Design Guidelines for Integrating Renewable Energy in Commercial Buildings ....
*Derived loosely from “The Passive Solar Energy Book, “ and “Designing Low.
Re-Arch: The Initiative for Renewable Energy in Architecture
Renewable Energy in Commercial Buildings Design Guidelines for Integrating Renewable Energy in Commercial Buildings By Loren Abraham, AIA, LEED AP
Part IV Standard “Rules of Practice” and Design Guidelines • General Principals and Recommended Practice for implementing Renewable Energy in Commercial Buildings including The Ten Commandments for Integrating Renewable Energy
• General rules and recommended practice for all solar applications • Rules of Practice for Solar PV • Rules of Practice for Solar Thermal Systems • Rules of Practice for Wind Power • Rules of Practice for Groundsource Heat Pumps 92 of 306
Re-Arch: The Initiative for Renewable Energy in Architecture
Selected 10 Best Practices 1. Use an integrated design process to system-engineer the building 2. Use computer simulations to guide the design process; these help designers analyze trade-offs and examine the energy impacts of architecture and HVAC choices 3. Simulate and measure the building’s energy performance at design, construction, and occupancy stages 4. Set specific, quantifiable energy performance goals 5. Design the building envelope to meet or minimize as many HVAC and lighting loads as possible 6. Size HVAC and lighting systems to meet loads not met by the envelope 7. Use daylighting in all zones adjacent to exterior walls or roofs 8. Install highly reflective surfaces in all daylit zones, especially ceilings 9. Monitor and evaluate post-occupancy energy performance 10. Carefully design and implement the use, control, and integration of economizers, natural ventilation, and energy recovery ventilators (ERVs). 93 of 306
Re-Arch: The Initiative for Renewable in Architecture General Principals andEnergy Recommended
Practice The Ten Commandments of Renewable Energy
Design Guidelines for Integrating Renewable Energy in Commercial Buildings
6. You should avoid unnecessary complexity. Don’t try to do too much…remember, technology is your friend – use it - but use it appropriately.
1. Thou shalt make all your buildings “SOLAR Ready.” Design for renewable energy even if it is not a certainty.
7. When possible use more than one renewable energy solution.
2. Make Roof design a first priority Consider loads, orientation, form, etc. 3. Integrate renewable energy with good energy efficient design.
8. As a rule use “state-of-the-shelf” technologies.
4. Use Energy Modeling early in design. Optimize, optimize, OPTIMIZE!
9. Always be willing to go against convention when circumstances suggest a different approach.
5. Be careful not to overstate savings - keep expectations reasonable.
10. Don’t rely only on your own knowledge and skill. Hire consultants with proven track records when appropriate. 94 of 306
Re-Arch: The Initiative for Renewable Energy in Architecture Design Guidelines for Integrating Renewable Energy in Commercial Buildings
General rules and recommended practice for solar applications Perform Site Assessment • solar access • •
future conditions – tree growth, undeveloped land, etc. land area and setbacks - is there space for RE equipment?
• • •
existing structural conditions – is a structural evaluation needed? existing site conditions – infrastructure,ecological (e.g. habitat, TES, etc.,) historical and cultural assets? existing conditions – energy profile or audit of existing structures? 95 of 306
Solar Path definitions:
General rules and recommended practice Site Assessment
Source: The Passive Solar Energy Book, by Ed Mazria
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Source: The Passive Solar Energy Book, by Ed Mazria
General rules and recommended practice Site Assessment
Solar position by Time of Day :
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General rules and recommended practice Site Assessment
Source: The Passive Solar Energy Book, by Ed Mazria
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Source: The Passive Solar Energy Book, by Ed Mazria
General rules and recommended practice Site Assessment
Solar Path Chart for Minneapolis:
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General rules and recommended practice Site Assessment Mapping obstructions:
Source: The Passive Solar Energy Book, by Ed Mazria
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Re-Arch: The Initiative for Renewable Energy in Architecture Design Guidelines for Integrating Renewable Energy in Commercial Buildings
General rules and recommended practice for all solar applications Perform Site Assessment •
solar access
• • •
future conditions – tree growth, undeveloped land, etc. land area and setbacks - is there space for RE equipment? existing structural conditions – is a structural evaluation needed? existing site conditions – infrastructure,ecological (e.g. habitat, TES, etc.,) historical and cultural assets? existing conditions – energy profile or audit of existing structures?
