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Making Solar Simple Solar Thermal History in North America 1891 – First patented solar water heating device 1900s – Regional growth in sunny areas 1920s – LA Natural gas discovery ended California market – 1920s – LA Natural gas discovery ended California market – 1941 ‐ Half of Miami homes had Solar Water Heaters, then low electric rates withered market 1974 and 1979 – Arab oil embargos 1974 d 1979 A b il b Rapid growth replaced conventional energy sources Government subsidies fueled boom 200+ solar panel manufacturers 1986 – Cheaper fossil fuel, ceasing of subsidies, inferior equipment lead to end of “first” solar era By 1995 – Most systems failed, were abandoned, or were removed removed 2 Seasonal Effects of Sun’s Energy 3 70% of Solar Energy Comes from the Middle 6 Months Average Daily Solar Energy Striking Solar Panel 60,000 14% 14% 14% 50,000 12% 12% 40 000 40,000 10% 10% 9% BTUs 8% 30,000 6% 6% 6% 20,000 4% 4% 3% 10,000 10 000 ‐ US Solar Map 63% 73% 61% 102% 98% 100% 112% 96% 86% Colorado’s solar resource: The short answer: It is really, really good! Average Daily Solar Radiation Btu/sqft day Btu/sqft*day 45 deg panel tilt, Hay and Davies model 6 Solar Demand Comes From All Regions R i 7 Technology Overview Technology Overview • Passive Solar Heating ‐ easy, beautiful, elegant • Solar Hot Water – heating and hot water “Thermal” measured in “ ” “ h “ h l” ” d “Btu” or “therms” electricity • Photovoltaics – electricity “PV” measured in “kilowatt hours” • Synergistic Effects – working together Passive Solar Space Heating In Winter: Sun shine enters through south windows warming space In Summer: Roof overhang limits solar g gain Doesn’t incorporate fans or circulators 9 Solar Thermal Diagram From http://powertomorrow.com Active Solar Thermal Systems Active Solar Thermal Systems Flat Plate Incorporate a pump to move liquid through system. li id th h t Use either: E t d Tube Pl t Evacuated T b Plate “flat plate collector” or “evacuated tube collector” 11 • Collect Store • St • Move • Control Slide 12 A1 Author, 8/19/2009 Active Solar Thermal Systems Jenni Energietechnik AG 13 Active Solar Systems Caleffi Lab ‐ Italy 3 Categories of Active Solar Thermal Panels Low Temperature Panels Swimming Pools Medium Temperature Panels Hot Water Heating oday s ocus Today’s Focus Space Heating High Temperature Panels Hi h T P l Industrial and Chemical processing 15 Solar Swimming Pool Panels 16 Flat Plate Collectors Most common collector in North America Absorber plate is principle p component Made of copper sheet and tubing “Selective surface” absorbs majority of solar radiation 17 Flat Plate Detail 18 Evacuated Tube Collectors Glass tubes with concentric inner and outer walls Acts like a Thermos bottle Coated copper absorber plate in inner glass Specialized fluid sealed within 19 Typical Evacuated Tube Heat Transmitter T i Critical detail to transfer heat 20 Flat Panel versus Evacuated Tube Which Performs Better? Factors Freeze Protection Method Used Shipping, Handling and Installation Ease Heat Load: Space Heating or Hot Water? Roof Area Requirements Maintenance Requirements Ability To Shed Snow Cost of Equipment Thermal Efficiency 21 Flat Plate Evacuated Tube • More efficient in temperate • More efficient in very cold, climates cloudy climates • Can be architecturally • Can produce higher water integrated into roofs more temperature – space easily heating advantage • When sloped 40 deg or • Must use antifreeze solution more, sheds snow sooner because of manifold design • Less expensive • Components are • L Longer design track d i t k assembled on site record for durability • Glass requires extra g handling care 22 Wet, Sticky Snow, Overcast Conditions C diti Courtesy Solar Skies Mfg. 23 23 Hours Later Courtesy Solar Skies Mfg. 24 24 Needs to Be Cleaned Off Evacuated tubes days after snowfall 25 email@example.com 26 g Orientating Solar Panels Ideal orientation is true south g generally results in less “Plus or minus 30 degrees” g y than 5% energy penalty Adjustment compass reading for “magnetic declination” 27 g g Solar Panels are Forgiving for Pitch Plus or minus 15 Degrees Results in Only 5% Penalty 28 Graph courtesy of Solar Skies Mfg. LLC, Minneapolis, Minnesota Ground Mount Array Ground Mount Array 29 Photo courtesy of Hot Water Products y Ground Mount Array 30 Photo courtesy of Hot Water Products Collectors- Flat Plate Collectors- Ground Mounted 31 Cedar Mountain Solar Santa Fe, New Mexico Awning Mount Awning Mount Photo courtesy of Hot Water Products 32 Flat Plate - Vertical