Busting the Myth: Passive Houses Only Work in Cold Climates (The Comfort Proposition) Alison Kwok, Ph.D., AIA, LEED AP, CPHC Alison G. Kwok Ph.D., AIA, LEED AP University of Oregon Walter T. Grondzik P.E., LEED AP Ball State University 6 th Annual North American Passive House Conference Silver Springs, Maryland October 28-29, 2011
What is Thermal Comfort? That condition of mind which expresses satisfaction with the thermal environment and is assessed by subjective evaluation. ASHRAE Standard 55-2010 Thermal Environmental Conditions for Human Occupancy
Subjective Evaluation Traditional 7-point status scale: -3-2 -1 0 +1 +2 +3 cold cool sl. cool sl. warm warm hot Alternative action scale: Would you prefer: to be warmer no change to be cooler
Comfort Standard That condition of mind which expresses satisfaction with the thermal environment and is assessed by subjective evaluation. ASHRAE Standard 55-2010 Thermal Environmental Conditions for Human Occupancy
Building-Influenced Comfort Factors ENVIRONMENTAL FACTORS air temperature (dry bulb, F) relative humidity (%) air speed (ft/min) radiant conditions (MRT F or radiation value Btuh/sf)
Surface Temperature House: http://www.nachi.org/ir-camera-overview-inspectors.htm Hand: http://www.handresearch.com/news/hands-biometry-technology.htm Camera: http://www.flir.com/us/
MRT MRT = mean radiant temperature MRT is the (uniform) temperature of surrounding surfaces with which the human body would exchange the same heat by radiation as occurs in an actual (non-uniform) environment 2 1 1 2 Diagram: Walter Grondzik
User-Influenced Comfort Factors PHYSICAL FACTORS Clothing insulation CLO Metabolic activity MET MENTAL State of mind (experiences, expectations, influence of other conditions...)
All Together Now: Parameters that Affect Thermal Comfort We must control: Air temperature Relative humidity Air speed We must consider: Clothing Activity level Mental state Radiant conditions MRT or solar intensity environmental factors personal factors
Comfort and Passive House USER FACTORS Clothing insulation Metabolic activity State of mind ENVIRONMENTAL FACTORS air temperature relative humidity air speed radiant conditions Empower House: Solar Decathlon 2011 Photo: Alison Kwok
Air Temperature 77 What is different between a PH and a conventional house? Temperature icon:http://www.bloomingfreedom.com/
Relative Humidity www.totaltravelbug.com www.essentialoilworld.com http://netzeroenergy.org/ What is different between a PH and a conventional house? Water icon: http://www.ecophon.com/en/
Air Speed http://rockybella.blogspot.com/ http://articles.nydailynews.com What is different between a PH and a conventional house? Wind icon: http://www.alterisinc.com/how-it-works/wind-technology/
MRT Poorly insulated roof Well-insulated roof Ecotech Lab, Yokohama National University Green Roof Test What is different between a PH and a conventional house?
Passive House Winter MRT 59 F 68.9 F 64.4 F 68.9 F 7 F 7 F 9 degree difference Conventional house: low surface temperature = discomfort 4 degree difference Passive House: min 64 F surface temperature = comfort
Passive House Summer MRT? F 77 F 85 F Passive House: maximum?? F surface temperature = comfort
Clothing (CLO) http://www.topix.com/album/detail/ca/lac-la-biche-ab/ http://www.cheapfootedpajamas.com/ What is different between a PH and a conventional house? Clothing icon: http://www.aokto.com/countries/singapore/
Activity (MET) youmemoir.com www.sbse.org (digital archives) What is different between a PH and a conventional house? Work icon: http://www.zazzle.com/
State of Mind mylifebody.com A. Kwok: Thermal Comfort in Tropical Schools What is different between a PH and a conventional house? Worry icon: http://burzumfen.deviantart.com/art/
Adaptive Comfort Standard Diagram: lunaspace.wordpress.com Worry icon: http://burzumfen.deviantart.com/art/
Summary: Hit or Myth? Fig. 4.186 Applicability of building cooling strategies. The Green Studio Handbook, 2e