A Retrofit Strategy for Aging Multi-unit Residential Buildings in Toronto

Marianne TouchieNovember 29th, 2012Passive House Canada AGM

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Outline

• Motivation for MURB energy retrofit research• Performance issues and the status quo• Current Research at the University of Toronto

including NTED™

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Motivation for MURB retrofit research

Source: CMHC, Tower Renewal Guidelines

Housing starts in the GTA

Housing Stock Residential GHG Emissions

30% 40%

Indoor Environmental Quality Issues:

Draughts and overheating

High relative humidity and mould growth

Transmission of smoke, odours, noise, insects

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Causes of performance issues

Minimal Thermal

Resistance

Uncontrolled Air Leakage

Thermal Bridge

through Slab

Image source: Tower Renewal Guidelines

Architectural

Causes of performance issues

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Operational + ++ +

+ ++ ++ ++ ++ ++ ++ +

Causes of performance issues

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OperationalNegative

Positive

Balanced

Dynamic pressures (wind, stack and

mechanical)

ArchitecturalLoose envelope and

interior partitions

+

=Uncontrolled

air flow

Overclad

Enclose balconies

Upgrade HVAC

controls

Install sensors

Replace MAU

Replace windows

Install solar thermal

Submeter

Replacelighting

Recaulk windows

Cost

Time Required for Implementation

Replace boiler

Install PVs

30%

Sources: Natural Resources Canada; Toronto Atmospheric Fund

Space HeatingRequirements

Typical Retrofit

Existing Building

Current Retrofit Strategies

IEQ issues remain

IEQ issues solved?

Emerging Techniques

Compartmentalization

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Reduced stack pressure results in less infiltration

Corridor ventilation remains insufficient

Source: CMHC 2005

Suite-based Equipment

Emerging Techniques

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Preferred by condo owners, building managers

In conjunction with a central system and without compartmentalization

Source: Finn Projects

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Proposed Solution: NTED™

18°C 0°C

Conduction and Air Leakage

Heat Transfer

Adiabatic and Airtight

-6°CEnclosedBalcony

Ventilation Air Heating

ExteriorApartment Heat Recovery

Zone

Combine emerging techniques with a modified version of Nested Thermal Envelope Design™ for single family homes

NTED™ Research ObjectivesDetermine the viability of NTED™ application in the MURB sector

Through monitoring, gather detailed information about MURB operation

Verify suite-level performance through laboratory testing

Develop model with energy simulation program

Image source: Tower Renewal Guidelines

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Monitoring Program

Building-level and suite-level monitoring

12-month period

35 Charles Street Student Family Residences

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Building-level: Natural gas (hourly) and electricity use (sub-hourly)

Suite-level: electricity use E

E

Monitoring Program

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ambient lighting sensors LL

D D

D

D

P

P

P

P

Monitoring Program

E

T/R

T/RSelected suites: pressure differential sensors P (at corridor, exterior, exhaust), displacement sensors D window),

Building-level: Natural gas (hourly) and electricity use (sub-hourly)

Suite-level: electricity use E temperature T relative humidity R

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Laboratory TestingClimate Simulator at the

University of Toronto

Enclosed Balcony

Warm Room

Cold Room

HP HRV

Apartment

Chill

er

Baffle

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Energy Modelling

Test various retrofit strategies Envelope Types

Base WallR2000 WallOptimized WallBase Wall + OvercladdingNew Wall + New Wall

In-Suite Mechanical componentsHeat Recovery Ventilator Heat Pump Domestic Hot Water Tank

Sensitivity AnalysesOrientationFenestration-to-wall ratioHRZ dimensionsEnvelope air tightnessEnvelope thermal resistance

Cooling season performance

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Laboratory ResultsRetrofit Strategies

for MURBs

Bringing it all together...

Building Monitoring

Laboratory Results

Energy Simulations

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References• Canadian Mortgage and Housing Corporation. 1997. Energy Audits of High-Rise Residential Buildings.

Technical Series 97-100. from http://www.cmhc-schl.gc.ca/publications/en/rhpr/tech/97100.htm

• Canada Mortgage and Housing Corporation. 2005. “Assessment of Suite Compartmentalization and Depressurization in New High-Rise Residential Buildings,” Technical Series 05-112.

• Dixon, E., Pressnail, K.D., Richman, R., Touchie, M. 2010. Thermal Performance of the Exterior Envelopes of Whole Buildings XI International Conference: NTED: An innovative design using nested thermal envelopes to achieve significant reductions in energy use.

• Finn Projects (Synchronicity Projects Inc.) 2003."Survey of In-Suite Space and Domestic Hot Water Heating Systems in Multi-unit Residential Buildings," Canada Mortgage and Housing Corporation Research Report.

• Kesik, T. and Saleff, I., 2009. Tower renewal guidelines. Toronto: University of Toronto.

• Natural Resources Canada. 2008. Comprehensive Energy Use Database Tables. [Online]. Available: http://oee.nrcan.gc.ca/corporate/statistics/neud/dpa/trends_res_on.cfm

• United Way. (2011) Vertical Poverty: Poverty by Postal Code 2. United Way Toronto.