Sustainable Construction Technical Review 3
SUSTAINABLE MEASURES in the Harvard Blackstone UOS Renovation
A rc h i te c t s a n d P l a n n e r s
Bruner/Cott Cambridge, Massachusetts w w w . b r u n e r c o t t . c o m
J u n e 2 0 0 6
Bruner/Cott & Associates, Inc. 130 Prospect Street Cambridge, MA 02139
T 617.492.8400 F 617.876.4002
www.br unercott.com
Introduction Blackstone Station, a stately presence on the Charles River for more than a century,
was originally developed as a coal-fi red electricity plant. Harvard University acquired the site, which now generates steam for University-wide use. While the main plant will continue in that capacity, the historic masonry outbuildings have been restored and sen- sitively transformed into offi ces and workshops for the University Operations Services (UOS).
The fi rst phase combines three buildings, bolstering systems effi ciency and optimiz- ing circulation routes and departmental adjacencies. The exterior features a strik- ing glass sliver, a new architectural element created to integrate two previously detached buildings with a sunlit interstitial space. The interiors, which highlight open, luminous spaces, are designed for utmost occupant comfort and adaptability. The structure will be seismically upgraded, but the original timber frame and deck- ing will remain unobscured.
The project is environmentally sustainable in several innovative ways: we replaced a signifi cant portion of asphalt with irrigation-free adaptive plantings, and salvaged or recycled 99.5% of construction-related waste. Stormwater runoff is treated to remove solids and phosphorus; and we installed a white membrane roof to mitigate the summer heat island effect. The building also features exceptional energy performance, and uses low-VOC interior products and fi nishes for improved occupant health and produc- tivity. The project is LEED-registered for Platinum certifi cation (pending.)
Harvard Blackstone Renovation
Site enhancements • Redevelopment of brownfi elds
• Impervious asphalt parking lot converted to green space
• Permeable paving prevents run-off
• No irrigation required by the use of native plants and no-mow grass
• Erosion and sedimentation controls in place during construction - silt fences, hay bales, fi lter fabric
rainfall suspended solids
oil and grease phosphorous
clean water
evapo-transpiration
soil sand
Bio-retention pond • Cleanses site stormwater of contaminants:
- microorganisms break down oil and grease
- nutrient uptake through plants reduces phosphorous
- sand bed fi lters suspended solids
• Reduces the rate and quantity of stormwater fl owing off-site
• Recharges the groundwater
• Contributes to biodiversity by being a habitat for native vegetation, micro-organisms and animals
SITE LANDSCAPE
bio-retention pond
native plants, no-mow grass and permeable paving reduce erosion and the need for irrigation
Bruner/Cott
rainfall suspended solids
oil and grease phosphorous
clean water
evapo-transpiration
soil sand
Managing stormwater on-site
bio-retention pond
• Cleanses site storm water of contaminants:
- microorganisms break down oil and grease
- nutrient uptake through plants reduces phosphorous
- sand bed or rocks fi lter suspended solids
• Reduces the rate and quantity of storm water fl owing off-site
• Recharges the groundwater
• Permeable paving prevents run-off
1.6/0.8 gallon
2.4/1.2 gallon D/F
1.6 gallon single flush
2 gallon single flush
3 gallon single flush
3.5 gallon single flush
Based on 1:4 solid/liquid usage. Figures calculated for an
average family of four.
Gallons per year
30 00
60 000
12 00
0 90
00 30
00 0
27 00
0 24
00 0
21 00
0 18
00 0
15 00
0
Reducing consumption
• Water use is reduced by 43% through the use of multiple strategies: dual-fl ush toilets, waterless urinals (reduction of 1,000 gallons per person, per unit per year (working hours only–50 weeks, 8 hour days), and low-fl ow sinks and shower heads.
• No irrigation required by the use of native plants and no-mow grass
Water-free urinals trap odor inside a cartridge fi lled with a liquid. This liquid has a lower density than water and thus creates an odor blocking seal.
