Solar Water Heating TS Friday 9:00am 12:00pm Chris Wisinski

        Solar Water Heating  TS 200‐1‐1  Friday 9:00am‐12:00pm  Chris Wisinski 

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Solar Thermal Heating 

Concepts & Design

Concepts & Design

Presented by:

Chris Wisinski

Chicago Chapter

Chicago Chapter

Solar Overview

Solar Overview

• Why Should We Use Solar?Why Should We Use Solar? • Solar Technology

C ll f i

• _{Collector Information} • _{Design Considerations}  • _{System Types}

• _{System Design and ComponentsSystem Design and Components}

• Chicago/ Illinois Specific Considerations

S Si i & T l

• System Sizing & Tools

Solar Heating Systems

Solar Heating Systems

ENVIRONMENTAL IMPACT – What are we saving?

Residential Solar DHW system in Chicago IL

ƒ Family of 4 - Hot water demand: 60 usg/ day

ƒ Solar collector system: 2 Collectors / 80 Gallon Storage Tank Residential Solar DHW system in Chicago, IL

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ƒ Energy supplied by solar: 11,010,000 Btu/year

ƒ Expected minimum lifetime of system - 20 years

Energ s pplied in 20 ears 220 200 000 Bt

ƒ Energy supplied in 20 years: 220,200,000 Btu

Emission reduction in 20 years: in 20 years: ƒ16.5 tons of CO₂ ƒ3330 lbs of NO ƒ3330 lbs of NO_X ƒ1950 lbs of CO

Designing for LEED

Designing for LEED

• LEED is about reducing energy & water usageLEED is about reducing energy & water usage – Design building to require less energy

Design building systems to be more efficient – Design building systems to be more efficient – Use strategies to maximize efficiency and reduce  upfront costs upfront costs – Use systems that help to meet requirements of  multiple categories multiple categories

Why Use Solar?

Why Use Solar?

• LEED Credits:LEED Credits:

– SS Credit 7.1 Heat Island non‐roof 1 credit

E&A Credit 2 Renewable Resources: 1 7 credits – E&A Credit 2 Renewable Resources:  1‐7 credits

• Reduce reliance on natural gas or electricity for 

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water heating

LEED – v3

LEED  v3

• Sustainable Sites ‐26 pointsSustainable Sites  26 points • Water Efficiency – 10 points

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• _{Energy & Atmosphere – 35 points} • _{Materials & Resources – 14 points}

• _{Indoor Environmental Quality – 15 points} • _{Innovation & Design Process ‐ 6 pointsInnovation & Design Process  6 points}

LEED – v3 (2009)

LEED  v3 (2009)

• 100 Base points 6 ID & 4 RP100 Base points, 6 ID & 4 RP

0 9 i C ifi d

• _{40‐49 points:  Certified} • _{50‐59 points:  Silver}

• _{60‐79 points:  Gold}

Solar Heating Systems

Solar Heating Systems

THE SOLAR CONSTANT is the AMOUNT OF  ENERGY that the SUN EMITS 440 BTUH/ft 440 BTUH/ft22 440 BTUH/ft 440 BTUH/ft ƒ 30 - 60% is absorbed and scattered and scattered ƒ 170 – 315 Btuh/ft2 reaches surface

Outer 440 Btuh/ft2 32 Btuh/ft2 space Losses by Atmosphere Losses by scattering Losses by absorption 95 Btuh/ft2 Atmosphere

Direct solar radiation Diffuse solar radiation

Earth’s surface

Global radiation

GLOBAL RADIATION

GLOBAL RADIATION 

Mainly diffuse radiation Mainly direct radiation

Irradiated power in Btu/ft2

Collector Losses

Global radiation 315 Btuh/ft2 Collector losses 95 Bt h/ft2 95 Btuh/ft2

Max collector available Losses are Optical & Thermal Max collector available

power - 220 Btuh/ft2 • Losses are Optical & Thermal

• 15-20% (50-60 BTU/ft2_{) represents Optical}

losses

• Thermal – depends on difference between ambient temperatures and fluid temperature

“Run it Cool!”

