21st Century Cooling for Dry Climates
For the Napa Valley Wine Technical Group
Dick Bourne, WCEC Assoc. Director
January 22, 2009
Electricity: Cooling is the Culprit
• July peak demand is 35% above January
• Cooling causes electricity peaks
 7% Load Factor for Residential
 22% Load Factor for Non-Residential
• Cooling peak reducers - best new peaking plants
Western Climates: Issues = Opportunities
• Large Diurnal Temperature Swings
 Issue – Poor Load Factor
 Opportunity – Thermal Storage
• Low Outdoor Humidity
 Issue – Non-Optimized Equipment
 Opportunity – Evaporation for Cooling, Radiant Cooling
Warm
air
HOT
air
WCEC: Who We Are
• Part of the Energy Efficiency
Center at University of
California, Davis
• Launched April 2007
• Current staff:
 Mark Modera, Director
 Dick Bourne, Associate Director
 Marshall Hunt, Programs Director
 Kristin Heinemeier, Senior
Engineer
 Seven Mechanical Engineering
Students
WCEC: Who We Are
• Affiliate Structure
 Utilities
• PG&E, SCE, SMUD, SEMPRA
 Manufacturers
• Delphi, Ice Energy, ICI, Lennox, Munters, NovaTorque, Seeley
Intl., Speakman, Thermal Flow, Trane, Viega, VRTX
 Contracting/Design Firms
• Beutler, Davis Energy Group, Timmons Design Engineers
 State Agencies
• CEC, DGS
 Retailers
• Wal-Mart, Target
WCEC Goals
• By 2030, reduce cooling demand and
energy use from 2007 baseline
 New buildings
• Zero cooling peak demand
• 50% reduction in cooling energy use
 Existing buildings
• 50% reduction in cooling peak demand
• 25% reduction in cooling energy use
What We Do
• Publicize cooling technologies optimized for hot, dry west
 Support affiliate alliances and partnerships
 Address market impediments (e.g. codes and standards)
 Help bridge commercialization “valley of death”
 Emerging technology demonstrations
• Research and development
 Identify, conduct and support key R&D
• Technology development
• Laboratory and field testing
• Modeling and analysis
• Outreach activities
 Catalog of energy-efficient cooling systems
 Website, newsletters, presentations, publications
 Education – university and professional
Current WCEC Activities
• Funded Projects
 CEC - PIER Advanced Cooling Support Program
 CIEE – State-building technology demonstrations (SDSU and UCSD lab
sash project)
 BERG – Improving the Cost Effectiveness of Radiant Floor Cooling
Systems
 SEMPRA- Energy Performance of Hotel Controls (with CLTC)
 SMUD –Hybrid OASys Field Test
 BERG at LBNL – Exhaust Duct Leakage Diagnosis in Multi-Family
Buildings
 EPRI – SEER Review, Status and Recommendations
 LANEY COLLEGE/NSF – HVAC training
 SCE
• Water Management for Indirect and Indirect-Direct Evaporative Air
Conditioning
• Water Use by AquaChill evaporative condenser
Current WCEC Activities
• Projects in Process
 CEC – Three-Year WCEC Research Support
 DOE – Development of lab tests for annual savings predictions
 SEMPRA/PG&E/SCE – Statewide Initiatives (Evaporative Cooling,
Hot Dry AC, Fault Detection/Diagnostics)
• Newly-Funded PIER Projects
 Radiant Cooling for Residences
 Non-Residential Fault Detection Diagnostics
Current WCEC Activities
• Current Key Activities
 Western Cooling Challenge – announced 6/5/08
 Water Initiative – recent ASHRAE presentation
 DOE SEER update
• Current Technologies of Interest