The cartridge acts as a funnel directing fl ow through the liquid sealant (1), preventing any odors from escaping. Next, the cartridge collects sediment (2), allowing the remaining waste to pass freely down the drain (3).
(dual fl ush graph from ‘Caroma’ appliances web-site; car- tridge diagram and above paragraph from ‘Sloan Waterfree
water saving dual fl ush toilet fi xture vs. single fl ush
water-free urinal cartridge
1
3 2
WATER MANAGEMENT
Harvard Blackstone Renovation
CONSTRUCTION WASTE MANAGEMENT AT BLACKSTONE
0
100
200
300
400
500
600
700
800
fur nis
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Demolition Waste Materials 99.54% of all demolition waste has been salvaged or recycled
0.46% of all demolition waste has been disposed
Construction waste constitutes about 40% of the total solid waste produced in the United States (LEED-NC v2.2).
Reducing construction waste by reusing and recycling building components not only signifi cantly reduces landfi lls, but also improves the embedded energy of building components.
In the Harvard Blackstone renovation, over 99% of the construction waste was reused or re- cycled. A few examples:
• Unpainted wood has been ground into mulch.
• Removed plumbing fi xtures were given to a small town in Guatemala for a water shelter.
• Windows were sent to Spanishtown, Jamaica to help rebuild areas after summer hurricanes.
The total salvaged and recycled demolition waste material equals energy savings of 8.546 MBTU.
This is equivalent to: 1474 barrels of oil or 68,949 gal. of gasoline.
All data used for the charts on this page was obtained from Institution Recycling Network
Bruner/Cott
U P
D N
D N
U P
DN
D N
U P
DAYLIGHT AND VIEWS/INDOOR ENVIRONMENTAL QUALITY
Two lightwells bring daylight from above into the interior of the building. (Light from windows on the side pen- etrates into the building via an open fl oor plan.)
Nearly all workspaces to have a view to the outside.
Daylight and views are crucial to a pleasant interior space. In addition, using daylight can contribute to signifi cant energy savings in an offi ce.
• The central communicating stair encourages occupant interaction while increasing daylight.
• Daylight and views are provided for 90% of occupants.
• Interior design allows light infi ltration deep into the building.
• Direct/indirect lighting reduces glare by refl ecting off the white ceiling.
• Operable windows provide occupants easy access to fresh air.
Main lightcourt with stair below
Harvard Blackstone Renovation
NEW AND RECYCLED MATERIALS AND BUILDING COMPONENTS
Using salvaged building components and materials
• Construction waste constitutes about 40% of the total solid waste produced in the United States (LEED-NC v2.2). Reducing construction waste by reusing building components not only signifi cantly reduces landfi ll use, but also improves the embedded energy of building components. The total life cycle analysis of buildings is thus improved both in terms of the energy used and the waste and toxic waste produced.
• The cubicles and the partition fabric used are salvaged material.
• 20% recycled fl y ash was used in all concrete work (inside as well as sidewalks.)
Using renewable and low embedded energy materials
“Recycled-content materials reuse waste products that would other- wise be deposited in landfi lls. Use of rapidly renewable materials minimizes natural resource consumption. Use of third-party certifi ed wood improves the stewardsthip of forests and the related ecosys- tems.” (LEED-NC v2.2, p.233)
• Bamboo fl ooring (Bamboo grows fast and binds CO 2 )
• Linoleum fl ooring (Linoleum is made with linseed oil rather than petroleum products.)
• Certifi ed wood used throughout for doors, sills and casework. (Wood has a very low embedded energy value compared to plastics or aluminium and can be recycled easily.)
Using non-toxic materials
• Low-VOC Materials:
- Carpet tiles (with recycled content)
- No VOCs in fabrics or adhesives
- Low VOC paints.
