Quantifying Comfort to Assist in the Window Selection Process Kerry Haglund, Efficient Windows Collaborative Jim Larsen, Cardinal Glass Industries June 18, 2015 WDMA Technical & Manufacturing Conference June 16 18, 2015
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Can a Furnace Offset Cold Windows?
How much SEER is needed for Hot Windows?
Agenda 1. Introduction to EWC 2. Comfort Basics ASHRAE Standard 55 3. Window Response to Weather 4. Weather Analysis 5. EWC Comfort Presentation 5 WDMA Technical & Manufacturing Conference June 16 18, 2015
History Team Effort Effectively met DOE s market transformation efforts. Developed effective and innovative tools and information that has impacted the marketplace. Provided unbiased information to consumers, designers, and industry professionals. 6 WDMA Technical & Manufacturing Conference June 16 18, 2015
EWC s Organization & Mission www.efficientwindows.org The EWC now a 501(c)3 organization is part of a greater group of organizations, educational institutions and government agencies that are working to promote energy efficiency in residential and commercial fenestration products. WDMA Technical & Manufacturing Conference June 16 18, 2015
EWC s Organization & Mission The mission of the EWC is to lead and support through the use of advanced window, façade and skylight technologies the transformation of the built environment toward greater energy efficiency. The purpose of the EWC is to provide unbiased information, outreach, education and research to the general public on the energy efficiency, technical considerations, and human considerations that influence window and façade design, selection and use. 8 WDMA Technical & Manufacturing Conference June 16 18, 2015
EWC s Window Selection Tool WDMA Technical & Manufacturing Conference June 16 18, 2015
EWC s Window Selection Tool WDMA Technical & Manufacturing Conference June 16 18, 2015
Comfort Science? WDMA Technical & Manufacturing Conference June 16 18, 2015
Comfort Acronyms 1. MRT: Mean Radiant Temperature Sums thermal radiation in all directions 2. PMV: Predicted Mean Vote Too Cold, Too Hot, Just Right 3. PPD: Predicted Percent Dissatisfied Statistical representation of group response WDMA Technical & Manufacturing Conference June 16 18, 2015
PMV: 7 Point Comfort Scale -3-2 -1 0 +1 +2 +3 Cold Cool Slightly Cool Neutral Slightly Warm Warm Hot WDMA Technical & Manufacturing Conference June 16 18, 2015
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-2-1 0 +1 +2 Cool Slightly Cool Neutral Slightly Warm Warm
Comfort Analysis from Std55 MRT analysis requires: Window size Person position relative to window Window surface temperature
Metabolic Rate
Comfort @ 70 o F
Clothing Insulation
1. Activity Level Standard Conditions 2. Adaptive Clothing
Surrogate for Air Temperature
Complex MRT Analysis
Window MRT Analysis: 2P Clear @ 0 o F
Single Point Cold Discomfort WDMA Technical & Manufacturing Conference June 16 18, 2015
Window Comfort Research 27
Solar Discomfort Issues Hot Glass (MRT) Direct Gain
-2-1 0 +1 +2 Cool Slightly Cool Neutral Slightly Warm Warm WDMA Technical & Manufacturing Conference June 16 18, 2015
Single Point Hot Discomfort WDMA Technical & Manufacturing Conference June 16 18, 2015
1. Two Conditions: EWC Whole Year Analysis Winter Night Summer Day West Elevation 2. Large Window & Close Proximity Patio Door 3 Away 3. Analyze for entire year (8,760 hours) and 100+ locations 4. Sum Hours of Discomfort 31 WDMA Technical & Manufacturing Conference June 16 18, 2015
WDMA Technical & Manufacturing Conference June 16 18, 2015
Determining Cold Weather Threshold Step 1: Calculate Average Surface Temperature w/o Wind
Determining Cold Weather Threshold Step 1: Calculate Average Surface Temperature w/o Wind Example: 0.30U ~ 56 o F @ 0 o F Step 2: Translate Surface Temp @ 0 o F to Hourly Ambient Example: Ambient = 35 o F New Surface Temp ~ 63 o F
Determining Cold Weather Threshold Step 1: Calculate Average Surface Temperature w/o Wind Example: 0.30U ~ 56 o F @ 0 o F Step 2: Translate Surface Temp @ 0 o F to Hourly Ambient Example: Ambient = 35 o F New Surface Temp ~ 63 o F Step 3: We Picked 56 o F as the Threshold for Patio Door Size
WDMA Technical & Manufacturing Conference June 16 18, 2015
Determining Hot Weather Threshold Step 1: Assume neutral comfort without sun (air-conditioner works!) Step 2: Calculate hourly solar gain
Determining Hot Weather Threshold Step 1: Assume neutral comfort without sun (air-conditioner works!) Step 2: Calculate hourly solar gain Step 3: Hour counts if PPD = +10%
Ranking Discomfort Hours Calculate hours of discomfort for 20 window set against weather data for each location using pass/fail criteria. Use (5) point Qualitative scale: Cold Cool Neutral Warm Hot Breakpoints from Neutral to Cool or Neutral to Warm is 1% of annual hours (similar to logic used for sizing HVAC) WDMA Technical & Manufacturing Conference June 16 18, 2015
Minneapolis Cold Discomfort
Kansas City Cold Discomfort
Houston Cold Discomfort
Houston Hot Discomfort
Kansas City Hot Discomfort
Minneapolis Hot Discomfort
Comfort Display in the EWC Window Selection Tool
Comfort and Energy in the Window Selection Tool
Summary & Conclusions Analysis should apply to residential & commercial Trade-off limits in energy code are important for comfort Triple pane suggested in Northern zone (??? ) DOE looking to incorporate into Energy Plus and HVAC design guidelines Give us your feedback! WDMA Technical & Manufacturing Conference June 16 18, 2015
Connect with Us www.efficientwindows.org www.commercialwindows.org www.facebook.com/efficientwindows www.linkedin.com/groups/efficient-windows-collaborative-4286505 twitter.com/ewcwindows 51 WDMA Technical & Manufacturing Conference June 16 18, 2015