Energy Recovery Ventilation ERV Basics The New Custom ...

ERV Basics

Presented by:

Dinesh Patel [email protected]

David Gaudet [email protected]

Energy Recovery Ventilation

&

The New Custom Express Tool

1

What is and Why ERV?

The recovery of energy from one air stream to another to

save energy

In New construction this enables downsizing the required

HVAC equipment. $$$$

May be eligible for utility incentives

Reduce operating Cost

May help qualify for LEED certification

2

IAQ and Ventilation

• Mechanical Ventilation Delivers Fresh Air for Control of IAQ

• ASHRAE 62.1 Sets MinimumRates Based on Dilution Principle

• Proven Health and Productivity Gains Above the Minimum

Dilution Principal Double ACH = ½ the Pollutant Level

3

Poll Question

4

Ventilation Rates Vary by Building Category

Category ACH

Office 1

Retail 1.75

Break Rooms 2.6

Science Labs 3.2

Classrooms 3.75

Bars 5.4

Health Club 6.6

• Ventilation Required

During Occupied Hours

• ACH Determined by:

• People (cfm/person)

• Area (cfm/ft2 )

• Ventilation Rates Should

Not be Lowered Below

the Area Rate per

ASHRAE 62

Examples:

Assumes 8’ ceiling for air change per hour comparison

5

2012 IECC Exhaust Heat Recovery

Requirements(6.5.6.1)

Climate Zone 1A,2A,3A,4A,5A,6A

% Outside Air at Full Design Airflow Rate

>30% and <40%

>40% and <50%

>50% and <60%

>60% and <70%

>70% and <80%

>80%

Design Supply Airflow Rate (cfm)

>5500 >4500 >3500 >2000 >1000 >0

6

Heat Recovery Requirement

Energy recovery system if required shall have at least 50%

effectiveness.

Effectiveness means a change in the enthalpy of outdoor air

supply equal to 50% of the difference between the outdoor

air and the return air enthalpies at design conditions

Provide bypass or controls to permit economizer operation

as required by section 6.5.1.1

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OA Ventilation and Energy

• Outdoor Air can be 50% or More of Total HVAC Load• The Higher the ACH, the Greater the Energy Demand• Building Exhaust Air (EA) = Wasted Energy Source

80°F72°FRoom Air Supply Air

Co

olin

g C

oil

Hea

t

OA

WASTED Low GradeTHERMAL ENERGY

72°F

0°F

EA

High Grade Energy (Gas & Electric)

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ERVs Recycle Energy

to Preheat Outdoor Air in Winter

80°F72°FRoom Air Supply Air

72°F

57°F

Co

olin

g C

oil

Hea

t

0°F OA

15°F

Heat Exchanger

ERV AHU

Reduces Natural Gas Consumption

9

Poll Question

10

55°F75°FRoom Air Supply Air

75°F

79°F

Co

olin

g C

oil

Hea

t95°F OA

91°F

Heat Exchanger

ERV AHU

ERVs Pre-Cool and Dehumidify Outdoor Air in Summer

Reduces Peak Demand and AC System Size

11

Outdoor Air Energy Comparison(Boston Health Club)

ERV 1 ERV 2

OUTDOOR AIRFLOW (CFM) 4000

(100%OA)

8000

(100%OA)

Incremental Cost $ 6000 8000

WINTER

Annual Gas Energy savings

(therms))

4176 2270

SUMMER

DX Unit Capacity (tons) 20 50

ERV Capacity (tons) 13 31

Peak Demand (kw) 7 16.5

ENERGY SAVINGS kWH -10,440 -955

NGRID Incentive $ 4500 4540

Based on 100 % OA air, $1.X therm, $0.XX/kwh, 70% heating and 75% cooling eff. ERV, 80% efficient gas heat.

Location Worcester MA

12

ERV Applications Considerations

For renovation, the return air

must be ducted from the space

to the ERV wheel. This may

require new ductwork on make-

up air only systems

Stay away from chemical

processes and laboratory

hoods as sources. Garages are

not desirable, kitchens are out!

13

Contamination Reduction

14

Carryover Prevention

15

Poll Question

16

Rooftop Configurations

17

Installed Hardware

18

Heat Pipe

Rotary Wheel

Design Trade-Offs• Effectiveness• Airflow• Pressure Drop

ERV Component Options

Run Around

Coils

19

ASHRAE 62.1

Environment classifications

Class 1- Air with low contaminant concentrations - Class

room, offices

Class 2 – Air with moderate contamination –Toilet Exhaust,

locker rooms

Class 3 – Air with significant contaminations - Chemical and

biological Labs

Class 4 – Highly Objectionable fumes – Laboratory hoods,

paint spray booths

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Existing Building Opportunity Matrix

Complex

Simple

Low Outdoor

Air Rates

High Outdoor

Air Rates

Hospitals 55% OA

Primary Schools 75% OA

Small Office 23% OA

Warehouse 26% OA

Large Office 16% OA

Retail 65% OA

Strip Mall 62%

Secondary Schools 69% OA

Fast Food 34%

Restaurant 36%

Medium Office 13% OA

Outpatient

Healthcare 50% OA

% OA based on Carrier EnergyX presentation

21

NATIONAL GRID

ERV CUSTOM EXPRESS TOOL

Applicability

New Construction (“D2”) and Retrofit (E1”)

Heat Recovery Devices : Sensible Wheel, Sensible Plate, Enthalpy Wheel, Enthalpy Plate, Heat Pipe, Glycol Run-around

Systems with Constant airflow and VAV Systems

The Tool Must not be Used in the Following Situations

If Proposed System is Not Exhaust Air Heat Recovery

If System is Equipped With DCV in Addition to Exhaust Heat Recovery

If Performance is Expected to be Significantly Degraded by Dirt or Other Site Conditions

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Why we developed the Tool?

Replacement or new installation of AHUs and RTUs

decisions are quick

Savings are local climate dependent

Savings calculations are need to be transparent to the Utility

Standardize savings calculations reduces time for

processing applications

Estimated incentives help customer, engineer and

contractors to select the options

23

NATIONAL GRID

ERV CUSTOM EXPRESS TOOL

Web Sites for Downloading custom express tool and user guide

NY Metro:

http://www2.nationalgridus.com/partners/index_ny_kedny.jsp

UNY:

https://www1.nationalgridus.com/TradePeopleContractors-NY-TPC

MA & RI:

https://www1.nationalgridus.com/TradePeopleContractors

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Questions and Feedback

Dinesh Patel [email protected]

David Gaudet [email protected]

Michael Blaney [email protected]

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