Rethinking  Energy,  Materials,  &  Transporta6on  in  Passive  Houses  

Source:  Hausbau-­‐Beratung24.de  

Embodied  Energy  and  Carbon  

Steelmaking  (Source:  Jupiter  Images  Corpora6on)  

Embodied  Energy  vs.  Carbon  Footprint  

Embodied  Energy  =  Sum  of  all  energy  needed  to  produce  any  product,  as  if  that  energy  was  incorporated  or  "embodied"  into  the  product  itself.  

Source:  Building  Green  

Carbon  Footprint  =  Sum  of  all  greenhouse  gases  emiQed  by  the  full  life  cycle  of  a  product.  

Life  Cycle  Energy  Assessment  for  Passive  Houses  =    Embodied  Energy  +  Opera6ons  +  Maintenance  

Source:  Stephan,  André,  Robert  H.  Crawford,  and  Kristel  De  MyQenaere.  "A  Comprehensive  Assessment  of  the  Life  Cycle  Energy  Demand  of  Passive  Houses."  Applied  Energy112  (2013):  23-­‐34.  Print.  

But  source  data  may  not  be  appropriate  for  our  context.    

DETAILS

 Base  case  passive  house:    

•  Period  of  analysis  =  100  years  

•  Usable  floor  area  =  3,197  a2  

•  Structure:  Steel-­‐framed,    concrete  floor  slabs  

•  Façade  =  Block  walls,  Glued  bricks  –  220  mm  of  polyurethane  insula6on  –    

•  Triple  glazed,  argon  filled,  wood  windows  

•  Roof  =  TerracoQa  6les  –  300  mm  of  polyurethane  insula6on  and  100  mm  of  rock  wool  insula6on  

 0  

200  

400  

600  

800  

1000  

1200  

Base  Case   As-­‐Built  

Stephan  et  al  Study  uses  Australian  figures  for  Belgian  case  

Energy  Choices  Not  Fixed  Study:  "The  embodied,  opera6onal  and  transport  energy  requirements  represent  40.0%,  32.8%  and  27.2%  of  the  total,  respec6vely."    Source:  Stephan  et  al  

However,  material  and  process  choices  have  a  significant  effect  on  embodied  energy.  

Map  of  Material  origina6on  loca6ons:  by  Linnean  

Carbon  Emissions  

Two  Very  similar  office  renova6on  projects    Upper  total  =  86  MJ/sf    Lower  total  =  43  MJ/sf  

Life  Cycle  Energy  Demand:  Embodied,  Opera6onal,  &  Transport  

Embodied:  4,001,000  kWh  145,332  kWh/C2  

 Graph  Compares    GJ  and  GJ/m2  1  GJ  =  278  kWh  1m²  =  10.8C²  

 

OperaLonal:  3,280,277  kWh  118,885  kWh/C2   Transport:  

2,273,333  kWh  98,700  kWh/C2  

Total:  10,013,611  kWh  362,918  kWh/C2  

 

100  Year  Analysis  Period      

Life  Cycle  Energy  Demand  of  Passive  Houses  Compared  with  Varia6ons    

Graph  Compares    GJ  of  energy  over  100  years  

 

Standard  house  with  electrical  appliances  now  powered  by  gas  uses  9,292,631  kWh  

Passive  house  with  electrical  appliances  now  powered  by  gas  uses  8,660,732  kWh  

Standard  house  with  electrical  appliances  now  powered  by  gas  plus  reduced  operaLonal  energy  

Passive  house  base  case  uses  10,013,611  kWh   Standard  

house  uses  10,070,277  kWh  

Embodied  vs.  Opera6onal  Energy  This  needs  some  explana6on.  What  are  the  two  bars  and  the  confidence  intervals?  

And  a  way  more  descrip6ve  6tle.  

EcoCalculator  for  North  East  Belgian  Style  =  7,376  GJ  

EcoCalulator  for  NE  US  Style  =  3,600  GJ  

OE  =  35  Kbtu/sf/yr    

Embodied  Energy  By  Material   Timber  use  in  base  case:  •  158.9  a3  -­‐  hardwood  

window  frames    •  247.2  a3  -­‐  parquet  

flooring;  hollow  core  MDF  doors;  roof;  cupboards  and  closets  

•  10.6  a3  -­‐  soawood  (framing)  in  hollow  core  MDF  doors  

•  416.7  a3  =  Total  

Carbon  Emissions  By  Material  

Other  poten6al  uses  of  6mber  in  passive  houses:  •  Upper  floor  slabs  •  Roof  structure  •  Columns  and  beams  

Source:  Coopera6ve  Research  Centre  for  Greenhouse  Accoun6ng  (Australia)  

Carbon  Emissions  

Key  Conclusions:  §  Metal  has  the  highest  carbon  intensity.  §  The  amount  of  carbon  generally  correlates  

with  the  amount  of  material.  

