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What cost-effective options are available for building owners interested in reducing their building’s energy use? CEE's Director of Engineering Services, Mark Hancock, P.E., will discuss rooftop unit retrofits as a scalable energy-saving approach and recommend next steps.
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OPTIMIZING EXISTING ROOFTOP
UNIT EFFICIENCY
A Study Focused on Cold Climate Conditions
Mark Hancock, P.E. |
Center for Energy & Environment
Webinar: November 12, 2014
Pg. 2
Pg. 3
Pg. 4
Current Field Research Projects
In Progress
• Improved Effectiveness of Commercial ERVs
• Condensing Boiler Optimization
• Optimized Operation of Pool Facilities
• Reducing Commercial Building Duct Leakage
• Multi-Family Building Envelope Aerosol Sealing
• Effective Ventilation in Multi-Family Buildings
• Secondhand Smoke Exposure in Vehicles
• DOE Building America | Retrofit Water Heating
• DOE Building America | Combi-System Measure Guidelines
• DOE Building America | Combustion Safety Guidelines
• DOE Building America | Demonstration House
2013-14 Archived Webinars &
Upcoming Publications
• Window Retrofit Technologies
• Large Building Air Leakage
• Tankless Water Heaters
• Heat Pump Water Heaters in MN
• Optimization of Existing RTUs
• Combi Systems
Pg. 5
Current Field Research Projects
In Progress
• Improved Effectiveness of Commercial ERVs
• Condensing Boiler Optimization
• Optimized Operation of Pool Facilities
• Reducing Commercial Building Duct Leakage
• Multi-Family Building Envelope Aerosol Sealing
• Effective Ventilation in Multi-Family Buildings
• Secondhand Smoke Exposure in Vehicles
• DOE Building America | Retrofit Water Heating
• DOE Building America | Combi-System Measure Guidelines
• DOE Building America | Combustion Safety Guidelines
• DOE Building America | Demonstration House
2013-14 Archived Webinars &
Upcoming Publications
• Window Retrofit Technologies
• Large Building Air Leakage
• Tankless Water Heaters
• Heat Pump Water Heaters in MN
• Optimization of Existing RTUs
• Combi Systems
Pg. 6
Current Field Research Projects
In Progress
• Improved Effectiveness of Commercial ERVs
• Condensing Boiler Optimization
• Optimized Operation of Pool Facilities
• Reducing Commercial Building Duct Leakage
• Multi-Family Building Envelope Aerosol Sealing
• Effective Ventilation in Multi-Family Buildings
• Secondhand Smoke Exposure in Vehicles
• DOE Building America | Retrofit Water Heating
• DOE Building America | Combi-System Measure Guidelines
• DOE Building America | Combustion Safety Guidelines
• DOE Building America | Demonstration House
2013-14 Archived Webinars &
Upcoming Publications
• Window Retrofit Technologies
• Large Building Air Leakage
• Tankless Water Heaters
• Heat Pump Water Heaters in MN
• Optimization of Existing RTUs
• Combi Systems
Pg. 7
Current Field Research Projects
In Progress
• Improved Effectiveness of Commercial ERVs
• Condensing Boiler Optimization
• Optimized Operation of Pool Facilities
• Reducing Commercial Building Duct Leakage
• Multi-Family Building Envelope Aerosol Sealing
• Effective Ventilation in Multi-Family Buildings
• Secondhand Smoke Exposure in Vehicles
• DOE Building America | Retrofit Water Heating
• DOE Building America | Combi-System Measure Guidelines
• DOE Building America | Combustion Safety Guidelines
• DOE Building America | Demonstration House
2013-14 Archived Webinars &
Upcoming Publications
• Window Retrofit Technologies
• Large Building Air Leakage
• Tankless Water Heaters
• Heat Pump Water Heaters in MN
• Optimization of Existing RTUs
• Combi Systems
Pg. 8
Current Field Research Projects
In Progress
• Improved Effectiveness of Commercial ERVs
• Condensing Boiler Optimization
• Optimized Operation of Pool Facilities
• Reducing Commercial Building Duct Leakage
• Multi-Family Building Envelope Aerosol Sealing
• Effective Ventilation in Multi-Family Buildings
• Secondhand Smoke Exposure in Vehicles
• DOE Building America | Retrofit Water Heating
• DOE Building America | Combi-System Measure Guidelines
• DOE Building America | Combustion Safety Guidelines
• DOE Building America | Demonstration House
2013-14 Archived Webinars &
Upcoming Publications
• Window Retrofit Technologies
• Large Building Air Leakage
• Tankless Water Heaters
• Heat Pump Water Heaters in MN
• Optimization of Existing RTUs
• Combi Systems
Pg. 9
Current Field Research Projects
In Progress
• Improved Effectiveness of Commercial ERVs
• Condensing Boiler Optimization
• Optimized Operation of Pool Facilities
• Reducing Commercial Building Duct Leakage
• Multi-Family Building Envelope Aerosol Sealing
• Effective Ventilation in Multi-Family Buildings
• Secondhand Smoke Exposure in Vehicles
• DOE Building America | Retrofit Water Heating
• DOE Building America | Combi-System Measure Guidelines
• DOE Building America | Combustion Safety Guidelines
• DOE Building America | Demonstration House
2013-14 Archived Webinars &
Upcoming Publications
• Window Retrofit Technologies
• Large Building Air Leakage
• Tankless Water Heaters*
• Heat Pump Water Heaters in MN
• Optimization of Existing RTUs
• Combi Systems
Pg. 10
Today’s Presenter
• With CEE since 1987
• Specializes in existing building
commissioning and HVAC field
diagnostics
• Former program director for the Public
Buildings Enhanced Energy Efficiency
Program (2009 – 2014)
Mark Hancock, P.E.
