Active Solar Heating By: Syed F. Ahmed

Parts of the Active Solar Heater Solar systems consist of collectors and electricity to distribute the Sun’s Energy Solar systems consist of collectors and electricity to distribute the Sun’s Energy The heart of a solar collector is black The heart of a solar collector is black Heat is moved by circulating water, antifreeze, and air Heat is moved by circulating water, antifreeze, and air Applications include heating swimming pools, domestic hot water usage, ventilation and industrial process Applications include heating swimming pools, domestic hot water usage, ventilation and industrial process

Types of Active Solar Heating Two types Two types LiquidLiquid AirAir Both systems collect solar radiation, then distribute and store heat Both systems collect solar radiation, then distribute and store heat If the system does not provide adequate heat then a back up heating source is needed If the system does not provide adequate heat then a back up heating source is needed

Liquid Systems Use water, antifreeze, or methyl alcohol Use water, antifreeze, or methyl alcohol Components are hydronic collectors, a storage tank, pumps, pipes, a heat exchanger, and controls Components are hydronic collectors, a storage tank, pumps, pipes, a heat exchanger, and controls Liquid Systems of have three operating modes Liquid Systems of have three operating modes Primary modePrimary mode Secondary modeSecondary mode Back up modeBack up mode

Storing Heat for Liquid Systems Store solar heat in tanks or in the masonry mass of a radiant slab system Store solar heat in tanks or in the masonry mass of a radiant slab system Storage tanks require L of water for m (1 square foot) Storage tanks require L of water for m (1 square foot) Tanks are usually made of steel, concrete, fiberglass-reinforced plastic (FRP), or wood Tanks are usually made of steel, concrete, fiberglass-reinforced plastic (FRP), or wood Each has its own advantages and disadvantages Each has its own advantages and disadvantages

Distributing Heat for Liquid Systems Heat is distributed by radiant slab heaters, a central air-forced system, or by using hot water baseboards or radiators Heat is distributed by radiant slab heaters, a central air-forced system, or by using hot water baseboards or radiators Solar heated water moves through the pipes and heats the floor Solar heated water moves through the pipes and heats the floor This then radiates the room This then radiates the room Radiant slab heaters are the best for liquid systems Radiant slab heaters are the best for liquid systems Hot water baseboards and radiators require water between (71.1°C to 82.2°C) Hot water baseboards and radiators require water between (71.1°C to 82.2°C)

Air Systems with Storage Air systems uses air as the working fluid for collecting heat Air systems uses air as the working fluid for collecting heat Air systems are composed of collectors, rock bin storage fans, ductwork, and controls Air systems are composed of collectors, rock bin storage fans, 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 System For storing heat, an air system delivers hot air from the collectors to the storage bin For storing heat, an air system delivers hot air from the collectors to the storage bin The air enters an empty mixing space at the top of the bin The air enters an empty mixing space at the top of the bin It passes down through the bin where the rocks absorb most of the heat It passes down through the bin where the rocks absorb most of the heat When storing heat, the top of the bin is usually 60°C and 21.1°C When storing heat, the top of the bin is usually 60°C and 21.1°C If the air in the bin is too cool then the back system kicks in If the air in the bin is too cool then the back system kicks in The air delivers warm air from the rock bin to the house through ducts The air delivers warm air from the rock bin to the house through ducts