Towards Smart Net-zero Energy Buildings and Communities: …€¦ · EcoTerra TM EQuilibriumTM...

Towards Smart Net-zero Energy Buildings and

Communities:

Integration of Energy Efficiency and Solar

Technologies

Andreas AthienitisScientific Director, NSERC Smart Net-zero Energy Buildings strategic

Research Network (SNEBRN)

Director, Concordia Centre for Zero Energy Building Studies (CZEBS)

NSERC/Hydro Quebec Industrial Chair

Concordia University, Montreal

Smart Net-zero Energy Buildings

strategic Research Network (SNEBRN)

Why Smart Net-zero? Path to Net-zero

• Net-zero annual energy balance: many possible

definitions depending on control volume: House?

Community? Net-zero cost?

• NZEBs are becoming adopted by many countries as a

long term target; ASHRAE vision 2020.

• Objective target for high performance buildings

promotes an integrated approach to energy

efficiency and renewables - path to net-zero.

• Why smart? Because NZEBs must be comfortable

and optimally interact with a smart grid.

2

Solar Community Design Towards Net-zero Energy

� Heating load is not significantly affected by the layout of streets, provided solar access is respected

� Some house shapes (e.g L-shape) are more beneficial in a specific site layout

Electricity generation 85%-110% of the total energy use of the neighborhood

3

Living area Living area

Heig

ht

≈2 times Height

Seasonal thermal storage (e.g. Okotoks)

BIPV Systems

BIPV Systems

District heating

Solar collectors

Design: C. Hachem

Residential energy use in Canada

0

5000

10000

15000

20000

25000

30000

35000

40000

Conventional R2000 Advanced

Houses

En

erg

y C

on

su

mp

tio

n (

kW

h)

Space Cooling

Lighting

Appliances

Water Heating

Space Heating

A net-zero energy house produces from on-site renewables as much energy as it consumes in a year (ZEBA/B definition)

Fact: The annual solar energy incident on a roof of a typical house far

exceeds its total energy consumption

4

Source: NRCan

Commercial/Institutional Buildings

• Electric lighting: transformation in building design that moved towards smaller window areas until the 1950s

• Followed by evolution to air-conditioned “glass towers” with large window areas: more daylight – but higher cooling and heating requirements

• Currently: renewed interest in daylightingand natural/hybrid ventilation

• Need to integrate BIPV/STPV in facades to approach net-zero

5

Major international trends in high performance buildings

• Adoption by engineering societies and developed countries of net-zero energy as a long term goal (ASHRAE Vision 2020)

• Measures to reduce and shift peak electricity demand from buildings, thus reducing the need to build new power plants; integrate with smart grids

• Steps to efficiently integrate new energy technologiessuch as controlled shading devices and solar systems

6

NREL RSF Bottom-up shades STPV BIPV/T

Challenge of fast technological developmente.g. Photovoltaics (PV) declining in price

-

33%

PV price has dropped by ~ 90% from 2000 to 2011!Now feasible to use PV as building façade and roof element on surfaces facing East-South-West (depends on location)

7

Efficiency of commercial PV modules approaching 20%

Source: NRCan

Towards net-zero energyBUILDING

SYSTEMS

CURRENT

BUILDINGS

FUTURE SMART NET-ZERO

ENERGY BUILDINGS

Building

fabric

Passive, not

designed as an

energy system

Optimized for passive design and

integration of active solar systems

Heating &

Cooling

Large oversized

systems

Small systems optimally controlled;

integrate heat pumps with solar,

CHP; Communities: seasonal

storage and district energy

Solar

systems

/renewables

No systematic

integration – an

after thought

Fully integrated: daylighting, solar

thermal, PV+heat pumps, hybrid

solar, geothermal systems, biofuels

Building

operation

Building automation

systems not used

effectively

Predictive control to optimize

comfort and energy performance;

online demand prediction 8



Canadian Research in NZEBsFrom SBRN to SNEBRN

• The NSERC Solar Buildings Research Network (SBRN) has performed research and demonstration projects on technologically advanced solar buildings (2005-2011); the first initiative of its kind.

