Active Solar Heating: Tech Details


 According to the Nasa Earth Observatory, Sunrays contribute 1360 Watts of power per square meter to the top layer of our atmosphere. Solar energy is limitless, and its applications are only growing in number day by day. Solar energy is finding its way into daily life with many applications like Active and Passive Solar Heating.

Active solar heating gathers energy in solar collectors and distributes it through external devices. These devices can be pumps, blowers, and regulators. This heat energy can be used to heat indoors, water, and swimming pool.

Both Active and Passive solar heating systems gather heat for storage and distribution. These systems accomplish the same task as the thermostat. The only difference is the process of heat storage and circulation. In Active solar heating, heat comes from the environment, and external energy is used to regulate its flow.

But, can Active solar heating replace the thermostat or the water heater? What exactly is Active 

Solar energy? How do Active solar heating structures gather heat from the sun?

What is active solar heating?

Active solar heating systems collect and store the energy from the Sunrays to implement it as heat energy. Active solar heating finds its application in cold climates where the cost of heating and gathering energy resources might be on the higher side. Mainly, Active solar heating is used for heating water for domestic use. Some other applications include pool heating and room heating.

Active solar heating is a type of home heating where parts of the mechanism are powered by an external source, usually electricity. Heat transfers from one medium to another. Active devices like water pumps, fans, and heat exchangers.

Out of all the renewable sources of energy, conventional or nonconventional, Solar power is the most implemented way of generating clean power. Mainly used at small scale level(domestic) for power and heating.

What are the main components of active solar heating?

All the components and dimensions are calculated according to the space, hours of sunlight per day, and temperature. Which includes the amount of Solar energy per square foot measured in BTU(British Thermal Unit). There are three main components of active solar heating systems. These components help to collect the heat energy and mobilize it for usage. 

  1. Solar collector

Solar collectors capture the heat from the Sun and use it to heat air or water. Usually, the solar collectors are a combination of a box with tubes inside. This model increases the overall efficiency of the system. A greenhouse glass box traps heat, and the pipes induce heat in the carrier.

For simultaneous solar power production, solar collectors are coupled with solar panels. Solar collectors gather the heat, and the panels convert the sunlight into electricity.

  1. Heat energy storage

The storage system has two points: one inlet and one outlet. The inlet lets the cold water enter the storage through a circulator. And at the other end, the heated water or air escapes the heat storage.

In place of water outlets, ducts are used for air heating. 

  1. Distributor or Circulator

A distributor or a circulator is the part of active solar heating which defines the whole system. The distribution system uses a combination of heat flow channels and Active devices.

The circulator uses two channels to transfer heat between the collectors and the storage. The flow of the heat is in a closed loop. 

The medium(antifreeze or water or air) carries heat from the collectors to the storage. 

How do active solar heat structures gather heat from the Sun?

Sun rays have a heating effect. Once heated, some objects cool down rapidly, but others take time. The ones that retain heat for long periods are known as good conductors of heat. That’s the material used in the Solar collectors to absorb and induce maximum heat in the fluid or air.

The material used to make these collectors is usually heat conductors and insulators. The collectors have a box shape with the top layer glazed to let maximum Solar power heat the pipes. All the other sides of the box are made of insulating material to reduce the rate of heat dissipation.

Solar collectors play an important role in Active solar heating systems. This is the place in the whole system where the heat energy is induced in the system.

How does active solar heating work? – Technical details

Active solar heating works on the principles of thermodynamics. Heat gets dissipated from high temperature to low: the sunlight to the target material or space. 

The surface of the pipes in the solar collectors gets coated for maximum absorption. The flat surface of the collectors is at a ninety-degree angle to the sun rays for maximizing absorption. This is critical in both active and passive sunlight heating. The location and angle of the solar collectors are set according to the time of year when the least sunlight is available.

Active devices

Water pumps or air circulators use conventional power to move the medium through the whole Active solar heating setup. These active devices in the system take the heated fluid or air from the collectors to the storage. Usually, the flow is regulated using regulators configured according to the rate of supply to the collectors.

Pumps are replaced by fans or blowers if the medium is air in the collector pipes. The rate of airflow is regulated according to the area of heating and the length of the collector pipes. 

Heat exchangers are used for heating swimming pools as active devices. They are connected to the water pump or filtration system.

Passive Solar Heating

Homes protect from natural elements like sun rays, rainfall, and wind. Passive solar heating involves conscious effort to let a set amount of sunlight enter the building. Unlike Active solar heating, no active device is used for heat distribution. Planning and modifications are done to get maximum heat from the Sun, especially in the winters.

Passive solar heating involves construction or modification to get the perfect orientation of the windows and openings in the structure. Usually, the south direction is best for the maximum impact. To increase the efficiency of the system, Sun shields, glass roofing panels, and heat-absorbing material for interiors can also be used. The technology in this field is only improving every year.

One disadvantage of passive solar heating comes in summer. Because the construction is done to get maximum sunlight, it might become a problem on the hot days of the year. That’s where a visor or sunscreens can be helpful as well.

Active Solar Heating VS Passive Solar Heating

Active solar heating systems have some distinct advantages over passive solar energy:

Passive systems don’t include controls and often need extra heating types of equipment like thermostats unless heat requirements are low. Else, Active or passive solar heating systems can replace the conventional electric thermostat.

AttributeActive Solar HeatingPassive Solar Heating
Power ConsumptionPower consumption is high. Active devices use power to move the heat.No active devices are involved. Power consumption is zero.
EfficiencyEfficiency is high.Efficiency is low.
CostDepends directly on the scale and output of the system.A one-time investment is required to get the desired and efficient structure.
FeasibilitySystem installation and modification are customizable.Feasibility is checked at the start of the project. Modifications can prove to be a tricky ordeal.

How to get an active solar heating system?

Choice of solar heating system size and configuration depends on factors like the size of the house, days of sunlight every year, cost, and climate.

These systems are best suited for locations with limited heating resources, and winters are harsh. Active solar water heating systems range from $3000 to $1000, depending on the customization and installation area.

Some firms are developing programs to calculate the cost and design the system to get the best out of the installation based on customer requirements.

What are the advantages of active solar heating?

Renewable Energy

The renewable energy market is expanding every year with new developments in the field of science. Solar is slowly gaining momentum with innovations in PV and solar energy storage.

The solar market is evolving and has the potential to become a cost-effective renewable source of energy. Different forms of solar energy include photovoltaic (PV) and solar thermal technologies.


Sun is present in the form of an unlimited source of power. Therefore the use of Solar Power is sustainable.

Solar heating can be used in any climate and in any country. It removes the dependency on fossil fuels.


The technology of active solar heating is cost-saving in the longer run. Technology upgrades through modification from time to time also help in making the most out of the system.

In the longer run, Solar heating proves power and cost-saving. 

Anything that uses electricity to heat requires a huge amount of energy which can increase the bill. Active solar heating removes the heating component from the bill and reduces the units of power consumed over the long run.

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