• •
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Re-Arch: The Initiative for Renewable Energy in Architecture Design Guidelines for Integrating Renewable Energy in Commercial Buildings
General rules and recommended practice
…for all solar applications • • • •
•
Study local zoning ordinances Research available rebate programs and net metering rules. Optimize Orientation and placement on site Perform Shading studies: • Physical model • Computer model (e.g., Sketchup, Revit, etc.) • Other issues such as wind speed and prevailing direction Optimize Passive solar opportunities before Active Systems are designed
Monticello High School Study, Charlottesville, VA Courtesy: Daybreak Technology and WM+P
Minneapolis City Hall Shading Study; Courtesy: Center for Sustainable Building Research (CSBR)
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Re-Arch: The Initiative for Renewable Energy in Architecture Design Guidelines for Integrating Renewable Energy in Commercial Buildings
General rules and recommended practice
…for all solar applications • •
Optimize Passive solar opportunities before Active Systems are designed Recommendations for rough sizing*: SHF 0.1 0.2 0.3 0.4
SW:FA .11 .24 .35 .40
or
LCR 96 39 21 11
Where: SHF is the Solar Heating Fraction, SW:FA is the Solar (S) Window-to-Floor Area Ratio and LCR is the Load Collector Ratio (Building Loads/Solar Collector Area.) *Derived loosely from “The Passive Solar Energy Book, “ and “Designing Low Energy Buildings with Energy 10” – Applicable for Direct Gain Systems only 103 of 306
Re-Arch: The Initiative for Renewable Energy in Architecture Design Guidelines for Integrating Renewable Energy in Commercial Buildings
General rules and recommended practice Solar PV Determining Feasibility Review the Site Assessment –
is there adequate solar access? …and is it likely to remain?
–
will there be adequate land or roof area?
–
If an existing structure – is there adequate structural support on the roof for the additional loads?
–
What rebates and tax incentives are avaialble?
–
What are the zoning restrictions?
–
Is it an effective use of PV technology? 104 of 306
PV Guide
Re-Arch: The Initiative for Renewable Energy in Architecture Design Guidelines for Integrating Renewable Energy in Commercial Buildings
General rules and recommended practice Solar PV System Sizing1 Method 1: Manual RE Goal Method Step 1: Calculate Probable Annual Energy Use for Project = EUI for building type (kBtu/sf) x Energy Reduction Target (%) x Floor Area (sf)
Step 2: Determine PV Power Production Requirement = RE Goal (%) x Total Building Energy Use (kWh)
Step 3: Calculate size of the PV array (kW) =
Annual Energy from the PV system (kWh) Solar Radiation (kWh/kW-year) x PV Efficiency (%))
Step 4: Calculate the Area of the Array based on W/sf output value =
PV Area (sf) = PV size (kW) x 1000 PV Product “nameplate” output (W/sf)
1
Note: The method shown here for calculating the size (kW) for a PV system, steps 1-3, is also the same for determining the size of any renewable energy system where electrical power is d d 105 of 306
PV Guide
Re-Arch: The Initiative for Renewable Energy in Architecture Design Guidelines for Integrating Renewable Energy in Commercial Buildings
General rules and recommended practice Solar PV System Sizing1
Method 1
Step1:1:Calculate CalculateProbable ProbableAnnual AnnualEnergy EnergyUse Usefor forProject Projectin kWh Step Example Montessori Preshool, Hastings, MN Target (%) x Floor Area (sf) = EUIProject: for building type (kBtu/sf) x Energy Reduction Gross Floor Area: 10,000 SF Construction Cost: ($2,000,000) = 75 kBtu/sf x 50% $200/SF x 10,000 sf = 375,000 kBtu/yr Avg. Site Energy Use: 75 kBtu/SF x 50% = 37.5 kBtu/SF Target Energy Use/Cost kWhData: Conversion factor: 1 kWh = 3.413 KBtu
= 375,000 kBtu / 3.413 = Total Annual Energy Use Avg. Annual Electric Use: Avg. Annual Gas Use:
Tot. Energy Use 110,000 kWh Total Energy @ 50% Reduction Cost used per year $/SF 375,000 kBtu $9,550 0.96 65,924 kWh $7,600 0.76 1,500 Therms $1,950 0.20
Step 2: Determine PV Power Production Requirement
= RE Goal (%)System x TotalProduction Building Energy Use (kWh) Renewable Energy Requirement: RE Contribution Goal Kwh Energy Use Reduction Target Cases = 10% x 110,000 kWh Total = RE11,000 kWh PV Production per year 1 10% of Total Energy Use
11,000 kWh
1
PV
50% Reduction Target 37.5 kBtu/SF
Note: The method shown here for calculating the size (kW) for a PV system, steps 1-3, is also the Guide onsame Conversion factor of 375,000 kWhpower x .10is= 11,000 kWh for determining the1kWh=3.413Btu size of any renewable energyBtu/3.413=110,000 system where electrical d d
1Based
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General rules and recommended practice Re-Arch: The InitiativeSolar for Renewable Energy in Architecture PV System Sizing
Method 1
Design Guidelines for Integrating Renewable Energy in Commercial Buildings
Solar Radiation Map Source: NREL 107 of 306
Re-Arch: The Initiative for Renewable Energy in Architecture
General rules and recommended practice Method 1 Design Guidelines for Integrating Renewable Energy in Commercial Buildings Solar PV System Sizing Step 3: Calculate Total Power output of PV array in kW = PVp (kW) = =
Step 4: = 1 This
Annual Energy from the PV system (kWh) Solar Radiation (kWh/kW-year) x PV system efficiency (%)
11,000 kWh 1,600 kWh/kW-year x .77
=
8.93 kW or 9 kW
Calculate the Area of the Array based PV size (kW) x 1000 PV Product “nameplate” output (W/sf)
=
9 kW x 1000 11.8 (W/sf)
= 763 sf 1
calculation would often be in panel quantity rather than total square footage.
