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?