Passive solar energy is using energy from the sun to heat, cool and provide light using the direct energy from the sun. Unlike using solar panels to convert sunlight into electricity, passive solar uses only the energy coming from the sun to reduce the heating needs of a building or to produce hot water. Let’s look at how some of these technologies work.
Passive Solar Heating
Passive solar building designs for heating use the free energy from the sun to heat the home or office space. Passive solar heating relies completely upon the building design to maximize the radiant heating effects of the sun. Passive solar heating is the most cost efficient way to heat a building. The goal is to use large energy efficient windows which face south and allow the sun’s radiant heat into the interior. The building also uses materials which absorb heat during the day and radiate the heat back into the interior at night. These materials are called thermal mass. They are building materials such as concrete and masonry. These materials are good at absorbing thermal heat from the sun and then releasing the heat back into the indoor environment. Passive solar construction is designed to be airtight to trap the heat and prevent cold air from entering the building. Extra layers of insulation are used to help keep the heat inside from radiating out through the walls and ceilings. The heat can be redistributed throughout the building by the use of ceiling fans.
We don’t normally think of using the sun to cool our spaces. Normally we think of the sun as a heat source. However, passive solar cooling is a real thing. It makes use of strategically placed sun blocking mechanisms and materials to help cool the structure. Passive cooling depends heavily on using reflective coatings on windows and outside walls and roofs. Using natural cross ventilation helps to distribute heat throughout the building thereby cooling the structure.
Active solar cooling is another use for solar energy. Although not technically a passive solar system due to its use of refrigerant or evaporative cooling, the system uses solar energy. The use of solar energy to power the system makes the active solar cooling system still many times more efficient than a standard HVAC system. Using an active solar cooling system you can actually use the heat from the sun to drive an exchange system with a chiller to remove heat from an area. This type of system is talked about in more detail here.
Solar Water Heater
A solar water heater uses the energy from the sun to heat water in a tank which can then be circulated into your existing water heater to reduce energy consumption. By using the free energy from the sun instead of the electrical heating coils in your water heater, you save energy. These energy savings translate into money saved. Solar water heating systems use a tank or coiled tubes to expose water to the heat energy from the sun. Anyone who has ever picked up a garden hose that has been lying in the sun and turned on the water has experienced how a solar water heater works. In fact, you can build your own solar water heating system for very little money. If you are comfortable with do-it-yourself projects you can save substantial money by building your own solar water heater.
With all the choices in using solar energy there has never been a better time to go green. Using the free energy from the sun will save you substantial money in the long run. It also help the environment by reducing greenhouse emissions. This not only helps you, but the entire planet.