AIA - In The Mix Solar Domestic Hot  Bob Ramlow  Midwest Renewable Energy Association Co- founder, BOD member, Workshop instructor  Wisconsin Focus on Energy Solar Thermal Technical Lead  Artha Sustainable Living Center 

Solar Water Heating Greetings! Overview  What do they do?  How do they work?  Building design impact  Benefits  Solar Economics

Solar Water Heaters  Preheat incoming water using free energy  Can provide up to 75% of annual domestic hot water  Require back-up water heater

Water Basics  Water expands when it freezes  Hard water can be hard on your system

Types of Collectors Evacuated Tube  Moderately high temperature collector  Collector design varies by manufacturer  Some tubes have moving parts  Glass tubes are fragile  Do not shed snow and frost as well as flat plate collectors

Types of Collectors Flat Plate  Proven Technology  Durable  Temperature operating range perfect for SDHW & space heating  Collectors shed snow  Repairable  Competitively priced

System Types Drainback  Drainback Advantages can withstand moderate freezing conditions not affected by hard water uses distilled water as the heat transfer fluid – most efficient and no fluid degradation virtually maintenance free can be part of a combination system versatile installation options using flat plate collectors Disadvantages can be damaged under severe freezing or snowy conditions require careful pipe installation require a high-head pump and a vertical distance between the collectors and the reservoir of less than 25 feet

System Types Drainback

System Types Closed Loop Antifreeze  Antifreeze Advantages not affected by freezing conditions not susceptible to mineral buildup from hard water no limit to the distance between collectors and storage can be PV powered has most installation options proven technology virtually maintenance free most systems have only one or two moving parts can be part of a combination space heating/domestic water heating system Disadvantages cost slightly more than other systems slight loss of efficiency due to heat transfer fluid fluid degradation under extended stagnation

System Types Closed Loop Antifreeze

Site Assessment Defining the Solar Window  Shortest day of the year December 21 st  Longest day of the year June 21 st  Solar collectors need full sun from 9 AM until 3 PM (FOE 10-2)

Site Assessment Solar Window Illustration

Site Assessment Installation Location Considerations  Access  Tree Growth  Distance from House or Collectors  Balance of System (BOS) Placement  Pipe Runs  PV Powered Pumps  Aesthetics  Neighbors  Future Construction  Topography  Roof Condition

Site Assessment Collector Mounting

Site Assessment Collector Mounting – Roof Mount  Advantages and Disadvantages of roof mounting  Advantages and Disadvantages of ground mounting

Site Assessment Collector Tilt  Collector tilt is the angle the surface of the collector makes with the horizon.  Fixed array  Tilt and latitude  Roof pitch and collector tilt

Site Assessment Collector Tilt Roof Pitch Tilt Angle 0:12 0° 1:12 5° 2:12 10° 3:12 14° 4:12 18° 5:12 23° 6:12 27° 7:12 30° 8:12 34° 10:12 40° 12:12 45° 14:12 49° 16:12 53° 18:12 56° 20:12 60° System UseTilt Angle 45° latitude Domestic hot water Year-round usage Latitude45° Domestic hot water Summer use only Latitude - 10° 35° Space Heating/ Domestic hot water combination Latitude + 15° 60°

System Sizing Sizing Design  Should not design a system to cover the entire annual load  Aim for 75% 100% of summer load and 50% of winter load  Check for weather irregularities at the site

System Sizing – First Step Energy Efficiency and Load Reduction Take quick showers instead of baths. Install low-flow shower heads or use a flow restrictor. Lower the thermostat to between degrees Fahrenheit. You don’t need water hotter than that. Wrap the back-up water heater in insulation if it is in an unheated area. Use cold water with the garbage disposal. Cold water solidifies grease so the disposal can get rid of it more effectively. When washing dishes in the sink by hand, don’t let the water run while rinsing. Fill one sink with wash water and the other with rinse water. Soak pots and pans instead of letting the water run while you scrape them clean. Whenever possible, wash only full loads. If your washer has a water selector, use the lowest practical level. Install covers on pools and spas. Insulate all of your hot pipes. Upgrade your appliances: Energy efficient and low water use dishwashers and front loading washing machines save a lot of hot water. Turn of the water while you shave.

System Sizing Simple Sizing Using Flat Plate and ICS Collectors  Work backwards: Consumption of 20 gal/day Need 20 gal/day of storage Need certain ratio of collector area to storage Need 20 ft 2 of collector to heat 20 gallons of water (in Wisconsin)  Alter simple figure according to: Household’s water consumption habits Size of household Geographic location and amount of solar radiation System type

System Sizing Simple Sizing Chart Number of People In Household Type of System Closed loop antifreeze or Drain-back Cool Climate 1-4’x10’1-4’x10’ or 2- 4’x8’ 2-4’x8’2-4’x10’3-4’x8’3-4’x10’ ’

System Sizing Sizing Using Computer Modeling Software  Three primary inputs Hot water load Meteorological data for the site Solar collector efficiency  Sizing evacuated tube collectors

Free Sizing and Economic Analysis Software  RETScreen International  Free Download from Canadian Government   Solar water heating module  Notes on the program:  Set security level to medium when downloading  Enable “macros” when running program  Some figures in metric  PC only at this time

Solar Ready  Install 2 - 3/4” copper pipes from attic to basement  Insulate pipes with high- temp pipe insulation (250 degree)  Cap both pipes top and bottom and label them.  Install 2 wire braded thermostat cable from attic to basement

Environmental Benefits  A typical solar water heating system will offset between 3/4 ton and 1 ton of CO2 per year - the equivalent of driving over 1,300 miles  Solar water heaters are one piece of the puzzle in reducing greenhouse gas emissions  Natural gas, just like oil, is a limited resource that is being depleated

Economics of SDHW Life Cycle Costing  Overall cost of comparable systems  Solar water heaters have no operating costs  Add initial cost plus operating expenses  Compare final cost after a period of time

Economics of SDHW Electric with Federal Incentive - Graph

Economics of SDHW Natural Gas with Federal Incentive - Graph

Cash flow makes the world go ‘round  Solar water heaters save money by replacing fossil fuel fired heat sources  Fossil fuel bills are reduced  The amount saved can often completely pay for the solar heater  Little or no cash-flow impact!

Cash Flow Impact with Federal Incentive