Transcript Active Solar Heating - University of Waterloo

Active Solar Heating
By: Syed F. Ahmed
Parts of the Active Solar Heater
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Solar systems consist of
collectors and electricity to
distribute the Sun’s Energy
The heart of a solar
collector is black
Heat is moved by
circulating water,
antifreeze, and air
Applications include
heating swimming pools,
domestic hot water usage,
ventilation and industrial
process
Types of Active Solar Heating
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Two types
• Liquid
• Air
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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
Liquid Systems
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Use water, antifreeze, or methyl alcohol
Components are hydronic collectors, a
storage tank, pumps, pipes, a heat
exchanger, and controls
Liquid Systems of have three operating
modes
• Primary mode
• Secondary mode
• Back up mode
Storing Heat for Liquid Systems
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Store solar heat in tanks or in the
masonry mass of a radiant slab system
Storage tanks require 3.8-7.6 L of water
for 0.093 m (1 square foot)
Tanks are usually made of steel, concrete,
fiberglass-reinforced plastic (FRP), or
wood
Each has its own advantages and
disadvantages
Distributing Heat for Liquid
Systems
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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
This then radiates the room
Radiant slab heaters are the best for liquid
systems
Hot water baseboards and radiators
require water between (71.1°C to 82.2°C)
Air Systems with Storage
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Air systems uses air as the working
fluid for collecting heat
Air systems are composed of
collectors, rock bin storage fans,
ductwork, and controls
Operates in three modes:
• Simplest mode
• Second mode
• Third mode
Delivering Heat to Home by the Air
System
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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
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
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