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INSTALLER TRAINING COURSE
MODULE 1 BASIC SOLAR THERMAL
Introduction to SHW
 Earth Energy Resources
 US Solar Radiation
 Why Go Green
 Why SHW
SHW Technology
 SHW Components...
The mission of the Helio Partner program is to ensure that
Heliodyne installing contractors have acquired the knowledge
an...
Step 1. Successful completion of in person training or
completion of on-line training with 100% passing
score on the exam ...
Helio Partners will have added visibility on the Heliodyne
web site dealer locator. The Heliodyne logo will appear next
to...
BASIC SOLAR THERMAL
Solar Resources
BASIC SOLAR THERMAL
Programs, Legislation and other Support
• Higher fuel prices
• 30% federal tax credit
• Tax credits
• ...
BASIC SOLAR THERMAL
U.S. Solar Hot Water Industry Growth
14
INTRODUCTION TO SHW
EARTH ENERGY RESOURCES
Solar Energy
World Annual Consump.
Uranium
Gas
Oil
Coal
INTRODUCTION TO SHW
EARTH ENERGY RESOURCES
INTRODUCTION TO SHW
WHY SOLAR HOT WATER
IT’S SUITABLE FOR ALL REGIONS
SHW ( HELIODYNE) GOBI 410
Output/day: 22.7 kWh
Area:...
Introduction to SHW
 Earth Energy Resources
 US Solar Radiation
 Why Go Green
 Why SHW
SHW Technology
 SHW Components...
1. Collector
2. Controller
3. Pumps
4. Heat Exchanger
5. Storage Tank
6. Tempering Valve
7. Expansion Tank
8. Air Vent
9. ...
SHW TECHNOLOGY
COLLECTORS
THREE TYPES OF COLLECTORS
Unglazed Collectors
Vacuum Tube Collectors
Flat Plate Collectors
BASIC SOLAR THERMAL
Types of Thermal Collectors
Evacuated Tube Collectors
Flat –Plate Solar Collectors Unglazed Tube-mat C...
BASIC SOLAR THERMAL
Comparing Collector Technologies
Source:
Home Power magazine
SHW TECHNOLOGY
COLLECTORS
UNGLAZED COLLECTORS
PRO
 Easy to install
 Inexpensive  Short Payback period
CON
 No insulati...
SHW TECHNOLOGY
COLLECTOR
VACUUM TUBE COLLECTORS
PRO
 Works well at high temperature ranges > 220°F
 Good for high temper...
BASIC SOLAR THERMAL
Evacuated Heatpipe Technologies
28
The sealed tube contains a small
amount of alcohol which vaporizes
...
SHW TECHNOLOGY
COLLECTOR
FLAT PLATE COLLECTOR
PRO
 Simple and proven technology
 Low maintenance
 Highly durability
 H...
BASIC SOLAR THERMAL
Flat Plate Collector
30
Features:
• Extruded aluminum frame
• Copper or aluminum absorber
• Black pain...
SHW TECHNOLOGY
COLLECTOR ABSORBER VARIOUS SURFACES
BLACK PAINT
 Low cost solution
 Recommended for warm climates with hi...
BASIC SOLAR THERMAL
Residential Flush-Mount Arrays
32
BASIC SOLAR THERMAL
Residential Tilt-up Arrays
33
BASIC SOLAR THERMAL
Residential Ground Mounted Array
34
BASIC SOLAR THERMAL
Small Commercial Systems
35
BASIC SOLAR THERMAL
Larger Commercial Systems
36
BASIC SOLAR THERMAL
Data Monitoring
40
Types of monitoring
• Manually read gauges
• Controller with digital display
• Wire...
SHW TECHNOLOGY
CONTROLLERS
T1
T2
The controller senses the temperature in
the collector and the bottom of the
tank and sta...
SHW TECHNOLOGY
PUMPS
The pumps main function is to circulate
the liquid in the solar loop from the
collectors to the tank ...
SHW TECHNOLOGY
HEAT EXCHANGERS
THREE TYPES OF HEAT EXCHANGERS
Tube-In-Tube
Heat Exchangers
Brazed Plate
Heat Exchangers
Tu...
SHW TECHNOLOGY
HEAT EXCHANGER
TUBE HEAT EXCHANGER
Common tube heat exchanger
designs are coil-in-tank, tube in tube,
wrapa...
