Overview of Energy Efficiency for GGR314 Danny Harvey, Professor.

Overview of Energy Efficiencyfor GGR314

Danny Harvey, Professor

The German Passive Standard for Residential Buildings:

• A heating load of no more than 15 kWh/m2/yr, irrespective of the climate, and

• By comparison, the average heating energy intensity of all housing in Canada (detached and multi-unit) is about 150 kWh/m2/yr (ten times the passive house standard!)

Source: “Energy Efficiency Trends in Canada, 1990-2005, Chapter 3, Residential Sector”, http://oee.nrcan.gc.ca/Publications/statistics/trends07/chapter3.cfm?attr=0

Estimated fuel energy use (largely for heating) in Canadian multi-unit residential buildings

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Thermal Energy Intensity, U of T Buildings

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Biotop Office Building, Austria

Reidberg high school, Frankfurt (Germany)

Source: Danny Harvey

Triple-glazing throughout, maximized passive solar heat gain

Source: Danny Harvey

Heating required during the winter for only a couple of hours Monday mornings, using two small biomass-pellet boilers

Source: Danny Harvey

South facade, Reidberg high school

Source: Danny Harvey

Retractable external shading

Source: Danny Harvey

Passive ventilation and night-time cooling; mechanical system shut off from ~ early May - end of September

Source: Danny Harvey

The Passive House standard has been achieved in several thousand buildings in Germany, Austria and other European countries (as far north as Helsinki, Finland), and in a wide variety of different types of buildings (residential, schools, day care centres, banks, gymnasia)

It is now the legally required standard for new municipally-owned buildings in a number of cities in Germany and Austria (the largest being Frankfurt)

Something close to the Passive Standard is likely to be the national requirement in several countries in Europe before 2020.

Specifically,

• City of Frankfurt: since 2007, all municipal buildings must meet the standard

• City of Wels, Austria: same thing since 2008• Vorarlberg, Austria: Passive Standard is

mandatory for all new social housing• Freiberg, German: all municipal buildings must

meet close to the PH standard• City of Hanover: since 2005, all new daycare

centres to meet the Passive House standard (resolution only – legal status not clear)

Climate Comparisons, Heating Season

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To achieve the Passive House standard requires

• High levels of insulation (U-values of 0.10-0.15 W/m2/K, R35-R60)

• High performance windows (usually TG, double low-e, argon-filled)

• Meticulous attention to avoidance of thermal bridges

• Meticulous attention to air-tightness• Mechanical ventilation with heat recovery• Attention to building form (much easier in multi-

unit than single family housing)

Example of a residential heat exchanger, where the two airstreams are divided into channels separated by thin

aluminum plates, transferring heat from warm outgoing stale air to the cold fresh incoming air

Source: Danny Harvey

Thermally-separated balconies

in Frankfurt

Source: Danny Harvey

Extra cost of building to the Passive House standard:

• About 5% of the construction cost in Germany or Austria

• About 10% of the construction cost in Canada (due to the need for specialized supervision of the construction process)

Progressive decrease, through learning, in the extra cost of Passive Houses in Germany

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1991 Prototype: experimental house,4 dwellings in Kranichstein usinghandicraft batch production

PH in Groß-Umstadt:Reduced costs bysimplification

Settlement in Wiesbaden:Serially produced windows & structural elements

Settlements in Wuppertal,Stuttgart, Hanover

Row houses in Darmstadt, 80 €/m2

Profitability with contemporary

interest rates & energy

The EnergyBase building in Vienna, Austria

Source: Danny Harvey

Interior view of south-facing facade, with tilted glass and adjustable reflective blinds

Source: Ursula Schneider, Pos Architekten, Vienna

Due to the inclination of the south-facing glazing, it functions like vertical north-facing glazing in the summer, while the solar irradiance on the PV panels is maximized

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Solarstrahlung auf vertikale Südfassade Solarstrahlung auf vertikale Nordfassade

W/m²

Source: Ursula Schneider, Pos Architekten, Vienna

Exhaust air is overheated by passing through a sort of solarium, then passes

through a heat exchange to heat the incoming fresh air to a greater extent than would be possible with a conventional heat exchanger system. And unlike systems for passive solar preheating of ventilation air, we still get the benefit of heat recovery on

the exhaust air at night

Combination of solar heating of fresh air and heat recovery from exhaust air in the EnergyBase building

Source: Ursula Schneider, Pos Architekten, Vienna

Air temperatures during flow through solarium and heat exchanger

Best Canadian example: Enermodal headquarters building (“A Grander View”) in Waterloo, Ontario: heating + hot water energy requirement of 27 kWh/m2/yr

(so heating alone would be close to the Passive House Standard)

Figure 4.30 Solar chimneys on the Building Research Establishment (BRE) building in Garston, UK

Source: Copyright by Dennis Gilbert, View Pictures (London)

