Common Uses of Solar Energy in Modern Homes

Without the light and heat from the sun, there would be no life on earth. Through photosynthesis, plants use sunlight to grow. Animals get their energy from the plants they eat. Even wind and the fact that liquid water exists on earth are due to the effects of sunlight. Solar energy can be used for a variety of purposes. There are three relatively new ways that humans use the energy from the sun. Windows are designed to make optimal use of natural sunlight. Solar water heaters use the radiant heat from sunlight to heat water. Photovoltaic cells convert sunlight directly to electricity.

Passive Solar Design

When windows are placed so that they catch the natural sunlight during the day, the interior of the home can be heated. Heating this way is important in cooler climates where there is a need for winter heating and where cost of other methods of heat, such as natural gas or electricity, are very expensive. A good passive solar design would include thermal mass in the interior of the home that is heated by the sunlight during the day and radiates the heat back into the home at night time. Examples of thermal mass include concrete and brick.

Solar Water Heaters

In solar water heaters, water is circulated through flat panels that are usually installed on rooftops. The water is then used as warm water in the dwellings or in swimming pools. Some solar water heaters have sealed systems using antifreeze. The heat is then conducted to the domestic water system through a heat exchanger. In warmer countries, solar water heaters provide approximately 85% of domestic hot water used.

Photovoltaic Cells

Solar cells convert light into electricity using the photovoltaic effect. What this means, in simple terms, is that light energy excites the electrons in the cells causing electricity. The current produced is DC so a converter is needed to change the power output into AC current. Solar power is used in many different ways. Some stand-alone devices include calculators, stop sign lights, emergency/camping devices, battery chargers, security cameras, garden fountains, walkway lighting, radios, and spacecraft. Sometimes, solar panels are connected electronically to a grid system. The energy from these grids is delivered to residential homes and businesses and can then be used to power any electrical device.

Ultimately, all energy on earth, aside from geothermal and nuclear, comes from the sun. Without sunlight, all life on earth would become extinct. Luckily for us, the sun is estimated to last for another 2-4 billion years.