Wall Mounted Cedar Mountain Solar 33 High Tilt for Space Heating 34 Ground Mount With Air Conditioner 35 Photo courtesy of Hot Water Products Reverse Pitch Mounting Beaver Brothers NC 36 Commercial SDHW Commercial SDHW 37 Photo courtesy of Hot Water Products Freeze Protection Methods y All active solar systems in the US and Canada should employ freeze protection “Manual draining” should be used only when freezing is extremely only when freezing is extremely rare 38 Drain back System Drain back System 39 Radiant Engineering, Bozeman, MT Gravity Drainback Systems i b l t l th t th ll t d ll d i i be it h d It is absolutely necessary that the collectors and all exposed piping b pitched a minimum of 1/4 inch per foot toward the storage tank for complete drainage. Entire collector array is sloped “Closed‐Loop Drain back” Freeze Protection Water from collect or drains automatically when collector automatically when collector is not collecting energy Relies on gravity and proper pitching of collectors and piping Anti freeze is not needed Anti‐freeze is not needed (however, some choose to anyway for extra protection) 41 “Closed Loop Glycol” Freeze Protection Uses anti‐freeze A heat exchanger transfers heat to t i t t k water in storage tank The majority of installers prefer over installers prefer over “drain back” protection 42 Glycol 40/60 Mix 43 Basic System Configurations 3 sizes: 1 Panel‐ Target 1 to 2 person household Ave 15,000 BTU harvested/day 2 Panels‐ Target 2 to 4 person household Ave 27,000 BTU harvested/day 3 Panels‐ Target 4 to 6 person household Ave 40,000 BTU harvested/day Sized to reduce energy costs 45% to 90% (depending on North American region) 44 Software for System Sizing, Performance…and Return on Investment! •RET Screen www.retscreen.net •F-Chart www.fchart.com •Maui Solar www.mauisolarsoftware.com •Tsol www.valentin.de 45 Configuration #1 Back- Storage Tank Electric Element Serves as Back-Up Heat Source (Optional Accessory) 46 Configuration #2 Storage Tank Feeds Dedicated Hot Water Heater (Optional Accessory) 47 Configuration #3 Back- Boiler Is Used For Back-Up Heat (Optional Accessory) 48 Remember, Always Use Thermostatic Mi i Valve! Mixing V l ! 49 firstname.lastname@example.org 50 email@example.com 51 Boulder, CO 4 person household with hot water heater Ave Daily HW Consumption = 80 gallons Ave Incoming Cold Water Temp = 46.7 degrees HW Temp Delivery= 120.0 degrees / Daily energy delivery = 8.33x80x(120‐46.7) 48,847 BTU /day Daily energy consumption (assuming 3% storage loss) yields 50 312 BTU /day 50,312 BTU /day Two panel Caleffi System produces 32,200 BTU / day solar energy Solar fraction = 32,200 / 48,847 = 64% How much money does, this save customer? 52 Since 2002, Average Annual Inflation: Electricity 3% y 10% increase projected for 2008/09 heating season! Source http://www.eia.doe.gov/steo Oct 2008 Update 53 Since 2002, Average Annual Inflation: Propane 15%, Heating Oil 22% p , g Source http://www.eia.doe.gov/steo Oct 2008 Update 54 Since 2002, Average Annual Inflation: Natural Gas 11% Source http://www.eia.doe.gov/steo Oct 2008 Update 55 Incentive Effect Example I i Eff E l -- 2 Panel Solar System g -- SRCC Rating 50,000 Btu 56 Energy Savings Analysis Average Daily Solar Harvest= 27,945 BTU/day Annual Avoidance = 27,945 * 365= 10,199,125 BTU 57 Solar Fraction Varies By Region 58 y p y The Fallacy of Simple Payback • It’s good for comparison (only!) g • It ignores inflation rate • It doesn’t look at lifetime • It ignores “afterwards” Payback Time Initial Cost Incremental Savings Solar Thermal Federal Income Tax Credits Credits Extended Through Year 2016 Residential Installation 30% of installed cost No cap on credit amount Commercial Installation 30% of installed cost No cap on credit amount 60 More Incentives More Incentives Solar grants for low and moderate income • Solar grants for low and moderate income families Utilities rebates on PV, sales and use tax • Utilities rebates on PV sales and use tax incentives Climate Smart loan program • Cli S l 61 OG- SRCC Label Certifying to OG-100 Standard Standard 62 Flat Panels Are Very Durable 63 Locating Rafters Electronically 64 Drill Stainless Steel Anchor Bolts Into Rafter B lt I t R ft 65 Threaded rod, cross block Threaded rod, cross block 66 L bolt under rafter L bolt under rafter 67 Close Ups Of Mounting Hardware 68 Stainless Steel Hardware 69 Panel To Panel Union 70 Roof Pitch Gauge 71 Adjusting Panels to Proper Pitch 72 Ideal Solar Panel Pitch Ideal Solar Panel Pitch • For Solar Water Heating Set –Set at local latitude (from horizontal) –Make the