Outer space 440 Btuh/ft2 _{32 Btuh/ft}2 Losses by scattering Atmosphere Losses by absorption 95 Btuh/ft2

Direct solar radiation Direct solar radiation Diffuse solar radiation

Gl b l

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Earth’s

surface

Global radiation

315 Btuh/ft

2

Collector losses

2

Max collector available power 220 Btuh/ft2

95 Btuh/ft2

Monthly Global Radiation

Every location on earth has different

Global Radiation in United States

Global Radiation in United States

Solar Heating Systems

Solar Heating Systems

Solar Collector Types

1. Solar Thermal collectors

Photovoltaic Systems – Charge Battery 

Boundary layer n-endowed silicon Negative electrode p-endowed silicon Positive electrode

Solar Thermal Systems

Direct heating of a liquid heat transfer fluid for

heat transfer fluid for DHW, space or pool heating g

Solar Panel Types

WHY SOLAR THERMAL??? WHY SOLAR THERMAL???

Solar Thermal collectors Solar Photovoltaic collectors

Flat Plate Collector: _{PV Collector:} Flat Plate Collector:

12 Sq Ft Panel

3 Hr Avg Peek Output around 2000 Watts

PV Collector: 12 Sq Ft Panel 3 Hr Avg Peek Output around around 2000 Watts _{Output around}

300 Watts

7-8 times the energy out of a Solar Thermal Collector At around 1/2 to 1/3 the Cost

Thermal Solar Panel Types

Parabolic collector / Concentrating Solar Collector

ƒ High Cost & Capacity – Used in Power Generation ƒ Construction:

ƒ Construction:

ƒ Adjusting Mirrors concentrate solar energy on a focal line

ƒ Evacuated glassg tube collector pipe with fluid heat transfer fluid fluid ƒ Sends high temperature fluid to heat exchanger

Thermal Solar Panel Types

Concentrating Solar Coolector

Collectors direct energy to single line or point

ƒ Heat Exchangers produce steam for Turbines ƒ Heat Exchangers produce steam for Turbines ƒ Extremely high temperatures

Thermal Solar Panel Types

Pool Collector

Unglazed / Uncovered

ƒ Low Cost & Capacity ƒ Construction:

ƒ Rubber or plastic tubing

directly exposed to the sun

ƒ Good at heating only slightly

above outdoor temperature above outdoor temperature

ƒ Do not work for year-round

Thermal Solar Panel Types

Pool Collector

Unglazed / Uncovered

Thermal Solar Panel Types

Example of unglazed flat plate collector

Solar Panel Ratings

www solar rating com

www.solar‐rating.com

Glazed Solar Panels

Flat plate collector:

ƒ Medium cost ƒ Construction: ƒ Construction:

ƒ Aluminum frame c/w insulation ƒ Copper tube c/w absorber sheet ƒ Low iron tempered glass coverp g

Vacuum tube collector:

ƒ Highest cost ƒ Construction:Construction:

ƒ Vacuum sealed glass tube

ƒ Copper tube c/w absorber sheet ƒ Insulated heat transfer header

Flat Plate Collector

Flat Plate Collectors

Gross area 30-40 ft2

Length 88 - 120”

Width 48”

Depth 3-4”

Vacuum Tube Collector

Evacuated tube ll t

collector:

Glazed collector based on the heat pipe principle

Vacuum tube collector

Collector components

Collector components

Rubber retaining bands bands Heat exchanger header (1) Vacuum tubes (20 or 30) _{Installation rails}

Vacuum tube collector 

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Principal of operation

Double-pipe heat exchanger Evacuated Condenser Flexible

connector heat exchanger

Absorber Evacuated glass tube Absorber plate Vapor Liquid Cross Section Heat pipe

Vacuum Tube Collector

Vacuum Tube Collector

Integrated temperature limiting

thermal valve in condenser tip that prevents the system fluid from

h ti d i t ti _{NOT BUILT TO BE A}

TEMPERATURE CONTROLLER! overheating during stagnation

periods (periods of sunshine with no heat consumption)

Evacuated tube collector

Evacuated tube collector

20 Tubes 20 Tubes 32ft2 30 Tubes 30 Tubes 49ft2

Solar Panel Comparison

Solar Panel Comparison

• Flat Plate Panels • Evacuated Tube Panels • Best suited for Medium temperature • Best suited for

High temperature applications – Medium temperature 

applications

– Sloped roof mounting

– High temperature applications

– Heating & Cooling

Process and space heating – DHW heating

– Indoor pool heating

– Process and space heating

Solar Panel Comparison

Flat plate collector:

Advantages:

