.7480/spool.2018.1.1938 |s2cid=115993307 |url=https://www.researchgate.net/publication/328072653 |access-date=24 November 2019}}</ref>
Moreover, the depletion of natural resources generated interest in renewable energy sources, such as [[solar energy]].<ref>{{cite journal |last1=Karakosta |first1=Charikleia |last2=Doukas |first2=Haris |last3=Psarras |first3=John |title=EU–MENA energy technology transfer under the CDM: Israel as a frontrunner? |journal=Energy Policy |date=May 2010 |volume=38 |issue=5 |pages=2455–2462 |doi=10.1016/j.enpol.2009.12.039|bibcode=2010EnPol..38.2455K }}</ref> 

Parallel to global population growth, energy consumption and environmental issues have become a global concern - especially while the building sector is consuming the highest energy in the world and most of the energy is used for heating, ventilation and air conditioning systems.<ref>{{cite journal |last1=Chan |first1=Hoy-Yen |last2=Riffat |first2=Saffa B. |last3=Zhu |first3=Jie |title=Review of passive solar heating and cooling technologies |journal=Renewable and Sustainable Energy Reviews |date=February 2010 |volume=14 |issue=2 |pages=781–789 |doi=10.1016/j.rser.2009.10.030}}</ref>

For these reasons, today's buildings are expected to achieve both energy efficiency and environmental-friendly design through the use of renewable energy partly or completely instead of [[fossil energy]] for heating and cooling. In this direction, the integration of passive solar systems in buildings is one strategy for sustainable development and increasingly encouraged by international regulations.<ref name="Hu">{{cite journal |last1=Hu |first1=Zhongting |last2=He |first2=Wei |last3=Ji |first3=Jie |last4=Zhang |first4=Shengyao |title=A review on the application of Trombe wall system in buildings |journal=Renewable and Sustainable Energy Reviews |date=April 2017 |volume=70 |pages=976–987 |doi=10.1016/j.rser.2016.12.003}}</ref>

Today's low-energy buildings with Trombe walls often improve on an ancient technique that incorporates a thermal storage and delivery system people have already used: thick walls of adobe or stone to trap the sun's heat during the day and release it slowly and evenly at night to heat their building.<ref>{{cite web |title=Building a Better Trombe Wall |url=https://www.nrel.gov/docs/legosti/fy98/22834.pdf}}</ref> Today, the Trombe wall continues to serve as an effective strategy of passive solar design.

The first well-known example of a Trombe wall system was used in the Trombe house of Odeillo, France in 1967.<ref name="Denzerbook">{{cite book| last =Denzer| first =Anthony| title =The Solar House: Pioneering Sustainable Design| publisher =Rizzoli| date =2013| url =http://solarhousehistory.com/book/| isbn =978-0847840052| url-status =dead| archive-url =https://web.archive.org/web/20130726200811/http://solarhousehistory.com/book/| archive-date =2013-07-26}}</ref><ref name="Mazria1979"/> The black painted wall is constructed of approximately 2 foot thick concrete with an air space and a double glazing on its exterior side. The house is primarily heated by radiation and convection from the inner surface of the concrete wall and the results from studies show that 70% of this building's yearly heating needs are supplied by solar energy. Therefore, the efficiency of the system is comparable to a good active solar heating system. PV, Photovoltaic for electrical production converts 15%-20% radiation to energy. Meaning its [[Efficient energy use|energy efficiency]] is low - 85% of the sun's radiation is lost. Whereas the solar thermal collector, Trombe Wall is able to convert 70%-80% of the suns radiation to heat, meaning, it is far more energy efficient and its heat production is powerful.

Another passive collector-distributor Trombe Wall system was built in 1970, in Montmedy, France. The house with {{convert|280|m3|cuft}} living space required 7000 kWh for space heating annually. At Montmedy-between 49° and 50° North latitude-5400 kWh were supplied by solar heating and the remainder from an auxiliary electrical system. The annual heating cost for electricity was approximately $225 when compared to an estimated $750 for a home entirely heated by electricity in the same area. This yields to a 77% reduction in heating load and a 70% reduction in the cost for winter heating requirements.<ref name="Michels1979">{{cite book |last1=Michels |first1=Tim |title=Solar Energy Utilization |date=1979 |publisher=Van Nostrand Reinhold Company |location=New York City, NY |isbn=0-442-25368-0 |pages=43–52}}</ref>

In 1974, the first example of Trombe wall system was used in the Kelbaugh House in Princeton, New Jersey.<ref name="McVeigh1983"/> The house is located along the northern boundary of the site to maximize the unshaded access to available sunlight. The two-story building has {{convert|600|sqft|m2}} of thermal storage wall which is constructed of concrete and painted with a selective black paint over a masonry sealer. Although the main heating is accomplished by radiation and convection from the inner face of the wall, two vents in the wall also allow daytime heating by the natural convection loop. According to data collected in the winters of 1975-1976 and 1976–1977, the Trombe wall system reduced the heating costs respectively by 76% and 84%.<ref name="Mazria1979"/>
[[File:Day time.jpg|thumb|The Trombe wall collects heat during the day.]]
[[File:Trombe Wall-Night time.jpg|thumb|Due to wall's time lag caused by the wall material's heat capacity, most of the heat is released at night.]]