E06 – Ventilation and Energy

Recovery in High-Rise

Residential Buildings – The

Emergence of Innovative

Approaches to Improve

Energy Use, Space Efficiency

and Occupant Health

• Stuart Hood: Integral Group

• James Dean: Core Energy Recovery Solutions

• John Breshears: Architectural Applications

James Dean

Cleantech Entrepreneur &

Passive House Owner

Stuart Hood

HVAC Consulting Partner &

Passive House Designer

John Breshears

Architect & Ventilation

Entrepreneur

Learning Objectives

• Understand the principles of energy recovery ventilation

• Understand ERV requirements of Mechanical codes

• Distinguish Pros and Cons of different approaches to residential

ERV

• Understand new ways to achieve greater energy, space, health,

and cost benefits using various residential ERV approaches

How are Codes & Standards Changing?

A move to absolute metrics

A focus on carbon

Reference Building - % Better?

Energy Performance of LEED-Certified Buildings from 2015 Chicago

Benchmarking Data

John H. Scofield and Jillian Doane

Department of Physics and Astronomy

Oberlin College

Performance Based Approaches

Reference Building Performance Targets

Total Energy Use – EUI

What is it?

• The energy required to power all

heating, cooling, ventilation and

lighting

• Includes efficiency

• Includes plug loads

Who uses it?

• California

• ASHRAE

What is it?

• Building demand for heating/cooling

• Lighting included as part of thermal

calculation

• Does not include equipment

efficiency or plug loads

Who uses it?

• Denmark, France

• Passive Haus, Minergie

• British Columbia

• CAGBC – Zero Carbon Framework

Thermal Energy Demand - TEDI

TEDI - Design Principles

Thermal Bridging

Images Courtesy: Infra-red of Aqua Tower: Dave Robley and Michael Stuart, Fluke Corp.

Aqua-Tower – Chicago, IL

TEDI - Design Principles

TEDI - Design Principles

Stale air to outside

Fresh air from outside

Fresh air to the home

Stale air from the home

RECOVERY

CORE

HRVs and ERVs:The lungs of the home

Typically recover 70% - 80% sensible (thermal),

and ERVs also transfer 40% - 50% latent (humidity)

Passive House Criteria

NOTE: For cooling, there is an additional energy

allowance for latent loads which varies by climate

TRIPLE GLAZING

UW ≤ 0.8 W/m2K

g-value/SHGC: 0.50-0.62

Yearly Heating Demand ≤ 15 kWh/(m2·yr)

or Peak Heat Load ≤ 10 W/m2

Yearly Cooling Demand ≤ 15 kWh/(m2·yr)

Primary Energy Demand ≤ 120 kWh/(m2·yr) Building

Airtightness ≤ 0.6 ACH@50

Excess Temp Frequency ≤ 10%

© Passive House Academy

Synergy of LEED with Passive House

Passive

House

Energy

Standard

Passive

House

Indoor Air

Quality &

comfort

InnovationIndoor

environment

quality

Materials &

Resources

Energy &

Atmosphere

Regional

Priority

Water

Efficiency

Sustainable

Sites

Location &

Transport

30

21

24

27

18

15

13

10

7

Kw

H/m

2/y

r

Kg

-Co

2e

/m2

/yr

EUI & TEDI Targets – BC Step Code

210

170

130120

100100

85

45

30

15

0

50

100

150

200

250

BCBC COV RZ 2014 Option 1 Option 2 PH Standard

4.75 KBTU/ft2/yr

Building Costs

TEDI = 4.75 KBTU/ft2/yr

Impact of Heat Recovery on TEDI

4.75 KBTU/ft2/yr

Importance of Indoor Air Quality

POOR Indoor Air Quality (IAQ)

• causes major health problems

• reduces productivity

• Impacts student performance

• Negatively affects sleep

On average, Americans spend about

75% of their time in their home and

about 90% of their time indoors.