SHW TECHNOLOGY
HEAT EXCHANGER
PRO
 Relatively small in size
 Relatively inexpensive
 High efficiency
CON
 Big fouling ...
BASIC SOLAR THERMAL
Tanks with Heat Exchangers
46
SHW TECHNOLOGY
EXTERNAL VS. COIL-IN-TANK HEAT EXCHANGER
Heat Transfer Efficiency
External Coil-In-Tank
EXTERNAL HEAT EXCHA...
Stores the water heated by the
collector and is typically larger than
regular water heater to allow adequate
accumulation ...
The water in a solar storage tank can get
very hot (180 oF) so its important to regulate
the HW output temperature to prev...
SHW TECHNOLOGY
EXPANSION TANK
Design Considerations
Expansion tank should be designed upon a
ratio of the total volume of ...
Air valves are either manually operated
or automatic and is mounted in the flow
to allow air to escape. Air valves should
...
The pressure relief valve protects
system components from excessive
pressures. Used to control or limit the
pressure in th...
SHW TECHNOLOGY
TYPES OF SYSTEMS
Thermosyphon
Drain Back
Fully Flooded
(Indirect)
Fully Flooded
(Direct)
BASIC SOLAR THERMAL
Types of SHW Systems
• Open Loop Batch
• Non-freeze climates
• Lowest cost
54
SHW TECHNOLOGY
TYPES OF SYSTEMS
THERMOSYPHON
PRO
 No pump required
 No controller required
 Less space required
 Relat...
BASIC SOLAR THERMAL
Integrated Collector Storage (ICS)
(also called a batch collector system)
• Simple installation (few p...
BASIC SOLAR THERMAL
Chinese ICS Solar Water Heaters
57
SHW TECHNOLOGY
TYPES OF SYSTEMS
FULLY FLODDED (DIRECT)
PRO
 Simple and well proven technology
 Easy to install
 Cost ef...
SHW TECHNOLOGY
TYPES OF SYSTEMS
DRAIN BACK
PRO
 Provides overheating protection
 Protects collectors from freeze damage
...
SHW TECHNOLOGY
TYPES OF SYSTEMS
FULLY FLOODED (INDIRECT)
PRO
 Simple and well proven technology
 Easy to install
 Cost ...
Introduction to SHW
 Earth Energy Resources
 US Solar Radiation
 Why Go Green
 Why SHW
SHW Technology
 SHW Components...
BASIC SOLAR THERMAL
Hot Water Usage
TERMINOLOGY
SIZING SOLAR SYSTEM FOR DHW
SOLAR FRACTION (SFn) AND SIZING GUIDELINES
Hot Water Demand = Solar Energy + Aux H...
Space heating
requirements
of small low energy
house
Energyrequirementorgain(%)
Space heating
requirements
of large house
...
SIZING SOLAR SYSTEM FOR DHW
SIZING DEPENDENCIES
HOT WATER CONSUMPTION
 Load Type (Showers, Baths & hot tubs, Hot water ap...
Design Assumptions:
 Domestic hot water temperature  120°F
 Glazed flat plate collector with good efficiency
 Tilt ang...
SIZING SOLAR SYSTEM FOR DHW
SFn SENSITIVINESS TO COLLECTOR ORIENT.
Change the Orientation to Southeast or Southwest
SFn = ...
SIZING SOLAR SYSTEM FOR DHW
SFn SENSITIVINESS TO COLLECTOR TILT
Note
Min. tilt in mild areas is 10° to
ensure that rain wa...
SIZING SOLAR SYSTEM FOR DHW
SFn SENSITIVINESS TO GEOGRAPHICAL LOC
81
Design Assumptions:
 Base case
 Impact on SFn when ...
82
 SHW systems need full sunshine to operate at
peak performance
 Shading should be avoided at all times and in
particu...
Introduction to SHW
 Earth Energy Resources
 US Solar Radiation
 Why Go Green
 Why SHW
SHW Technology
 SHW Components...
AUXILIARY HEATING
PREHEATING
SRCC requires installation of isolation
valves to ensure that the solar system
can be taken o...
AUXILIARY HEATING
SINGLE TANK SYSTEMS
In a standard 2 element electric hot water
heater the bottom element should be
disco...
AUXILIARY HEATING
SINGLE TANK SYSTEMS
SHW SYSTEM WITH INSTANTANEOUS (ON DEMAND) WATER HEATERS
The solar storage is install...
