COOLING LOADS AND OCCUPANT COMFORT IN HIGHLY GLAZED BUILDINGS

Scott R. Armstrong, CET, LEED AP MMM Group

2014 © MMM GROUP

COOLING  LOADS  AND  OCCUPANT  COMFORT  IN  HIGHLY  GLAZED  BUILDINGS  

THE  EFFECTIVE  EVALUATION  OF  WINDOW  RETROFITS  

 

Sco:  R.  Armstrong,  CET  MMM  Group  –  Building  Performance  ArmstrongS@mmm.ca    

2014 © MMM GROUP

COOLING  LOADS  AND  OCCUPANT  COMFORT  IN  HIGHLY  GLAZED  BUILDINGS  

■  ENERGY  LOADS  –  how  building  form  influences  energy  loads    ■  EXISTING  CONDITIONS  –  how  is  the  building  performing  and  

what  are  the  concerns  ■  RETROFIT  STUDY  –  window  retrofit  case  study  ■  THE  TAKE-­‐AWAY  

  Founded  in  1952    Over  2,000  staff  across  Canada    Ac]ve  in  public,  private,  P3  sectors  

with  focus  on  Buildings,  Transporta]on  and  Infrastructure  

  Extensive  experience  in  Alternate  Project  Delivery  

   Owners  Representa]ve  (PDC,  OE,  BF  and  DBFM  roles)  

MMM  GROUP  CORPORATE  PROFILE  

FIRM  EVOLUTION  

Services for Buildings

Mechanical Engineering

Electrical Engineering

Structural Engineering

Sustainability & Energy

Building Performance

Civil & Stormwater

Traffic

IT/Security

Specialty Lighting

Planning & Landscape

Primary Sectors

Healthcare

Transit

Telecom

Commercial

Institutional

Luxury Residential

Mission Net Zero

INTEGRATED  SERVICE  DELIVERY  

Architravel.com

Niagarafallsmarriott.com

Theismaili.org Condoblog.minto.com Urbantoronto.com Normandthegang.wordpress.com

SELECT  PERSONAL  EXPERIENCE  

2014 © MMM GROUP

COOLING  LOADS  AND  OCCUPANT  COMFORT  IN  HIGHLY  GLAZED  BUILDINGS  

■  ENERGY  LOADS  –  how  building  form  influences  energy  loads    ■  EXISTING  CONDITIONS  –  how  is  the  building  performing  and  

what  are  the  concerns  ■  STUDY  –  window  retrofit  case  study  ■  THE  TAKE-­‐AWAY  

2014 © MMM GROUP

NET  POSITIVE  ENERGY  TO  THE  BUILDING    

2014 © MMM GROUP

NOT  NET  POSITIVE  ENERGY  TO  THE  BUILDING  

2014 © MMM GROUP

R3

R4

R2

OVERALL  WALL  +  WINDOW  R-­‐VALUE  

2014 © MMM GROUP

MMM  Group  Research  for  CMHC:  Impact  of  Architectural  Form  and  Features  on  the  Energy  Performance  of  High  Performance  MURBs  

0°

Square

Bar

90° 180° 270°

‘L’

‘U’

‘H’

North

UNDERSTANDING  COOLING  (AND  HEATING)  LOADS  -­‐  RESIDENTIAL  

2014 © MMM GROUP

WHEN  YOU  POOR  OPAQUE  WALLS,  MORE  GLASS  CAN  HELP  

MMM  Group  Research  for  CMHC:  Impact  of  Architectural  Form  and  Features  on  the  Energy  Performance  of  High  Performance  MURBs  

COOLING LOAD INTENSITY

Floor plate and Orientation

2014 © MMM GROUP

WHEN  YOU  POOR  OPAQUE  WALLS,  MORE  GLASS  CAN  HELP  

MMM  Group  Research  for  CMHC:  Impact  of  Architectural  Form  and  Features  on  the  Energy  Performance  of  High  Performance  MURBs  

COOLING LOAD INTENSITY

Solar Heat Gain Coefficient (SHGC)

2014 © MMM GROUP

WHEN  YOU  POOR  OPAQUE  WALLS,  MORE  GLASS  CAN  HELP  

MMM  Group  Research  for  CMHC:  Impact  of  Architectural  Form  and  Features  on  the  Energy  Performance  of  High  Performance  MURBs  

COOLING LOAD INTENSITY

Window Wall Ratio (WWR) & SHGC

2014 © MMM GROUP

COOLING  LOADS  AND  OCCUPANT  COMFORT  IN  HIGHLY  GLAZED  BUILDINGS  

■  ENERGY  LOADS  –  how  building  form  influences  energy  loads    ■  EXISTING  CONDITIONS  –  how  is  the  building  performing  and  

what  are  the  concerns  ■  RETROFIT  STUDY  –  window  retrofit  case  study  ■  THE  TAKE-­‐AWAY  

