Active Solar Water Heating For Home Hot Water

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Active Solar Water Heating For Home Hot Water

• By Clare Freeman
• and
• Laura Mitchell

http//www.solardepot.com/r_solar_hot_water.htm
http//www.solardepot.com/r_solar_hot_water.htm
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What is the main goal?

• To reduce our contribution
• to the greenhouse effect
• It is clean and renewable its a good step
  towards making our society self-sustaining
• Reduces dependence on Non-renewable energy
  sources like coal, natural gas, and oil.
  (especially foreign oil!)
• Reduce SOx and NOx emissions and their
  contribution to acid rain

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PSESSID8295964ef77b413805c62f8c72cb5278
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It will make a difference!

• About half of the earths carbon emissions come
  from building energy use, which solar water
  heating systems would reduce
• A typical system provides between 50 and 75 of
  the water needed yearly
• They can last over 40 years if made well

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How would it help me personally?

• Save hundreds of dollars on water heating bills
  (over time)
• Hedge against increasing energy prices
• Gain satisfaction in
• knowing you arent
• contributing as much
• to air pollution!

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Obstacles

• You must have a sunny location
• Installation costs are high
• If you live in an area with a lot of earthquakes
  or hurricanes there may be a limit to the weight
  or type of equipment installed on your roof.

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aipan.jpg
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Obstacles continued

• Keep in mind, there will be cloudy days. You
  would need a backup.
• Acidic water corrodes systems that circulate
  water
• They require parts that run on electricity
• Dont work well in climates that experience
  freezing temperatures for long periods of time

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Also

• Select systems that are tested and certified by
  the Solar Rating and Certification Corporation
  (SRCC).
• There should be about 10-15 square feet of solar
  panels for each person that lives in the house

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How it is installed

• Solar panels are normally installed on the roof.
• It is best to use them in places with as much sun
  as possible!
• The collectors should face south at approximately
  30 degrees.

http//www.tjsradiantheat.com/viessmann/images/fla
t_plate_collector.jpg
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Five parts

• 1. Solar Panels
• 2. A storage tank
• 3. A circulation system to move a fluid between
  the collectors to a storage tank

http//www.eere.energy.gov/consumer/images/active_
closed_loop_solar_wa.gif
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• 4. Backup heating system for cloudy days
• 5. Control system to regulate the overall system
  operation

http//www.solardepot.com/r_solar_hot_water.htm
http//www.solardepot.com/r_solar_hot_water.htm
http//www.solardepot.com/r_solar_hot_water.htm
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Direct system

• The domestic hot water is circulated directly
  from the storage tank into the collectors.
• There are two types of direct systems - draindown
  and recirculating.

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The Draindown System

• Has a valve that will take the water out of the
  collectors when the outdoor temperature reaches
  38 degrees (water will not freeze and bust the
  pipes)
• Drawbacks
• The draindown valves can fail, causing the
  expensive solar collectors to break. This is not
  uncommon as the valves arent used constantly.
• Mineral deposits in the collectors can reduce
  their efficiency.

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The Recirculating System

• Will pump heated water from the storage tank
  through the collectors when the temperature drops
  to 38 degrees
• Drawbacks
• Buildup is circulated from water heated from the
  storage tank
• A lot of energy is wasted with the cooling and
  heating of the water

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Indirect Systems

• Systems that use antifreeze fluids need to be
  inspected atleast every two years. Oil or
  refrigerant circulating fluids are sealed into
  the system and do not need to be maintained,
  although they are more expensive.

http//www.eere.energy.gov/consumer/your_home/wate
r_heating/index.cfm/mytopic12850
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The Drainback System

• Distilled water is the collector circulating
  fluid
• The collectors only hold water when the pump is
  operating. They collectors wont freeze at night
  or when the power goes out.
• This system is reliable and requires very little
  maintenance

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• Drawbacks
• The collectors must be mounted higher than the
  drainback tank/heat exchanger. This might not be
  possible if the collectors are mounted on the
  ground.

http//www.greenbuilder.com/sourcebook/HeatCool.ht
mlACTIVEDHW
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In-floor radiant heating systems

• Hot water is sent through pipes under the floor
  and heats the space.
• They are the most efficient
• the annual cost is about 30-40 less, but they
  are more expensive to install.

http//www.allaroundthehouse.com/lib.ghi.h4.htm
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Cost

• Cost of installation is high (1000-3000 or
  more) although operating cost is low.

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Negative environmental impacts

• Trees might have to be cut down if they are in
  the way of the sun

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Bibliography

• http//www.eere.energy.gov/de/solar_hotwater.html
• http//www.solardepot.com/r_solar_hot_water.htm
• http//www.greenbuilder.com/sourcebook/HeatCool.ht
  mlACTIVEDHW