Adaptation and mitigation Strategies for buildings in a changed climate

Transcription

1 Adaptation and mitigation Strategies for buildings in a changed climate Terry Brennan Camroden Associates, Inc. June 7, 2010 National Academy of Sciences Workshop on Climate Change and Indoor Environment Potential Climatic Changes Considered Temperature and moisture - some locations will become: warmer others cooler dryer or wetter Severe weather events may become frequent or more severe: More extremes in temperature and rainfall Increase in hurricanes and floods Rising sea level 1

2 Buildings both contribute to and are impacted by climate change. the building sector accounts for approximately 48% of annual GHG (greenhouse gas) emissions The indoor environment in buildings is impacted as a consequence of climate change and as a consequence of our efforts to reduce GHG emissions from building related activities Building Contributions to GHG production Extraction, manufacture (embodied energy) 8-12% total GHG production Direct energy use 36% total greenhouse gas production Plus distribution Realizing residential building greenhouse gas emissions reductions: The case for a Web-based geospatial building performance and social marketing tool Hal Knowles III 2

3 Increased use of air conditioning This has already happened as the result of market forces It has resulted in increased indoor moisture problems Increased use of air conditioning increases GHG emissions (CO2 and refrigerants) Energy efficient cooling strategies with good part-load dehumidification performance Colonizers - If you build it, they will come. 3

4 Organisms may expand their range: Impacts Related to Climate Change Organisms that contribute to the onset or aggravation of disease or impact IAQ directly e.g. Rodents; mosquitoes; dust mites; roaches Organisms that lead to the pre-mature failure of buildings may expand their range, e.g. termites Increased pesticide use in and around buildings is a likely response to both situations Design and maintain buildings and landscapes to be resistant to pest species colonization 4

5 Colonizing organisms must be controlled by changing the carrying capacity of the building intervening in food, water, shelter or dating bars. Population time 5

6 Increase in the frequency of hurricanes and floods and rise in sea level Provide effective, economic mold clean-up in existing houses Design flood resistant buildings for changing flood zones What happens when the power goes out? Provide for IAQ in emergency shelters Reducing GHG Emissions For existing and newly designed buildings: Lower ventilation rates Increased insulation levels Impact of internal gains Changing behavior to reduce energy use 6

7 Lower ventilation rate methods: Reduced accidental ventilation: Air tightening the enclosure Air tightening and distribution systems Managing air pressure differences Hi efficiency furnace replacement Reduced intentional ventilation Lower recommended ventilation rates 62.2 and 62.1 are inconsistent in recommendations 7

8 Lower ventilation rate effects Reduced dilution of air contaminants from indoor sources Changed condensation potential: Higher cold weather indoor humidity (increased risk of condensation in enclosure) Less airflow through enclosure (decreased risk of heating and cooling mode condensation in enclosure) Air sealing distribution systems may increase cooling mode condensation risk (shorter-ac runtimes) Lower ventilation rate interventions Reduce sources of indoor air contaminants Building related - difficult Occupant related really difficult Provide minimum recommended ventilation rates How low can we go? Improved indoor air filtration IAQ procedure National Center for Energy Management and Building Technologies filtration project Manage indoor dewpoint/relative humidity 8

9 Equilibrium CO2 (ppm) Outdoor Air (cfm/person) SBS Rtsk Factor History of Minimum Ventilation Recommendations Reid 1844 Tredgold 1836 Billings 1895 Nightengale 1865 F l u g g e Yaglou 1936 smoking smoking ASHRAE ASHRAE A S H R A E equilibrium co2 sbs data sbs curve fit Ventilation (cfm/person) Sick Building Syndrome data from Jan Sundell Swedish Office Building Study 9

10 Increased insulation levels More complex enclosures Layers of insulation added to exterior or interior of frame to reduce thermal bridging vapor barriers in the wrong place Lower heat flow through enclosure increases drying time Design enclosures to work in all US climates (Enclosure must control condensation in both heating and cooling mode) 10

11 strategies Energy efficient cooling strategies with good part-load dehumidification performance Design and maintain buildings and landscapes to be resistant to pest species colonization Provide effective, economic mold clean-up in existing houses Design flood resistant buildings for changing flood zones Design for operation during extended power failure Provide for IAQ in emergency shelters Reduce sources of indoor air contaminants Provide minimum recommended ventilation rates Manage indoor dewpoint/relative humidity Design enclosures to work in all US climates (Enclosure must control condensation in both heating and cooling mode) Change behavior to reduce energy use and improve IAQ Teach design, construction and buildings and grounds folks how to do what we already know about this stuff 11

12 Research Needs: Non air conditioning and energy efficient cooling methods for US climates Design pest species out Minimum containment and worker protection for mold remediation Design for operation in the event of extended power failure Minimum ventilation rates Source management and filtration to reduce minimum ventilation rates Changing behavior to reduce energy use and improve IAQ 12