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Active Solar Vs Passive Solar

The Difference Between Active And Passive Solar Systems

Solar Energy Understanding Active and Passive Solar Heating

27 Sep, 2018

Understanding the difference between active and passive solar systems can be tedious at times. Weve identified their main differences and the functionality of both the systems and overall performance.

Both are capable of converting the suns energy to electricity, but the setup and performance happen to be a little different, although they perform the same function. Weve listed some of the positives and negatives of both of the solar systems.

Passive Vs Active Solar Energy: Why It Matters

As a property owner, you might have heard about solar energy that can power your home. You can even question how it is possible. Passive and active energy can be captured from the suns infinite power that can be converted into various energies you can use. After reading this article you are sure to find what is the difference between passive and active solar energy so that you can choose the right one as per your home needs. Before knowing about the details of passive vs active solar energy, let us understand some basics on this given subject about solar energy.

Since the existing fossil fuel offers different issues related to the environment, people across the globe have started switching to the sun as an alternative source of energy like the people from ancient civilizations always did, several centuries ago. From harnessing the suns energy, you can able to convert it into usable electric power for your home, business place, and many more.

Being known as the largest energy generator in our solar system, the sun radiates energy in the form of photons which can be captured by the solar panels, which find many house rooftops around the world. Now, you can find here more inputs about active and passive solar energy which you can deploy in your home, offices, etc.

Active And Passive Solar Energy: The Difference And Why It Matters

Solar energy can power our world. How you may ask? Active and passive solar energy capture the suns 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.

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The Solar Path In Passive Design

The ability to achieve these goals simultaneously is fundamentally dependent on the seasonal variations in the sun’s path throughout the day.

This occurs as a result of the inclination of the Earth’s axis of rotation in relation to its orbit. The sun path is unique for any given latitude.

In Northern Hemisphere non-tropical latitudes farther than 23.5 degrees from the equator:

  • The sun will reach its highest point toward the south
  • As winter solstice approaches, the angle at which the sun rises and sets progressively moves further toward the south and the daylight hours will become shorter
  • The opposite is noted in summer where the sun will rise and set further toward the north and the daylight hours will lengthen

The converse is observed in the Southern Hemisphere, but the sun rises to the east and sets toward the west regardless of which hemisphere you are in.

In equatorial regions at less than 23.5 degrees, the position of the sun at solar noon will oscillate from north to south and back again during the year.

In regions closer than 23.5 degrees from either north-or-south pole, during summer the sun will trace a complete circle in the sky without setting whilst it will never appear above the horizon six months later, during the height of winter.

Why Use Active Solar Energy

Solar heating systems can slash your energy bill. We explain passive ...

Having an active solar system installed in your home can prove beneficial for you. Since solar energy is probably the cleanest energy available, why not use it to the fullest.

Here are some prime benefits of active solar energy you should know about.

  • Active solar energy is the best alternative in cold climate conditions with good solar resources available. It can displace the more expensive heating fuels, such as electricity, propane, and oil.

  • Some states offer sales tax exemptions, income tax credits or deductions, and property tax exemptions or deductions for solar energy systems. For example, if you live in Great Britain you can also receive payments for the surplus energy under the scheme.

  • You can get an active solar system installed in your home regardless of the orientation or the design.

  • Solar collectors come with a warranty of more than ten years. This means it can last a decade

  • The heat energy produced can be used for several purposes. Ultimately it can reduce our electricity bills.

  • A solar heating system will also affect the pollution levels and greenhouse gases that result from the use of fossil fuels for heating or generating electricity.

There are some notable points to remember about active solar energy.

  • Active solar energy is a better option as it allows us to use solar energy according to our time of need.

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What Is Active Solar Energy

Active solar energy is when a device collects, stores, converts, and distributes solar power. Photovoltaic panels get used to make these things happen.

The panels sit on a roof or an area aligned with the sun to capture solar energy. Active solar energy systems can supplement your heating system, such as an HVAC system.

Active solar energy systems come in all shapes and sizes. That gives you the flexibility to find the best system for your needs.

Check out to see examples of mobile active solar energy systems.

Which Solar Energy System Is Best For Me

Before you start the debate of whether to switch to active systems versus passive solar systems, first you should ask yourself: Are you sure youre ready for the change to solar energy? Though youll be contributing to a more sustainable environment, you should always weigh the pros and cons before making such a momentous decision.

