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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
7
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)
8
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!
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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
20
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
22
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
24
Questions and Feedback
Dinesh Patel [email protected]
David Gaudet [email protected]
Michael Blaney [email protected]
25
![1 SAMSUNG ELECTRONICS Co. LTD. HQ SE INSTALLER ERV VER. 01- Jan. 2011 ENERGY RECOVERY VENTILATION [ERV Plus]](https://img.pdfslide.net/doc/110x75/56649ced5503460f949ba4c3/1-samsung-electronics-co-ltd-hq-se-installer-erv-ver-01-jan-2011-energy.jpg)