1/2 t 1/3 th t f t b ll t

Solar Panel Comparison

ƒ 1/2 to 1/3 the cost of vacuum tube collector

ƒ Multiple mounting options (mount at any angle) ƒ Vacuum tubes must be 25 degrees or higher

“V ti M d ” ti h d h t

ƒ “Vacation Mode” operation – shed excess heat ƒ Does not allow snow / frost accumulation

ƒ Comparable cloudy day performance ƒ Allowable for drainback application

Disadvantages:

ƒ Not suitable for higher temperature generation

ƒ Support mechanism necessary for flat roof mounting (anchoring

Solar Panel Comparison

Vacuum tube collector:

Advantages:

Solar Panel Comparison

ƒHigher efficiency with large temp differences

between air and absorber

ƒMore effective for space heating and

air-conditioning applications

ƒEasier replacement within a panel

ƒAbsorbers can be turned towards sun direction

Disadvantages:

ƒHigher cost than flat plate

ƒMust be at least 25o _inclination

N t “V ti M d ” ti

ƒNo true “Vacation Mode” operation

ƒCannot be used in drainback operation

Solar Panel Comparison

Snow melts off and accumulates below collector below collector Snow reflection actually helps performance

Snow or frost accumulates Snow or frost accumulates

on panel, panel does not contain enough heat to melt it, blocking sunlight

Collector Efficiency

Sunny Day Performance

Summer Day

Outside Air Temperature 80°F

1.4

Sunny Day Performance

“Run it Cool!”

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Fluid Temperature in Panels 120°F Temperature Difference (40 °F) 1 1.2 2 /day 0.8 1 CLEAR Flat plate 0 0 BTU/ft 2 0.4 0.6 CLEAR Vacuum tube u tput -1 ,0 0 0 0.2 Panel O u ‐25 0 25 50 75 100 125 150

Collector Losses

Global radiation 315 Btuh/ft2 Collector losses 95 Bt h/ft2 95 Btuh/ft2

Max collector available Losses are Optical & Thermal Max collector available

power - 220 Btuh/ft2 • Losses are Optical & Thermal

• 15-20% (50-60 BTU/ft2_{) represents Optical}

losses

• Thermal – depends on difference between ambient temperatures and fluid temperature

“Run it Cool!”

Collector OUTPUT

“Run it Cool!”

1.4 V t b 1 1.2

2 /day _{Vacuum tube}

0.8 1 CLEAR MILD CLOUDY 0 0 BTU/ft 2 Fl t l t 0.4 0.6 CLOUDY CLEAR MILD CLOUDY u tput -1 ,0 0 Flat plate 0 0.2 Panel O u ‐25 0 25 50 75 100 125 150

Solar Panel Comparison

• Flat Plate

Solar Heating Systems

Solar Heating Systems

Collector Angle of Inclination

Collector Angle of Inclination

Collector performance best Collector performance best when suns rays 90o to surface

Collector Angle of Inclination

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Optimum angle of inclination: Solar DHW heating only

Solar DHW heating only

ƒ Latitude of location

Solar DHW & Space heating Solar DHW & Space heating

ƒ Latitude of location +15o

Chicago - 42° North Latitude

United States Latitudes

United States Latitudes

Collector Azimuth Angle

N

g

E W S Direct south

45o west or east of south acceptable facing is best

Notes on Azimuth

Notes on Azimuth

• Remember 45 degrees within South isRemember 45 degrees within South is 

acceptable within 10% system performance • If the panels must face East or West

• If the panels must face East or West,  significant shading will occur for portions on  the day the day – Lay the panels flatter if this is required f h l f h • _{If the panels must face North} – Please move the building to the southern  hemisphere

Solar Fraction – Chicago, IL

Solar Fraction  Chicago, IL

DHW l d 60 l/d t 130oF

DHW load – 60 gal/day at 130o_F

Solar System Types & Components

Open System

Use collector fluid directly iin process - Thermosiphon A ti - Active Cl d S t Closed System

Collector fluid in a dedicated loop

Drainback system

Open Loop Solar System

Thermosiphon System

Storage tank is placed above the panel

Hot water rises through Hot water rises through the collector and goes into the tank, displacing cold

ater into the panel water into the panel

Uses system water

N t th d f f t ti

No true method of freeze protection without draining the system

N i t

No moving parts

Open Loop Solar System

Active System

Same as a thermosiphon system but uses a pump and

controller to move heated fluid out of the panel into the tank controller to move heated fluid out of the panel into the tank