• Main energy & buildings university initiative in Canada; over 100 graduate students were trained, over 400 publications, innovative demonstration projects linked to research projects and four conferences.

• SNEBRN (2011-2016) is a network that continues and expands the work of SBRN with focus on smart NZEBs; about 30 researchers from 15 Canadian Universities, 20 partners, 100 grad students.

• Key approach: objective driven – strategic.

9

10

Construction

Industry, Engineers,

Architects, …

NSERC Smart Net-Zero

Energy Buildings

Strategic Research

Network

11Smart NZEB research and education at

Concordia University, Montreal

� Leader of the SBRN and SNEBRN Networks.

� A leader in building engineering (programs at

BSc, Master’s and PhD levels) in Canada.

� Established Concordia Centre for Zero Energy

Building Studies (CZEBS) – 8 Professors and

nearly 40 HQPs.

� Dept of Building, Civil and Environ. Engineering.

12

JMSB Building-integrated

photovoltaic/thermal (BIPV/T) system

– a world first:

Generates solar electricity, heats fresh

air and is fully integrated with the

building and its energy system

Solar simulator testing BIPV/T Environmental Chamber

Network Vision: to perform the research that will facilitate widespread adoption in key

regions of Canada, by 2030, of optimized Smart NZEB energy design and operation

concepts suited to Canada.

Concordia Centre for Zero Energy Building Studies

Vancouver

Edmonton

Calgary

Toronto

HalifaxMontreal

Ottawa

Some important facts

• Most of Canada is quite sunny,

with cold winters

• Ground temperatures 6-10 °C in

most populated areas (lat 42-53 N)

PV potential map of Canada with location of the 15 SNEBRN Universities

Lat 45 N

Degree-days

4519

Lat 53 N

Degree-days

5212

SNEBRN: 30 researchers from 15 Universities

• Building and energy industry leaders

(from solar, utilities, HVAC sectors)

• Govt labs (NRCan CanmetENERGY)


strategic Research Network (SNEBRN) 14

Optimal combination of solar and energy efficiency technologies and techniques provides different

pathways to reach net-zeroSolar energy: electricity + daylight + heat

Integrated approach to energy efficiency and passive design

Integrated design & operation

Solar optimization: requires optimal design of building form

Smart NZEB concept

Optimization of buildings for solar collection

0 10 20 30 40 50 60 70 80 904

4.5

5

5.5

6

6.5

Slope (degrees)

Dai

ly i

nci

den

t so

lar

rad

iati

on

(k

Wh

/sq

m)

Slopes 40-50 degrees desirable

Aspect ratio higher than 1; around 1.3

Two roof forms for

the same floor

plan

Solar energy on

roof

Important design variables:

Roof slope and aspect ratio L/W

Also window area

Aw

Optimize surfaces Ar and façade Aw simultaneously

Ar

15

Slope (degrees)Slope (degrees)In

cid

ent so

lar

rad

iation k

Wh

/m2

Slope = latitude



Electricity demand and generationTypical profile for NZEB (home, electric) on cold clear day

16

NZEBs need to be designed based on anticipated operation so as to have a largely predictable impact on the grid; reduce and shift peak loads

Ontario has a summer

(due to cooling) peak

demand

27 GWe

Quebec has a winter

peak demand

38 GWe on Jan. 24,

2011 7:30 am with

To = -33 C in Montreal

Peak heating demand can be reduced

through predictive control



Building Integration of PV

• Into roofs or facades, with energy system of

building.

• Roofs need to shed water: think of PV

panels doing some of the functions of roof

shingles; shingles overlap hiding nails.

• Functional integration, architectural and

aesthetic; recover heat, and transmit

daylight in semitransparent PV.