Sources: Global Healing Center and Cool Today

Sources of Indoor Air Pollutants

Advancing the value of residential

ventilation for healthier living.®

Source: EPA

Source: RDH-‐BC Hydro: “Deep MURB Retrofit Pilot Project Update” 2012

Stack Effect

Air Tightness in Homes

Source: LBNL Residential

Diagnostics Database (CZ4, dry),

DOE Residential Energy Code Field

Study (climate zone 4-5), 2018 IECC

(climate zone 3-8)

Benefits of Building Airtight

Improve energy performance

• significant savings from cost effective

weatherization

Improve comfort

• less drafty and quieter

Water and moisture management

• Durability and structural integrity

Multi-family compartmentalization

• Prevent transfer of contaminants between

dwelling units

Required by code!

• IRC and IMC low-rise: blower door test required

to prove airtightness; < 3 air changes per hour

at 50 Pascals of pressure

HRVs and ERVs:Differences

Heat Recovery Ventilation (HRV)

•Transfer of sensible heat only

•Reduces indoor humidity in cold

climates

•Aluminum HRV Core

•Condensation Produced

Energy Recovery Ventilation (ERV)

• Transfers sensible and latent (moisture)

• Reduces cooling loads in humid climates

• Avoids over-drying in winter

• Membrane ERV Core

• No Condensate Produced

Humidifies in winter & dehumidifies in summer, reducing energy costs &

providing fresh air & optimal indoor comfort

Ventilate with Energy Recovery

Payback Period of ERVs in Difference Climate ZonesStudy by Newport Partners-February 2018

Key Features of ERVs and HRVs

✓ For Net Zero Carbon Buildings 80% to 90%

✓ Very Low Fan Power 0.77 Watts/ CFM

✓ Very Quiet Bedrooms NC 25

✓ In cold climates defrost control essential

✓ Capacity Control via bypass or wheel speed

✓ Energy recovery required in Cold dry and hot humid climates

✓ Balanced supply and exhaust

✓ Variable Air Flow for unoccupied and boost air flow requirements

Residential Ventilation Standard

ANSI/ASHRAE 62.2

• Required by: ✓ EPA’s ENERGY STAR; EPA’s Indoor airPLUS; LEED for Homes; State of California

• Recognized by: ✓ National Green Building Standard (ICC 700); Earth Advantage

• Prescriptive requirements for local exhaust and dwelling unit ventilation

• The tighter the building, the lower the infiltration credit

• Lower ventilation rates are allowed for balanced systems

• Ventilation energy use is outside scope of 62.2

Residential Ventilation Codes

International Residential Code (IRC)

• Low-rise, single-family (no apartments)

International Mechanical Code (IMC)

• Apartments, multi-family

International Energy Conservation Code (IECC)

• Energy efficiency of residential ventilation systems

New changes in ASHRAE 90.1 2016

All residential dwelling units (except hotels) shall be provided with an outdoor air energy recovery ventilation system.

Exceptions

1. Heating energy recovery in Climate Zones 0, 1, 2, and 3C.

2. Cooling energy recovery in Climate Zones 3C, 4, 5, 6, 7, and 8.

3. Dwelling units with no more than 500 ft2 of conditioned floor area in Climate Zones 0B, 1, 2, 3, 4C, and 5C.

ERV’s must meet a minimum of 50% enthalpy recovery ratio (ERR) in cooling season and 60% ERR in heating season

Impact of Code Changes

Centralized ERV

System Configuration

Typical Ventilation Decentralised ERV

Approaches to Energy Recovery Ventilation in High-Rise Residential Buildings

Fan Coil or Heat-PumpIntegrated With ERV Central Air Handling Unit with Energy Recovery

In-Suite Stand-alone ERV

Comparison of 3 Buildings with Different Approaches to ERV

Montreal

(Central ERV)

Vancouver

(In-suite ERV)

Toronto

(ERV Integrated with Fan-coil)

Criteria for Evaluating Advantages & Disadvantages

• First Cost (Equipment, ducts, installation)

• Energy Savings (Energy Recovery Efficiency, Specific Fan Power)