Tank can be below the solar panel the solar panel

Use system water No true method of

freeze protection ith t d i i without draining the system

Closed Loop Solar System

A closed loop solar system cycles an antifreeze (propylene glycol solution) through the collectors and uses a heat exchanger to transfer heat to a storage tank

transfer heat to a storage tank

Freeze protection is provided by the glycol mixture

Needs secondary protection from over-heating Can be:

A heat dump loop Water heat dump Secondary tank Secondary tank

Does not introduce oxygen into the panels

Closed Loop Solar System Components

1 S l P l 1. Solar Panel

2. Manual Air Vent 3. Storage Tank 4. Solenoid Valve 5. Relief Valve 6. Expansion Tank 7. Pump with Checktrol Checktrol 8. Heat Exchanger 9. Thermometer 10. Glycol Fill Pump 11. Shutoff Valve 12. Pressure Gauge 13. Automatic Air Vent Vent 14. Controller 15. Circuit Setter 16. Air Separator

Drainback Solar System

A drainback system is a closed loop system that cycles collector fluid through a storage tank

If the pump shuts off, the fluid from the solar loop dumps into this tank

Helps with freeze protection and also over-heating Helps with freeze protection and also over-heating

Can use water in the panels instead of glycol mixture

Does introduce oxygen into the panels

More likely to cause scaling or corrosion in the panels Degrade panel life

Simple Drainback System

Simple Drainback System

Solar Heating Systems

Solar Heating Systems

Solar System Controllers

Solar System Controllers

• Differential setpoint controllers – View panel temperature and tank temperature – Provide signal to relay to run pump – Options for freeze protection, overheat  protection, and vacation modes

Non‐ASME Tank – Solar & Boiler or 

El t i B k

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120

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Electric Backup ‐ Under 120 gallons

Optional Top-Coil: Electric or Boiler back-up Bottom coil: Solar collectors

Commercial Double Wall Tank Options

p

ASME Storage Tank w/ Double Wall Brazed Plate or U‐Tube HX

• 10 Year Non-Pro-Rated Warranty • ASME Coded Unit

• G8 Cement Lining / Stainless Fittings

• Double Wall Brazed Plate Heat Exchanger • Double Wall U-tube Heat Exchangers

• 3” Insulation

• 20 Gauge Steel Jacket w/ enamel paint • Packaged Operating Controls

Plate & Frame Heat Exchanger

True counter flow can deliver a 

“Temperature  Cross” of the heating  liquids

Heat Transfer to Storage Tank

• Hot Water storage tank with  internal solar coil  120o_F • High solar water return  temperature 160o_F 120oF • Lower collector efficiency  H t W t t t k ith Pl t 40o_F 90-110o_F • Hot Water storage tank with Plate  & Frame solar heat exchanger  • Lower solar water return  160 F 120o_F temperature (temperature cross) • Higher collector efficiency  160o_F 40o_F 45o_F 40oF

Closed Loop Solar System Components

1 S l P l 1. Solar Panel

2. Manual Air Vent 3. Storage Tank 4. Solenoid Valve 5. Relief Valve 6. Expansion Tank 7. Pump with Checktrol Checktrol 8. Heat Exchanger 9. Thermometer 10. Glycol Fill Pump 11. Shutoff Valve 12. Pressure Gauge 13. Automatic Air Vent Vent 14. Controller 15. Circuit Setter 16. Air Separator

Solar Heating Systems

Solar Heating Systems

Solar System Design Consideration

Stagnation temperatures & Overheating

Systems can be protected against overheating in one (or more) of the following ways:

Stagnation temperatures & Overheating

ƒ Continuing to operate the pump at night when the stored water is too

hot (Vacation Mode)

ƒ By draining an amount of hot water from the tanky g

ƒ By running fluid through a fan-coil or other heat dissipating medium ƒ By removing fluid from the solar panels (drainback)

ƒ By covering the solar panels

ƒ Install collectors on steeper angle to avoid summer stagnation and increase winter solar yield.

