Solar Thermal Heating Lessons Learned and New Opportunities Presented to: Better Buildings by Design Conference – 2009 Leigh Seddon Alteris Renewables, Inc.
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
The Battle of the RTUs
Planning in the design stage can help avoid unnecessary shading and layout costs.
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
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