For example, remember that solar systems, though a green and renewable source of energy, still arent the most efficient if your home or business requires a lot of power. With solar panels installed on your rooftop, only 14 percent of the sunlight captured can generate viable electricity. Plus, consider your location. Sure, solar systems can draw from stored energy, but just how much? If you live in an area with consistently cloudy or rainy weather, now may not be the right time to transform your building into a greenhouse.

Still ready to take the leap in your humanitarian efforts to preserve the planet? Consider the advantages and disadvantages of both active and passive solar systems.

Active solar systems: First, lets look at the pros of switching to an active solar system:

  • Since it still utilizes the power of your external devices, you dont have to worry about deriving power from sources other than the sun.
  • It releases no carbon dioxide into the atmosphere.
  • Heating of the PV panels helps keep them clean, especially in poor weather conditions.
  • There is usually no wind noise generated from the solar panels.

Now, consider the negatives:

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C Active Vs Passive Solar Power: Benefits And Drawbacks

The table below compares some of the benefits and drawbacks of active and passive solar power.

A sustainable source of heating.No additional technology is required for it to work.No harmful chemicals are involved in the process. Very little control over temperatures, as the sun and house design, dictates what is achievable.The efficacy is limited, especially by the weather.Overheating is a likely concern in hotter areas.

Although both are sustainable sources of heat energy, neither is truly efficient in energy conversion.

Passive systems are cheaper than active but are limited by the orientation of your house. I feel that a passive system has the potential to be better if all the factors work together and you find the sweet spot.

The reality is that technological developments have improved over the last couple of decades in enhancing solar energy . There is, however, still a long road ahead before solar power and green energies, in general, replace the efficiency and wide-scale use of fossil fuels.

Efficiency And Economics Of Passive Solar Heating

SunEarth Solar Brief – Active vs. Passive

Technically, PSH is highly efficient. Direct-gain systems can utilize 65â70% of the energy of solar radiation that strikes the aperture or collector.

Passive solar fraction is the percentage of the required heat load met by PSH and hence represents potential reduction in heating costs. RETScreen International has reported a PSF of 20â50%. Within the field of sustainability, energy conservation even of the order of 15% is considered substantial.

Other sources report the following PSFs:

  • 5â25% for modest systems
  • 40% for “highly optimized” systems
  • Up to 75% for “very intense” systems

In favorable climates such as the southwest United States, highly optimized systems can exceed 75% PSF.

For more information see Solar Air Heat

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The Difference Between Active Vs Passive Solar Can Get Confusing

All over the country, people are installing solar panels on their roofs to produce their own electricity and save some cash. In fact, residential solar grew about 1,250% from 2010 to 2016 talk about an explosion! But this wasnt the first solar explosion. 40 years ago, there was a huge explosion in solar as well.

Back in the late 1970s, at the height of the oil crises, renewable energy was in. President Carter installed thermal solar panels on the White House, the first federally-sponsored renewable energy lab was founded, and both the federal and local governments were actually handing out financial incentives for solar panels.

But it wasnt the electricity-producing solar panels we so frequently see today that they were subsidizing. They were actually thermal solar panels, which harness the sunlights heat to preheat water for home use. Even now, driving throughout the west, youll see old thermal solar panels dotting roofs, either pumping away hot water or rusting away as a reminder of those times.

Okay, enough of a history lesson. Why do we even bring this up? Two reasons, actually.

First off, its just interesting! Its almost like a prelude to todays boom in renewable energy setting the stage for what was to come.

How Does Solar Power Work Anyway

As of December 2016, India had a total installed large-scalesolar capacity of 9,018 MW and a solar pipeline of 14,030 MW according to MercomCapital Group. But how do these solar energy systems convertsunlight into electricity?

According to LiveScience, a solar panel works by allowing photons, or particles oflight, to knock electrons free from atoms, generating a flow of electricity,.Well, this is a technical explanation of saying that the photovoltaic cells ofthe solar panels convert the energy in suns photons to electricity.

Now dont be worried about how this process works at night or on cloudy days. The solar panels store the surplus energy captured during the day to draw from it even when its night-time or a cloudy day.

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A Brief Passive Solar Energy Guide

Passive solar energy directly takes energy from the sun and uses it. There arent systems in place to convert it to electric power.

This is used a lot in architecture, where south-facing windows are larger to collect as much sunlight as possible. The heat gets trapped inside and distributed throughout the building.

That can reduce the amount of heat and power required to maintain the temperature in the building.

Special equipment isnt used, and theres nothing to install with passive energy systems. The upfront work gets done in a buildings development phase to ensure the best orientation to the sun.

Other examples of passive solar energy are greenhouses and soil. Greenhouses are closed structures that take in the suns direct light.