PV overhangs

Queen’s University

(retrofit)

Not just adding solar technologies on buildingsAthienitis house



EcoTerraTM EQuilibriumTM House (Alouette Homes)

Transformative SBRN work; IEA SHC Task 40 / ECBCS Annex 52 case study

2.84 kW

Building-

integrated

photovoltaic-

thermal

system

Passive solar

design:

Optimized

triple glazed

windows and

mass

Ground-

source heat

pump

NRCan, CMHC

Hydro Quebec



BIPV – integration in EcoTerra

• Building integration: integration with the roof (envelope) and with HVAC

• BIPV/T – (photovoltaic/thermal systems): heat recovered from the PV panels, raising overall solar energy utilization efficiency

• Heat recovery may be open loop with outdoor air or closed loop with a circulating liquid; possibly use a heat pump

• Open loop air system used because it can work for a long time with little maintenance and no problems

EcoTerraTM

Open loop air BIPV/T

19



BIPV/T roof construction in Maisons Alouettes factory as

one system

Warm/hot air

flow from

BIPV/T

Sun

Air intakes

in soffit

Building

integrated PV arrays

Air cavity

Graduate students and researchers involved in design and

monitoring; linked to Theme 1 projects



Assembly of House Modules (in about 4-5 hours)Prefabricated homes can reduce cost of BIPV through integration

House now occupied: feedback from owners on operation/comfort

Owners presented at CMHC workshop along with SBRN



BIPV/T roof in 5 sections for analysis - Energy model

INSULATEDDUCTBRINGS HOT AIRFROM ROOF

PHOTOVOLTAIC

PANELS

section 1

section 54

3

2

0 2 4 60

8

16

24

32

40

Distance along flow path (m)

Tem

per

ature

(C

)

An open loop air system is utilized for the BIPV/T system as opposed to a

closed loop to avoid overheating the photovoltaic panels.

Outdoor air

Solar-heated air



EcoTerra: Ventilated Concrete Slab (VCS) – store heat from

BIPV/T (also can be used for night cooling)

Full scale prototype and numerical model developed

115

89

76

64

38

Normal Density Plain Concrete

Steel Deck (Canam P-2436, galvanized steel)Ventilation Channel (cavity)

Metal Mesh (e > 5mm)Rigid Insulation

Water/vapor Barrier

Gravel (earth)

Unit in mm

Th

_cn

c

• Construction

Concrete

Air from

BIPV/T

Active and passive thermal storage to reduce peak electricity demand

Insulation

Passive design and integration with active systems

Near net-zero house; a higher efficiency PV system covering same area would result in net-zero.

Study of occupancy factors indicated importance of controls.

IEA Task 40 case study

Geothermal

heat pump

EcoTerra energy system 24



• Solar house with close to net-zero energy consumption: about 10000 kWh/yr (of which 3000 kWh is due to occupant additions); i.e. 7000 kWh based on design.

• Emphasis on integration and lowering of cost through prefabrication.

Family room

To get to net zero

1. Use of a more efficient BIPV system

(with PV efficiency = 15 %).

2. Better integration to utilize collected heat.

3. Replacement of garage electric heater

with heat from BIPV/T system.

Lessons learned



JMSB BIPV/T Solar Facade:

A NSERC Solar Buildings Research Network

Demonstration Project

Funded by NRCan TEAM Program

through CanmetENERGY Varennes

Brendan O’Neill – research engineer,

Josef Ayoub - NRCan

Back façade

of new building

(JMSB- Concordia)



Building Integration of PV – with HVAC and envelope: BIPV/T

• From one building surface with an area of about 288 m2 generate both solar electricity (up to 25 kilowatts) and solar heat (over 75 kW of ventilation fresh air heating);

• Total peak efficiency over 55%;

• The system forms the exterior wall layer of the building i.e. it is NOT an add-on.

• Mechanical room is directly behind the BIPV/T façade.

