Active Solar Heating

Liquid Solar Heating System

Travis Ricard

Objective

To outline and provide relevant information on the following

What is Active Solar Heating How Does a Liquid Active Solar Heating System Work In-Floor Radiant Heating Controls Performance and Maintenance

Cost and savings

What is Active Solar Heating

A system which relies upon the collection and storage of solar radiation in order to be transferred into energy for the purpose of heating

How Does a Liquid Active Solar Heating System Work

Solar radiation collectors are installed to collect direct sunlight

Usually placed on the roof, but they can also be wall or ground mounted

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A liquid is circulated through the collector

Usually consists of water, antifreeze, or methyl alcohol

The heat collected by the collector is transferred to the liquid

A photovoltaic panel attached to the collectors operates a pump which circulates the liquid

The heated liquid is pumped into the storage container

Cold water from the storage container is then sent through the system be heated.

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The heated water can then be used with the aid of a heat exchanger to provide hot water or in floor radiant heating.

Often a secondary heating device is used when there is not enough solar radiation to heat the water

This device is typically a natural gas boiler

http://homepage.eircom.net/~solaris/pages/products1.html

In-Floor Radiant Heating

Liquid active solar heating systems are often used to supply hot water for in-floor radiant heating

The hot water is directed through plastic or rubber pipes embedded in a concrete floor

The circulating hot water then heats the floor, which in turn radiates to heat the room

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In floor radiant systems require water temperatures of 71.1°C to 82.2°C

Often these temperatures cannot be achieved through solar heating alone.

Typically the secondary system (natural gas boiler) is used to bring the pre-heated water up to the required temperature.

Controls More complex then the typical household heating system

This is due to the fact that the system must analyze more signals and control more devices

Use sensors, switches, and motors to operate the system and to provide back-up heating

The main component of the system is the differential thermostat, which measures the difference in temperature between the collectors and storage container.

When the collectors are 6.7°C to 12.2°C warmer than the storage unit, the thermostat turns on the pump to circulate water through the collector to heat the storage container or the house.

Performance Quality, durability, system design, and installation dictate how

well an active solar energy system will perform

Active solar energy systems typically provide 40% to 80% of the home's heating needs.

Systems providing less than 40% of the heat needed for a home are usually not cost effective as they due not provide enough savings to justify their more expensive implementation costs

The size of the system determines how much heat it can provide.

Maintenance

Most systems require between 8-16 hours of maintenance ensure optimal performance and to avoid failures.

Much of this maintenance involves checking pipes and ductwork for leaks and collectors for damage.

Pumps and fans must also be cleaned and lubricated on an annual basis

Cost and Savings

Typical costs of solar radiation collectors vary from $30 and $80 per square foot installed (depending on the type of panel)

Further cost associated with storage container and pumping system

It is estimated that an in floor radiant heating system can reduce a

heating bill by 20-40%

This value will increase further if the secondary heating system is used as little as possible.

Conclusion

Liquid Active Solar Heating Systems are a cost effective and efficient way to heat a home

Reliable and relatively maintenance free

Many options with regard to type and size of system

The higher initial cost is quickly off set by the annual energy savings

References

Refer to the below links for further information

http://www.healthgoods.com/Education/Energy_Information/Renewable_Energy/heating_with_active_solar.htm

http://www.newenergy.org/sesci/publications/pamphlets/active.html