• Ownership of Equipment (strata versus home owner)

• Floor Space (taken by duct chases)

ECONOMICS

AIR QUALITY

SERVICE

• Air flow distribution (stack effect)

• Odour cross-over between apartments

• Air leakage from penetrations

• Odour recirculation between ducts

• Code issues (separation distance of ducts)

• Architectural look

• Headroom issues

with bulkheads

• Roof Space

• Maintainability

(ease of access)

• Reliability/

Redundancy

ASTHETICS

Central ERV: Evolo in Montreal

Location Montreal

Certification LEED Gold

Number of Suites 250

System Used Central AHU

CFM/Suite 19,000 cfm (32300 m3/h)

fresh air (76 CFM (130

m3/h)/Suite)

ERV Efficiency 63% Sensible/42% Latent

Specific Fan Power 1.08 Watt/CFM

Cost/Suite $756

# of penetrations 2 Per Building

Lost floor space 26 ft2 (2.4 m2) per floor (780

ft2 – 72.5 m2 total)

Lost roof space 491 ft2 – 13.4 m2

Lost headroom 5“ – 127mm

Ducting length 10,100 ft (3080 m) Horizontal

+1,500 ft (457 m-3'x2' duct)

Vertical

Central ERV

Advantages Disadvantages

1 Ease of access for maintenance 1 Less ventilation in lower floors due to stack effect

2 Fewer penetration through walls 2 Lost floor space for duct chases (lost revenue)

3 Fewer bulkheads 3 No redundancy

4 Loss of roof space

5 Greater fan power required

Central Ventilation Unit: Evolo in Montreal

Central ERV: No Rooftop Terrace

Central ERV: Lost Sales from Duct Chases

NYC: $2,577/sq-ft Toronto: $1,000/sq-ft Vancouver: $1,200/sq-ft Montreal: $500/sq-ft

780 ft2 (72.5 m2) of chases x $1000/ft2 = $780,000 in Sales

250 Suites @ $960/ERV = $240,000 (Total ERV Cost)

RDH Study: Pressurized Corridor Impact on IAQ

Vancouver, BC Typical Ventilation Approach in High-Rise MURBs 1

RDH Study: Pressurized Corridor Impact on IAQ

As newer buildings become more

airtight, there is less tolerance for

poor performing ventilation

Stack-effect impacts air

flow and IAQ in

different floors

In-suite ERV: Vancouver House

Location Vancouver

Certification LEED Gold

Number of Suites 388

System Used In-suite ERV

CFM/Suite 85 CFM (144 m3/h)/ERV

ERV Efficiency 67% Sensible/42% Latent

Specific Fan

Power

0.32 Watts/cfm

Cost/Suite $960

# of penetrations 2 per ERV

Lost floor space 0

Lost roof space 0

Lost headroom 12” (0.3 m) per bthrm/6” (0.15 m) per bulkhead

Ducting length 37,000 ft – 11,277 m

(12"x5" duct)

In-suite ERV’s

• Self Balancing Air Flow

• EC Motors with low specific

fan-power

• Compact profile (9” – 22.9 cm)

• Multiple suppliers

Vancouver House Rooftop Patios

Advantages Disadvantages

1 Better ventilation- ducted to the suite 1 Bulkheads for ducts in suite

2 No lost floor space from chases and equipment 2 Additional 1-2 penetrations required per suite

3 Low specific fan power, less static pressure 3 Requires access to maintain

4Control of ventilation at the suite level. Save

energy & control humidity4

Complexity locating ducts if minimum separation

required by code

5 No need for fire dampers

In-suite ERV: Vancouver House

In-suite fan-coil integrated with ERV

Location Toronto

Certification LEED-ND Silver

Number of Suites 363

System Used In-suite Fan Coil w/ ERV

CFM/Suite 75 CFM (127 m3/h)/ERV

ERV Efficiency 69% Sensible/49% Latent

Specific Fan Power 0.86 Watts/CFM

Cost/Suite $750 (ERV portion)

