Green Buildings; Green Cities

Why so long?

Phil Jones

20km (m90%)

Global warming < 1.5oC by 2050

based on pre industrial times

Built environment a major target for reducing CO2 emissions

• A major source of CO2 emissions

• Climate change impact, especially vulnerable groups

Low energy design:

• Energy efficient design

• Thermal insulation

• Air tightness

• Efficient HVAC

Passive design:

+•Solar

• Daylight

• Natural ventilation

• Thermal mass

Sustainable design:

+•Materials

• Renewable energy

• Community

Zero Carbon design:

+• Reduce energy demand

• Renewable energy supply

• Appliance energy

• Low embodied energy

1970’s 2018

Energy Positive design

+• Nearly zero energy demand

• Renewable energy supply

• Energy storage

LOW ENERGY TO ZERO CARBON

Building City Scale

New Build Retrofit

320ppm—409ppm

0.8oC

2030 targets:•Reducing greenhouse gas emissions by 40% (from 1990 levels)• Increasing the share of renewable energy to at least 27%•Continued improvements in energy efficiency (at least 27%)

2020 Targets

• 20% cut in greenhouse gas emissions (from 1990 levels)

• 20% of EU energy from renewables

• 20% improvement in energy efficiency

2040 targets:•Reducing greenhouse gas emissions by 60%

2050 targets:•Reducing greenhouse gas emissions by 80%

POLICY

EUROPE

• The Energy Performance of Building Directive (EPBD)

• new public buildings after December 31, 2018

• all new buildings after December 31, 2020.

• A NZEB is a building that "has a very high energy

performance with the nearly zero or very low amount of

energy required covered to a very significant extent by

energy from renewable sources, including energy from

renewable sources produced on-site or nearby".

• Implemented through Building Regulations.

(D'Agostino et al., Synthesis Report on the National Plans for NZEBs; EUR 27804

EN; doi 10.2790/659611 )|

Nearly Zero Energy Buildings (NZEBs)

POLICY

INCREMENTAL

ELEMENTAL

HOLISTIC APPROACH

0

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1965

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U-V

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S wall roof floor

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zero carbo

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kW

h/m

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1965

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U-V

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S wall roof floor

Thermal Insulation

Energy

Storage

TECHNOLOGY AND DESIGN TOOLS

We have the technologies,

and the modelling capabilities,

to design and construct buildings and cities by

simulating energy and environmental performance.

Transpired Solar Air Collectors (TSCs)

Energy Generating Building Envelopes

Solar PV and Solar thermal

Renewable Energy

Cardiff University researchers completed energy-harvesting façade and roof retrofit

in Tibet as part of its HABITAT Global Challenge Research project.

0.0

100.0

200.0

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400.0

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700.0

800.0

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Monthly energy supply, PV power storage and exportation

Direct from PV From Battery Heating storage by PV power Surplus power to grid From grid

Energy: kWh

AIR

CO

LL

EC

TO

R

SYSTEMS APPROACHREDUCE DEMAND

RENEWABLE SUPPLY

ENERGY STORAGE

Structurally insulated Panel Construction

After retrofit

Before retrofit

1 2 3 4 5

1 2 3 4 5

RETROFIT

EMPA near-zero carbon office, Zurich

TECHNOLOGIES + TOOLS

WINTER

SUMMER

COMFORT IN GREEN BUILDING ?

Surface heating and cooling

Solar gains

Chilled beams/panelsVentilation

Internal gains

Façade design

H2020 EeB-07-2017 EU contribution €6m

2017-2021

Plug-n-Harvest

OPTIONS:

Thermal insulation; PV generation; battery storage;

solar thermal air heating; mechanical ventilation;

Renewable generationPV and Thermal

Technical Zonestorage; ventilation

Thermal insulation

URBAN SCALE

Sustainable High Density Cities Lab

CityComfort+

Air Ventilation Analysis：

Daylighting Analysis：

Building Energy：

Thermal comfort：

URBAN SCALE TOOLS

Option1

Option2 Option3

Existing condition

0.00

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1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59

Energy supply per building

Heating Cooling Lighting Small power Fan power

kwh/m2/annual

Building ID

0.00

5.00

10.00

15.00

20.00

25.00

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Energy supply per area

Heating Cooling Lighting Small power Fan power

kwh/m2/month

Large Scale low carbon Urban Developments

50% Building Integrated

Renewables

Integrated Model:

Urban Microclimate (UMM) + Energy (HTB2)

UMM HTB2 Surface temperatures

Air exhaust

Air temperatures Wind flow

3-D Geometry / Weather data / Building properties Plants cooling Traffic heat gains

Improve external comfort

Reduce building energy demand

URBAN TEMPERATURES

Model Testing on a Scale Concrete City (Guangzhou)

A zonal model for assessing street canyon air temperature of high-density cities, Weihui Liang, Jianxiang Huang, Phil Jones, Qun

Wang, Jian Hang, Building and Environment Vol 132, 15 March 2018, Pages 160-169

CITY AS A BUILDING

Heat gains

Ventilation

Cooling

Daylight

Noise

Renewable

energy

After retrofit

Before retrofit

1 2 3 4 5

1 2 3 4 5

Energy

Positive

Zero

Carbon

Near-Zero

Carbon

Low

Carbon

NE

W B

UIL

DR

ET

RO

FIT

UR

BA

N

SC

AL

E

BUILT ENVIRONMENT

Buildings

Communities

Grids

Renewable Energy

+

Energy Storage

Future Energy Systemsand

The Built Environment

BARRIERS AND BENEFITS

WHY SO LONG?

• Lack awareness

• Industry resists change

• Government does not push

• Procurement lock-in

• Uncertainties: costs / performance

• Who owns it - architect, engineer,

building physicist?

BENEFITS (MULTIPLE)

Building / Community

• Energy cost savings

• Comfort, health and well-being

• Productivity increase

• Increase asset and rental value

• Less pollution

National / Global

• Carbon emissions reduction.

• Reduced use of resources.

• Security of energy supply.

• Reduced environmental damage

• Public health savings

Chinese Vice Premier Liu Yandong visits the SOLCER House

Thank You