AUXILIARY HEATING
SINGLE TANK SYSTEMS
Using a bottom fired gas water heater as a
solar storage tank with gas as a back up
...
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  • The annual amount of energy from the sun per ft2 in Alaska is the same as 2.5Gl of oil similar to what it is in Germany. Germany is the biggest solar hot water market in Europe.
  • Fossil fuels will not last forever Solar will
  • Source: www.oilposter.org
  • Brief description of how the SHW system works and outlining the components
  • Controlling the flow on each side of the heat exchanger makes the external heat exchanger with two pumps approximately 25% more efficient in transferring energy from the collectors to the tank
  • Transcript of "1. basic solar thermal training v3 robert cooley"

    1. 1. INSTALLER TRAINING COURSE MODULE 1 BASIC SOLAR THERMAL
    2. 2. Introduction to SHW  Earth Energy Resources  US Solar Radiation  Why Go Green  Why SHW SHW Technology  SHW Components  Different Types of SHW Systems Sizing Solar Domestic Hot Water System  Solar Fraction (SFn) and Sizing Guidelines  Sizing Dependencies  SHW Sizing  Other Factors Auxiliary Heating  Basic considerations  Preheating  Dual Tank Systems BASIC SOLAR THERMAL COURSE OUTLINE
    3. 3. The mission of the Helio Partner program is to ensure that Heliodyne installing contractors have acquired the knowledge and skills to effectively promote Heliodyne products, successfully install Heliodyne products, and to provide lasting customer support to end-users thereby representing the Heliodyne brand in the best possible way and in addition increase for the dealer: productivity, customer satisfaction, repeat sales and referrals. BASIC SOLAR THERMAL HELIO-PARTNER MISSION
    4. 4. Step 1. Successful completion of in person training or completion of on-line training with 100% passing score on the exam portion. Step 2. Submit to Heliodyne current copy of applicable contractor’s license and proof of liability insurance. Minimum: $1,000,000.00 Step 3. Complete successful installation of a Heliodyne Pro system with proof of performance through Heliodyne’s on-line web monitoring system. Step 4. Sign and return Helio Partner agreement. BASIC SOLAR THERMAL BECOMING A HELIOPARTNER
    5. 5. Helio Partners will have added visibility on the Heliodyne web site dealer locator. The Heliodyne logo will appear next to Helio Partner’s listing. Homeowners and business owners will be drawn to Helio Partners because they will know that partners have successfully completed training, have installed Heliodyne products, and carry adequate licensing and insurance. Helio Partners will receive preference in receiving leads and referrals that come from trade shows, advertising, and direct contact with Heliodyne. BASIC SOLAR THERMAL HELIOPARTNER BENIFITS
    6. 6. BASIC SOLAR THERMAL Solar Resources
    7. 7. BASIC SOLAR THERMAL Programs, Legislation and other Support • Higher fuel prices • 30% federal tax credit • Tax credits • Grants and cash rebates • Obama stimulus package Go to: www.dsireusa.org 13
    8. 8. BASIC SOLAR THERMAL U.S. Solar Hot Water Industry Growth 14
    9. 9. INTRODUCTION TO SHW EARTH ENERGY RESOURCES Solar Energy World Annual Consump. Uranium Gas Oil Coal
    10. 10. INTRODUCTION TO SHW EARTH ENERGY RESOURCES
    11. 11. INTRODUCTION TO SHW WHY SOLAR HOT WATER IT’S SUITABLE FOR ALL REGIONS SHW ( HELIODYNE) GOBI 410 Output/day: 22.7 kWh Area: 80 ft2 (2 panels) Installed Cost: $7,000 PV (SHELL SQ 165-PC) Output/day: 22.3 kWh Area: 456 ft2 (18 panels) Installed Cost: $30,000 Hawaii Alaska IT’S THE MOST COST-EFFECTIVE RENEWABLE WAY TO HEAT WATER Solar hot water systems perform efficiently all over the US, from Hawaii to Vermont, and Alaska to Florida.
