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Solar Hot Water SystemsNorth Country Sustainable Energy Fair 2007
Matt BullwinkelAlternative and Renewable Energy Applications Program
SUNY CantonApril 28, 2007
Video
Systems
PV Panel to Power Pump
HelioStat Solar II
Kramer Valley CAPower Plant
Jets Stadium NYC “1000 of
Thermomax tubes..”
http://www.thermotechs.com/NY%20Jet%20Stadium.php
Why not solar water heating?
Capital cost ($5K vs. $200-$1K for conventional electric or gas heater)
System failures Freezing Overheating Leaks
Aesthetics Perception: not enough sun/ too cold Finding qualified designers/installers
Why solar water heating? Free Fuel* High Fuel Costs Modest capital cost (vs. PV, wind) Big Bang for Buck: DHW ~30% energy
bill Well established: retro fit, “just works” Favorable economics to provide fraction
of DHW 60-70% Federal &State Tax credits Renewable
*We have a fuel crisis, not an energy crisis, energy always conserved (kinda)
Too Cold /Not Enough Sun
Florida Solar Research CenterNC State Solar CenterUniv Wiscosin Solar Research !
http://www.fsec.ucf.edu/en/consumer/index.htm
Applications
DHW (Domestic Hot Water) Pool Heating Space Heating Cooling Process hot water Electric Power
Outline System Types Solar Resource Operating Principles Background Example Installations Economics Organizations:Promoting Solar, Incentives, Training
System Components Solar Collector:
absorb radiation and transfer heat to fluid (water/air/glycol)
Mounting Hardware Holds collector: wind & seals roof
Plumbing & Pumps Move fluid to/from collector
Controls Turn pump on/off
Freezing Over temperature
Heat Exchanger Storage Tank
Heat Transfer
Conduction Loss Back & Sides
Conduction, Radiation and Convection Loss Top
Cold Fluid(Water) IN
Hot Fluid(Water) OUT
ABSORBER PLATE (Metal)
Radiation Insolation IN
COVER PLATE(Glass/Polymer)
“Good” Greenhouse Effect~Transparent to Incoming radiation~Opaque to Outgoing radiationTrap Energy and Transfer to Fluid
Sun Earth/AET Collector
Thermomax
http://www.thermotechs.com/Downloads/How%20Works.pdf
Thermomax “heat pipe” high conductance thermal conductor. Heat transfer rate is thousand's times greater
than solid heat conductor closed container consisting of a capillary wick
structure and a small amount of vaporizable fluid.
employs an evaporating-condensing cycle accepts heat from an external source uses this heat to evaporate the liquid (latent heat) releases latent heat by condensation (water header) return condensed fluid back to the heat zone.
http://www.thermotechs.com/Downloads/How%20Works.pdf
Differential Control
Collector Types
Flat Plate with Cover w/o cover (pool)
Evacuated Tube “Thermomax” Concentrating Collector
Parabolic Trough
Selective Surface
Absorber Plate absorbs large fraction (>.9) of energyBut doesn’t emit a lot of energy (>.1)
Direct (open loop) Pumped
Circulate Potable water Pump turns on when
water in collector 15-20 deg warmer than tank
Turns off when 3-5 deg warmer than tank
Couple of freezes/year OK
Recirculates warm water if collector starts to freeze
http://www.fsec.ucf.edu/en/consumer/solar_hot_water/homes/system_types.htm
PV operated system
http://www.fsec.ucf.edu/en/consumer/solar_hot_water/homes/system_types.htm
Pump turns on when enough sun to run pump
Collector is warm too South
Indirect Pumped System Closed Loop Northern climates Circulate
Antifreeze solution
Heat Exchanger Differential
Controller
http://www.fsec.ucf.edu/en/consumer/solar_hot_water/homes/system_types.htm
Drain Back System Remove all water
from collector when freezing
When pump off, collectors drain by gravity to inside tank
Integral Collector Storage (ICS) System Collector is
storage Cold water supply
flows directly to collector where heated
Then into tank with aux heater
Florida etc.
Thermosiphon System Tank above collector Circulate by density
differences Hot water rises from
collector into tank Cold water in tank
flows down into collector be heated
Need to protect from freezing
Drain back system Installed
Basement Collector
How much Energy required?
Conventional DHW 2 peopleFuel ElectricPrice $0.15 per kWhVolume 40 gallonsTin 50 degFTout 120 degFdensity 8.34 lb/galmass 333.6 lbCp 1 BTU/(degF*lb)Nominal energy needed 23,352 BTU/day
6.84 kWhEfficiency 0.80Actual energy needed 8.56 kWh/day 3,123 kWh/yrCost to heat $1.30 per day $473.59 /yr
BTU saved is BTU doesn’t have to be generated Low flow shower heads
Cold water laundry
Available Solar Resource Sun Position Time
Hour Month
Latitude Longitude
Incident radiation Beam Diffuse Reflected
Clouds Collector Tilt Ground Conditions
Albedo Shading
Solar Pathfinder
Available Solar Resource
Combination Weather Data Empirical Results Computer simulation
NREL
F Chart: Fraction from Solar
F Avg=0.65
Thermomax Burlington VT (simulation)
System Economics
1 sqft/gal storage@80 gal= 80 sq ft collector North Country weather (Massena) Electric bill $0.15 kWh Paid by 20 yr mortgage
System Cost
Simple Payback $5000/$500- 10 years BUT
Payback on Couch? Payback on Elec Water heater? need hot
water! Need better model of usage Did not include incentives CO2 reduction
Incentives: DSIRE
http://www.dsireusa.org/
tracks federal financial incentives for renewables
Especially residential
Federal Tax Incentives
NYS Tax Incentives
System Economics
Breakeven!
Organizations
NYSERDA-NYS Incentives, R&D, Edcn ISPQ-Training and Certification NABCEP Training and Certification IREC SRCC- Solar Rating Certification
Center Industry -Testing of Collectors DSIRE- Incentive database
IREC
http://www.irecusa.org /
Trade organization Consumer Protection Education Quality Installation Skills Installers Trainers Master Trainers
IREC: Task Analysis
Training and Certification
SUNY Canton AREA Program
NYSERDA ISPQ Certification NABCEP Certification
Questions?