cooling loads and occupant comfort in highly glazed...
TRANSCRIPT
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 [email protected]
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
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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 $22,000 per year) ■ The cooling costs are not significantly impacted by peak cooling
demand ■ Electrical consump]on generally is unaffected by weather
2014 © MMM GROUP
COOLING LOADS AND OCCUPANT COMFORT IN HIGHLY GLAZED BUILDINGS
■ ENERGY LOADS – how building form influences energy loads ■ EXISTING CONDITIONS – how is the building performing and
what are the concerns ■ RETROFIT STUDY – window retrofit case study ■ THE TAKE-‐AWAY
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Visible Near Infrared Infrared UV
LIGHT, HEAT & BRIGHTNESS
Energy
Brightness perception
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Visible Near Infrared Infrared UV
LIGHT, HEAT & BRIGHTNESS
Solarban60 equiv.
Solarban70 equiv.
INITIAL CONSIDERATIONS
RETROFIT CONSIDERATIONS ■ Exterior-‐mounted automated blinds ■ Exterior-‐mounted fixed blinds ■ Interior-‐mounted automated blinds ■ Interior-‐applied window film
RETROFIT CASE STUDY
GLASS ZONE
INTERIOR ZONE
75% WWR / 60% VLT / 0.31 SHGC
OCCUPANT COMFORT CASE STUDY
SOLAR CONDITION INDEX
OCCUPANT COMFORT CASE STUDY
TEMPERATURE ZONE READINGS (FILM 1)
OCCUPANT COMFORT CASE STUDY
TEMPERATURE ZONE READINGS (FILM 2)
OCCUPANT COMFORT CASE STUDY
BTU TRANSMISSION READINGS
ENERGY CALCULATIONS
Fixed flat rate cooling
($ 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