Solar Water Heating Basics

8/7/2019 Solar Water Heating Basics

1/39

Solar Water Heating Basics

Progress Energy Florida

Solar Water Heater Incentive Program

Colleen Kettles

Florida Solar Energy Research & EducationFoundation (FlaSEREF)


2/39

Solar Water Heating Basics How It Works

How Much Energy It Saves How It Helps the Environment

How To Purchase

How Much It Costs What Incentives Are Available


3/39

Types of SystemsActive System

Direct Pumped

Water is the collector fluid

Freeze protection provided by drain-back tankor freeze valves

Indirect Pumped Anti-freeze is the collector fluid

Heat exchanger utilized within storage tank


4/39

Active Solar Water Heater


5/39


Direct Pumped


6/39


Direct PV Pumped


7/39


Indirect Pumped


8/39


9/39

The Storage TankActive System

Specially designed, heavily insulated tank(R value of 16 or greater)

Sizes range from 52 to 120 gallons forresidential applications

Has only a top electric element In a system using antifreeze, the tank will

have an internal heat exchanger


10/39

Balance of System Components

Active System

Pump (ac or dc)

Differential Controller, or

Photovoltaic Panel

Assorted valves and vents

Copper Piping

Insulation


11/39

Types of SystemsPassive System

Integral Collector Storage Collector provides additional water

storage

No moving parts


12/39

Passive Solar Water Heater

Integral Collector Storage


13/39


Integral Collector Storage


14/39

The CollectorIntegral Collector Storage (ICS)

The collector is also the storage medium

Insulated box with 4 copper tubingwelded together to serve as the absorber

Glass cover

Fluid is water Designed to reach temperatures as high as

160 F


15/39

The Storage TankIntegral Collector Storage (ICS)

Collector provides of the storage (32-50gallons)

Existing or conventional tank provides thebalance of storage


16/39


ICS System

Assorted valves and vents

Anti-scald valve (optional)

Copper piping

Insulation


17/39

Types of SystemsPassive System

Thermosiphon Tank is roof mounted above collector

Uses flat plate collector

No moving parts

Reminiscent of early solar systems


18/39

Early Thermosiphon Solar

Water Heater


19/39

Thermosiphon System


20/39


Thermosiphon System


21/39

The CollectorThermosiphon System

Uses flat-plate collector

Insulated box with copper pipingintegrated into a black absorber and glasscover

Fluid is water or anti-freeze

Designed to reach temperatures as high as160 F


22/39

The Storage TankThermosiphon System

The storage tank is specially designed tobe mounted on the roof above the collector

An auxiliary tank with electric element isinstalled in the home


23/39


Thermosiphon System

Assorted vents and valves

Copper piping

Insulation


24/39

Household Hot Water Use 15% 20% of total household energy

consumption

Daily usage is 20 gallons each per dayfor the first two occupants; 15 gallonsper day for each additional occupant

Example: Four person household willuse 70 gallons of hot water and willneed 80 gallons of storage


25/39

Collector BTU Ratings

/Solar Fraction Central Florida ambient water

temperature is 72 degrees

Solar fraction is the proportion of hotwater provided by the solar system

Optimal solar fraction is 70% and is

based upon annual performance


26/39

Collector Btu Ratings

/Solar Fraction 38,000 Btus will be needed to raise 80

gallons of cold water to 122 degrees

A 32 square foot ICS system is rated at28,700 Btu/day and will provide a 77%solar fraction

A 40 square foot active collector israted at 34,400 Btu/day and willprovide a 92% solar fraction


27/39

SavingsThe kWh equivalent of 38,000 Btu/day is11.13 kWh per day x 365 days = 4,063

kWh/year (electric load) A solar fraction of 70 will offset 2,844 kWh

A solar fraction of 77 (28,700 Btu/day) = 8.4kWh/day x 365 days, saves (or produces) 3,066

kWh/year A solar fraction of 92 (34,400 Btu/day) = 10

kWh/day x 365 days, saves (or produces) 3,650kWh/year


28/39

SavingsAt an average residential rate of $.115

per kWh:

A solar fraction of 70 will save$325/year

A solar fraction of 77 will save

$350/year A solar fraction of 92 will save

$420/year


29/39

Back-up Hot Water All solar water heaters will have a

conventional energy back-up

No consumer action is required toactivate the back-up

Back-up is needed for periods of

excessive hot water use or inadequatesolar resource


30/39

How It Helps the Environment Emission Reductions (One Solar Water

Heater Saves Annually) Carbon Dioxide (5,000 lb) Sulfur Dioxide (20 lb)

Nitrogen Oxide (12 lb)

Renewable Energy Credits The environmental attributes of solar

energy are a commodity


31/39

How to Purchase Contact reputable solar companies

www.flaseia.org

www.findsolar.com Verify contractor licenses

www.myfloridalicense.com

Voice: 850-487-1395

Solar contractor (CV) Specialty solar (CW)

Plumbing contractor (CF)

Local solar license (RX)


32/39

How to Purchase Get more than one estimate, and get

them in writing

Avoid high pressure sales tactics

Compare system types, sizes, pricesand warranties

Ask for FSEC system certification

Ask for local references


33/39

How to Purchase A local building permit should be obtained

prior to installation (although some

jurisdictions no longer require) Contractor, not the homeowner, is

responsible for the permit

If in doubt, homeowner should contact the

local building department Deed restricted communities will typically

require prior approval (which cannot bedenied)


34/39

How Much It Costs Cost of a system varies depending upon

the type of system and the size of

system Prices range from $3,000 to $5,000 in

general

Rising material costs and the cost ofdoing business (gasoline, insurance,etc.) have resulted in price increases


35/39

Financial Incentives Incentives are designed to lower the

cost to the consumer

Sales Tax Exemption (6-7%)

Florida Solar Rebate ($500)

Progress Energy Rebate ($450)

Federal Tax Credit (30% with cap of$2,000)


36/39

Interaction of Incentives Rebates should be deducted from the

cost of the system before the federal

tax credit is calculated IRS has not issued regulations under

this tax credit law

Exception would be if rebates areincluded as gross income


37/39

Interaction of IncentivesExample

System cost: $4,000

State rebate: - $500

PEF rebate: - $450

Actual cost: $3,050Federal tax credit: (.30 x 3,050) = $915

Net system cost: $2,135


38/39

Impact of Incentives on

Consumer SavingsNet System Price of $2,135

Annual Savings of $325 = 6.5 yearpayback

Annual Savings of $350 = 6.1 yearpayback

Annual Savings of $420 = 5 yearpayback


39/39

For More Information www.flaseref.org

www.flaseia.org

www.fsec.ucf.edu

www.floridaenergy.org

800-59SOLAR

THANK YOU

Solar Water Heating Basics

Documents

Transcript of Solar Water Heating Basics