Active Solar HeatingActive Solar Heating

By: Syed F. AhmedBy: Syed F. Ahmed

Parts of the Active Solar HeaterParts of the Active Solar Heater Solar systems consist of Solar systems consist of

collectors and electricity to collectors and electricity to distribute the Sun’s Energydistribute the Sun’s Energy

The heart of a solar The heart of a solar collector is blackcollector is black

Heat is moved by Heat is moved by circulating water, circulating water, antifreeze, and airantifreeze, and air

Applications include Applications include heating swimming pools, heating swimming pools, domestic hot water usage, domestic hot water usage, ventilation and industrial ventilation and industrial processprocess

Types of Active Solar HeatingTypes of Active Solar Heating

Two typesTwo types• LiquidLiquid• AirAir

Both systems collect solar radiation, Both systems collect solar radiation, then distribute and store heatthen distribute and store heat

If the system does not provide If the system does not provide adequate heat then a back up adequate heat then a back up heating source is needed heating source is needed

Liquid SystemsLiquid Systems

Use water, antifreeze, or methyl alcohol Use water, antifreeze, or methyl alcohol Components are hydronic collectors, a Components are hydronic collectors, a

storage tank, pumps, pipes, a heat storage tank, pumps, pipes, a heat exchanger, and controls exchanger, and controls

Liquid Systems of have three operating Liquid Systems of have three operating modes modes • Primary mode Primary mode • Secondary modeSecondary mode• Back up mode Back up mode

Storing Heat for Liquid SystemsStoring Heat for Liquid Systems

Store solar heat in tanks or in the masonry Store solar heat in tanks or in the masonry mass of a radiant slab systemmass of a radiant slab system

Storage tanks require 3.8-7.6 L of water Storage tanks require 3.8-7.6 L of water for 0.093 m (1 square foot)for 0.093 m (1 square foot)

Tanks are usually made of steel, concrete, Tanks are usually made of steel, concrete, fiberglass-reinforced plastic (FRP), or woodfiberglass-reinforced plastic (FRP), or wood

Each has its own advantages and Each has its own advantages and disadvantages disadvantages

Distributing Heat for Liquid Distributing Heat for Liquid SystemsSystems

Heat is distributed by radiant slab heaters, Heat is distributed by radiant slab heaters, a central air-forced system, or by using hot a central air-forced system, or by using hot water baseboards or radiators water baseboards or radiators

Solar heated water moves through the Solar heated water moves through the pipes and heats the floorpipes and heats the floor

This then radiates the room This then radiates the room Radiant slab heaters are the best for liquid Radiant slab heaters are the best for liquid

systems systems Hot water baseboards and radiators Hot water baseboards and radiators

require water between (71.1°C to 82.2°C)require water between (71.1°C to 82.2°C)

Air Systems with StorageAir Systems with Storage

Air systems uses air as the working Air systems uses air as the working fluid for collecting heat fluid for collecting heat

Air systems are composed of Air systems are composed of collectors, rock bin storage fans, collectors, rock bin storage fans, ductwork, and controls ductwork, and controls

Operates in three modes:Operates in three modes:• Simplest modeSimplest mode• Second modeSecond mode• Third modeThird mode

Delivering Heat to Home by the Air Delivering Heat to Home by the Air System System

For storing heat, an air system delivers hot air For storing heat, an air system delivers hot air from the collectors to the storage bin from the collectors to the storage bin

The air enters an empty mixing space at the top The air enters an empty mixing space at the top of the bin of the bin

It passes down through the bin where the rocks It passes down through the bin where the rocks absorb most of the heat absorb most of the heat

When storing heat, the top of the bin is usually When storing heat, the top of the bin is usually 60°C and 21.1°C60°C and 21.1°C

If the air in the bin is too cool then the back If the air in the bin is too cool then the back system kicks in system kicks in

The air delivers warm air from the rock bin to the The air delivers warm air from the rock bin to the house through ducts house through ducts