Figure 4.31 Torrent Centre, Ahmedabad, India

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Source: George Baird (2001, The Architectural Expression of Environmental Control Systems, Spon Press, London)

Figure 4.32 Torrent Centre, Ahmedabad, India

Source: George Baird (2001, The Architectural Expression of Environmental Control Systems, Spon Press, London)

Chilled ceiling cooling

• Our perception of temperature depends roughly 50:50 on the air temperature and on the radiant temperature (the temperature of the surroundings, which are a source of infrared radiation on our bodies)

• A nice sensation of coolness is achieved if the ceiling is cooled to 16-20ºC by circulating water at this temperature through panels attached to the ceiling

• The result is a much higher chiller COP than conventional cooling systems (which use water at 6-8ºC) and warmer permitted air temperature

Figure 4.48 Chilled Ceiling cooling panels

Source: www.advancedbuildings.org

Because the ceiling panels need water cooled down to only 16-20ºC, and the cooling tower

almost always produces water at this temperature, the cooling tower water can be directly used in a chilled ceiling cooling system most of the time –

providing yet further energy savings

Displacement ventilation

• Ventilation air is introduced from vents in the floor at a temperature slightly below the desired room temperature

• The air is heated from internal heat sources and rises in a laminar manner, displacing the pre-existing air, and exiting through vents in the ceiling

• 40-60% less airflow is required than in a conventional ventilation system (which we assumed to be already reduced to the flow required for air quality purposes only)

Figure 4.49 Displacement ventilation floor diffuser

Source: Danny Harvey

Renovations to the Passive House Standard (15 kWh/m2/yr heating load)

• Dozens carried out in old (1950s, 1960s) multi-unit residential buildings in Europe, resulting in 80-90% reduction in heating energy use

• Two examples will be shown here:-BASF buildings in Ludwisghafen, Germany- apartment block in Dunaújváros, Hungary

Figure 4.83 BASF residential retrofit, Germany, before and after

Source: Wolfgang Greifenhagen, BASF

Figure 4.84 BASF retrofit (a) installation of external insulation, (b) installation of plaster with micro-encapsulated phase change materials

Source: Wolfgang Greifenhagen, BASF

Figure 4.85 Renovation to the Passive House Standard in Dunaújváros, Hungary. Before:

Source: Andreas Hermelink, Centre for Environmental Systems Research, Kassel, Germany

After:

Source: Andreas Hermelink, Centre for Environmental Systems Research, Kassel, Germany

Net result:

• 90% reduction in heating energy use – this saves natural gas that can be used to generate electricity at 60% efficiency (or even higher effective efficiency in cogeneration), thereby serving as an alternative to new nuclear power plants

• Problems of summer overheating were greatly reduced

• A grungy, deteriorating building was turned into something attractive and with another 50 years at least of use

In Toronto

• There are opportunities for similarly large reductions through retrofitted old 1960s and 1970s apartment towers

• Single-family houses will be harder and more expensive, but are doable

• But what will we do with all the glass condominiums and office towers being built now?

Table 4.34 Current and projected energy use (kWh/m2/yr) after various upgrades of a typical pre-1970 high-rise apartment building in Toronto.

DHW=domestic hot water, IRR=internal rate of return, HRV=heat recovery ventilator.

N a tu r a l G a s M e a su re H ea t in g D H W

E lec -tr ic ity

P r im a ry E n e rg y

C o st ($ /m 2 )

P a y b a ck (y e a rs)

IR R (% /y r )

C u rren t b u ild in g 2 0 3 3 6 7 1 4 4 3 R o o f in su la tio n 1 8 4 3 6 7 0 4 2 0 1 3 11 .4 11 .3 C la d d in g u p g r a d e 1 6 7 3 6 6 9 3 9 8 4 4 1 8 .1 3 .4 W in d o w u p g r a d e 1 2 2 3 6 6 4 3 3 6 7 3 1 3 .5 9 .2 B a lco n y e n c lo su re 1 2 2 3 6 6 8 3 4 5 1 2 1 2 1 4 .3 A ll o f th e a b o v e 4 7 3 6 6 4 2 5 2 1 9 9 1 8 .6 5 .6 B o ile r u p g r a d e 11 8 3 6 7 0 3 4 7 2 3 5 .5 2 3 H R V 1 3 6 3 6 6 8 3 6 2 1 7 7 .8 2 5 .8 W a ter c o n se rv a t io n 2 0 3 2 5 7 0 4 3 0 5 3 .4 3 5 .1 P a r k a d e lig h tin g 2 0 3 3 6 7 0 4 4 0 0 4 .4 2 8 A ll o f th e a b o v e 9 .4 2 5 5 9 1 8 5 2 5 7 1 6 .9 6 .7 A b o v e w ith 5 0 % less te n a n t e le ctr ic ity 2 4 .1 2 5 2 9 1 2 8

Further reading (books published by Earthscan):

2006 March 2010 April 2010