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Active and Passive Solar Energy: The Difference and Why it Matters

active vs passive solar - house with solar panels

Solar energy can power our world. How you may ask? Active and passive solar energy capture the sun’s massive power and turn into forms we can use. Solar energy also gets rid of the need for nonrenewable resources like coal and oil. But what are active and passive solar energies and how do they work? I believe by understanding our resources we can step closer to using them wisely.

What Is Solar Energy?

sun shining through window on plant

In its simplest form, solar energy is when we harness the sun’s energy and turn it into usable electricity for homes, businesses, and more. The sun is a massive energy generator. It creates and sends out energy in the form of photons which can be captured with solar panels.

Solar panels are made up of tiny solar cells. The cells use silicon semiconductor wafers to create positive and negative layers which create the same effect as a battery. The solar cells then connect together to form a panel and the panels can also link together to form your whole system. When a photon hits the solar cell, it knocks electrons loose to run through the circuit, generating electricity for your home or business.

Why Is It Important?

Solar energy is one of the cleanest, most easily accessible sources of energy. In fact, every hour the sun is giving off more energy than all of humanity will use in a whole year. If we can harness that power, we can move away from polluting our Earth with fossil fuels and other unclean energies.

Unfortunately, while we have the technology, solar energy only makes up 1.3% in the U.S. of the total energy used. This number is shocking considering the vast breakthroughs in solar technology.

The good news is solar energy is now the fastest growing power market. This means solar power is becoming cheaper and easier to use with more ways to harness energy than ever before. And solar is slated to be one of the top sources of energy by 2050, if predictions are correct. If you want to be a part of changing to renewable energy sources, now is the time to do it.

Active Solar Energy

But what is the difference between active and passive solar energy? Active solar energy is what's used in solar panels. Because of its design, it works well for both heating systems in homes and powering electricity to whole homes and communities. With active solar energy, you can use flat-plate PV panels which can be mounted or stationary to collect the suns energy.

The way active solar energy works is by using air or liquid to capture the sun's heat. The fluid is then moved to a storage container until it is converted to energy. Active solar energy systems must use external devices to collect, store, and convert the sun’s solar energy into usable power (i.e. solar panels).

Liquid is commonly used because it is a better conductor of heat and energy. However, air has the benefit that it doesn’t freeze. Both fluids can be used in the heating and cooling of a home or building. Liquid collectors are called hydronic collectors while air systems are simply called air collectors.

Passive Solar Energy

Passive solar energy, unlike its counterpart, requires no external devices to collect or store solar heat. It relies entirely on itself and thermodynamics to collect solar heat and turn it into power. The passive solar energy system works best for heating and cooling systems, especially with small homes. However, this system may not work as well in places where the weather is especially rainy or cloudy.

If you’ve ever parked your car in the sun on a cold winter day, you already understand the basics of passive solar energy. As your car sits in the sun, the glass captures and traps the heat. You may also know this as "the greenhouse effect". The heat builds and builds, similar to how a greenhouse works. When you get inside, you slide into a warm pleasant car instead of the chilly winter air.

Passive solar energy works in the same manner. Special windows are placed on the south-facing side of the building to capture solar heat that shines through. Some systems may be supplemented through PV panels but then you're combining both active and passive solar. Using thermodynamics which means heat will move from the warm areas to cool ones, heat is redistributed through the area until its evenly heated.

Should You Get Active or Passive Solar

Deciding to move into renewable energy sources is a big choice and you want to make sure you are making the right one. Much of solar energy has improved tremendously since it first began and it's still improving today.

Active solar energy has benefits, such as not needing a power source other than the sun. Active solar energy also utilizes external devices (solar panels) which are low maintenance and very dependable.

Passive solar energy, on the other hand, is typically cheaper than active solar energy. Unfortunately, passive solar energy relies more on the weather. You may also have the potential of overheating a building if you’re located in a warm climate because you can't regulate the temperature as well.

At the end of the day, we favor active solar because the energy harnessed by your panels can be used for more than just heat. You can use it for your air conditioner, stove, lights or anything else that draws power in your home. If you're considering going solar, contact use here for a free, no-obligation quote on your home.



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