pitch at least 40 degrees in snowfall climates For Space Heating • For Space Heating –Set at local latitude + 15 degrees 73 Tilt Brace Assembled 74 75 76 77 Solar Flex In PVC Sleeve ‐ Attic View 78 Splitting Solar Flex 79 g g Solar Flex Through The Building 80 Procedure: Setting System Pressure • Set to accomplish 20psi at top of solar panels • Procedure: – For every floor level between solar panel and storage tank top, add 5 psi – Example: Tank i i basement and panels are on • T k is in b t d l roof of one story home. • Set pressure to = 20 psi + 5 psi/floor * 2 floors = 30 psi fl i • Adjust expansion tank pressure to equal the y p system pressure Spin off 81 Flow Setter Reading For flow above 4 GPM, read from bottom of impeller indicator Shows 2.0 GPM 82 g Procedure: Setting Flow Rate • Desired Flow Rate Value: – For one panel system: 1.5 GPM – For two panel system: 2.0 GPM – For three panel system: 3.0 GPM Open balancing valve full open and set pump speed to • O b l i l f ll d d lowest setting Adjust controller to manual on to activate pump • Adjust controller to “manual on” to activate pump • If flow rate is greater than desired value, use balancing valve to adjust back to desired value • If flow rate is less than desired value, set pump to second (or third if needed) speed setting and adjust back to desired value. back to desired value. 83 • g g Procedure: Purging Air 1) Open air vent ball valve on solar panel 1) Open air vent ball valve on solar panel – You will likely hear air being expelled from air vent • 2) Manually open air vent located in pumping station – Air should also expel. When fluid begins to expel, close vent. • 3) Within the next few days after fluid heats: Repeat step 2) above after manually turning on – R t t 2) b ft ll t i pump. When only fluid expels when manual vent is opened, system air has been sufficiently removed. Check that pressure hasn’t changed. – Close air vent ball valve on solar panel. The air vent is no longer needed and can be removed if desired for aesthetic purposes. 5) Repeat step 2) approximately every 12 months and expel any • 5) Repeat step 2) approximately every 12 months and expel any trapped air. Check pressure gage to ensure pressure hasn’t dropped below desired level. If so, re‐pressurize system to maintain optimal performance. 84 Pump Speed Control Operating Sequence • Pump automatically adjusts speed based on the heat gain in the panel. The faster the heat gain, the faster the pump speed. –Optimizes thermal transfer efficiency in the tank p –Minimizes electrical consumption. • Sequence (starting at night with a cooled tank) • Sun starts to rise. Delta T reaches 12F. • seconds, Pump activates to 100% speed for 10 seconds then drops to 40% • If Delta T rises to 20F, speed increases to 50% • If Delta T rises to 24 F, speed increases to 60% • This process continues – pump speeds up and slows down based on Delta T. • Once Delta T drops below 8F, pump turns off. 85 Built In Heat Protection Operating Sequence Operating Sequence • Heat transfers from panel to tank until tank temperature reaches 140 F. Pump then becomes temporarily disabled even though panel temperature may continue to climb though panel temperature may continue to climb • If panel temperature rises to 250 F, the pump activates, cooling the panel. Tank temperature may rise above 140 F t il temporarily. • If either the panel temperature reaches 285 F, or the tank temperature reaches 203 F, the system shuts down (stagnates) and the control flashes. Under prolonged (t t ) d th t l fl h U d l d “stagnation” states, the antifreeze properties can degrade. • Pump will re‐energize when panel temperature cools below 285 t kt t l b l 203 285, or tank temperature cools below 203. • Annual glycol ph checks are recommended to detect stagnation occurrence. 86 87 Differential Temperature Controller is “The Brains” Monitors two temperatures When collector temp exceeds storage tank temperature by about 12 F, pump circulates When temperature difference falls to about 8 F, controller turns pump off Frequency of energizing cover, wind, depends on cloud cover wind shading, energy consumption 88 y p Yearly Check‐Ups • System pressure check, glycol property check, and air purge should be performed every year to ensure adequate p performance. • Record any glycol adjustments on glycol tag provided. 89 Solar Interest is Not Exclusive to Just the Affluent! firstname.lastname@example.org 91 email@example.com 92 Solar Thermal and PV 93 Solar Thermal and PV 94 Thanks for considering solar!!
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