Western Cooling Efficiency Center - Emerging Cooling

Technologies

September 16, 2009ETCC Meeting

Mark P. ModeraDirector, Western Cooling Efficiency Center, UC Davis

Emerging Technologies for Cooling in the West

• Existing Residential

• Hot Dry Air Conditioners

• Existing equipment

• High-EER

• Evaporative Condensers (SCE)

• Hybrid evaporative/vapor-compression equipment (PIER)

Emerging Technologies for Cooling in the West

• Residential New Construction

• Radiant Cooling (PIER/GTI)

• Chilled-water storage (PIER/GTI)

• Water capture/re-use

• Hybrid evap/vapor-compression (PIER)

Emerging Technologies for Cooling in the West

Existing Commercial

• RTUs = 70% of Market

• Replacement

• Western Cooling Challenge

• Retrofit (PIER-PG&E Target)

• Indirect Evaporative Outdoor Air Cooling

• Evaporative Pre-Cooling of Condenser Air

• Condensate Evaporation (Wickool – PIER)

 WCEC Initiative: Western Cooling Challenge

• Target Market

• Roof-Top Units (RTUs) with 3 – 30 ton capacity

• Target Performance

• 40% reduction in energy use and peak electricity demand

• Achievable without complete redesign

• Reward Structure

• MOUs w IOUs and SMUD for incentives

• Retailer program sponsorship

 WCEC Initiative: Western Cooling Challenge• Performance Targets:

• Ground-up re-design eliminates major manufacturers

• Allow existing high-efficiency equipment with accessories

• Technology Entries:

• Hybrid ground-up designs

• Indirect evaporative, DX, high-η motors and fans

• Accessorized existing equipment

• Evaporative condenser pre-coolers

• Indirect outdoor-air pre-cooling

• High-efficiency variable-speed motors

 WCEC Initiative: Western Cooling Challenge• Current Status

• Coolerado RTU first to meet the Challenge

• Testing completed at NREL

• Inspired Press Release by UC Davis

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WCC Performance Comparison

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 WCEC Initiative: Western Cooling Challenge• Current Status

• Projected savings from single points - EnergyPlus simulations in process

• Second entry being tested this week

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Savings vs. DOE 2010

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RTU Retrofit: Wickool

Concept§ Evaporate condensate at condenser§ Eliminate need for condensate piping

Status§ Patent in Process

§ Licensed to Octus Energy§ Lab Testing Complete

§ 400% improvement over initial units

§ Field Testing Initiated§ Davis Target Store

RTU Retrofit: Wickool

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Lineare Regression für Lineare Regression für Lineare Regression für

Air Velocity, m/s

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Emerging Technology for Cooling in the West:

New-Construction Radiant Floor

• Prior cost $6-7/ft2• Rollout cost ~$2/ft2• Full-scale installations at Wal-

Mart stores• Currently investigating non-

chemical water treatment (PIER)

Radiant Floor or Ceiling Benefits

• Reduces latent cooling and blower energy• Facilitates non-compressor cooling• Projected savings 60-65%

Western Cooling Issue: Water Consumption

Accelerated Testing: Impact of Hard Water§ OASys Indirect/Direct Evaporative System (SCE)§ Initial testing with no maintenance water

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ECER (Using Input Capacity)

Hours Of Operation

Fan HIGH, Temps 99-105

Fan HIGH, Temps 105-110

Fan HIGH, Temps 110-118

Western Cooling Issue: Water Consumption

Accelerated Testing: Impact of Hard Water§ Continuous Operation: Capacity and ECER initially improved slightly

before decreasing to end at initial point§ Cyclic Operation: Steady decrease in performance§ Performance changes not dramatic even with significant mineral build up

on evaporative media

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ECER (Using Input Capacity)

Gallons of Water

Fan HIGH, Temps 99-105

Fan HIGH, Temps 105-110

Fan HIGH, Temps 110-115

Western Cooling Issue: Water Consumption

§ Calculate condenser temperature change per unit of water evaporated

§ Use EER change to calculate extra cooling delivered for the same electricity consumed

%3015−=ηcc

Water Use for Condenser-Air Pre-Cooling§ Calculate change in EER with respect to condenser air temperature§ Relatively linear§ 1-2% change per oF

Combined On-Site and Off-Site Water Use

• Evaporative Cooling = 4.6 gal/ton h (CA avg electric)

= 5.5 gal/ton h (CA avg electric)

• Condenser Pre-Cooler = 5.7 gal/ton h (CA avg electric)

On-Site Water Use• Rainwater Capture and Storage

• Grey-water Treatment

• Compressor Cooling

* Using 4.6 gal/kWh CA avg, 30 SEER for evaporative, 10 SEER for compressor, 15 oF avg WB depression, and 1.5%/oF impact of condenser air on efficiency

Future Cooling Technologies

Warm air

HOT air

Warm air

HOT air

Unsolicited Inquires for WCEC Support- Evaporative Pre-Cooling for Condensers

- Indirect Evaporative Coolers

- Solid-State Cooling

- Nozzle-Expansion Cooling

Performance Analysis

- Conventional vs. Carnot η

)( coldhot

cold

c TT

T

−=η

Future Cooling Technologies

Warm air

HOT air

Warm air

HOT air

Heat Exchange vs. Refrigeration Circuit

Tcold Thot COP EER

80oF 95oF 36 123

45oF 140oF 5 18

Emerging Western Cooling: Summary

Existing RTUs• Western Cooling Challenge• Wickool

Radiant Cooling in New Construction• Residential and Commercial

Need to Address Water Consumption• Rainwater capture - grey-water treatment

Future Trends• Heat Exchange vs. Refrigeration Circuit

http://wcec.ucdavis.edu/ mpmodera@ucdavis.edu