solar water heating by solar texas. two basic types open loop – household water is circulated...
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Solar Water HeatingSolar Water Heatingby Solar Texasby Solar Texas
Two Basic TypesTwo Basic Types
• Open Loop – Household water is circulated through the collectors and gains heat directly from the sun.– Subject to damage from freezing
• Closed Loop – Heat transfer fluid/heat exchanger– More complex– Good freeze protection
Solar Water Heating in TexasSolar Water Heating in Texas
• Solar Texas recommends Closed Loop systems almost throughout Texas.
• Closed Loop systems use a Closed Loop systems use a heat exchange fluid to transfer heat exchange fluid to transfer heat from the sun to a heat from the sun to a separate water storage separate water storage system. system.
• Main benefit: Freeze Main benefit: Freeze protection.protection.
Solar
Loop
Household
Water
Heat Exchanger
StorageStorage
System TypesSystem Types
1. Batch Water Heating1. Batch Water Heating
2. Integrated Collector and Storage (ICS)2. Integrated Collector and Storage (ICS)
3. Passive or Thermosiphon (no pumps)3. Passive or Thermosiphon (no pumps)
4. Active (pumps)4. Active (pumps)
For Diehard Enthusiasts
Recommended
Closed Loop PassiveClosed Loop Passive
• Good performance and storage.
• No pumps, controllers or electronics.
• Standalone system (has integrated backup).
• Can cope with light to short moderate freezes.
• Storage tank must be positioned above collectors.
Closed Loop PassiveClosed Loop Passive
How Does it Work?How Does it Work?• Sun shines on fluid in collectors
• Cooler fluid descends to bottom of collectors
• Transfers heat to the household water
• Warmer fluid in collectors rises and proceeds to a jacket around the household water, and
If the Storage Tank is Moved from Position Above Collectors…
If the Storage Tank is Moved from Position Above Collectors…
• Thermosiphon process won’t work
• Pump/s must be incorporated to move the heat transfer fluid
• Temperature sensors and a controller must be included to activate the pump/s when heat is available
• This is an ACTIVE system
Active DrainbackActive Drainback• Excellent long term
operation
• Excellent freeze protection
• Failsafe with power loss
• High temp limited
• Double pump system – Double pump system – mainly retrofitsmainly retrofits
Active DrainbackActive Drainback
• Collector on roof.
Flow
Active DrainbackActive Drainback
• Storage tank, drainback reservoir with internal heat exchanger.
Retrofit to a 50 Retrofit to a 50 Gallon electric Gallon electric water heater.water heater.
Active DrainbackActive Drainback• Requires care in
installation
• Takes up a little more space than most SHW’s
• Owner can provide basic maintenance
• Single pump system Single pump system
Active PressurizedActive Pressurized• Excellent freeze
protection
• Flexible in site requirements
• Specialized installation equipment
• Can be problem with power blackouts
Solar TexasSolar TexasP.O. Box 840P.O. Box 840
Helotes, TX 78023Helotes, TX 78023
Ph. (210) 669-2504Ph. (210) 669-2504
Web: www.soltx.comWeb: www.soltx.com
Email: [email protected]: [email protected]