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Transcript of Phoenix Convention Center Phoenix, Arizona Challenges of Localized Cooling Systems Integrated Energy...
Phoenix Convention Center • Phoenix, Arizona
Challenges of Localized Cooling Systems
Integrated Energy District Heating and Cooling – Optimized Comfort
Brian BoydPacific Northwest National Laboratory
August 12, 2015
Energy Exchange: Federal Sustainability for the Next Decade2
This Presentation
Provides an example of challenges federal locations may experience if localized systems are implemented
Session IntentCompare the dynamics of localized versus district heating and cooling systems
with an emphasis on system performance for optimized occupant comfort
Introduction
Energy Exchange: Federal Sustainability for the Next Decade3
Background
• The site has 40 cooling towers and 42 water-cooled chillers
• Total water-cooled chiller capacity exceeds 3,000 tons
• Some systems operate seasonally, others operate year round
The Federal Energy Management Program (FEMP) sponsored a team from PNNL to provide O&M support in FY 2014 for a Naval facility in Japan having challenges with their evaporative cooling systems
Energy Exchange: Federal Sustainability for the Next Decade4
Cooling Towers – Two Different Designs
Induced-draft, counter-flow• Manufactured by Shinwa, Kuken, and
Mitsubishi• Range in size from 20 to 150 tons
Induced-draft, cross-flow• Manufactured by Shinwa and
Mitsubishi• Range in size from 100 to 150 tons
Energy Exchange: Federal Sustainability for the Next Decade5
Chiller Technologies
A variety of chiller
technologies are used
Daikin, Hitachi, and Toshiba units were
observed
Vintage and configuration varied
from building to building
Energy Exchange: Federal Sustainability for the Next Decade6
• Located on the ground, near the buildings they serve
• Evidence of algae on the fan blades and screens on top of the units
• Channeling and loss of flow through the tower fill
Counter-flow towers
Observed Challenges
Energy Exchange: Federal Sustainability for the Next Decade7
• Open distribution decks• Indications of compromised
water flow
Cross-flow towers
Observed Challenges
Energy Exchange: Federal Sustainability for the Next Decade8
Impact of Condenser Scale Deposits on Chiller Efficiency
Performance Implications
Condenser Deposit Thickness
(in.)
Equivalent Measurement
(mm)
Range of Efficiency Loss
(%)0.006 0.15 ~5
0.012 0.3 5-10
0.024 0.6 15-18
0.036 0.9 25-30
0.048 1.2 >35
Energy Exchange: Federal Sustainability for the Next Decade9
Uniform deposits are between 0.6 mm and 0.9 mm present throughout the condenser
Loss in efficiency is costing between $990 and $1,490 annually for this single chiller (based on $0.112/kWh electricity rate and calculated operating hours)
Cost Implications
Energy Exchange: Federal Sustainability for the Next Decade10
Discussion of localized versus district heating and cooling tends to
focus on the economic benefits of localized
systems
There may be upfront economic benefits, but
there are O&M challenges that can
increase lifecycle costs
This presentation highlighted observed
O&M challenges at one Naval facility and the
associated costs
Conclusions
Energy Exchange: Federal Sustainability for the Next Decade11
FEMP’s Water Efficiency Webpage:
energy.gov/eere/femp/water-use-reduction
For More Information…
Brian BoydResearch EngineerPacific Northwest National [email protected] – (509) 371-6724