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Northern Climate System Types

Northern Climate System Types. System Types. Active Uses a pump Passive Does not use a pump – relies on natural forces. Active System. A pump circulates heat transfer liquid through the collector. Solar collector. System types. Direct

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Northern Climate System Types

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  1. Northern Climate System Types

  2. System Types • Active • Uses a pump • Passive • Does not use a pump – relies on natural forces

  3. Active System A pump circulates heat transfer liquid through the collector.

  4. Solar collector

  5. System types • Direct • City potable (or well) water is circulated from the tank to the collector and back • For warm climates • Indirect • Fluid circulating through the collector never comes in contact with the city potable water in the storage tank • A heat exchanger is used to transfer heat from the circulating fluid to the potable water • For cold climates - freeze

  6. System types

  7. Available System Types • Active indirect using a differential controller and flat plate collectors • Active indirect drainback using a differential controller • Indirect thermosiphon

  8. Closer look at each system • What makes the system unique • Basic operation and components • Freeze prevention mechanisms • Maintenance requirements • Advantages and disadvantages of direct and indirect systems

  9. Thermosiphon System

  10. Thermosiphon System

  11. Thermosiphon System

  12. Thermosiphon System • Passive system • No pump or controller • Thermosiphon action • Simple, reliable system

  13. Thermosiphon System • Considerations + • Simplicity, ease of understanding by service personnel • Most common system internationally • Considerations - • Installation • Weight on roof • Heat transfer fluids – periodic check

  14. Active Indirect System

  15. Active Indirect System • Two types • Indirect using a • Heat exchanger • Differential controller • Anti-freeze solution • Indirect drainback using a • Heat exchanger • Differential controller • Drainage of fluid from collector

  16. Indirect Drainback • Key feature is that the heat transfer liquid in the collector and collector loop drains back into a drainback reservoir • When drained, there is no liquid in the collector to freeze

  17. Indirect Drainback • System includes a drainback reservoir • Also uses a differential controlled to regulate pump operation • Heat exchanger is also incorporated into the system. Can be: • Within the drainback reservoir • Within the solar tank • Collector and collector loop piping must be sloped to allow proper drainback

  18. Indirect Drainback

  19. Indirect Drainback Drainback reservoir

  20. Indirect Drainback • Freeze protection • All fluid drains from the collector and collector loop • Fail safe method but piping and collector must be sloped to allow complete drainage • In colder climates glycol is mixed with water for added freeze security

  21. Indirect Drainback • Considerations + • Positive freeze protection • Thermal energy from collector is conserved in drainback tanks – not lost in exposed collectors

  22. Indirect Drainback • Considerations – • Collectors have to withstand dry stagnation • Required elevation differences between collectors and drainback tanks • Higher collector loop pump capacity required • Collector and piping must be carefully installed to provide positive drain

  23. Indirect Pumped System

  24. Indirect Pumped System • Use where freezing is common • Anti-freeze heat transfer fluid • Heat exchanger • Internal or external • Expansion tank • Differential controller • Various valves

  25. Indirect Pumped System

  26. Indirect Pumped System • Considerations + • Freeze protection provided by anti-freeze fluid • glycols • Collector loop remains full and pressurized • Careful sloping of piping is not critical

  27. Indirect Pumped System • Heat transfer properties of antifreeze fluids inferior to water – reduced performance • Periodic maintenance required to ensure heat transfer fluid properties have not deteriorated • Collectors and antifreeze have to withstand stagnation when summer load is satisfied early in day • Venting through T-P valve under stagnation conditions • If excessive will require refilling of system to proper operating pressure

  28. System Certification • Systems installed should be certified to insure product safety and proper design • Florida Solar Energy Center (Florida) • www.fsec.ucf.edu • Solar Rating & Certification Corporation (National) • www.solar-rating.org

  29. Listing of Renewable Energy www.dsireusa.org DSIRE is a comprehensive source of information on state, local, utility, and federalincentives that promote renewable energy and energy efficiency.

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