Energy Conservation in Building Standards

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Energy Conservation in Building Standards
Passive design
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Three steps towards zero carbon

• England
• In 2010, 25 improvement in the energy / carbon
  performance
• In 2013, 44 improvement
• by 2016, all new homes in England will be
  required to achieve zero carbon

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One step towards zero carbon

• Wales
• There is an aspiration that in 2011, Code level
  5 will be expected for all homes.
• A similar aspiration is held for non-domestic
  buildings in 2011

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Building Regulation Part L 1

• Criterion DER lt TER
• TER Target CO2 Emission Rate
• DER Dwelling CO2 Emission Rate
• kg CO2/m2 yr
• Governments Standard Assessment Procedure (SAP)/
• Simplified Building Energy Model (SBEM)

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Ecohomes

• Criteria
• Energy
• Transport
• Pollution
• Material
• Water
• Land Use and Ecology
• Health and Well-being
• Management

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Code for sustainable homes

• Criteria
• Energy Efficiency /CO2
• Water Efficiency
• Surface Water Management
• Site Waste Management
• Household Waste Management
• Use of Materials

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AECB Standard
Criteria
Silver
Gold
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Passivhaus
Alternative energy forms
Insulated building envelope
South facing aspect
Energy efficient appliances
Alternative energy forms
Maximum 0.6ACH
Mechanical ventilation with heat recovery
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Comparison of standards
Lower standard
Mandatory
Voluntary
Higher standard
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Design Model
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Weather Data
Absolute Humidity ()
Wind Speed (s/m) Direction
Relative Humidity ()
Average Precipitation (mm)
Illuminance
Sound levels
Built Environment
Direct Solar Radiation (w/m2)
Diffused Solar Radiation (w/m2)
Cloud Cover ()
External Air Temperature (C)
Underground Temperature (C)
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Solarhaus Freiburg
Aspect Ratio
City hall, London
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Building Layout
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Building Layout
Plusenergiehaus - Solarsiedlung Freiburg
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U- Value
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MINUS U- Value
Schreiber house, Aarau
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Thermal Mass
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Solar Control
Schreiber house, Aarau
EMPA External Shading
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Sun Space
Winter
Daytime
Night time
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Sun Space
Summer
Daytime
Night time
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Trombe Wall
Winter
Fresh air
Night time the vent is close to prevent heat
loss from glazing. The room is kept warm by the
heat stored in trombe wall through the night.
Daytime when immediate heating is needed, the
vent is open to draw warm air from the cavity
into living space
Daytime air trapped in the cavity between the
glazing and the wall is heated and the heat is
absorbed by the trombe wall
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Trombe Wall
Summer Case 2 (work as solar chimney for
cooling)
Summer Case 1(combined with night-time
ventilation for cooling)
Night time
Daytime
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Solarhaus Freiburg
Trombe Wall

• South facing triple glazed windows
• 300mm calcium silicate blocks 120mm of
  transparent insulation glass panel

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Natural Ventilation

• Stack Effect

• Wind pressure

Warm Air
Shade
Cool Air
Cp surface pressure coefficient ? density of
the air wind speed wind speed
or
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Natural Ventilation Wind Effect
UMNO OFFICE - Penang
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Natural Ventilation
Tsing Hua Low Energy Demonstration Building
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Night Time Ventilation
To use cool outside air flowing directly through
the treated space to remove heat from thermal
mass of the building by direct convection
Night time Open the building Cool the
structure Store coolth
Day time Close the building Sink internal heat
to the structure
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Daylighting
Light Pipe
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Daylighting
Prismatic Glazing

• Reflect or redirect most direct sunlight
• Only allow diffuse light through

Design Centre Linz
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Building Integrated Systems
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Heat Pump
Principles Vapour Compression Circle
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Heat Pump
Vertical GCHP
Horizontal GCHP
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Heat Pump
Vertical GCHP
Require relatively small plots of ground In
contact with soil varies very little in
temperature and thermal properties Requires
small amount of pipe and pumping energy Most
efficient GCHP system performance Higher cost to
drill the borehole Limited availability of
contractor to perform such work
High density polyethylene tubes filled with
solid medium
A minimum borehole separation distance 6m
20-40 mm nominal diameter
Bore depths 15-180m
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Heat Pump
Horizontal GCHP
Less expensive than vertical GCHPs Trained
equipment operators are more widely available A
larger ground area required Ground temperatures
and thermal properties fluctuate with season,
rainfall, and depth Slightly higher pumping
energy requirements Relatively lower system
efficiencies
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Heat Pump System Design
Sizing Ground Coupled Heat Pump
Size heat load
q heat transfer rate tw liquid temperature
Select heat pump
Soil test
R effective thermal resistance of the ground tg
ground temperature
Size ground heat exchanger
L required bore length
Lmax (Lh, Lc)
Piping Arrangements and Pumps
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Heat Pump