•     Time  Value  of  Carbon  Savings          Carbon  saved  now  is  worth  more  than  Carbon  later          (area  under  the  line  is  total  carbon  emiQed)  

   

10%  reduc6on  per  year  

Start  slow  -­‐  increase  rate  of  reduc6on  

Start  fast  -­‐  decrease  rate  of  reduc6on  

Time  

Car

bon

Red

uctio

n WHY  FOCUS  ON  EMBODIED  CARBON?  

Carbon  &  Chemical  of  Concern  Accoun7ng  

§  Typical  Interior  Office  Renova6on    §  Calculated  carbon  emissions  for  materials  

and  contractor  commu6ng  §  Assessed  VOC  quan6ty  and  quality  of  

materials  §  Evaluated  economic  impact  on  local  and  

na6onal  community  

Toxicity  of  Materials  

PVC  piping  (Source:  True  Well  Pipes)  

Red  Lists  and  Transparency  

“Red  lists,”  such  as  the  Living  Building  Challenge’s  are  increasingly  common  but  cau6on  is  advised,  as    new  subs6tutes  for  listed  chemical  may  be  as  bad  or  worse.  

LEED  ra6ng  system  rewards  projects  for  using  products  with  low  VOC  emissions,  but  doesn’t  address  chemical  cons6tuents  of  building  products.  

LEED  

Materials  &  Resources   Energy  &  Air  Quality  

Risks  From  Adhesives  &  Sealants  

Source:  Green  Building  Supply   Source:  Building  Green  

Greener  Adhesive  Choices  

Acrylic  Tape  

Butyl  Rubber  Tape  

Source:  Building  Green  

To  minimize  environmental  and  health  impacts:      •  Select  low-­‐emiyng  tapes  over  

solvent-­‐based,  wet-­‐applied  products.    

•  Provide  adequate  worker  training  and  protec6on.  

Risks  From  Insula6on  

Spray  Polyurethane  Foam  (SPF)  

Extruded  Polystyrene  (XPS)    

“The  more  insula6on  the  beQer”  is  common  refrain  in  green  building  industry.  Insula6on  =  strategy  for  net-­‐zero-­‐energy  &  carbon-­‐neutral  performance    

 But  both  XPS  and  SPF  contribute  to  climate  change  via  embodied  energy  and  blowing-­‐agent  leakage.  And,  the  brominated  flame  retardant  HBCD  in  XPS  is  persistent,  bioaccumula6ve,  and  toxic  in  animal  studies.  

 

Greener  Insula6on  Choices  

Mineral  Wool  

Cellulose  

Source:  Building  Green  

Wood  

•  Compared  with  nonrenewable  building  materials,  wood:  –  is  produced  largely  from  input  of  sunlight  (through  photosynthesis),    

– sequesters  carbon  in  its  produc6on,    – carries  low  embodied  energy,  and    –  is  nontoxic,  reusable,  and  biodegradable.  

Increasing  Demand  for  Materials    with  Low  Emissions  and  VOCs  

Improve  IAQ  Increases  11%  from  2008  McGraw-­‐Hill  Construc7on,  2013  

0%   10%   20%   30%   40%   50%   60%   70%   80%  

Reduce  Energy  Consump6on  

Lower  Greenhouse  Gas  Emissions  

Protect  Natural  Resources  

Reduce  Water  Consump6on  

Improve  Indoor  Air  Quality  

2012  2008  

Most  Important  Environmental  Reasons    for  Building  Green  

Chemicals  of  Concern  Present  in  Project  

§  Formaldehyde  was  found  in  plywood  –  a  frequently  used  product  

§  PVC  was  found  in  some  ‘green’  flooring  §  Phthalates  were  found  in  adhesives  

Chemicals  of  Concern  per  Building  Product  

§  Carpet  by  far  the  worst  VOC  emiQer,  mainly  because  of  the  amount  of  product  used.  

§  Sheetrock  contains  formaldehyde;  there  is  an  es6mated  22  mg  in  base  case  passive  house.  

Total  Weight  of  Chemicals  of  Concern  in  the  Project  

Contractor  Transporta6on  

During  Construc6on  

New  Bedford:  .90  MT  C02e  for  140  labor  hours  (1  MT/156  hours)  

Easton:  3.62  MT  C02e  for  1,274  labor  hours  (1  MT/354  hours)  

Woburn:  1.89  MT  C02e  for  1,205  labor  hours  (1  MT/638  hours)   Boston:  .44  MT  C02e  

for  1,873  labor  hours  (1  MT/4,257  hours)  

Contractor  Transporta6on  

During  Construc6on  

Transporta6on  Post-­‐Construc6on  

Study  Trans  Energy  per  year  =  93  MBtu  

Ques6ons  As  we  reduce  opera6onal  energy,  how  can  we  find  similar  reduc6ons  in  other  impacts?  

•  Reduce  embodied  carbon  materials?  

•  Lower  toxicity  of  materials?  •  Minimize  loca6on  effects?