Unlike PVC which is made of petroleum products, Lino- leum is made of Linseed seeds
Bamboo fl oor
Most built-in cabinets and counters are made of wood (Blackstone UOS)
Salvaged material: cubicles (Blackstone UOS)
Bruner/Cott
ADAPTIVE REUSE
Maintaining the building shell (exterior wall and more) is one of the most sustainable measures possible. “Maintaining occupancy rates in existing buildings reduces redundant de- velopment and the associated environmental impact of pro- ducing and delivering all new materials. Reuse of existing buildings, versus building new structures, is one of the most effective strategies for minimizing environmental impacts.” (LEED-NC v2.2, p.233)
Blackstone building, before and after, exterior and interior views.
Adapting older buildings to a new program and today’s energy and comfort standards is challenging and requires specifi c expertise.
Bruner/Cott has had over thirty years of experience in converting old mills and factories into housing, offi ces and museum space.
Harvard Blackstone Renovation
If we are to reduce energy consumption signifi cantly, we need to re-use existing structures. Adaptive reuse becomes more critical every year, especially when we factor in population growth and urban/suburban densifi cation.
Blackstone adaptive reuse, before and after, interior views
ADAPTIVE REUSE
Our 1976 poster for the Piano Craft Factory
Bruner/Cott
IMPROVED BUILDING ENVELOPE IN OLD BUILDINGS
Perm-a-barrier – an air and watertight foil – seals the connection between the wall opening and the window, thus reducing infi ltration and preventing moisture from entering the wall.
Masonry wall and added insulation and air- tightness barrier
“Buildings consume approximately 37% of the energy and 68% of the electricity produced in the United States annually,” according to the U.S. Department of Energy.
Buildings mainly consume energy for operation: heating, cooling, lighting and ventilation (the order depends on climate and program.)
Reducing heat loss In the Northeast U.S., heating is the primary source of energy consumption. A very simple and effi cient way to reducing energy con- sumption is to reduce the rate at which buildings lose heat to the outside in the winter or gain heat from the outside in the summer.
Improving envelope insulation and tightness Heat is primarily lost to the outside via poorly insulated walls (conduction) and via leaky (non-tight) building enve- lopes (infi ltration). Radiation is less of an issue in terms of net energy loss, in terms of comfort and human perception however, cold interior surfaces contribute to an overall feeling of cold and the impulse to increase the heat to compensate.
Measures at Blackstone Older buildings usually do not meet current standards for insulation and building tightness. Old masonry walls allow air to pass through at many points such as cracks, joints, win- dows, doors, ducts, etc.) This involuntary and uncontrolled air exchange leads to a major energy loss. In addition, masonry walls do not have high insulating capacities.
While from an energy standpoint it is desirable to add insu- lation and air barriers to the old masonry construction, this is problematic as humidity can get caught in the wall and cause the wall to deteriorate.
• The insulation at Blackstone is thus a special foam that is vapor permeable, allowing the humidity to leave the wall.
• The gypsum board on the inside acts as an air barrier.
• The use of perm-a-barrier (an airtight foil) around win- dows and doors further improved the air tightness.
• An ‘EnergyStar’ roof reduces the heat island effect and cooling load by providing additional insulation.
Harvard Blackstone Renovation
83 ˚F 30 ˚F
52 ˚F
54 ˚F
57 ˚F -1500 ‘
- 800 ‘
water table
52 ˚F
54 ˚F
57 ˚F
45 ˚F
45 ˚F
45 ˚F
52 ˚F
54 ˚F
57 ˚F
70 ˚F
70 ˚F
70 ˚F
temperature of ground and groundwater at various depths
Because the amount of returning water is small in comparison to the amount of ground (and ground water flowing through the well), the ground and ground water represent a constant heat source in the winter and heat sink in the summer.
Submersible pump electrical line
perforated intake area
Soil (unconsolidated)
Steel Casing typically 8 in, dia.
Water Table borehole wall (uncased)
typically ~ 6 in. dia.
Ground Surface
Well Head
he at
ad ve
ct ed
by re
gi on
al gr
ou nd
w at
er flo
w
convective mixing in borehole
conduction through pipe walls
Depth = 250-1,500’
conduction + convection at borehole wall
water recharge to
formation
water discharge
from formation
climatic factors
Porter Shroud
submersible pump
buoyancy-driven flow in formation
ANATOMY of STANDING COLUMN WELL
Bleed Circuit
R o
c k
C o
n s
o l i
d a
t e d
GEOTHERMAL HEAT
Standing column wells
While the temperature on the surface of the earth changes with the seasons (in New England from 0˚F to 100˚F), the temperature of the ground is much more constant (52˚F at -20 ft to 57˚F at -1500 ft.)