    12. 12. Introduction to SHW  Earth Energy Resources  US Solar Radiation  Why Go Green  Why SHW SHW Technology  SHW Components  Different Types of SHW Systems Sizing Solar Domestic Hot Water System  Solar Fraction (SFn) and Sizing Guidelines  Sizing Dependencies  SHW Sizing  Other Factors Auxiliary Heating  Basic considerations  Preheating  Dual Tank Systems BASIC SOLAR THERMAL COURSE OUTLINE
    13. 13. 1. Collector 2. Controller 3. Pumps 4. Heat Exchanger 5. Storage Tank 6. Tempering Valve 7. Expansion Tank 8. Air Vent 9. Pressure Relief Valve 10. Auxiliary Energy 1 2 3 4 10 5 6 7 SHW TECHNOLOGY SYSTEM BASICS AND COMPONENTS 8 9 Heat transfer fluid is pumped through the collectors, heated by the sun and circulated to the heat exchanger. The fluid exchange heat to the water in the storage tank and returns to the collector to be reheated. This repeats as long as there is sun or until the tank is charged
    14. 14. SHW TECHNOLOGY COLLECTORS THREE TYPES OF COLLECTORS Unglazed Collectors Vacuum Tube Collectors Flat Plate Collectors
    15. 15. BASIC SOLAR THERMAL Types of Thermal Collectors Evacuated Tube Collectors Flat –Plate Solar Collectors Unglazed Tube-mat Collectors Integrated Collector Storage Collectors 24
    16. 16. BASIC SOLAR THERMAL Comparing Collector Technologies Source: Home Power magazine
    17. 17. SHW TECHNOLOGY COLLECTORS UNGLAZED COLLECTORS PRO  Easy to install  Inexpensive  Short Payback period CON  No insulation Efficiency sensitive to wind and ambient temperature  Low temperature range (75°F - 95°F )  Aesthetics  May be considered visually unpleasing  Low durability Unglazed collectors are typically made of plastic tubes combined into an absorber and used for residential pool heating to extend the pool season
    18. 18. SHW TECHNOLOGY COLLECTOR VACUUM TUBE COLLECTORS PRO  Works well at high temperature ranges > 220°F  Good for high temperature industrial applications CON  May be considered aesthetically unpleasing  Relatively higher maintenance  Sensitive to loosing vacuum  High installation complexity  Relatively expensive  Relatively fragileDouble wall glass tube with vacuum in between or a glass tube with a top seal and a pumped vacuum containing an absorber. The vacuum efficiently insulate the absorber minimizing collector heat loss and sensitiveness to wind and ambient temperature
    19. 19. BASIC SOLAR THERMAL Evacuated Heatpipe Technologies 28 The sealed tube contains a small amount of alcohol which vaporizes when heated and condenses when cooled
    20. 20. SHW TECHNOLOGY COLLECTOR FLAT PLATE COLLECTOR PRO  Simple and proven technology  Low maintenance  Highly durability  High Performance in Cold and Hot Climates  Cost-effective (More energy per Dollar)  Easy Installation CON  Relatively heavy to carry  Limited temperature range of up to 220°FConsists of an insulated weather sealed metal box containing the absorber and closed with a transparent cover typically made of tempered glass. Frame Glass Insulation Absorber
    21. 21. BASIC SOLAR THERMAL Flat Plate Collector 30 Features: • Extruded aluminum frame • Copper or aluminum absorber • Black paint or blue sputtering • Life expectancy of over 25 years • Rated by SRCC Installation: Weight: 120 - 160 lbs. full
    22. 22. SHW TECHNOLOGY COLLECTOR ABSORBER VARIOUS SURFACES BLACK PAINT  Low cost solution  Recommended for warm climates with high solar radiation α = 0.85 ε = 0.25 BLACK CHROME  First generation selective surface  Tough surface  Recommended for cool climates α = 0.95 ε = 0.12 BLUE SPUTTERED  State of the art technology  Optimal heat absorption with minimal emission  Suitable for all types of installations and regions  Recommended for cool climates α: Absorptivity  A measure of an object's ability to absorb incident energy ε: Emissivity  The ability of a material to hold or release heat α = 0.95 ε = 0.05
    23. 23. BASIC SOLAR THERMAL Residential Flush-Mount Arrays 32
    24. 24. BASIC SOLAR THERMAL Residential Tilt-up Arrays 33
    25. 25. BASIC SOLAR THERMAL Residential Ground Mounted Array 34
    26. 26. BASIC SOLAR THERMAL Small Commercial Systems 35
