Sustainable Building Design and Renewable Applications...Low-cost self-cleaning nano-coating for curtain walls Conventional self-cleaning glass curtain wall involves chemical vapour

THE HONG KONGPOLYTECHNIC UNIVERSITY

香港理工大學

Sustainable Building Design andRenewable Applications

Dr. Lu Lin, Vivien

Associate Professor

Department of Building Services EngineeringThe Hong Kong Polytechnic University

Overview

Introduction of building sustainable design

Passive architectural design sensitivity analysis and optimization

Green building nanomaterial development

Building energy efficient systems (Fluid mechanics and heat/mass transfer)

Renewable energy applications






Building sustainable design background

Energy use in buildings accounts for about 92.7% of all electricityconsumption according to statistics published in 2013

People spend about 80% to 90% of the time on indoor activities

Building sustainable design technologies

To keep indoor environment comfortable while achieve energy saving, passive or active building designs can be adopted:

Passive design use ambient energy sources, including daylighting, natural ventilation, and solar radiation.

Active design use or create purchased energy to keep the building comfortable.

Hybrid design use both energy sources

Passive Active

Architectural Design

Green Material

Energy Efficient Systems

Renewable Applications

Design to Construction Time Line

Degree of Effort Building Sustainability

Program Predesign

Schematic Design

Design Development

Construction Document

ConstructionManagement

Post -Construction

Building sustainable strategies from early design stages

Source: The ASHRAE GreenGuide

Research Target






Passive architectural design in green building rating tools

Building Layout:Building orientation and external obstructions

Building Geometry: structural ratios and external shadings

Thermal Physics:Envelope physical properties

Infiltration:Air-tightness criteria

Building Passive architectural design classification

Statistical analysis of Passive architectural design strategies

Construct building model and determine inputs

Statistical modelling

Generate Monte Carlo matrix

Sensitivity analysis

Determine sampling size

Multiple linearregression

Rank transformed regression

Multiple linear regression

Non-parametric regression

Determine sensitivity coefficient Determine surrogate model

Bootstrapping Cross-validation

Passive architectural design case study buildings

Over 90% of the population in HK lives in high-rise domestic buildings of 10 to 40 floors

Public Rental Housing (PRH) provided accommodations for over 30% the local residents

Importance of different building design factors on building energy consumption

-1.000 -.500 .000 .500 1.000

Building Orientation

External Obstruction Angle

External Wall Thermal Resistance

External Wall Specific Heat

Window SHGC

Window U value

WGR

Overhang Projection Ratio

Infiltration Air Mass Flowrate…

SRRC

1

2

3

4

5

• To determine the ranking of various design strategies

• To estimate the uncertainty of annual energy consumption

Multi-objective building optimization

0102030405060708090

Lighting Energy Cooling Energy Total Energy

Ener

gy C

onsu

mpt

ion

(kW

h/m

2 )

Optimized Baseline

41.6%

77.8%

77.8% IEQ

Security

Ventilation

Hygiene

Thermal Comfort

Acoustics

Lighting Quality

Amenities

IAQ

• Energy performance including cooling and lighting

• Indoor environmental quality including thermal comfort, lighting quality and ventilation.

• Non Sorting Genetic Algorithm II (NSGA-II) adopted to obtain Pareto frontier

Trade-offs






• 2015/16 HKSAR Government ITF (UICP): Development of Novel High Dispersed Transparent Heat Insulation Paints for Glass (UIM/265)

Nano-paints for window heat insulation

Buildings emitted 8.3 Gtcarbon dioxide each yearaccounting for more than30% of the greenhousegas emissions in manydeveloped countries.

Windows or curtain walls, taken as the day-lighting structure of a building, is stillsuffering from the balance of thermalinsulation and visible transparency.