ƒ Stopping the pump and letting the collector fluid boil in the collector IS NOT a suitable means for controlling overheating. The heat

transfer fluid will break down and form caustic solution, damaging the piping panel header and panels

Heat Exchangers

• ASME Coded Unit

• Double Wall U‐tube Heat Exchangers

• Diamond back pattern allows for numerous failure  paths to vent

• Copper (outer) / Copper (inner)Copper (outer) / Copper (inner) • Positive open air gap

• ILLINOIS CODE

• A solar‐heated system shall use a 

double‐walled heat exchanger which is  exposed or vented to the atmosphere exposed or vented to the atmosphere  between the walls.

DHW Mixing Valves (ASSE 1017 Listed)

To maximize functionality we want to get the tanks as hot as  possible.  This can create tank temperatures well above 120F.   An ASSE 1017 rated mixing device needs to be used due to  code.

Solar DHW Installation Example – Additional  Input Connect One Single Coil Solar Tank & Water Heater g

Solar Heat Transfer Fluid / Boiling Point

400 350 in o F 300 m perature 250 o iling te m 200 35 40 45 50 55 60 B o Recommended concentration 35 40 45 50 55 60

Solar Heat Transfer Fluid/Freezing Point

30 40 0 10 20 u re in o F ‐30 ‐20 ‐10 e mperat u 60 ‐50 ‐40 30 F reezing t e ‐60 0 10 20 30 40 50 60 P l l l t ti i % F

Closed Loop Solar System Components

1 S l P l 1. Solar Panel

2. Manual Air Vent 3. Storage Tank 4. Solenoid Valve 5. Relief Valve 6. Expansion Tank 7. Pump with Checktrol Checktrol 8. Heat Exchanger 9. Thermometer 10. Glycol Fill Pump 11. Shutoff Valve 12. Pressure Gauge 13. Automatic Air Vent Vent 14. Controller 15. Circuit Setter 16. Air Separator

Storage Tanks

ASME T k • ASME Tanks – ASME Stamp required on any pressure vessel 120 gallons and larger – ASME Stamp required on any heater with a BTUH input greater than  200,000 BTUH

• ASME CategoriesASME Categories

– Section IV, Direct‐fired vessels

• Gas & Electric Water Heaters • Gas & Electric Water Heaters

– No inspection 12” x 16” manway required Section VIII Indirect fired vessels

– Section VIII, Indirect‐fired vessels

• Solar Water Heaters and Steam/Boiler Water Heaters

I ti 12” 16” i d

Tank Linings

d l • Hydraulic Cement – Suitable for immersion service to 335o _F – Expands & contracts at same coefficient as steelp – Does not require an anode • Phenolic Epoxy – Suitable for immersion service to 140o _F – Becomes brittle and shrinks at higher temperatures – Requires an anode * • Glass – There are holidays in the lining due to manufacturing processes – Requires an anode * d lif i l d d hi h • Anode life is greatly reduced at higher water temperatures,  • And requires periodic inspections

Keys to Performance

Keys to Performance

• Panel Layouty

– What is the flowrate through a panel?

– How do off‐peak loads affect temperature/control?How do off peak loads affect temperature/control?

– What temperature does the sensor see?

– How big is the piping?How big is the piping?

• Heat Loss

• Installation cost

Panels in parallel / arrays in parallel

Panels in parallel / arrays in parallel

• 32 panels = 8 arraysp y • 1‐1.5 GPM/panel =  32 48 GPM total 32 ‐48 GPM total • _{2” – 2‐1/2” pipe} • _{Vents on cold water} • _{Sensor low at end} • 10o_{F band in summer} • 2o_{F 4}o_{F in} • 2o_{F ‐ 4}o_F in lower months

Panels in parallel / arrays in parallel

Panels in parallel / arrays in parallel

• 32 panels = 8 arraysp y • 1‐1.5 GPM/panel =  32 48 GPM total 32 ‐48 GPM total • _{2” – 2‐1/2” pipe} • _{Vents on cold water} • _{Sensor low at end} • 10o_{F band in summer} • 2o_{F 4}o_{F in} • 2o_{F ‐ 4}o_F in lower months

Panels in parallel / arrays in parallel

Panels in parallel / arrays in parallel

• 32 panels = 8 arraysp y • 1‐1.5 GPM/panel =  32 48 GPM total 32 ‐48 GPM total • _{2” – 2‐1/2” pipe} • _{1 vent on hot water} • _{Sensor high at endg} • 10o_{F band in summer} • 2o_{F 4}o_{F in} • 2o_{F ‐ 4}o_F in lower months