    27. 27. BASIC SOLAR THERMAL Larger Commercial Systems 36
    28. 28. BASIC SOLAR THERMAL Data Monitoring 40 Types of monitoring • Manually read gauges • Controller with digital display • Wireless remote monitoring • Web based monitoring
    29. 29. SHW TECHNOLOGY CONTROLLERS T1 T2 The controller senses the temperature in the collector and the bottom of the tank and start/stop the pump at various differential temperatures ∆T. Pump start setting is usually at 18°∆T, while pump stop setting is usually at 5°∆T. ∆T start/stop settings are different to avoid continuous start/stop of the pump Design Considerations Stagnation/Overheating Protection Provides high limit shut-off by turning off the pump when a preset tank temperature has been reached (Typically 180°F) Other Types  Timers  Differential pressure
    30. 30. SHW TECHNOLOGY PUMPS The pumps main function is to circulate the liquid in the solar loop from the collectors to the tank or heat exchanger and back into the collectors. Pumps in closed loop systems are usually fitted with a cast iron housing whereas pumps in open loops with direct contact to the portable water are fitted with bronze housing to avoid corrosion Design Considerations Pumps needs to cope with the desired static pressure of the system and overcome the pressure losses in the pipes, collectors and water heater and at the same time ensure an adequate flow rate in the solar loop Flow Rate The flow rate in a solar loop is typically set at 0.025 GPM per ft2 of collector Other Types  Variable Speed Pump Keeps a proper temperature in the collectors, while using minimum electricity
    31. 31. SHW TECHNOLOGY HEAT EXCHANGERS THREE TYPES OF HEAT EXCHANGERS Tube-In-Tube Heat Exchangers Brazed Plate Heat Exchangers Tube and Shell Heat Exchangers
    32. 32. SHW TECHNOLOGY HEAT EXCHANGER TUBE HEAT EXCHANGER Common tube heat exchanger designs are coil-in-tank, tube in tube, wraparound-tube and tube in shell. Heat transfer occurs when one fluid moves through the inner tube while a second fluid moves in a different direction on the outside of that tube. PRO  Low Flow Rate  Less Electricity  Not Costly To Operate  Fewer Joints  Low fouling factor  Good option for high SFn > 70%  Resistant to high pressure CON  Relatively big in size  Has to be insulated Primary feed Secondary feed Tubes Shell
    33. 33. SHW TECHNOLOGY HEAT EXCHANGER PRO  Relatively small in size  Relatively inexpensive  High efficiency CON  Big fouling factor  Thus, sensitive to water quality  Should not be used with SFn above 40%  Higher maintenance required FLAT PLATE HEAT EXCHANGER Composed of multiple, thin, slightly- separated plates that have very large surface areas and fluid flow passages for heat transfer. Can be more effective, in a given space, than the shell and tube heat exchanger
    34. 34. BASIC SOLAR THERMAL Tanks with Heat Exchangers 46
    35. 35. SHW TECHNOLOGY EXTERNAL VS. COIL-IN-TANK HEAT EXCHANGER Heat Transfer Efficiency External Coil-In-Tank EXTERNAL HEAT EXCHANGER Hot-water tank COIL IN TANK HEAT EXCHANGER
    36. 36. Stores the water heated by the collector and is typically larger than regular water heater to allow adequate accumulation of solar energy Design Considerations Proper tank stratification (hottest water on top, and coldest at the bottom) is important to have maximum solar hot water efficiency. Tall slim tank with a height equal to 3-4 times diameter is optimal. Choosing a copper or stainless steel tank over an enameled tank can lengthen the service life significantly but price is likely a factor 3-4. Enameled tanks are fitted with sacrificial anodes and if properly maintained can have a satisfactory service life. Solar storage tanks should have a proper insulation (min. R16) to minimize heat loss. SHW TECHNOLOGY STORAGE TANK
    37. 37. The water in a solar storage tank can get very hot (180 oF) so its important to regulate the HW output temperature to prevent scalding. The tempering valve can be set at different HW output temperatures and automatically mixes the hot solar water with the cold water inlet. Typical set temperature is between 120-140 oF SHW TECHNOLOGY TEMPERING VALVE Other Types  Anti-Scalding Valve Like the tempering valve it mixes hot and cold water to deliver water at a preset temperature but functionsalso as a safety valv by closing off the flow if the hot or cold mixing supply fails From Storage Tank From Cold Water Line To Fixtures M