PV Guide
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Re-Arch: The Initiative for Renewable Energy in Architecture Design Guidelines for Integrating Renewable Energy in Commercial Buildings
General rules and recommended practice Solar PV System Sizing
Method 2
Method 2: Seat-of-the-pants (Quicker & Easier) Method Step 1: Calculate Rough Annual Energy Use for Project = 10,000 sf (Bldg SF) x 10 kWh/sf (EUI) = 100,000 kWh (Use =$1/sf)
Step 2: Determine PV Power Production Requirement = 10 % (RE Goal) x 100,000 kWh (EU) = 10,000 kWh (PV Production)
Step 3: Calculate size of the PV array (kW) =
10,000 kWh x 1.5
= 10 kWp (PV Power)
1500 kWh/kW-yr
Step 4: Calculate the Area of the Array =
(Aha…!)
10 kW x 100 sf/kW
= 1,000 sf PV Area
RE Goal x Bldg SF = PV area
PV Guide
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Re-Arch: The Initiative for Renewable Energy in Architecture Design Guidelines for Integrating Renewable Energy in Commercial Buildings
General rules and recommended practice Solar PV Determining Feasibility •
Determine Probable Size for Array (10W/sf x Bldg sf x RE Goal % = Wp)
•
Determine Probable Maximum Cost
Example Bldg (10,000 sf) . = 10,000 Wp (RE Goal 10%)
(Wp x $10.00) = $100,000 - 50,000 (incentives)
= $50,000 +/-
•
Annual Energy Savings = 12,000 kWh + Peak = $2,500 +/-
•
Most likely payback
•
For a more accurate financial analysis
(10 – 20 years)
15 years (avg.)
Use a Software Tool such as: • • • •
PV Watts RETScreen Solar Design Studio Pro Energy 10
PV Guide 110 of 306
Re-Arch: The Initiative for Renewable Energy in Architecture Design Guidelines for Integrating Renewable Energy in Commercial Buildings
Rules and recommended practice Solar PV System Design Orientation and Tilt for a Fixed Array •
Orientation (Azimuth) South +/- 10°
•
2-3% efficiency loss at 10°Deviation 4-5% loss at 15% deviation –
•
Magnetic South in this location is 2° W of Solar South Collector tilt recommendations (Altitude) Latitude +/- 10° but snow is a factor:
–
NE Minnesota
40-45°
–
SW Minnesota
35-40° 111 of 306
NE SW
PV Guide
Re-Arch: The Initiative for Renewable Energy in Architecture Design Guidelines for Integrating Renewable Energy in Commercial Buildings
General rules and recommended practice Solar PV Other Requirements •
Structural Loads Flexible Membrane or Shingle Standard Panel Array Insulated PV Panels Tracking System
Consult with Structural Engineer
•
Snow & Wind Loads
Consult with Structural Engineer
•
Maintenance Costs
•
Roof Area Requirement
1 lb./sf 3-4 lb./sf 4-5 lb./sf
$1-2/sf/yr
PV Guide 112 of 306
Re-Arch: The Initiative for Renewable Energy in Architecture Design Guidelines for Integrating Renewable Energy in Commercial Buildings
General rules and recommended practice
Solar PV Other Requirements SOLARBUZZ PRICE SURVEY: JANUARY 2007 •
Solar Electricity 21.41 cents per kWh
•
EUROPE €4.82 per Watt
•
UNITED STATES $4.88 per Watt
•
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