Advanced Direct Evaporative Pre-Cooling for Air Cooled Condensers (DEPACC)
Program OverviewTechnology OverviewEnergy SavingsCustomer Benefits
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What is DEPACC? – Program Overview
• Technology: Direct Evaporative Pre-Cooling for Air Cooled Condensers used with unitary DX air conditioning equipment, typically RTUs
• New for 2014 – All Air-cooled Chillers• Program: Prescriptive incentive program to increase the adoption
of evaporative pre-condensing as a retrofit measure• Part of the existing Xcel Cooling Efficiency Program
• Preapproval is not required
• Any nonresidential• Dedicated data centers must apply through custom process
• Minimal system size is 10 tons
• Incentive is $100/ton
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DEPACC – Technology Overview
• Evaporative pre-cooling:• Cools hot outside air before cooling the
condenser coils
• AC system operates as if it were 20O or more cooler at the coil than ambient dry bulb
• Typical results in 15 – 30% improvement in cooling energy efficiency
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Two Types of Systems
Mist with saturated membrane – no sump or recirculation
Saturated membrane with sump and recirculation
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Qualified Solutions
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Once Through Systems
Recirculation Systems
System Providers & Installations
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HydrEVAP by RCF Inc., distributed by ATEC/Indirex
EVAPORCOOL by Evaporcool Inc. distributed by Evaporcool
Dual Cool by Integrated Comfort Inc., distributed by ATEC/Indirex
Smart Mist by Cloudburst
Program Eligibility Requirements
• DX RTU and Air-Cooled Chillers• System Size not less than 10 tons cooling capacity• Evaporative pre-condensing system must provide a minimum of 75%
temperature reduction of the potential total wet bulb depression available at all ambient conditions when the compressor operates.
• DEPACC system shall be configured such that no water mist or spray to contact or accumulate on the condenser coils.
• DEPACC system must include a mechanical or chemical water treatment system to prevent scaling
• System should be equipped with controls that limit water use• Dedicated data center facilities are ineligible as prescriptive
measure and must use Xcel custom measure process
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Targeted Building Types
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• Program Savings per ton of cooling are correlated with building use type and location
• Hospitals, Lodging & Offices yield highest savings
Expected Annual Savings by Building Type per Ton
$/ton Front Range Western Slope
PSC-SGL PSC- SG & STOU PSC-SGL PSC- SG & STOU
Education - Community College $44 $29 $51 $34
Education - Secondary School $27 $18 $32 $21
Education - University $59 $39 $68 $46
Health/Medical - Clinic $50 $33 $58 $39
Health/Medical - Hospital $97 $65 $113 $75
Lodging $81 $54 $95 $63
Office $66 $44 $77 $51
Retail $59 $39 $68 $45
Targeted Equipment – RTUs
Larger Systems are somewhat better•Installed cost per unit diminishes as system size increases
Key Variables • Water available on the roof• Size of the equipment• Roof accessibility for contractor
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Breadth of Energy Bill Savings
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• Cost Savings:$44 to $115 / ton annual
savings
• Simple Payback:Less than 2 years
Representative Project Energy Savings
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Denver Office Building 150,000 sf 320 tons Cooling (4-80 ton RTU’s)
Peak Summer Week 40% Cooling Energy Savings
Annual 19% Cooling Energy Savings 2,400 kWh / week average
Representative Project Energy Savings
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Denver Office Building 150,000 sf 320 tons Cooling (4-80 ton RTU’s)
Peak Summer Week 15% Total Building Energy Savings
Annual 4% Total Building Energy Savings2,400 kWh / week average
Savings
What are the Customer Benefits?
•DEPACC program can deliver good ROI and reliable savings• Typical 1-2 YR Simple Paybacks
•Proven improvements in Air Conditioner performance• Cooler low side temperatures which allow for colder conditioned air
• Reduce energy consumption 15-20%
• Reduce energy peak demand typically 15-35%
•Help protect coils from damage and debris build-up• Simplifies & Reduces condenser coil cleaning
• Enhances life of the DX unit• Reducing head pressure
• Protects contamination of condenser coils
•Can reduce the need for over-designing new and existing building
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Project Scoping
Initial Customer Qualification Screen:
• System equal to or larger than nominal 10 tons of cooling
• Building type and location
Project Delivery
•Customer or HVAC Service Contractor obtain equipment information
•Contact DEPACC system provider for equipment pricing
•Utility bill records & tariff information if available
•Prepare Economic ProForma: Energy at Risk or other tool
•Execute Installation Contract & submit for rebate
•Contact Cypress for assistance
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