is the heat and light radiated from the Sun that powers Earth’s climate and supports life. Solar technologies allow controlled use of this energy resource. Solar power is a synonym of solar energy or refers specifically to the conversion of sunlight into electricity by photovoltaics, concentrating solar thermal devices and various experimental technologies.

The controlled use of solar energy is an important consideration in building design. Thermal mass is used to conserve the heat that sunshine delivers to all buildings. Daylighting techniques optimize the use of light in buildings. Solar water heaters heat swimming pools and provide domestic hot water. In agriculture, greenhouses grow specialty crops and photovoltaic-powered pumps provide water for grazing animals. Evaporation ponds find applications in the commercial and industrial sectors where they are used to harvest salt and clean waste streams of contaminants.

Solar distillation and disinfection techniques produce potable water for millions of people worldwide. Family-scale solar cookers and larger solar kitchens concentrate sunlight for cooking, drying and pasteurization. More sophisticated concentrating technologies magnify the rays of the Sun for high-temperature material testing, metal smelting and industrial chemical production. A range of prototype solar vehicles provide ground, air and sea transportation.

Solar thermal energy (or STE)^[1] is a technology for harnessing solar energy for heat. Solar thermal collectors are characterized by the US Energy Information Agency as low, medium, or high temperature collectors. Low temperature collectors are flat plates generally used to heat swimming pools. Medium-temperature collectors are also usually flat plates but are used for creating hot water for residential and commercial use. High temperature collectors concentrate sunlight using mirrors or lenses and are generally used for electric power production. This is different from solar photovoltaics, which convert solar energy directly into electricity.

Solar lighting

The history of lighting is dominated by the use of natural light. The Romans recognized the Right to Light as early as the 6th centure and English law echoed these judgments with the Prescription Act of 1832.^[26][27] In the 20th century artificial lighting became the main source of interior illumination.

Daylighting systems collect and distribute sunlight to provide interior illumination. These systems directly offset energy use by replacing artificial lighting, and indirectly offset non-solar energy use by reducing the need for air-conditioning.^[28] Although difficult to quantify, the use of natural lighting also offers physiological and psychological benefits compared to artificial lighting.^[28] Daylighting design carefully selects window type, size and orientation and may also consider exterior shading devices. Individual features include sawtooth roofs, clerestory windows, light shelves, skylights and light tubes. These features may be incorporated into existing structures but are most effective when integrated in a solar design package that accounts for factors such a glare, heat flux and time-of-use. When daylighting features are properly implemented they can reduce commercial lighting-related energy requirements by 25%.^[29]

Hybrid solar lighting (HSL) is an active solar method of using sunlight to provide illumination. HSL systems collect sunlight using focusing mirrors that track the Sun and use optical fibers to transmit the light into a building’s interior to supplement conventional lighting. In single-story applications, these systems are able to transmit 50% of the direct sunlight received.^[30]

Although daylight saving time is promoted as a way to use sunlight to save energy, recent research is limited and reports contradictory results: several studies report savings, but just as many suggest no effect or even a net loss, particularly when gasoline consumption is taken into account. Electricity use is greatly affected by geography, climate and economics, making it hard to generalize from single studies.^[31]

Solar Hot Water

refers to water heated by solar energy. Solar heating systems are generally composed of solar thermal collectors, a fluid system to move the heat from the collector to its point of usage, and a reservoir or tank for heat storage and subsequent use. The systems may be used to heat water for home or business use, for swimming pools, underfloor heating or as an energy input for space heating and cooling and industrial applications.

In many climates, a solar heating system can provide a very high percentage (50% to 75%) of domestic hot water energy. In many northern European countries, combined hot water and space heating systems (solar combisystems) are used to provide 15 to 25% of home heating energy.

In the southern regions of Africa like Zimbabwe, solar water heaters have been gaining popularity, thanks to the Austrian^[1] and other EU funded projects that are promoting more environmentally friendly water heating solutions.

Residential solar thermal installations can be subdivided into two kinds of systems: compact and pumped systems. Both typically include an auxiliary energy source (electric heating element or connection to a gas or fuel oil central heating system) that is activated when the water in the tank falls below a minimum temperature setting such as 50 °C. Hence, hot water is always available. The combination of solar hot water heating and using the back-up heat from a wood stove chimney to heat water^[2] can enable a hot water system to work all year round in northern climates without the supplemental heat requirement of a solar hot water system being met with fossil fuels or electricity.

Solar electricity

Sunlight can be converted into electricity using photovoltaics (PV), concentrating solar power (CSP), and various experimental technologies. PV has mainly been used to power small and medium-sized applications, from the calculator powered by a single solar cell to off-grid homes powered by a photovoltaic array. For large-scale generation, CSP plants like SEGS have been the norm but recently multi-megawatt PV plants are becoming common. Completed in 2007, the 14 MW power station in Clark County, Nevada and the 20 MW site in Beneixama, Spain are characteristic of the trend toward larger photovoltaic power stations in the US and Europe.^[59]

Solar cars

combine technology typically used in the aerospace, bicycle, alternative energy and automotive industries. The design of a solar vehicle is usually severely limited by the energy input into the car (batteries and power from the sun). Virtually all solar cars ever built have been for the purpose of solar car races (with notable exceptions).

Like many race cars, the driver’s cockpit usually only contains room for one person, although a few cars do contain room for a second passenger. They contain some of the features available to drivers of traditional vehicles such as brakes, accelerator, turn signals, rear view mirrors (or camera), ventilation, and sometimes cruise control. A radio for communication with their support crews is almost always included.

Solar cars are often fitted with gauges as seen in conventional cars. Aside from keeping the car on the road, the driver’s main priority is to keep an eye on these gauges to spot possible problems. Cars without gauges available for the driver will almost always feature wireless telemetry. Wireless telemetry allows the driver’s team to monitor the car’s energy consumption, solar energy capture and other parameters and free the driver to concentrate on just driving.

Our thanks to Wikipedia for this information!