SOLAR PV + HOT WATER: An Introduction

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Brook Austin
7 years ago
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1 SOLAR PV + HOT WATER: An Introduction

2 Myths About Solar Portland doesn t get any sun Almost all of Germany and Japan get less Solar doesn t make financial sense Solar is a great long-term investment Your roof MUST point South A west facing roof only loses 13%. You need batteries The grid is a 100% efficient battery We get all clean hydro power! Most residences get coal power

roof MUST point South A west facing roof only loses 13%.

3 Siting Solar- TSRF Total Solar Resource Fraction (TSRF) > 75% TSRF = Peak Solar Fraction x Tilt and Orientation Peak Solar Fraction = annual shading Tilt and Orientation Factor = south is best, latitude Ex: PSF (0.80) x TOF (0.95) = TSRF (0.76)

Solar Fraction = annual shading Tilt and Orientation Factor

4 Siting Solar- Pathfinder Plastic dome is lens. Transfer images to paper $299

5 Siting Solar- SunEye Uses a fisheye lens Calcs TSRF automatically Edit images on the fly $1495

6 Siting Solar- TOF

7 Siting Solar- Example X PSF (0.84) x TOF (0.95) = TSRF (0.76)

8 Is Solar DHW Feasible? Hot water usage is the 2nd largest load The more you use, the more you may save Shading is less critical than for solar PV Aesthetics play a big role

9 How Does SDHW Work? Just like a garden hose in the sun Sunlight heats up collector Controller turns on pump, water absorbs heat The preheated water is stored in a tank Backup heat is added, as needed

10 How Does SDHW Work?

11 How Does SDHW Work?

12 System Types Pressurized Drainback Steamback Overheat Protection Freeze Protection none Gravity Drain Steamback Glycol Gravity Drain Gycol Pros simpler, no gravity drain fewer worries best of both Cons overheat risk extra tank, pump energy neither Evacuated Tube Collectors: Great for high-temp or extreme cold environments

no gravity drain fewer worries best of both Cons overheat risk extra tank, pump

13 Sizing Solar Hot Water Residential: 2 collectors for 3-4 people. Residential: OG-300. System performance rating Commercial: Determine Average Daily Usage Commercial: Divide usage by 58 Example: 1000 gal/day DHW / 58 = 17 collectors Otherwise: Convert to Btu/day, look up OG-100

System performance rating Commercial: Determine Average Daily Usage

14 Sizing Solar Hot Water O # Btu = # gal x 8.3 #/gal x Delta T (70F)

15 Incentives / Costs Residential SDHW Shuco Example Retail $9,000-$12,000 $9,200 Energy Trust Incentive $0.3-$0.4/kWh $920 Out of Pocket Cost $8,280 ODOE Tax Credit $0.6/kWh to $1.5k $1,380 FED Tax Credit 30% $2,484 Final Cost $5,000-$8,000 $4,416 Savings kwh/yr 2300 kwh/yr Equity Added $20 per $ saved $4,600

4/kWh $920 Out of Pocket Cost $8,280 ODOE Tax Credit $0.6/kWh to $1.

16 Incentives / Costs Commercial 20 collectors Retail $3500-$5000/collector $70,000 Energy Trust Incentive $0.4/kWh $8,000 ODOE Tax Credit 50%, limited $23,500 FED Tax Credit 30% $21,000 FED MACRS About 10% $7,000 Final Cost About 10-15% $10,500 Savings 1000 kwh/yr per panel 20,000 kwh/yr Incentives info:

4/kWh $8,000 ODOE Tax Credit 50%, limited $23,500 FED Tax Credit 30% $21,000

17 Is Solar PV Feasible? Solar PV provides electricity, which may only be a part of your energy usage Shading is critical Aesthetics play a big role

18 How Does PV Work? Sunlight is converted to DC Power DC is converted to AC power Sent to your electrical circuits Excess sent to the grid (neighbors!) A new meter credits you the difference No power in blackouts!

19 How Does PV Work?

20 Sizing Solar PV Take Annual kwh usage, divide by 1000 kwh/kw Example: 10,000 kwh / 1000 kwh/kw = 10kW PV Use 1250 kwh/kw east of the mountains See PVWatts (

21 Sizing Solar PV Ohm s Law V = IR, P = IV Strings: Panels in series for high V, low I String Sizing: 600VDC max, voltage up with cold Inverter windows from 150 VDC - 600VDC Use Inverter websites (PVPowered, SMA, Fronius) See PVWatts (

22 Sizing Solar PV

23 Monitoring Solar PV Connect inverter to internet Watch solar insolation, wind, cell temp, etc Also watch building demand Fat Spaniel, PVPowered, SMA, Fronius, Onset

24 Incentives / Costs Residential PV 3kW Example Retail $7-$10/W $24,000 Energy Trust Incentive $2-$2.25/W to $20k $6,750 Out of Pocket Cost $17,250 ODOE Tax Credit $3/W to $6k $6,000 FED Tax Credit 30% $5,175 Final Cost 25% $6,075 Savings 1000 kwh per kw 3000 kwh/yr Equity Added $20 per $ saved $6,000

25 Incentives / Costs Commercial PV 100kW Example Retail $5-$9/W $600,000 Energy Trust Incentive $0.9-$1.75/W to $230k $150,000 ODOE Tax Credit 50% to $8.5/W $300,000 FED Tax Credit 30% $180,000 FED MACRS About 10% $60,000 Final Cost 0-10% -$90,000 Savings 1000 kwh per kw 100,000 kwh/yr Incentives info:

26 Examples of PV

27 Examples of PV

28 Examples of PV

29 Examples of PV

30 Solar is a Great Choice! You can make a difference It s a smart financial move Supports local economy You ll be the pride of the neighborhood!

Application for Purchased Systems Oregon Department of Energy

Application Form for Residential Energy Tax Credit Certification Instructions Solar Electric System (Photovoltaic) Application for Purchased Systems Oregon Department of Energy ELIGIBILITY To qualify for