# of penetrations 2 per suite

Lost floor space 20”x20” (51 cmx 51 cm) per suite (97 ft2 – 9 m2 total)

Lost roof space 0

Lost headroom 10” – 25.4 cm

Ducting length 29,000 ft – 8840 m

In-suite fan-coil integrated with ERV

Advantages Disadvantages

1 Better ventilation- direct ducted to suites 1 Duct bulkheads in suite

2 No lost floor space from chases and equipment 2 Additional 2 penetrations required per suite

3 Low specific fan power, less static pressure 3 Access to maintain

4 Individual control of ventilation at the suite level 4Complexity locating ducts if minimum separation

required by code

5 Single duct required if on building perimeter

6 Only 1 system to install

In-suite Fan-coil Integrated with ERV

Intake & Exhaust Vents: In-suite ERV

Comparison of Costs

Central

(Montreal)

In-Suite

(Vancouver)

Integrated

(Toronto)

Equipment Cost/Suite $756 $750-960* $750

Ductwork length/

Suite† 160 ft/ suite 112 ft/suite 85.4 ft/suite

*85.4 ft/suite

Comparison of Energy Recovery Effectiveness

Central

(Montreal)

In-Suite

(Vancouver)

Integrated

(Toronto)

Ventilation Rate 76 CFM 85 CFM 75 CFM

Sensible Effectiveness 63% 67% 69%

Latent Effectiveness 42% 42% 49%

Specific Fan Power 1.08 Watt/CFM 0.32 Watt/CFM 0.86 Watt/CFM

Conclusions

1. In-suite ERVs provide better IAQ, require less ductwork,

eliminate the cost for fire damper and allow more sellable floor

area for the developer

2. In-suite ERVs are proven and well adopted in Canada

3. As buildings in the USA become more airtight and codes change

in-suite residential ERVs will become common

In-wall ERVA Different Approach

AirFlow™ Panel

Conventional heating/cooling

A hybrid ventilation/exterior

envelope solution.

The large, modular exchanger

increases the benefit (heat &

moisture transfer) while

decreasing the penalty (fan

power).

The panelized, in-wall from

eliminates the equipment

space penalty.

In-wall ERVA Different Approach

A distributed,

modular, wall-

integrated

ventilation approach

providing:

improved energy

savings

enhanced indoor air

quality increased

usable floor area

lower construction

cost

In-wall ERV

In-wall ERV

In-wall ERV

Decoupled Conditioning

In-wall ERV with Decoupled Conditioning

In-wall ERV with Decoupled Conditioning

Central

(Montreal)

In-Suite

(Vancouver)

Integrated

(Toronto)

In-Wall

(Atlanta)

Ventilation Rate 76 CFM 85 CFM 75 CFM 200 CFM

Sensible Effectiveness 63% 67% 69% 85%

Latent Effectiveness 42% 42% 49% 71%

Specific Fan Power 1.08 Watt/CFM 0.32 Watt/CFM 0.86 Watt/CFM 0.90 Watt/CFM

Atlanta, Georgia

In-wall ERVSupply Air Comparison

Central

(Montreal)

In-Suite

(Vancouver)

Integrated

(Toronto)

In-Wall

(Atlanta)

Equipment Cost/Suite $756 $750-960* $750 6720**

($8,280) ***

Ductwork length/

Suite160 ft/suite 112 ft/suite 85.4 ft/suite 45 ft/suite

* $960 units include EC motor fans

** Includes cost of AirFlow™ Panel less offsetting cost of exterior wall

*** Includes cost of AirFlow™ Panel less offsetting cost of exterior wall & floor area reduction of 20 square feet

Comparison of Costs

Date: November, 2016

Type: Middle School, Portland, Oregon

Size: 29,534 gsf floor, 13,065 sq. ft. ext. wall

Comparison of Costs

Wall-integrated ERVSpace Advantage

Increased Usable Floor Area

space & performances advantages in new and retrofit applications

questions