Active Solar and Passive Solar

Solar energy is the new wave of the future in power generation. Its benefits of being eco-friendly, wallet-friendly and even DIY-friendly is well known even outside of the alternative energy community such that an increasing number of households and commercial establishments are going the way of solar power. The government on the federal, state and local levels is also getting in on the act by providing for incentives, grants and tax breaks for both active solar and passive solar installations.

Between the two types of installations, it is the passive type that attracts many homeowners mainly because of the ease of installation of the non-mechanical components. But this does not necessarily mean that the passive solar installation is the best one for all households as the active energy systems are still the best in terms of performance efficiency. So, before you go jumping on the passive solar bandwagon, always consider the superior benefits of the active energy systems for installation in your house.

This begs many questions. What are the differences between the active and passive types of solar energy installations? What are the main benefits of active over passive energy systems? Read on and find out the answers to these questions.

Active Type

As the name implies, active solar energy systems utilize mechanical and/or electrical equipment to capture, convert and multiply the radiation energy from the sun into usable electricity for use in the house. The equipment used vary from pumps and fans to focusing mirrors, metal plates and solar panels, all of which are designed to maximize the radiant energy captured at the hottest times of the day. Other accessories to the system can include batteries, inverters and charge controllers as is the case with solar panel energy systems.

Basically, an active solar energy system uses collectors to absorb the radiant energy, converts it to heat and then transfers it to the heat exchanger for immediate use or to the battery for later use. In a solar panel setup, the batteries store the electricity generated until such time that it is needed while a solar hot water system uses heat collectors to perform a similar job. The main similarity is the option to either immediately use the heat generated or to store the electricity as the need arises.

Nowadays, active energy systems are used to heat water for the bathroom, kitchen sink and laundry as well as for swimming pools in the home. The heating capacity is dependent on the size of the system itself, the number of hours of maximum sun exposure in the area and the number of users, among other factors. This is also true for the use of solar panels in an active solar energy system to generate electricity, which can either be partially or completely off the main grid.

But contrary to popular notion, it is not just heat that an active energy system can produce in residential spaces. It can also be used to provide cool air to indoor living spaces mainly by providing power to the cooling device. Indeed, the sun may radiate heat but it can be harnessed to produce artificial cool air just as the sun’s actions on the earth’s atmosphere generate a cool breeze sweeping in from the sea.

An active solar energy system requires a greater level of planning for most efficient design and a higher level of spending for the components than its passive counterpart. The good news is that the benefits over the short-term and long-term period for an active system outweigh the initial costs, which may not be true with passive systems. But we are jumping ahead of ourselves.

Passive Type

In contrast, the passive solar systems do not require the use of mechanical and/or electrical devices to achieve its purpose. Architects, civil engineers and other building professionals design the homes, offices and other commercial establishments so that windows, walls and floors can efficiently collect or reject the sun’s radiant heat depending on the weather. This is in contrast with active solar energy systems where the components are designed to collect and store radiant energy for both immediate and future use.

Thus, in the cold months of winter, the walls, windows and floors of the house are designed to efficiently collect, store and distribute radiant heat in a process known as passive solar heating. In the hot months of summer, these components of the house are also designed to reject the sun’s radiant heat in a process called as passive solar cooling. The above mentioned building professionals have their work cut out for them to find the materials, implement the design and maintain the components in the performance of dual functions.

Many of the principles used in active solar energy systems are used for passive systems. For example, solar panels are placed in an area with the maximum sunlight usually the south-facing side while big windows are also placed on the house’s south side to take advantage of the natural sunlight.

Comparison of Active and Passive Solar

With that being said, what are the advantages of an active solar energy system in comparison with its passive counterpart? These superior benefits include but are not limited to the following:

• Active energy systems are often provided with preferential incentives, grants and tax breaks than the passive systems. This will vary from one locality to the next, of course, but homeowners soon find the truth about such preferential treatment and find it to their liking.
• Active energy systems provide for higher financial savings for the cost of electricity mainly because of the great advances in heat transfer, energy conversion and other technologies related to these systems. For example, solar panels can generate more electricity to power up the appliances, thus, leading the way to greater independence to the main grid until such time that partial to complete off-the-grid living can be achieved. In contrast, a passive system of energy-friendly windows, walls and floors can only lessen energy use by a fraction while still hooking up the entire house to the main grid.

If you are to consider becoming more eco-friendly without putting a black hole in your pockets, then an active solar energy system is the best way to go.