Mechanical room

BIPV/T



25 kWe

Up to

15000 cfm

fresh air =

over 75 kW heat

Partners: Concordia University, Conserval, Day4 Energy, NRCan,

Schneider Electric (Xantrex)



Air flow paths in BIPV/T system

Special design to promote heated air

behind PV to flow into transpired collector

PVAir flow

Clamp

25 kW electricity

Solar heating of up to 15000 cfm

of fresh air

Control of airflow will be optimized

- Variable speed fan

Transpired

Collector

cladding



Just 288 sq.m. was covered.

Imagine possible generation

with 3000 sq.m. BIPV/T

Note snow melting from BIPV/T roof

Integration

Passive air circulation in BIPV/T melts snow in winter.

40 degrees slope

Normal roof collects snow

Athienitis house, Domus award finalist

Note difference in south facing

window areas

Private

project

Integration – BIPV/T (1.9 kWe)

Passive solar – superior comfort

Geothermal system (2-ton)

Efficient controls

Passive solar design + BIPV/T + Geothermal + efficient 2-zone controls

Mass

Athienitis House

Domus award finalist

Modelling, Design, and Optimisation ofNet-Zero Energy Buildings (Pub. Wiley & Sons); edited by Athienitis & O’Brien

Authors:

Andreas Athienitis

Shady Attia

Josef Ayoub

Paul Bourdoukan

Scott Bucking

Salvatore Carlucci

José Candanedo

Maurizio Cellura

Yuxiang Chen

Véronique Delisle

François Garde

Francesco Guarino

Mohamed Hamdy

Ala Hasan

Konstantinos Kapsis

Aurélie Lenoir

Davide Nardi Cesarini

William O’Brien

Lorenzo Pagliano

Jaume Salom

Joakim Widén

Samson Yip

verify .

IEA SHC Task 40/ECBCS Annex 52: Towards Solar NZEBs - 5 year Task (2008-2013)

Book from Subtask B:

EcoTerra archetype redesign

34

-12000

-10000

-8000

-6000

-4000

-2000

0

2000

4000

6000

8000

10000

12000

14000

Base C

ase

(a

s b

uilt

)

Re

moved

air c

lean

er

an

dre

du

ce

d fa

n u

se

Re

move D

ivid

ers

Sha

din

g C

on

tro

l

Basem

ent a

nd W

all

insu

lation

Add

ed

PV

Ele

ctr

icit

y U

se

(kW

h/y

ear)

Controls

Equipment

HRV/Air Cleaner

DHW

Heat Pump: Cooling

Heat Pump: Heating

Lighting, appliances, andplug loads

PV generation



Modeling, design and optimization of NZEBS

What is the appropriate model resolution for each stage of the design?

What is the role of simple tools versus more advanced detailed simulation?

What other tool capabilities are needed to model technologies such as building fabric-integrated storage (PCMs), BIPV/T + heat pumps?

IEA SHC Task 40 / ECBCS Annex 52 Subtask B

RSF archetype - alternative design investigation

Fixed louvers versus motorized (between glass)

36

0 10 20 30 40 50 60 70 80 900.2

0.3

0.4

0.5

0.6

0.7

0.8

Profile angle (Degree)

Tra

nsm

itta

nce

(Peng 2009)



Solar Neighborhood Design: optimizing solar potential

•Develop optimal energy design of solar homes with BIPV, BIPV/T, solar thermal, and/or combinations of technologies

•Consider different building forms and layouts, and street planning

•Consider community peak energy generation and peak demand

Renewable Energy Systems for Solar Communities

•Explore optimal community energy system options suitable for Canada through the development of modeling and optimization tools to maximize use of solar energy

•Consider energy generation and demand diversity of NZEBs in solar community energy planning systems

Solar Community Design and Density Effects

•Identify density effects on solar community design; Consider clusters of six or more heterogeneous mix of solar buildings arrangements using conventional, new urbanism, fused-grid etc.