Our ongoing ITF project

Problems for traditional coating

1. High cost (Foreign monopoly)2. Bad transparence (Poor dispersion)3. Solvent based coating (Environmental problems)

Project Objective

1. Independent research to reduce the cost (Break up foreign monopoly)2. Good transparence (Stable colloid)3. Water based coating (Environmentally friendly )

Novel High Dispersed Transparent Heat Insulation Paints for Glass

Acrylic resin

Size of ATO: 5nm Size of ATO: 50nm Size of FTO: 20nm

secondary particle size (in water): <200nm

Thermal insulation coating

Graphene

Precursor of ATO

Hydrothermal reactor

Ball millATO-Graphene

1. Good dispersion, no sediment

2. Secondary particle size (in water): <150nm

3. Primary particle size: <30nm


Number of samples

Vis-Light Transmission

IR-Light Transmission UV-Light Transmission

1 73 28 13

2 85 24 8

3 70 30 14

4 83 27 11

6 75 25 9

7 87 22 7

9 82 22 12

Insulation Performance of the Coating:

Vis-Light Transmission: >75% IR-Light Transmission: <30% UV-Light Transmission:<15%


Self-cleaning coatings

Super-hydrophobic , θ(Lotus leaf)>150°

Super-hydrophilic，θ（clean glass）<10°

Super-hydrophobic self-cleaning glass

Super-hydrophilic self-cleaning glass

Low-cost self-cleaning nano-coating for curtain walls

Conventional self-cleaning glass curtain wall involves chemical vapourdeposition and sputtering technologies.

A comparison between PV modules with and without self-cleaning coatings after one month’s outdoor exposure.











15:59 20:59 1:59 6:59 11:59 16:59 21:59 2:59 7:59 12:59

20

25

30

35

40

45

50

55

Interior surface temp. of PV facade

TEM

PERA

TURE

(o C)TIME

PV facade Conventional facade

• Natural ventilated PV façade (experimental and numerical)0/ YT

0/ YT

10 20 30 40 50 60 70 80 90 1000

50

100

150

200

=7oC

12oC

Heat

flux

(w/m

2 )

Air gap thickness (mm)

Optimum air thickness in the range of 60-80mm for energy savings in HK

0 xT

0 xT

VY ,

UX ,TVU ,,

open cavityclosed cavity

Building-integrated solar PV systems

• Optimal installation orientation of PV modules • Development of solar cells and PV product, etc.

Dye-sensitized solar cells based on graphite fibers

Direct-Integrated PV Roof Claddings

500

700

900

1100

1300

1500

0 10 20 30 40 50 60 70 80 90

Tilted Angle (degree)

Yera

ly S

olar

Rad

iatio

n (k

Wh/

y)

0 -90-45 45

90

Solar cell development and installation orientation optimization

The overall energy performance of BIPV facade: • real-time power generation performance • thermal performance • natural lighting performance

Ventilated BIPV and new modules

The potential PV electricity output is about 4674GWh,accounts for 10.7% of the total electricity use in 2014.

• Evaluating the PV-suitable roof-top areas by using remote sensing imagery;

• Rooftop extraction from remote sensing imagery is employed to estimate the utilization rate of urban roofs

Rooftop solar photovoltaic applications in Hong Kong

Simulation and experiments of vertical and inclinedboreholes

Thermal performance of ground-source heat pumps

We firstly proposed a reliable analytical solution both considering the finiteness of heat source and difference of thermal property in the molding process.

Development of heat exchanger foundation pile considering its thermo-mechanical behaviour

Thermal vertical stresses distributions

Cracks may occur for long-term operation, and we need to explore its long-term operation with fatigue test to know its ultimate bearing capacity in the whole life-cycle.

Solar direct heating

Solar heat pump heating

Ground-source heating

Solar coupled ground source heating

Solar energy storage and recharging

DHW production

1

2

3

4

5

6

Solar-assisted ground source heat pump system

Thank you!

Documents

Sustainable Building Design and Renewable Applications...Low-cost self-cleaning nano-coating for curtain walls Conventional self-cleaning glass curtain wall involves chemical vapour