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Duct Sealing Evolution: A Puget Sound Area Pilot Approach. Bruce Manclark, Delta T. March 2, 2009. Agenda. Description of Puget Sound Area Prescriptive Duct Sealing pilot Description of Quality Assurance Inspections and Thorough Data Collection RTF Decision:
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Duct Sealing Evolution: A Puget Sound Area Pilot Approach Bruce Manclark, Delta T March 2, 2009
Agenda • Description of Puget Sound Area Prescriptive Duct Sealing pilot • Description of Quality Assurance Inspections and Thorough Data Collection • RTF Decision: • For homes completed under this pilot, allow the utilities to claim the current PTCS duct sealing kWh savings.
Current PTCS Hurdles • Complexity • Training focused on testing, not duct repair • Standards – 50% reduction and 10% rules didn’t necessarily result in maximum savings • Duct blaster counts all leaks as equal (all at 50 Pa) but at normal operating conditions plenum may be at 125 Pa, and boot at 2 Pa so some leaks are more important than others • Test data (leakage at 50 Pa) can’t be used to calculate savings • Contractor hurdles • Testing and bidding is costly • Testing equipment is costly and tough to learn • Fear of failing > Result: Limited market share
Delta Q • Tested 40 homes using Duct Blaster ® and Delta Q (leakage estimated at operating conditions through curve-fit) • Data allowed for direct calculation of kWh resulting from leakage at operating conditions • Findings: • Delta Q testing requires high level of skill and understanding • kWh were significantly higher than current PTCS savings under these controlled conditions (2,058 kWh vs PTCS 1,056 kWh for HP system) • Even good duct sealers lacked basic duct repair skills and tools • Floor insulators occasionally damage ducts
New Approach • Training adjusted to emphasize fixing ducts (not just sealing) • Prescriptive Sealing • Focus on high static pressure (especially furnace can cut-in) • Inspect all ducts for disconnects • Determine whether supply or return is bigger problem • Referrals to experts for complicated system problems • High rate of QA inspections • Research quality data collected on a sample of homes (pre and post) • Cost to deliver is lower, allowing incentive to cover the full cost of duct sealing >Test Hypothesis: Determine savings from this new approach
Hypothesis Testing • “The simplified protocol results in comparable savings to PTCS duct sealing when applied to a high volume utility supported program.” • Develop 140 case random sample from field • Provides a 90/5 sample criteria • Based on sampling as work assignments come in • Allows before /after testing on the random sample of cases • Assess performance based on comparison to existing PTCS database • Assess final leakage rate • Assess change in leakage rate • Develop billing analysis • Develop a small control group from utility records • Assess gross and net energy savings from the sample • Evaluate the entire program with a billing analysis
Utility Motivations • More duct sealing will get done • Research quality testing will allow us to determine if there are more savings per home • Lower the cost of delivery • Not testing • Bidding costs reduced • Better skilled contractors • Consistent rules and more buyin for contractors in region • We have to think big • Goals are increasing significantly • Tacoma - 5x • PSE – plan to do 2000 duct seal jobs this year compared to 300 last year • Snohomish -
Utility Programs Puget Sound Energy • Train floor insulators to become duct sealers and • Require duct sealing on every floor insulation job (free to customer) • Require at time of furnace replacement Tacoma Power Snohomish PUD > Consistent training and sealing specs for contractors > Consistent QA and test protocol > Consistent data analysis
Research Plan • 2000 homes • Visual QA on 25% (higher early on, with sample recall if high defect rate is found) • Detailed Research quality testing pre and post on sample of 140 • Supply leakage at 25 Pa – Duct Blaster® • Supply leakage at 50 Pa – Duct Blaster® • Return leakage at 25 Pa – Duct Blaster® • Return leakage at 50 Pa – Duct Blaster® • Plenum pressure measurement – long pitot tube/manometer • Air flow measurement – TrueFlow plate • Additional pre –leakage data sets (200 + homes) will be analyzed
RTF Decision • “For the purpose of this pilot, allow utilities to claim currently defined PTCS savings for duct sealing.” • Justification: • Prescriptive approach has the potential to result in higher savings for many homes • Current PTCS allows someone to go from 10.5% to 9.5% - with little savings resulting • Prescriptive sealing of furnace can cut-in represents a large savings potential that may have been missed on PTCS homes • It’s possible that some homes may have lower savings, but it is expected that the mean savings will be at least as high • Current PTCS does screen for “not leaky enough” homes, but we don’t know precisely how many meet this criteria • The data to be collected will provide more reliable information about the leakiness of the duct systems and the savings from sealing the ducts