The ground is thus warmer than the outside air in the winter and cooler than the outside air in the summer. This makes the ground a heat source in the winter and a heat sink in the summer.
The geothermal wells used at Blackstone, Harvard Dance Center, and Radcliffe gymnasium adaptive reuse projects are ‘standing column wells’. A 1500 ft deep (6” diameter) hole is drilled into the bedrock. Inside this hole a 4’’ PVC tube transports water up to the heat- pump on the surface via a submersible pump.
Geothermal wells produce less noise than traditional chillers. This was a decisive factor for using them at Blackstone because of the surrounding residential neighborhood.
courtesy of “Water Energy Distributors, Inc.”
Bruner/Cott
VENTILATION
warm exhaust air
warmed fresh incoming air
cool outside air
cooled exhaust air
heat recovery system: heat exchanger
In the summer, cool but used exhaust air absorbs heat from warm
outside air, thus cooling it.
cool exhaust air
cooled fresh incoming air
warm outside air
warmed exhaust air
heat recovery system: heat exchanger
In the winter the warm exhaust air passes its heat on to cool incoming air.
INSIDE OUTSIDE
Heat Recovery Systems
While infi ltration (uncontrolled air exchange) is undesirable in buildings, very tight building envelopes require controlled air exchange in order to get a comfortable level of fresh air.
Though this can be achieved through opening windows, mechanical ventilation allows for a higher comfort level (via a more controlled air exchange) and for signifi cant energy savings (mainly via a heat recovery system).
In a heat recovery system warm but used inside air fl ows out through very thin metal fi ns. On the other side of these fi ns cool outdoor air fl ows in. The warm air gradually heats the fresh outside air. Today heat recovery systems achieve a 75% energy recovery.
CO2
fresh air
CO2 sensor
Decoupling of ventilation from heating and cooling • Allows for more effi cient and comfortable heating and cooling:
heating and cooling with water is more effi cient - especially if coupled to a geothermal well and heat pump.
• Radiant heating and cooling is more comfortable than heating and cool- ing with air (no draft, lower temperatures).
Controlled ventilation • Controlled ventilation optimizes the amount of fresh air that is brought in.
Air is monitored for CO 2 content. This allows for an optimal air exchange
rate avoiding either extreme: too high (unnecessary energy consumption) or too low (poor air quality).
Heat recovery system • Mechanical ventilation systems can be coupled with heat recovery sys-
tems. The latter are heat exchangers that pass the heat of the outgoing exhaust air on to the incoming fresh air.
In the winter the warm exhaust air passes its heat on to cool incoming air.
(black and white diagram from ‘Xetex’ website)
Harvard Blackstone Renovation
Energy effi cient appliances
• Lighting fi xtures use
- daylight sensors and occupant sensors
- compact fl uorescent bulbs
- LED exit signs
• Energy star appliances
ENERGY EFFICIENT EQUIPMENT
Energy effi cient elevator (KONE Ecospace)
• EcoSpace uses no hydraulic fl uid which can potentially contami- nate the groundwater
• The energy consumption of EcoSpace elevators is 1/2 of the energy consumption of traction elevators and 1/3 of the energy consumption of hydraulic elevators.
• EcoSpace saves space since it does not require a machine room. The installation is thus simplified. No extra scaffolding or cranes are required.
• Initial building costs for an emergency generator are reduced because of the lower starting amperage of the machine.
• The noise level is reduced from 70-80 dBA to 50-55 dBA (measured 3’0” from the machine).
Energy consumption (kWh/yr)
0.00
5000.00
10000.00
15000.00
20000.00
25000.00
30000.00
EcoSpace Traditional Traction
Hydraulic Solution
Kone EcoSpace elevator