    38. 38. SHW TECHNOLOGY EXPANSION TANK Design Considerations Expansion tank should be designed upon a ratio of the total volume of fluid in system and allow for total potential thermal expansion of fluid The expansion tank absorbs excess water pressure, and provides overpressure protection which could otherwise damage the plumbing structure or exhaust fluid through the pressure relief valve. Normally pre- charged by manufacturer to a set psi. DIAPHRAGM BLADDER Diaphragm Expansion Tank  Sensitive to correct install (Has to be in vertical position)  Relatively large in size Bladder Expansion Tank  The flexible bladder maintains a constant pressure on the fluid while allowing it to expand and contract as it heats and cools  Not sensitive to correct install  Smaller in size
    39. 39. Air valves are either manually operated or automatic and is mounted in the flow to allow air to escape. Air valves should be installed vertically in pipe air locks and/or at the highest point in the solar loop. Air locks will restrict flow of the fluid and reduce the heat transfer in the solar loop. SHW TECHNOLOGY AIR VENT Design Considerations Since air valves are typically installed at the collector return the fluid can be very hot (up to 430 oF when stagnating). The air valve thus needs to be compatibility with this temperature. Most standard automatic air valves jams after a few months which is fine since all the air is usually out by then. When refilling its recommended to replace the air valve. Other Types  Micro-bubble air vents
    40. 40. The pressure relief valve protects system components from excessive pressures. Used to control or limit the pressure in the system which can build up by a temperature upset. For solar loops its usually set at 125-150 psi. Offers a higher degree of reliability and is often required through regulations SHW TECHNOLOGY PRESSURE RELIEF VALVE Design Considerations Mandatory in closed solar loops and should have a pressure rating lower than other ratings of system components, typically 125 psi Other Types  Temperature-pressure relief valve Protects system components from excessive pressures and temperatures. Typically set at 150 psi and 210°F
    41. 41. SHW TECHNOLOGY TYPES OF SYSTEMS Thermosyphon Drain Back Fully Flooded (Indirect) Fully Flooded (Direct)
    42. 42. BASIC SOLAR THERMAL Types of SHW Systems • Open Loop Batch • Non-freeze climates • Lowest cost 54
    43. 43. SHW TECHNOLOGY TYPES OF SYSTEMS THERMOSYPHON PRO  No pump required  No controller required  Less space required  Relatively inexpensive CON  Tank exposed to external environmental condition  Efficiency Reduction  Aesthetics  May be considered visually unpleasing  Not suitable for cold climates  Strong support structure needed  Sensitive to poor water quality (scaling)  Not Scalable The thermosyphon system uses natural convection to circulate the liquid in a vertical closed-loop which allows it to operate without a pump or control. Tank will need to be positioned above the solar collector for the natural convection to occur
    44. 44. BASIC SOLAR THERMAL Integrated Collector Storage (ICS) (also called a batch collector system) • Simple installation (few parts) • Mild freeze protection available • Very economical • Good for the tropical climates 56
    45. 45. BASIC SOLAR THERMAL Chinese ICS Solar Water Heaters 57
    46. 46. SHW TECHNOLOGY TYPES OF SYSTEMS FULLY FLODDED (DIRECT) PRO  Simple and well proven technology  Easy to install  Cost effective  Moderately scalable CON  Pump and controller required  Not applicable in climates with temperatures below 42oF  Sensitive to poor water quality (scaling) The heat transfer fluids in the solar loop stays fully flooded. In warm regions the heat transfer fluid is typically the portable water coming directly from the storage tank or water heater.