Soil absorbs the suns heat and energy. It releases that energy overnight, which regulates the ground temperature.

Which Type Of Solar Energy Is Best For Me

Passive Solar Heating: Solar Thermal Energy for Hot Water

As you may have browsed through the various advantages and disadvantages, you must have developed a good idea regarding what each type of energy offers. With this in mind, choosing which solar system suits you depends solely on your purpose.

Passive energy is the way to go if you live in a relatively warm area and do not require much internal heating. However, if you need a more efficient and reliable heating system for your house, you will need to invest in active solar energy. Remember that passive energy will only work if built into the structure.

These days houses are built with a solar design in mind, so there should already be passive heating elements that are working to keep your house warm. Similarly, there is no reason that you have to go for one or the other as both have some pros and cons. You can use both to create highly efficient and eco-friendly heating for your house.

Understanding the different types of solar energy allows you to utilize both to the max. Learn about functioning, advantages, disadvantages, and comparisons.

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Passive Solar Design In Buildings:

Passive solar technology uses the heat of the sun and building/material design to provide internal and water heating without the use of electricity or combustion. Buildings designed with passive solar heating can stay warm in the winter and cool in the summer by use of proper orientation, devices and materials. Passive solar is different than active solar in that active solar uses electrical and mechanical devices. Designing passive solar systems is the realm of engineers with heat transfer, architecture and materials engineering backgrounds.

Below: a community of passive solar homes in Taos, New Mexico

Understanding thermal properties of materials is important as the correct choice of materials allows for slowing/hastening temperature changes when desired. Mirrors can be used to capture energy and focus it in a solar furnace and solar forge. In buildings chimneys, doors, ventilation systems and windows are all designed to control temperature based on the local climate, latitude, humidity and wind patterns. See the video below where the Edison Tech Center takes a tour of a passive solar house in a special community in New Mexico. This style of passive solar house has been branded “Earthship”by designer Mike Reynolds.

What Are Passive Solar Systems

In simple terms a passive solar home collects heat as the sun shines through south-facing windows and retains it in materials that store heat known as thermal mass. Well-designed passive solar homes also provide daylight all year and comfort during the cooling season through the use of nighttime ventilation.

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Distributing Heat For Liquid Systems

You can use a radiant floor, hot water baseboards or radiators, or a central forced-air system to distribute the solar heat. In a radiant floor system, solar-heated liquid circulates through pipes embedded in a thin concrete slab floor, which then radiates heat to the room. Radiant floor heating is ideal for liquid solar systems because it performs well at relatively low temperatures. A carefully designed system may not need a separate heat storage tank, although most systems include them for temperature control. A conventional boiler or even a standard domestic water heater can supply back-up heat. The slab is typically finished with tile. Radiant slab systems take longer to heat the home from a “cold start” than other types of heat distribution systems. Once they are operating, however, they provide a consistent level of heat. Carpeting and rugs will reduce the system’s effectiveness. See radiant heating for more information.

Hot-water baseboards and radiators require water between 160° and 180°F to effectively heat a room. Generally, flat-plate liquid collectors heat the transfer and distribution fluids to between 90° and 120°F . Therefore, using baseboards or radiators with a solar heating system requires that the surface area of the baseboard or radiators be larger, temperature of the solar-heated liquid be increased by the backup system, or a medium-temperature solar collector be substituted for a flat-plate collector.

Passive Vs Active Solar Energy

Passive and Active Solar Architecture

So, what is the difference between passive and active solar energy?

Passive solar energy does not require mechanical equipment and electronic devices to gather and distribute solar energy. It also does not need power coming from an external, conventional source.

Active solar systems rely on pumps, sophisticated electronic devices, and motors to effectively collect and systematically provide solar energy. For these motors and electronic equipment to run, active solar systems need to be hooked up to an external power source.

Since passive solar systems do not usually depend on an external power source to operate, they rely on their heat-absorbing properties, particularly the materials used in the system. Sensors and motors running on conventional energy make active energy systems work, also maximizing their operability and effectiveness in harnessing the power of the sun.

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Positives Of Active Solar Systems

  • The main construction material includes flat-plate PV panels. This kind of panel uses advanced designs which are formed by connecting all the panels with each other.
  • The common practice is to use liquid or air in solar collectors as a conductor. Mainly, the solar collectors are used to store and conduct energy.
  • The conductors that use liquid are normally known as hydronic collectors. The ones that use air are called air collectors.
  • Liquid conductors are more commonly used as compared to air based conductors. Though air based conductors only have one drawback i.e they dont freeze.

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