Director of Engineering
Services
Pg. 11
This project was supported by a grant from the
Minnesota Department of Commerce through the
Conservation Applied Research and Development
(CARD) program.
OPTIMIZING EXISTING ROOFTOP
UNIT EFFICIENCY
A Study Focused on Cold Climate Conditions
Mark Hancock, P.E. |
Center for Energy & Environment
Webinar: November 12, 2014
Pg. 13
So Why Roof Top Units (RTUs)?
Pg. 14
RTU Market
• 46% of all commercial space conditioned by RTU’s
• 2.7 billion ft2 of commercial retail floor space (CBECS 2003)
• Wide variety of applications
• Office
• Commercial
• Manufacturing
• Industrial
• Warehouse
• Retail
• Medical
Pg. 15
RTU’s are widely used
Source: Google maps
5 RTU’s 6 RTU’s
Pg. 16
RTU’s are widely used
Source: Google maps
20 RTU’s
Pg. 17
RTU’s are widely used
Source: Google maps
50 RTU’s
Pg. 18
Why RTU’s
• Packaged units
• Integration of heating and cooling in a single unit
• Reliability
• Low initial cost
• Wide range of sizes to meet requirements of the space
• Plug and Play
• Network of trained installers and service technicians
Pg. 19
The evolution of a Cell phone
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The evolution of RTU
Pg. 21
What’s the problem with RTU?
• Generally RTUs operate inefficiently • Standard efficiency
• Constant speed
• No options for advanced controls
• Lack of maintenance
• Compacted design results in challenges for control
• Stand alone control • Settings conflict with neighboring RTU
• Schedules (if used) don’t match space requirements
• Often over sized • Pick and place from manufacture
Pg. 22
Goals of our study
• Evaluate advanced RTU control strategies
• For efficiency
• For cost effectiveness
• For large scale delivery for CIP offering
• Confirm savings found by other projects
• Small projects in very different climates
• What are the savings in Minnesota?
• Collect performance data
• Target 60 RTUs
• Collect data that spans MN winter and
summer conditions
Pg. 23
The Optimization Packages
• Premium Ventilation
• Digi-RTU Optimizer
• Catalyst Optimizer
Pg. 24
Targeted Optimization Packages
Pg. 25
Premium Ventilation
Source: RTU Premium Ventilation Proof of Concept Field Test
2
Roof Line
Pg. 26
Premium Ventilation
Source: KMC FlexStat Product Literature
Pg. 27
Targeted Optimization Packages
Pg. 28
Digi-RTU Optimizer
Pg. 29
Standard Operation
Pg. 30
Variable speed control
Pg. 31
Targeted Optimization Packages
Pg. 32
Catalyst Optimizer Installation
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Pg. 34
Manufactures Claims
• Premium Ventilation
• 18% to 44% of HVAC use (vary regionally)
• Source “Unitary HVAC Premium Ventilation Upgrade” Reid Hart
2011
• Digi-RTU
• 40% to 60% reduction in energy
• 30% to 60% decline in demand
• Source Bes-Tech / Digi-RTU website
• Catalyst
• 25% to 50% reduction in Energy use
• Source Transformative Wave / Catalyst website
Pg. 35
Previous Studies
66 RTUs
66 RTUs
Pg. 36
Climate Zones
Pg. 37
Our Test sites
Pg. 38
How we collected data
• Internet connected data loggers • For data collection
• For control
• Flip/Flop Test protocol • Allowed for collection of two years of data in one year
• Accounted for changes in the building • Occupied times
• Production
• Staffing
Standard Optimized
S S O S S O S S S S O O O O O
Year one Year two
Pg. 39
Data Collection Period
Pg. 40
Our Test sites
Pg. 41
Distribution of RTU’s: Cooling N
um
ber
of
RTU
’s
Pg. 42
Analysis
• Primary Objectives
• Estimate electric and gas use with and without optimizers
• Estimate savings from optimizers
• Compare savings between optimizer technologies
• Estimate savings for each site
• Calculate simple payback
• Based in measured data and installed costs
• Develop energy savings calculator
• Secondary Objectives
• Analyze IAQ and indoor comfort with and without
optimizers
Pg. 43
Savings: Electric
Pg. 44
Savings: Electric
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Savings: Gas
Pg. 46
Savings: Gas
Pg. 47
Savings: By Site
Digi, Prem Vent
Prem Vent Catalyst Digi-RTU Prem Vent Digi-RTU Optimization
Pg. 48
Savings: By Site
Pg. 49
Savings: By Site
Digi-RTU Digi-RTU Prem. Vent Catalyst Prem. Vent Optimization
Pg. 50
Optimizer Economics
Pg. 51
Optimizer Economics
Pg. 52
Cost Effectiveness
Pg. 53
Paybacks by Capacity
Field Measured Data
Pg. 54
Savings: By groups
Pg. 55
Savings: By groups
Pg. 56
Space Temperature Control
Pg. 57
Space Temperature Control
Pg. 58
IAQ Control
Pg. 59
Key Findings
• All technologies achieved significant
electric savings
• Gas savings were negative or statistically insignificant
• Savings were highly variable
• Fan settings and minimum OA dampers settings were
not consistent
• Advanced controls did not achieve cost-effective
energy savings
• Larger units with more operation would improve cost
effectiveness
Pg. 60
Key Findings
• Control Units were affected by Optimizers
• Best optimizer for a space depends on situation
• “One size does not fit all”
• Market is rapidly expanding
• New innovation
• Product maturity
• Contractor support critical to success of products
• Products tested had issues with MN Climate (Zone 6)
Mark Hancock | 612.335.5861
Question & Answer
Webinar Archive Link:
http://www.mncee.org/Innovation-Exchange/Resource-Center/
Pg. 63