•Consider building shapes and sizes, and spaces between buildings to examine the impacts on neighbourhood energy demand and generation

37

Example SNEBRN project: Design of New Solar Communities

Work under project 5.2a• Solar community concepts with non-rectangular or rectangular

house shapes and designs that may be employed with

appropriate BIPV/roof designs while also allowing for optimal

design passive solar gains.

• These designs also affect significantly the peak generation of

electricity and the peak demand.

• Can shift and reduce the peak of electricity supplied to the

grid, while also reducing the peak demand from the grid as well.

(c)

(a)

U2

U1

U5

U4

U3U2

U1

U5

U4

U3

U2

U1U5

U4

U3

U2

U1

U5

U4

U3U2

U1

U5

U4

U3U2

U1U5

U4

U3

(b)

U3U2U1 U1 U3U2 U1 U3U2



Road layout

Neighbourhood Design

� The average heating load is

not significantly affected by

the layout of streets.

� If energy use / energy

production is considered,

some configurations are more

beneficial in a specific site

layout.

Site I

Site II

Site III

Ratio of energy generation to energy use for all the neighborhood

Site Site I Site Site II Site III

Density

shape

Detached Attached Density

shape

Detached Attached Detached Attached

Rectangle 0.65 0.66 rectangle 0.62 0.58 0.63 0.70

L shape 0.74 0.75 L Variants 0.81 0.81 0.85 0.82

L variants 0.79 0.79 Obtuse 0.74 0.73 0.75 0.85

C. Hachem



Development and Optimization of BIPV/T systems:Solar simulator & Environmental Chamber (Concordia)

40

Concordia solar simulator

testing BIPV/T system

similar to EcoTerra

BIPV/T prototype (JMSB)

tested in vertical position;

JMSB BIPV/T: Peak efficiencies

(thermal + electric) of 55% +

Accurate model

development for

innovative systems

that was not

possible with

outdoor testing

2-storey high

environmental chamber

with solar simulator



Typical configuration of test in environmental chamber of SSEC facility with test façade and thermal storage

Test-room

Thermal storage

e.g. PCM panels

or VCSTest

facade

Environmental

chamber: -40 to 50 C



RETROFITS

• Renovation of existing buildings

provides the opportunity to

cover facades with cladding that

heats ventilation fresh air and

generates solar electricity,

42

JMSB BIPV/T

Peak eff. 55%

SIQ building (Montreal) considered for

possible BIPV/T retrofit 42Background



Concordia Engineering Building (hybrid ventilation schematic -original concept)

High mass building;

studied in 2 PhD and 1

MASc theses

MPC potential is

significant for night

cooling to reduce peak

demand.

Install variable speed

fan.

Fan

43

Atrium 1

Five 3-storey atria – solar chimney

Air inlet grilles

On two sides

Atrium 5

Atrium 1

Varennes NZEB Library final design (Montreal)

South elevation

SNEBRN provided advice: choice and integration of

technologies and early design building form

Design required several iterations - e.g. final choice of BIPV

system required minor changes in roof design for full

coverage; note also skylights that allow deep penetration

of daylight. Roof slope close to 40 degrees.

Design charettes organized by NRCan

2000 sq.m. NZEB



Solar source heat pump connected to BIPV/T

• The BIPV/T system can be used as the source of a heat

pump to heat a water tank.

• Can utilize excess electricity and heat to charge

chilled/hot storage for later use: REDUCE PEAK EXPORT

OF ELECTRICITY.

45

The path towards Smart NZEBs and Communities – an opportunity for innovation

• Buildings undergoing a transformation to reach net-zero

• Opportunity for leadership – construction is engine of economic growth, high quality of life

• NZEBs will lead to many novel products, exports, jobs

• Challenges:

– fragmentation of building industry

– transformative changes to building design and operation

– ambitious R&D programs: from basic research to full scale demos with a research component

– incentive measures with multiple benefits such as production of renewable energy at times of peak demand

– training of engineers and architects

46

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