In recent years the press coverage of environmental issues has increased greatly, causing commercial manufacturers to realise the benefits of having green credentials. This is driving companies to access the way they run their businesses, the buildings they work in and their carbon outputs. To address environmental issues the HVAC industry has investigated alternative solutions such as heat pump systems. These developments mean that solar power has now finally emerged as a viable way of powering, or partially powering, an air conditioning system.
Generally buildings require air conditioning during a very hot day, when the sun is shining… this provides peak time for harnessing the suns energy, thus making solar powered air conditioning immensely practical. Air conditioners use the largest amounts of energy, so using solar power to run them can save a great deal of money and energy. The solar air conditioning units are not only limited to daylight however as the come with batteries last between twelve and twenty-four hours, which can then be recharged in the sunlight. The energy for the air conditioners comes from solar panels placed on or around the building, the panels heat up water until it evaporates, the water vapour extracts heat from the ventilation air flowing into the building thus making it cool and dry.
The air conditioning unit works using photovoltaic cells. These cells, either in banks or individually, use semiconductors to generate electricity directly from sunlight, they have only recently become more commonly manufactured due to a recent reduction in manufacturing costs and the range of cost-effective uses for solar power is growing. Universally, solar energy is being used extensively, from the illumination of road signs, to generating residential electricity. Its popularity is enhanced by schemes where excess generated electricity can be sold back to the national grid.
Solar air conditioners have no harmful effects or waste products, using water instead of other chemical coolants. They are independent of the power grid and so save energy by eliminating heat and friction produced by the wires of a conventional air conditioner. Solar air conditioners work best in sunny, dry climates, i.e. Southwestern United States or Northern Africa, however they can also be run on battery power, so can be used in wetter, cloudier climates, although as humidity tends to shorten the life of this appliance so areas of regular rainfall are not particularly practical.
In the most commercially used AC models, the photons in the sunlight hit the solar panel cells and are absorbed by silicon which is a semi-conducting material. Negatively charged electrons are then knocked loose from their atoms, which in turn facilitates flow through the material to produce electricity. This electricity enters the inverter as DC electricity. The inverter then turns this DC electricity into 240-volt AC electricity, necessary for air conditioning. The AC power enters the utility panel and is distributed to the air conditioning system. When the air conditioning is not being used, the electricity can be diverted to power other facilities, or flow into the national grid. Solar power should be seriously considered as an option, not only for air conditioning but to produce electricity all kinds of things.
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Posted under Gas & Electricity, House & Home, Product Innovations, Renewable Energy
This post was written by Hannah Walker on July 21, 2008