Building-Integrated Cooling
Swimming-Pool Heating
WicKool
Dedicated Outdoor Air Systems
WCEC Technology Portfolio
• Most technologies appropriate for new and retrofit
 Rooftop units
 Evaporative cooling technologies
• Hybrid evaporative/vapor-compression equipment
• Water-cooled condensers
 Swimming-pool-based air conditioners
 Thermal distribution performance
 Night-sky radiative cooling
• Some opportunities unique to new construction:
 Low-cost chilled water storage
 Radiant floor cooling
Example Technology: DualCool
• Accessory system for RTUs
• Pre-cools condenser and
A
C
ventilation air
D
• DOES NOT add moisture
to indoors
• 25-30% energy and
demand savings
B
SYSTEM SCHEMATIC
A - High quality condenser air pre-cooler
B - Pump & copper supply/return piping
C - Ventilation air precooling coil
D - Controls
Example Technology: Roll-Out Radiant Floor
• Prior cost
$6-7/ft2
• Rollout cost
~$2/ft2
• Full-scale
installation
at Wal-Mart
store
Example Technology: Radiant Floor Benefits
•
•
•
•
Reduces latent cooling and blower energy
Facilitates non-compressor cooling
Projected savings 60-65%
Projected demand reduction 45%+
Example Thermal Storage Technology
• Residential/Commercial Swimming Pools
 Night-time cooling (non-refrigerative) makes pool water
available for day-time low-temperature heat rejection
• 20-40oF reduction in refrigerant condensing temperature
• 20-50% improvement in EER – higher at peak conditions
 Rejected heat serves useful function
• Eliminates/reduces gas consumption for pool heating
Power Draw [KW]
Energy Used on Peak Day of Cooling
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
Existing
Pool only
Pool + Cool
Tower
0
4
8
12
Hour
16
20
24
WCEC Market Activities
• Demonstrations
 Integrated retrofits for strip malls
 Technology demonstrations on state-owned buildings
• Policy and Market Drivers
 Western Cooling Challenge
 Hot, Dry Air Conditioners
 Water Initiative
• Water management for evaporative air conditioning
 DOE
• SEER regional standards
• Lab tests for annual savings predictions
Western Cooling Challenge
• Target Market:
Rooftop Units (RTUs) with 3 – 30 ton
capacity (>500-unit production capacity)
RTUs cool 70% of non-residential floor
space in the Western US
• Target Performance: 40% reduction in energy use and peak
electricity demand
• Reward Structure:
MOUs w CA IOUs and SMUD for incentive
programs – Retailer program sponsorship
Western Cooling Challenge: Schedule
January 2009
Laboratory testing of WCC entries can begin
June 2009
Field testing of WCC entries can begin
January 2010
Shipments of WCC-compliant products can begin
New Indirect Heat Exchangers
Coolerado
• Unique multi-stage
indirect design
• 90%+ effectiveness,
balanced flow
• 250 cfm per module,
10” high, 20” long,
19” wide
• Used in Coolerado &
Desert Cool Aire
prototypes
New Indirect Heat Exchangers
HyPak
• High-speed
production
process
• 80%+ effective
in lab test
• Delivered 4.3
tons for 2’ width
• Many other
applications
Example Market Issue: Water Initiative
• Impediments to water-based cooling
 On-site water use
 Equipment maintenance
• Successful water-based systems for buildings




Cooling towers
Pressurized domestic water
Pools
Irrigation
• Water conservation
 Techniques exist
 Not optimized for small-scale evaporative cooling
Evaporative Cooling: Water Use Metrics
• Evaporative Cooling Water Use
 Cooling potential = mass of water * heat of vaporization
 Potentially as low as 1.37 gallons/ton-hr
• Maintenance Water Use
 Rule of Thumb: 2/3 evaporation, 1/3 maintenance
 Large Impact of Water Quality
• Indirect Water Consumption for Electricity Generation
 Enormous range of values - 0.1-72 gal/KWh

Water Use for Condenser-Air Pre-Cooling
• Analysis Technique
 Calculate change in EER with respect to condenser
air temperature
• Relatively linear
• 1-2% change per oF
 Calculate condenser
temperature change per unit
of water evaporated
 Use EER change to calculate
extra cooling delivered for the
same electricity consumed
Example Market Issue: Water Issue Resolution
• Roles for the WCEC
 provide “institutional memory”
on water issues
• water-use yardsticks
 access large cadre of water
scientists at UCD
 pursue water conservation
solutions
• save rain runoff for cooling
• irrigate w/flushed water
• night-sky water cooling
Wine Industry Opportunities
•
•
•
•
Evaporative condensing and pre-cooling
Pre-cooled ventilation air (e.g. Fetzer)
Thermal storage (wine is ideal!)
Radiant cooling to reduce blower power (may
need desiccants in high humidity areas)
• CHP (e.g. Vineyard 29)
• Others?
WCEC Mission Summary
“Partner with stakeholders to identify
technologies, conduct research and
demonstrations, disseminate information, and
implement programs that reduce coolingsystem electrical demand and energy
consumption in the Western United States.”
http://wcec.ucdavis.edu/
Mark Modera
mpmodera@ucdavis.edu