Panels in series / arrays in parallel

Panels in series / arrays in parallel

• 32 panels = 8 arraysp y • 1‐1.5 GPM/panel = 8 12 GPM total 8 ‐12 GPM total • _{1” – 1‐1/4” pipe} • _{Vents at high points} • _{Sensor high at endg} • 40o_{F band in summer} • 10o_{F 20}o_{F in} • 10o_{F ‐ 20}o_F in lower months

Solar Heating Systems

Solar Heating Systems

System Sizing Parameters

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g

Examples of Rules of thumb

• Chicago Solar Collection Capabilities

• 30,000 BTU/Panel/Day30,000 BTU/Panel/Day

• Pool Heating Applications

• Pool area * .5 = Solar Collector Area S H ti A li ti

• Space Heating Applications

• Install 3 times the square footage of DHW collector area

• Chicago is at 42° Latitude

• DHW Application - Solar Arrays should be installed at a 40-45° slope

• Maximum BTU for the entire year

• Comfort Heating Application- Solar Arrays should be installed at a 55-60° slope ( or Latitude plus 15°) – FALL, WINTER, SPRING

• Pool Heating Application- Solar Arrays should be installed at a 30-40° slope (or Latitude less 10-15°) – SPRING, SUMMER, FALL

• IF THE SYSTEM IS UNDERSIZED, IT WILL STILL OPERATE

System Sizing Parameters

ƒHow many collectors do I need? ƒWhat size storage tank do I need?What size storage tank do I need?

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System Sizing Parameters

Questions???

System Sizing Parameters

Questions???

How big is the DHW

l d??

load??

ƒ How much DHW is used per dayp y

ƒ # of people living in house

# f t t

Collector array sizing for Residential DHW

System Sizing Parameters

Collector array sizing for Residential DHW

Flat Plate For 60% S l Chicago Area: Small Residential 13 16 ft2 _{/ person} Solar Fraction 13 – 16 ft2 _{/ person}

1 panel per 2 people

Small Apartments 8 - 12 ft2 _{/ person}

1 panel per 3 people

Larger Apartments Larger Apartments 6 – 8 ft2 _{/ person}

Flowrate Requirement for Collectors

Flowrate Requirement for Collectors

Flat plat collector:

0.5 to 1.25 GPM per collector – 30 Sq. Ft. 0.75 to 1.5 GPM per collector – 40 Sq. Ft.

Vacuum tube collector:

0.7 to 1 GPM per collector – 20 Tubes 1 0 to 1 25 GPM per collector 30 Tubes 1.0 to 1.25 GPM per collector – 30 Tubes

Sizing Parameters

Storage tank sizing

Storage tank size recommended:

Sizing Parameters

Commercial / Large Residential

Commercial / Large Residential

Estimate DHW usage on a per day basis

Size solar panels to output

p y

daily usage during the summer

30,000 BTU/panel/day

= 45 Gallons @ 80oF / panel / day = 45 Gallons @ 80 F / panel / day = 36 Gallons @ 100o_{F / panel / day}

Sizing Parameters

Commercial / Large Residential

Minimum Storage tank should be sized for the ability to absorb the entire days energy input x 1 00 (or another factor of your choice)

Commercial / Large Residential

1.00 (or another factor of your choice).

1.00 * (1000 BTU/Day Ft( y 2)* Panel Area Sq. Ft.) q (Tank Temp. – City Water Temp) * 8.34 lb/gal V Tank Min =

V 1 00 * (30 000) * # f l V _{Tank Min} = 1.00 * (30,000) * # of panels

(140°F – 40°F) * 8.34 lb/gal

V _{Tank MinTank Min} = 36 x # of panels or 1.2 gallons/ sq. ft of panel p g q p

V _{Tank Min} = 45 x # of panels or 1.5 gallons/ sq. ft of panel

(140°F – 40°F)

Solar System Sizing

Solar System Sizing

• There are several available programs • _{You can size a system by handYou can size a system by hand}

– This helps best with overheating / oversizing  concerns concerns – This has more difficulties with weather & sunlight  patterns as well as panel orientation through the  p p g year – It also makes calculating a yearly solar fraction  very difficult

Keys To Sizing

Keys To Sizing

• Building loadBuilding load

– Get a daily water demand • _{Building occupancy} • _{Building occupancy} – 5 or 7 days a week ( ) – Off periods (holidays, breaks, etc) • Location • Method of safety

Example: How Many Panels?

Example: How Many Panels?

• 7 day a week 64 unit apartment building7 day a week 64 unit apartment building

• 64 units / 30 GPD @ 120o_{F each = 1,920 GPD} ( ) 30 f l 30 000 /d i • _{(1) 30 sq ft panel – 30,000 BTU/day in summer} • _PANELS – 1,920 GPD @ (120o_F‐60o_{F) = 960,000 BTU/day} – 960,000 BTU/day ÷ 30,000 BTU/panel/day = 32 panels 

Example: How Much Storage?

Example: How Much Storage?

• 7 day a week 64 unit apartment building7 day a week 64 unit apartment building

• 64 units / 30 GPD @ 120o_{F each = 1,920 GPD} ( ) 30 f l 30 000 /d i • _{(1) 30 sq ft panel – 30,000 BTU/day in summer} • _STORAGE – 960,000  BTU/day ÷ (150o_F‐60o_{F) ÷ 8.34lb/gal} = 1,280 Gallons – 960,000  BTU/day ÷ (120o_F‐60o_{F) ÷ 8.34lb/gal} = 1,920 Gallons,

Let’s try an Example

Let s try an Example

• Apartment ComplexApartment Complex • 50 Units

i i ff f

• _{Base our sizing off summer performance} • _Size Panels

• _{Size TanksSize Tanks}

Example – Demand Per Day

Example  Demand Per Day

50 units x ________ GPD / unit = _____ Total GPD18 900

The most difficult part in all solar sizing

1.5 x 8 x 1.5 GPM shower min people per unit

The most difficult part in all solar sizing Hints:

Get water meter data Survey the tenants

Use a design program Use a design program Take an educated guess

Example – Energy Per Day

Example  Energy Per Day

Total GPD x 8 34 x o_{F rise = BTU/D}

900 50 375,300 ____ Total GPD x 8.34 x ___ F rise = _____BTU/D 120 - 70 , Let’s calculate the usage into an equivalent energy 1LB x 1oF rise = 1 BTU  → 1 Gal x 1oF rise = 8.34 BTU What is the desired temperature and what is the

What is the desired temperature and what is the  incoming temperature (remember this is for 

summer) summer)

Example – Solar Panel Count

Example  Solar Panel Count

BTU/D ÷ panel BTU/D = # of panels

375,300 31,800 12 ____ BTU/D ÷ ____ panel BTU/D = ____ # of panels h h l d ? , , 15 24,900 How much energy can each panel produce? Base off SRCC ratings for warm weather conditions 12 panels = 12 panels 350 sq ft 15 panels =p 525 sq ft

Example – Storage Tank Volume

Example  Storage Tank Volume

BTU/D ÷ 8 34 ÷ storage temp difference =

375,300 90 ____ BTU/D ÷ 8.34 ÷ ____ storage temp difference = ____ # of gallons , 160 - 70 ₅₀₀ What Temperature are we storing the tank at? Do we have a mixing valve?

Are the panels pressurized? Are the panels pressurized?

How to take care of excess heat

How to take care of excess heat

• Circulate into the domestic systemCirculate into the domestic system

• Use somewhere else

h h h d l

• _{Run through a heat dump loop} • _{Store more water}

• _{Solenoid valve to drain} • _{Drainback SystemDrainback System}

• Momentarily stall panels

C h l

How to take care of excess heat

How to take care of excess heat

• Circulate into the domestic systemCirculate into the domestic system – Add energy input to the system Lowest cost – Lowest cost – Dissipated by the recirculation system W t h t h t ff d t ff – Water heaters shut off and stay off h l • _{Use somewhere else} – Condenser water reheat – Could be simple

How to take care of excess heat

How to take care of excess heat

• Run through a heat dump loopRun through a heat dump loop – Shed heat outside

Is the heat useful? – Is the heat useful? • Store more water – Does the building run cycles? – Is the usage 5 days a week? • Solenoid valve to drain – Dump excessively heated domestic water to… • Drain • Cooling Tower / Evaporative Roof Cooling

How to take care of excess heat

How to take care of excess heat

• Drainback SystemDrainback System

– Summer only operations / extended off times Lose system efficiency (start/stop and cycle) – Lose system efficiency (start/stop and cycle) • Momentarily stall panels / – Stop/start system draw heat away • Cover the panels – Seasonal off time

Solar Heating Systems

Solar Heating Systems

Cost Estimates

Cost Estimates

• EquipmentEquipment

– Solar Panels $1,000 ‐ $2,500 / panel

Storage Tanks $1 500 $3 000 / 100 gallons – Storage Tanks $1,500‐$3,000 / 100 gallons – Heat Exchangers $300‐$500 / panel P $500 $2 000 / t – Pumps $500‐$2,000 / system – Controls & Electrical ‐ $1,000 ‐ $10,000 / system Mi E i $500 $5 000 /

– Misc Equipment ‐ $500 ‐ $5,000 / system

– Piping & Insulation ‐ $500 ‐ $15,000 / system • _{Total appx $3,000‐$5,000 / panel}

Cost Estimates

Cost Estimates

• Equipment – 24 panelsEquipment  24 panels – Solar Panels = $45,000 Storage Tanks = $30 000 – Storage Tanks = $30,000 – Heat Exchangers = $14,000 P $1 000 – Pumps = $1,000 – Controls & Electrical = $3,000 Mi E i $2 000 – Misc Equipment = $2,000 – Piping & Insulation = $5,000 • _{Total Equipment Cost = $100,000}

Cost Estimates

Cost Estimates

• InstallationInstallation

– Usually similar to equipment costs (x 1 – 1.5) • _{For 24 panel system @ $100 000 equipment} • _{For 24 panel system @ $100,000 equipment}

– Additional $125,000 • _24 Panels

Cost Estimates

Cost Estimates

• What else has impact on costWhat else has impact on cost

– Roof Mounting

Piping Distances – Piping Distances

– Packaged equipment

• not as much influence on total cost • not as much influence on total cost

– Crane / Roof coordination

Database of State Incentives for 

Renewable Energy

www.dsireusa.org

Federal Tax Credit - Commercial

Solar. The grant is equal to 30% of the

basis of the property for solar energy. basis of the property for solar energy. Eligible solar-energy property includes equipment that uses solar energy to generate electricity, to heat or cool (or

id h t t f i ) t t

provide hot water for use in) a structure, or to provide solar process heat. Passive

solar systems and solar pool-heating systems are not eligible. Hybrid solar-y g y

lighting systems, which use solar energy to illuminate the inside of a structure using fiber-optic distributed sunlight, are eligible. 30% Tax Credit for commercial buildings

Database of State Incentives for 

Renewable Energy

www.dsireusa.org

Federal Tax Credit - Residential

30% Tax Credit for residential buildings $2,000 Cap Limit

Database of State Incentives for 

Renewable Energy

www.dsireusa.org

Examples of Local Opportunities Beyond Grants & Rebates

Tax Assessment Recognition

Solar Energy Equipment is valued at no more than a conventional energy

t / dditi t t l

system / no addition to property value for taxes

Building Permitting Assistance

Possible partial waiver of consultant code review fees and expedited permitting process

Government Support

www.flaseia.org

www energystar gov

www.illinoissolar.org www.energystar.gov

Additional Support

www seia org www.seia.org

National trade association for the solar industry

Solar Industry employs about y p y

Government Support –

How long 

will it last?

The American Recovery and Reinvestment Act of 2009 The American Recovery and Reinvestment Act of 2009 Tax credits are available for 30% of the cost, with NO CAP  through 2016 for: G th l H t P Geothermal Heat Pumps Solar Hot Water Systems Small Residential Wind Systems Solar Photovoltaics The cap has been removed for residential applications. 

Equipment must be SRCC Rated

Total Cost = Install + Equip – State Subsidies

ENVIRONMENTAL IMPACT – What are we saving?

Residential Solar DHW system in Chicago IL

ƒ Family of 4 - Hot water demand: 60 usg/ day

ƒ Solar collector system: 2 Collectors / 80 Gallon Residential Solar DHW system in Chicago, IL

y

Storage Tank

ƒ Energy supplied by solar: 11,010,000 Btu/year

ƒ Expected minimum lifetime of system - 20 years pected u et e o syste 0 yea s

ƒ Energy supplied in 20 years: 220,200,000 Btu

Emission reduction in 20 years: in 20 years: ƒ16.5 tons of CO₂ ƒ3330 lbs of NO ƒ3330 lbs of NO_X ƒ1950 lbs of CO

Solar Water Heating

Chris Wisinski