Solar Power Solutions: Active vs. Passive Designs


As heating and cooling costs inch up and the fossil fuels behind them begin to disappear from the face of the earth, there’s good reason to look skyward for a solar power solution. Harnessing the power of the sun for comfort at home is an idea that’s thousands of years old, but finding solar solutions is returning to our attention now that the impacts of other forms of energy are showing up in globally warming ways.

With a little attention and planning, you can introduce solar power solutions into your own homescape, and may already have some shining opportunities built right in. To shed some light on the possibilities, here are overviews of both passive and active design approaches that can help cut energy costs by making the most of natural, no-cost, nonpolluting sunlight.

Passive solar power design.  Passive solar design solutions make use of the natural movement of air and the sun’s rays, with little or no help from special equipment or circulation systems, creating a natural solar solution for your home. The sun’s daily and seasonal travel patterns guide the placement of built-in elements, which can generate comfort and savings by helping to cut down on the need to use your heating system.

New construction is a great opportunity to integrate passive solar solutions, but the basics are often present in existing builds or can be upgraded with minor improvements. Here are the five basic passive solar solution design principles, according to the California Energy Commission’s Consumer Energy Center:

  • Orientation: The way a structure is positioned in a landscape helps it to hitch an energy-generating ride with the sun during its daily travels. Taking a cue from the builders of the west’s early haciendas and missions, situating the largest, longest side of a home toward the south provides the greatest opportunity to soak up sunshine and create comfort indoors.
  • Overhangs and shading: Properly sized overhangs are among the best and least costly elements contributing to a passive solar solution plan. When the sun is high during summertime, overhangs shade interiors, and when the sun sits lower in the sky during winter, they usher in much-needed natural warmth. Smart landscaping around a home also contributes to the solar solution; deciduous trees, for instance, can lend shade to walls and rooftops during warm months, and let sunshine through during cold seasons.
  • Insulation: Once solar heat gets into a home, proper insulation keeps it there by forming a non-transferring barrier between interiors and falling temperatures outdoors. For best passive solar results, all exterior walls and surfaces meeting up with unconditioned zones of the indoors (such as the garage, basement and attic) should be well insulated.
  • Windows: Windows are major solar power collectors and a perfect solar solution, and along with patio doors, do the most for interior comfort when they’re located on the south side of a home, to let in both sunshine and cool breezes, depending on the seasonal need. Just be warned that too much glass on a structure’s southern exposure can lead to uncomfortable temperature extremes, so designing with smart moderation is key. That also applies to the placement of windows on the north, east and west sides of a home, which should be limited to insulate against summertime heat gain and winter cold.
  • Thermal mass: Thermal mass is an element of construction that absorbs and stores solar energy while the sun shines, and releases it at night to warm rooms via radiation, convection and conduction. This solar solution can take the form of a concrete or masonry wall or floor, or involve water, as in a tube wall.

Active solar design.  Active solar design takes sunshine saving to the next level by linking solar collection methods with mechanical equipment that converts solar heat into usable, directable energy. New solar solutions in this realm are getting more affordable as the interest in development expands; in fact, these solar power solutions and designs have received special attention and clever spins as collegiate participants in the Solar Decathlon brought their strictly sun powered home designs to life in a solar village on the National Mall in Washington, D.C.

Until one of these completely solar powered homes comes into your life, active solar amenities and solar solutions are available to supplement current home systems for savings on traditional energy bills. Heat transferred from solar collectors by circulating water, air or antifreeze to pumps and heat exchangers can power a domestic hot water system, heat a pool or warm up radiant flooring. These setups usually involve connection to a conventional, backup power source for times and durations when the sun doesn’t cooperate with solar powered plans. They also involve special planning and, for now, a bit more expense than traditional systems, but these active solar amenities and solar power solutions can yield unbeatable benefits as long as there’s a sun in the sky.

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