Characteristics of crystalline silicon photovoltaics

Crystalline silicon photovoltaics is the most widely used photovoltaic technology. Crystalline silicon photovoltaics are modules built using crystalline silicon solar cells (c-Si), developed from the microelectronics technology industry.

Crystalline silicon solar cells have high efficiency, making crystalline silicon photovoltaics an interesting technology where space is at a premium.

There are two types of crystalline silicon solar cells used in crystalline silicon photovoltaics:

- Mono-crystalline silicon, produced by slicing wafers from a high-purity single crystal ingot
- Multi-crystalline silicon, made by sawing a cast block of silicon first into bars and then into wafers Mono-crystalline silicon solar cells have higher efficiencies than multi-crystalline silicon solar cells.

In crystalline silicon photovoltaics, solar cells are generally connected together and then laminated under toughened, high transmittance glass to produce reliable, weather resistant photovoltaic modules. The glass type normally used for this technology is rolled low iron glass such as Pilkington Sunplus™, often in toughened form, combined with an anti-reflective coating, to ensure that the maximum solar radiation reaches the crystalline silicon solar cells. It is also possible to use low iron float glass such as Pilkington Optiwhite™

Characteristics of solar thermal collectors

Solar water heating systems are generally composed of solar thermal collectors, a water storage tank or interconnecting pipes and a fluid system to move the heat from the collector to the tank. The sun's energy is used to heat water flowing through the interconnecting pipes. The water can be heated for a wide variety of uses, including domestic, commercial and industrial applications.

Flat-plate solar thermal collectors consist of an insulated box which contains a dark absorber plate under a glass cover that hermetically seals the system while maximizing the energy input. The glass cover plate will transmit the sunlight while protecting the system from harsh weather.

Toughened, high transmittance glass is required for this application; our Pilkington Sunplus™ and Pilkington Optiwhite™ are ideal for such applications.

Our range of patterned low iron glass Pilkington Sunplus™ products includes:

• Pilkington Sunplus™ SM: ultra high solar energy transmittance and low light reflectance due to a combination of a prismatic pyramidal pattern on one surface (S), and a matt pattern on the other (M)
• Pilkington Sunplus™ MM: ultra high solar energy transmittance and low light reflectance due to the matt pattern (M) on both surfaces
• Pilkington Sunplus™ SM AR: ultra high solar energy transmittance with Anti-Reflective properties due to the application of an AR coating, designed and optimised for crystalline silicon photovoltaics

Pilkington Sunplus™ is used extensively for the cover glass in crystalline silicon solar cells.

The properties of our Pilkington Sunplus™ products are summarised in the table below: