Solar Thermal HeatingLessons Learned and New Opportunities

Presented to:

Better Buildings by Design Conference –

2009

Leigh Seddon

Alteris

Renewables, Inc.

End of an Energy Era100 years of exponential growth in fossil fuel use HASHAS come

to an end due to environmental and economic constraints

Our Solar Power Plant

Solar Corona: Yohkoh

Satellite

Safe

Reliable

No Transmission Costs

No Emissions

Delivered to Everyone

The Solar Energy Resource

In a single one hour period, the sun sends enough energy to our planet to meet all of our energy needs for an entire year.150,000 kWh a year of solar energy falls on every 1,000 sq feet of south facing roof in N.E.Solar thermal conversions efficiencies run as high as 50% for low temperature applications like radiant heating and domestic hot water.

Solar Technologies

Daylighting0 -

4¢/kWh saved

Passive Heating & Cooling0 -

4¢/kWh saved

Active SHW & Heating4 -

8¢/kWh saved

Photovoltaics15 -30¢/kWh saved

Isn’t Solar Water Heating for California and Florida?

The Northeast is one of the best regions for solar thermal because:

Fuel costs are among the highest in the country.

Solar radiation is plentiful enough on a year-round basis to supply 2/3 of a facility’s water heating energy.

Ground water temperatures are much lower in the Northeast, raising solar thermal conversion efficiency.

Solar technology is proven, affordable, and cost-effective in Vermont.

50% energy savings are possible with less than 10% increase in construction costs.

Solar electric and thermal systemAnnual energy savings – 4,000 kWhWeybridge, VT

Solar “Net Zero”

is Possible in Vermont

“River House”

By William Maclay Architects

Solar/Geothermal

13 kW grid-tie PV

15 kW solar thrm

Solar Assisted Geothermal Heat Pump

“River House”

Mechanical Design

by LN Consulting

& Energy Balance

Average BTU per Day by MonthFlate Plate collectors - 9 sq meters

Boston, MA insolation

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

90,000

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Solar BTUper day

Solar Energy Profile & Load Matching

Hot water load for 4 person household

Optimal Annual Solar Fraction --

about 65%

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

180,000

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Heat Load

Solar Energy Profile –

Heat Load

192 SF collector array

Unused Energy

Effect of Collector Angle

Average daily Insolation for different collector anglesBoston, MA

0

1

2

3

4

5

6

7

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Month

kWh/

M2

025405590

SHW & Radiant Floor Heating

6 - 4x10 Flat Plate

240 Sq. Ft Array

10,000 kWh/Year thermal

60 degree collector tilt to optimize winter performance

Building Integrated Systems

Integration at design phase can provide:

•Easier installation•Better aesthetics•Better performance•Material savings

Thermal Energy Storage Systems

“Softank”

systems

Non-pressurized tank

EPDM rubber lining

Ships as 4 x 12 flat

Copper coil heat exchangers

Thermal energy must be used immediately or stored

Southern VT Recreation Center, Springfield VT130 kW thermal array saves $15,000 a year in fuel

Commercial

Heating Systems

•Pool heating

•Process heat

•Dairy farms

•Hotels

•Laundramats

Very cost-effective due to high solar conversion efficiency and economies of scale

Solar Pool Heating

S. VT Recreation Center

130 kW thermal

$15,000 / year savings

The Battle of the RTUs

Planning in the design stage can help avoid unnecessary shading and layout costs.

Hospital Hot Water System

Santa Rosa Hospital

SanAntonio, TX

Drainback

SHW Operation

Commercial Radiant Floor Heat

ThermodynamicsHalifax, NS

90 sq. metersCollector surface

285 MMBTU/yr

Vertical Wall Installation

Thermodynamics, LTDHalifax, NS

5 4x8 collectorsper “bank”

to

control expansion

Building integratedbut using modularcollectors

Evacuated Tube or Flat Plate?

Thermomax SystemPentagonWashington, DC

Which is best depends on application, climate, and delivery temperature

Efficiency in Perspective

DHW HEAT

Cost of Energy in Vermont (Jan 2009)

Delivered Cost of Energy

05

1015202530354045

Fuel O

ilKero

sene

Propan

e

Nat Gas

Electric

ity

Wood

Pellets

Solar*

Fuel Type

$/M

MB

TU

End use cost with high efficiency equipment

*Solar –

20-year annualized cost

Life-Cycle Analysis –

SHW Example

Cost Item

Electric

LPG

Solar

Capital Cost

$750

$750

$6,250*

First year fuel cost

$850

$860 $250

25-yr fuel cost**

$18,760 $18,980

$5,520

25-yr maintenance**

$550

$550

$1,500

Total Life Cycle Cost

$20,910 $21,140

$13,520

* includes $750 for back-up LPG hot water heater, less state incentives** present worth based on inflation at 4%, discount rate at 7%** prices based on January 2006 average cost for New England

System Performance Monitoring

Necessary for thermal billing and RECs

Fat Spaniel Web View

Solar Cooling –

An Emerging Market

Solar Cooling –

The Perfect Load Match

Quiz

What state has the highest per capita number of solar installers?

In what state was the first New England solar collector manufacturer located?

The contractor who installed the first White House solar system in 1978 was located in what state?

Vermont is Solar “Shovel”

Ready!