Gallium arsenide solar cells are very efficient but are expensive. Their efficiency reaches as high as 29% in laboratory and about 20% in real world. Multi junction or tandem solar cells can show even up to 40.9% efficiency. These solar cells are formed by depositing several thin layers of single crystal layers on top of the substrate. The layers are doped oppositely to conduct electricity. Due to heat resistivity and high absorption they have found extensive applications in spacecrafts.

Polycrystalline solar cells are cheaper than mono crystalline solar cells but are costly as compared to thin film cells. Their efficiency is less than mono crystalline cells but greater than thin film solar cells. In February of 2009, Mitsubishi Electric Corporation achieved 18.9% efficiency with polycrystalline solar cells whereas thin film solar cells convert have just 11% efficiency.

A solar pool cover is energy-efficient and prevents the loss of heat from the pool water. It also prevents evaporation of water and saves it. A solar pool cover transfers heat energy from sun to the pool water to warm it, reducing your energy bills up to 75%.

Quantum dot or nano crystalline solar cells have very high efficiency and are formed by spin coating. The ability of carrier multiplication has made it many times more efficient than other solar cells. Carrier multiplication means it can excite many electrons per incident photon. The materials used in these cells include lead selenide (PbSe), cadmium telluride (CdTe), titanium dioxide (TiO₂) and lead sulfide (PbS).

Thermosiphon water heating system is a passive water heating system. It works under the principle of convection. Hot water rises up and warm goes down. Gravity is responsible for pulling the cold water down. That is why these systems are generally vertical. Hot water from the top layers is utilized. Heating can be done directly or through a heat transfer fluid.

Mono crystalline solar cells are the earliest form of solar cells. They are formed by depositing thin silicon wafers over rigid glass substrate. They have polka dotted shape. They are very efficient but are expensive and wasteful of material. These are being replaced by polycrystalline solar cells in the market.

Gas Hybrid cars are becoming more and more popular in the auto industry due to the features they offer when comparing to the conventional cars. Before buying a hybrid gas car or even making a decision, one must decide whether features offered by Gas Hybrid cars suits his lifestyle or not!

Alernative energy resources are an urgency that need to be dealt with. The governments of countries like Brazil have already started to settle for it, and so should others. Because alternative energy resources are now not a luxury, but a need that soon will be sought to as oil and gas amounts near their end.

Every now and then a person gets in to a situation, when he needs his gadget and all he gets in reply is battery low. To counter these situations have a look on Scottevest Solar powered jacket – which can charge all of USB charger suppoted gadgets while you are on the move.

Ever growing prices of renewable fuel are also increasing the magnitude of utility bills so it is worthwhile to choose renewable energy sources. One must understand some facts about Solar power to help him decide – why to choose Solar power for that big investment out of so many renewable enrgy options?

Eco concept cars are creating hype in the automobile engineering industry. Many renowned brands are introducing eco concept cars, to save the environment together with auto industry. So, check out the most awaited eco concept cars and admire the inventors.