    47. 47. SHW TECHNOLOGY TYPES OF SYSTEMS DRAIN BACK PRO  Provides overheating protection  Protects collectors from freeze damage CON  Requires drain back reservoir  Can be more complicated to install  All pipes and collectors have to drain back to reservoir  Limited to maximum height of pump  Limited Scalability The heat transfer fluid in the collector loop drains into a tank or reservoir whenever the solar pump stops. When drained the system is protected from overheating. In cold climates with freezing, potable water can be used in the collectors as they drain at night or when there is no sun
    48. 48. SHW TECHNOLOGY TYPES OF SYSTEMS FULLY FLOODED (INDIRECT) PRO  Simple and well proven technology  Easy to install  Cost effective  Easily scalable CON  Pump and controller required  Care need to be taken to avoid freeze damage  System sizing is critical to avoid overheating The heat transfer fluids in the solar loop stays fully flooded. In cold regions the heat transfer fluid is typically an antifreeze such as propylene glycol to avoid freeze damage to the collectors. As such the heat transfer from the solar loop to the storage tank is done indirectly using a heat exchanger
    49. 49. Introduction to SHW  Earth Energy Resources  US Solar Radiation  Why Go Green  Why SHW SHW Technology  SHW Components  Different Types of SHW Systems Sizing Solar Domestic Hot Water System  Solar Fraction (SFn) and Sizing Guidelines  Sizing Dependencies  SHW Sizing  Other Factors Auxiliary Heating  Basic considerations  Preheating  Dual Tank Systems BASIC SOLAR THERMAL COURSE OUTLINE
    50. 50. BASIC SOLAR THERMAL Hot Water Usage
    51. 51. TERMINOLOGY SIZING SOLAR SYSTEM FOR DHW SOLAR FRACTION (SFn) AND SIZING GUIDELINES Hot Water Demand = Solar Energy + Aux Heating Consumption Production Solar Fraction Considerations  SFn of 100% will overheat and create problems in the summer season  An undersized system will not provide a feasible rate of return on investment A SFn of around 60-80% is optimal Solar Energy Hot Water Demand Aux Energy Hot Water Demand Solar Energy Aux Energy SFn = Solar Energy Hot Water Demand
    52. 52. Space heating requirements of small low energy house Energyrequirementorgain(%) Space heating requirements of large house DHW requirements Solar yield from 160 ft2 collectors Solar yield from 54 ft2 collectors
    53. 53. SIZING SOLAR SYSTEM FOR DHW SIZING DEPENDENCIES HOT WATER CONSUMPTION  Load Type (Showers, Baths & hot tubs, Hot water appliances)  Patterns (Morning/Night peaks vs. continuous consumption)  Users (Number of people living in the household) OTHER FACTORS  Shading (Trees, Buildings)  Space Limitations COLLECTOR  Tilt of the collector  Orientation in relation to due south  Collector efficiency LOCATION  Solar Radiation (Intensity)  Climate (Clouds, Fog, etc)  Seasonal Variations (Sun path during seasons, Day Vs. Night)
    54. 54. Design Assumptions:  Domestic hot water temperature  120°F  Glazed flat plate collector with good efficiency  Tilt angle  35° (Optimum)  Orientation  Due South (Optimum) SIZING SOLAR SYSTEM FOR DHW SHW SIZING TO VARIOUS HW LOADS SFn = 58.6% Sizing Storage Capacity  1.5 Gl/ft2 of Collector up to  2.0 Gl/ft2 of Collector Sizing Collector Array  10 ft2/Pers: Low Hot Water Demand (15 Gl/Pers)  12 ft2/Pers: Average Hot water Demand (20 Gl/Pers)  14 ft2/Pers: High Hot Water Demand (25 Gl/Pers) Example: Base case (used in following slides)  4 Person Household  Average Consumption (20 Gallons/Person)  GOBI glazed high selective absorber  Location: Boston, MA. Sizing:  Array: 4 x 12 = 48 ft2  2 GOBI 406  Storage: 48 x 1.5 = 72 Gl  80 Gl
    55. 55. SIZING SOLAR SYSTEM FOR DHW SFn SENSITIVINESS TO COLLECTOR ORIENT. Change the Orientation to Southeast or Southwest SFn = 56.5%  Base case SFn of 58.6% Minor deviations from a due south collector orientation does not have a significant impact on Solar Fraction 79 Design Assumptions:  Base case  Impact on SFn when changing collector orientation to Southeast/Southwest  Impact on SFn when changing collector orientation to East/West Change the Orientation to East/West SFn = 41.0% compared to Base case SFn of 58.6% Significant deviations from due south will require a relative larger collector array from base case. A factor 2 on East/West orientations provides an adequate SFn. Storage capacity should be calculated as if collectors were due south, however, using 2 Gl/ft2
    56. 56. SIZING SOLAR SYSTEM FOR DHW SFn SENSITIVINESS TO COLLECTOR TILT Note Min. tilt in mild areas is 10° to ensure that rain water drains off the collector. In cold, snowy regions min. tilt is 30° to avoid heavy snow loads on the glass 80 Design Assumptions:  Base case  Impact on SFn with a collector tilt of +/- 20%  Impact on SFn with a collector tilt of 10 o or 90 o Change the Collector Tilt to 28 o or 42 o SFn = 52%  Base case SFn of 58.6% Minor deviations from an optimum tilt of 35 o does not have a significant impact on the SFn Change the Collector Tilt to 10 o or 90 o SFn (10 o )= 43.0% and SFn (90 o )= 31.0% compared to Base case SFn of 58.6% Significant deviations from optimum tilt will require a relative larger collector array from base case. A factor 2 on 10 o or 90 o provides an adequate SFn. Storage capacity should be calculated as if collectors were due south, however, using 2 Gl/ft2