2014 © MMM GROUP

EXISTING  CONDITIONS  –  GLAZING    

APPR

OX.  75%

 GLAZING  

SPAN

DREL  

2014 © MMM GROUP

EXISTING  CONDITIONS  -­‐  GLAZING  

4  MM  

2014 © MMM GROUP

EXISTING  CONDITIONS  -­‐  INTERIOR  

2014 © MMM GROUP

EXISTING  CONDITIONS  –  ENERGY    

■  Consump]on-­‐related  cooling  costs:  approximately  $113,000  per  year  ■  Fixed  (unrelated  to  consump]on)  cooling  costs:  approximately  

$95,000  per  year;  ■  Cooling  load  a:ributable  to  weather  (solar  and  thermal  transmission):  

approximately  20%  (or  $22,000  per  year)  ■  The  cooling  costs  are  not  significantly  impacted  by  peak  cooling  

demand  ■  Electrical  consump]on  generally  is  unaffected  by  weather  

2014 © MMM GROUP

COOLING  LOADS  AND  OCCUPANT  COMFORT  IN  HIGHLY  GLAZED  BUILDINGS  

■  ENERGY  LOADS  –  how  building  form  influences  energy  loads    ■  EXISTING  CONDITIONS  –  how  is  the  building  performing  and  

what  are  the  concerns  ■  RETROFIT  STUDY  –  window  retrofit  case  study  ■  THE  TAKE-­‐AWAY  

0

0.2

0.4

0.6

0.8

1

1.2

0

200

400

600

800

1000

1200

1400

1600

1800

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4

So

lar

Sp

ectr

al Ir

rad

ian

ce (

W/m² µm

)

Wavelength (µm)

Visible Near Infrared Infrared UV

LIGHT,  HEAT  &  BRIGHTNESS  

Energy

Brightness perception

0

0.2

0.4

0.6

0.8

1

1.2

0

200

400

600

800

1000

1200

1400

1600

1800

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4

So

lar

Sp

ectr

al Ir

rad

ian

ce (

W/m² µm

)

Wavelength (µm)

Visible Near Infrared Infrared UV

LIGHT,  HEAT  &  BRIGHTNESS  

Solarban60 equiv.

Solarban70 equiv.

INITIAL  CONSIDERATIONS  

RETROFIT  CONSIDERATIONS  ■  Exterior-­‐mounted  automated  blinds  ■  Exterior-­‐mounted  fixed  blinds  ■  Interior-­‐mounted  automated  blinds  ■  Interior-­‐applied  window  film  

RETROFIT  CASE  STUDY  

GLASS  ZONE  

INTERIOR  ZONE  

75%  WWR  /  60%  VLT  /  0.31  SHGC  

OCCUPANT  COMFORT  CASE  STUDY  

SOLAR CONDITION INDEX

OCCUPANT  COMFORT  CASE  STUDY  

TEMPERATURE ZONE READINGS (FILM 1)

OCCUPANT  COMFORT  CASE  STUDY  

TEMPERATURE ZONE READINGS (FILM 2)

OCCUPANT  COMFORT  CASE  STUDY  

BTU TRANSMISSION READINGS

ENERGY  CALCULATIONS  

Fixed  flat  rate  cooling  

($  es6mated)  

Consump6on  cooling  ($  es6mated)  

%  of  cooling  weather  related  

Total  weather-­‐related  cooling  

costs  (es6mated)  

Es6mated  solar  heat  gain  contribu6on  

Solar  heat  gain  cooling  costs  (est.)  

$  95,000  /  year  

$113,000  /  year  

20  %   $  22,600  /  year   40%   $8,800  /  year  Solar  heat  gain  

cooling  costs  (est.)  SHGC  (original,  es6mated)  

SHGC  (with  film)  

SHGC  improvement  

Poten6al  cooling  savings  (approx.)  

$  8,800  /  year   0.66     0.176   73%   $  6,400  /  year  

Solar  heat  gain  cooling  costs  (est.)  

BTU  energy  reduc6on  with  film  

Poten6al  cooling  savings  (approx.)  

$  8,800  /  year   39%   $3,432  /  year  $  8,800  /  year   52%   $4,224  /  year  

2014 © MMM GROUP

COOLING  LOADS  AND  OCCUPANT  COMFORT  IN  HIGHLY  GLAZED  BUILDINGS  

■  ENERGY  LOADS  –  how  building  form  influences  energy  loads    ■  EXISTING  CONDITIONS  –  how  is  the  building  performing  and  

what  are  the  concerns  ■  RETROFIT  STUDY  –  window  retrofit  case  study  ■  THE  TAKE-­‐AWAY  

2014 © MMM GROUP

TAKE-­‐AWAY  

■  Easily  applied  to  interior  with  li:le  disrup]on  to  tenants  ■  Op]ons  are  available  that  have  li:le  visual  impact  on  exis]ng  IGUs  ■  Reduced  overall  BTU  energy  transmission  through  glazing  ■  Reduced  temperature  differen]al  between  interior  and  perimeter  

zones  ■  Long  payback  based  on  various  energy  calcula]on  methods  (with  

some  increase  in  total  hea]ng  costs)  ■  Immediate  ‘perceived’  benefit  from  tenants  (comfort)  Further  considera]ons  ■  Reduced  glare  may  encourage  open  blinds  ■  Opportuni]es  for  integra]ng  daylight  control  ligh]ng  

2014 © MMM GROUP