Passive Solar Gain.How passive solar gain works?This form of energy is often taken for granted; but can contribute a significant amount of the energy demands of a well-designed building in the heating season.Orienting the house so that the more often used rooms face south;Larger windows on the south side, smaller on the north;Using building materials that store heat by adding “thermal mass” to the house andLaying out housing developments so that buildings do not over-shadow each other.Highly optimised passive solar design can provide 40% of the space heating load of a property.solar water heating system.A solar thermal panel is simply a black surface that absorbs light, heats up and transfers the heat into a working fluid. It can be unglazed or glazed. Glazed panels can be flat, or made up of a collection of glass tubes. The working fluid moves the heat to a place where it is useful – perhaps a hot water store, swimming pool or directly to space heating for a building. Panels with higher levels of insulation, such as a glazed cover above and thermal insulation behind do not require direct sunshine to operate and will collect heat on a cloudy day. Most commonly, the energy is used to provide for low temperature applications such as hot water for washing, space heating, feeding heat into district heating networks or providing heat to industrial processes.In recent years, progress has been made using heat from solar thermal panels as an energy input to drive air conditioning plant, though these implementations remain largely experimental in nature.concentrating solar system.If the sun's rays are concentrated by mirrors, much higher temperatures can be created. The light is focused onto a central point with a carrier fluid such as oil flowing through it. The oil heats up to around 400C, hot enough to heat water and make high pressure steam that can drive a turbine and generate electricity.Solar concentrators only work in direct sunshine. The mirror is held on a support that can turn to follow the sun as it moves throughout the day, adding to complexity and cost. Because of this, they are only used in areas benefiting from a sunny climate, with more clear-sky days. solar photovoltaic cell.Photovoltaic (PV) cells, which convert light directly into electricity, first found application in space before becoming commonplace on devices such as calculators and watches and also providing power to locations without a connection to the electricity grid. As costs have fallen and efficiencies of PV materials have risen, governments (notably those in Germany and China) provided generous support that has seen the levels of solar deployment soar. Efficiencies of scale and fierce global competition drove the cost down, creating a virtuous circle of lower prices driving higher levels of demand and leading in turn to even lower prices that has been the defining feature of the industry in recent years. Solar PV has now reached a point where without subsidy it can compete with the retail cost of electricity in developed economies, and with wholesale electricity in sunny climates.The most common technology uses thin wafers of silicon semiconductor materials, connected in series in a photovoltaic panel or module.The direct current (DC) electricity the solar PV panels produce needs to be converted to alternating current (AC) for grid-connected applications. A solar inverter performs this trick, enabling any energy generation in excess of local demand to be exported to the grid and used elsewhere.