    57. 57. SIZING SOLAR SYSTEM FOR DHW SFn SENSITIVINESS TO GEOGRAPHICAL LOC 81 Design Assumptions:  Base case  Impact on SFn when changing geographical location further north  Impact on SFn when changing geographical location to a mild region  Impact on SFn when changing geographical location to a tropical region Change the Geographical location to Vermont (White River Junction) SFn = 50%  Base case SFn of 58.6% Minor correction to collector array required especially if orientation and/or tilt is also slightly off Change the Geographical location to California (San Francisco) SFn = 66%  Base case SFn of 58.6% No corrections needed Change the Geographical location to Hawaii (Honolulu) SFn = 84%  Base case SFn of 58.6% Solar fraction is on the high side and could cause over heating problems. Changing the collector absorber surface from high selective to black paint would be beneficial
    58. 58. 82  SHW systems need full sunshine to operate at peak performance  Shading should be avoided at all times and in particular between 10 am – 2 pm SIZING SOLAR SYSTEM FOR DHW OTHER FACTORS  Take in consideration deciduous roof structure, and shading (trees, chimneys, etc)  Roof conforms to current building codes for loading Sun Path Roof Structure
    59. 59. Introduction to SHW  Earth Energy Resources  US Solar Radiation  Why Go Green  Why SHW SHW Technology  SHW Components  Different Types of SHW Systems Sizing Solar Domestic Hot Water System  Solar Fraction (SFn) and Sizing Guidelines  Sizing Dependencies  SHW Sizing  Other Factors Auxiliary Heating  Basic considerations  Preheating  Dual Tank Systems BASIC SOLAR THERMAL COURSE OUTLINE
    60. 60. AUXILIARY HEATING PREHEATING SRCC requires installation of isolation valves to ensure that the solar system can be taken out for service without interrupting the hot water supply. Tempering valves are typically installed between the two tanks to prevent the HW high temp limit fuses to blow if the solar water is too hot. Electrical The solar storage tank is installed in the supply line to the water heater (WH) preheating the water. If the solar supply temperature is above the WH set temperature the heating element will not come on. If not it will heat the water to the desired hot water temperature as normal. The solar controller and the WH controller operates independently Gas Design Considerations SHW SYSTEM WITH ELECTRICAL OR GAS WATER HEATERS
    61. 61. AUXILIARY HEATING SINGLE TANK SYSTEMS In a standard 2 element electric hot water heater the bottom element should be disconnected. The top element can be connected to power and can serve as an auxiliary heater for the top third of the storage tank The top element will reheat the top of the tank irrespectively of possible solar gains. Collector feed tube connects to cold water supply. Collector return tube should ideally exhaust below heating element separately from the hot water supply line to ensure that cold or luke warm water from the solar system does not feed directly into the hot water supply. SHW SYSTEM WITH ELECTRICAL BACKUP Design Considerations The electric heating element functions as back-up when solar energy is not available or when hot water demand exceeds the solar-heated supply Solar Heat Transfer Appliance
    62. 62. AUXILIARY HEATING SINGLE TANK SYSTEMS SHW SYSTEM WITH INSTANTANEOUS (ON DEMAND) WATER HEATERS The solar storage is installed in the supply line to the on demand heater. If the temperature is above the WH set temperature, the on demand heater will not come on. If it isn't, the WH will heat the water to the desired hot water temperature as normal. The solar controller and the on the demand controller operates independently On demand heater has to be designed for high water inlet temperature coming from the solar system. If it can’t, it’s recommended to install an automatic temperature sensitive by pass valve around the on demand heater. The on demand heater has to be modulating i.e. heating to a preset hot water output temperature only. Standard incremental heating is not recommended. Design Considerations
    63. 63. AUXILIARY HEATING SINGLE TANK SYSTEMS Using a bottom fired gas water heater as a solar storage tank with gas as a back up requires an electrical ignited burner which can be connected to a solar controller priority relay or the normally open terminal on relay #2 on the Heliodyne Delta T Pro controller. A pilot flame burner does not work. SHW SYSTEM WITH GAS BACKUP The solar heat transfer appliance is connected directly to the gas water heater provided it has the required storage capacity. SolarHeatTransfer Appliance Design Considerations
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