• Four identical energy efficient bungalows
• Horizontal closed-loop GCHP slinky coil
• Heat pump installed capacity 4 kw (heating)
• Space heating and a proportion of DHW

New Build Marazion, Cornwall

• A vertical closed-loop GCHP system
• Integrated roof-mounted water-to-air heat pump
• Heat pump installed capacity 68 kw (heating)
• 
  100kw (cooling)
• The running costs 50-60 lower the CO2
  reductions 60-70

Retrofit Charleston, Cornwall
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Mechanical ventilation Heat Recovery
Heat exchanger airflow configurations
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Mechanical ventilation Heat Recovery
Technical considerations

• Air leakage
• Maintenance
• Filtration
• Controls
• Fouling
• Corrosion
• Condensation and freeze up

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Combined Heat and Power
Principles
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Combined Heat and Power
CHP for domestic hot water supply for community
Micro CHP for future use
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Floor Heating
Principles
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Floor Heating System Design
For every floor heating system there is a maximum
allowable heat flow density qG

• Thickness of the layer above the pipe Su
• Heat conductivity ?E of the layer above the pipe.
  
• Thermal conduction resistance R?,B of floor
  covering.

The maximum surface temperature?F, max29 ? at
s0 ? At the peripheral area, the maximum
surface temperature?F, max35 ? at s0 ? s
temperature difference between supply return

• Pipe spacing T
• Pipe external diameter Dda
• Heat conductivity of the pipe ?R
• Heat conducting devices, KWL
• Contact between the pipes and the heat conducting
  devices or screed, ak

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Floor Heating Simulation
Outdoor temperature Zone temperature
Floor heating
Floor heating
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Radiant Cooling
Thermal energy is exchanged between the heat
loads present in the space and the cool ceiling. 
Suspended panel ceiling
Capillary tubes
Concrete core conditioning
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Radiant Cooling

• Low cost per unit surface area
• Larger active surface
• Better suited to buildings with high-performance
  envelopes, moderate climates
• Can be used to remove solar loads directly from
  receiving structural elements
• Associate with low energy cooling systems
• Does not provide air conditioning therefore
  air temp decrease leads to RH increase
• Thermal energy can be transported more
  efficiently with water than with air
• Cooling mode operating surface temperatures tend
  to be on the order of 13-15 ? for suspended panel
  systems 17-20 ? for concrete slabs

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Solar Thermal System
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Solar Thermal System
Flat plate collector
Solar evacuated tubes

• Most of the day
• High efficiency
• Expensive

• Only at noon
• Low efficiency
• Cheap

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Domestic Hot Water System Design

• 40 - 60 liters / person / day
• A minimum of 80 and preferably 100 liters storage
  per m2 of collector
• A typical size for a family of four will be
  between 200 and 300 liters

• Size the storage cylinder
• Select the collector type system
• Position the collector
• Size the pipe line
• Size the circulation pump

• A flat plate or evacuated tube
• A direct or indirect distribution system
• Gravity or pumped circulation
• A single cylinder with twin coils or the
  placement of a distinct pre-heat tank before the
  conventional cylinder

• The flow rate required
• Maximum allowable flow velocity
• Economic aspect
• Size the circulation pump
• Meet the required flow rate
• Operate at the best efficiency

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Photovoltaics
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Photovoltaics

• Combine solar cells in series
• Standard modules 50W to 150W 0.5 m2 1.5 m2
• PV strings module connected in series
• PV array strings combined in parallel
• Estimate

• A C/33
• A (m2) required area of PV module
• C (W) desired PV system output

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Photovoltaics Installation

• South facing (northern hemisphere)
• A tilt angle near to the local latitude
• 3. Stand-alone systems
• 4. Grid-connected systems

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Wind Turbine
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Wind Turbine
Stand alone system
Grid-connected system
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Wind Turbine
Grid-connected system

• Average annual wind speed
• Vgt 4.5 m/s
• Utility-supplied electricity is relatively
  expensive
• Connecting a wind system to the utility grid is
  not prohibited or overly burdened with
  bureaucratic roadblocks
• Incentives available for the sale of excess
  electric generation

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Wind Turbine Specification

• Research land use issues
• Evaluate the wind source
• (wind direction annual average wind speed
  V m/h)
• Electricity requirements C kWh/year
• Size the wind turbine Rotor diameter D m
• C0.1446D2V3
• Locate the turbine and establish tower height
• The bottom of the rotor blades should be at
  least 9m above any obstacle.

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Bio-mass

• The sum total of all the Earths living matter
  within the biosphere
• Regenerated by the sun through the process of
  photosynthesis
• Carbon neutral

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Bio-mass Source

• Fast-growing trees and shrubs
• Residues from agricultural crops
• Animal waste
• Industrial residues
• Municipal solid waste

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