bill mccullough director erv products - ashrae · an energy recovery ventilator: recovers the...
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Bill McCullough
Director ERV Products
Dallas, TX
1. ERV Definition & Benefit
2. Indoor Air Quality
3. Energy Efficiency
4. ERV Technology & Operation
5. Stand-Alone ERVs
6. Compact ERVs
TOPICS
An Energy Recovery Ventilator:
Recovers the Energy from the
airstream discharged from
a building and transfers this energy
to the incoming air used for
Ventilation.
What is an ERV?
In Twenty-One Words…
ERV Operation
A Picture Is Worth a Thousand Words…
96º F Outside Air for
Ventilation
81º F Tempered Air Into
Building
Incoming Ventilation Air Temperature Reduced by 15º
89º F
Exhaust Air from
Building
75º F
Exhaust Air from
Building
ERV Operation
A Picture Is Worth a Thousand Words…
-1º F Outside Air for
Ventilation
47º F Tempered Air Into
Building
Incoming Ventilation Air Temperature Increased by 48º
22º F
Exhaust Air from
Building
72º F
Exhaust Air from
Building
• Energy Savings
• Improved Indoor Air Quality
• Code Compliance
• Utility Rebates
Benefit of ERVs
70% Energy Recovery
ERVs Typically
Recover About 70%
of the Energy
Exhausted from
Buildings
25% HVAC Load Reduction
On new construction, ERVs
can typically reduce the
ERVs Reduce HVAC
Load by Up To 25%
on New Construction
Energy Recovery
Frequently Used Here
• Schools
• Assisted Care Facilities
• Retirement Facilities
• Gyms & Fitness Clubs
• Pet Care & Boarding • Office Buildings
• Health Care
• Restaurants
• Theatres
• Retail Space
Energy Recovery
Technologies
Types of Air-to-Air Energy Recovery
Plate Exchangers – Sensible Recovery With Limited Latent Recovery
– Typically Less Than 50% Effective
– Airstream Separation When Exhaust Pollution is A Concern
– Exchangers Tend to Get Very Large And Heavy in Larger CFM’s
Types of Air to Air Energy Recovery
Rotary Wheels
– Highest Sensible and Latent
Recovery
– 60 – 80% Effective
– Most Compact in Larger CFM’s
– Easy to Maintain
– “Self” Cleaning
Typical Rotary Enthalpy Wheel
Segmented
Thinner
Cost Effective
Permanently Bonded Type
A Silica Desiccant
Vapor Transfer
No Condensate
Low Frost Temperature
Rotary Enthalpy Wheel Maintenance
• Wheels Slide Out for Service
• Pie Segments on Wheel Can be Removed Individually for Easy Cleaning
• Rinse With Tap Water
• Tougher Dirt Soak in Dishwashing Soap
Adjustable
Motor Support
Wheel Pie
Segment
Silica Will Not Wash Away
Brand new wheel
After 3 years in a smoking
environment and 6 washes
Polymeric Frost Considerations
Vapor State = Low Frost Threshold
Frost Threshold Depends on Return/Exhaust Air Humidity and
Temperature
Example of Rotary Wheel ERV
Configured without Frost Control
ERV in Winnipeg:
Ordered Without
Low Ambient Frost
Control Kit
This ERV Wheel Is NOT Damaged
Typical Rotary Wheel Performance Data
Customer Benefit:
Improved IAQ & Code Compliance
• “Ventilation for Acceptable Air
Quality” - ASHRAE Standard 62.1
• Specific CFM Quantity Requirement
• Classrooms Generally 15 CFM Per
Occupant
• CO2 Space Limitations
• Occupant Health and Well Being
• Productivity
• Loss Time
ASHRAE 62.1
Classes of Air
Class Contaminant
Concentration
Sensory-
Irritation
Intensity
Odor Maximum Air
Leakage
1 Low Low Inoffensive Not Specified
2 Moderate Mild Mildly
Offensive
10%
3 Significant Significant Offensive 5%
4 High High High 0%
ASHRAE 62.1
Classes of Air
Class Examples
1 Offices, Public Assembly Spaces
2 Gym, Pet Shops, Restaurants
3 Daycare Sickroom, General Mfg
4 Paint Fumes, Laboratory Fumes
AHRI Standard 1060
for Air-to-Air ERVs
AHRI Standard 1060
for Air-to-Air ERVs
Certified Ratings for Heat Exchanger
The following certification program ratings are verified by test:
1. Sensible Effectiveness at 100% Summer, 75% Summer, 100% Winter, and 75%
Winter, %
2. Latent Effectiveness at 100% Summer, 75% Summer, 100% Winter, and 75%
Winter, %
3. Pressure Drop at 100% airflow laboratory ambient conditions, in H2O
4. Exhaust Air Transfer Ratio (EATR) at three pressure differentials, 0.00 in H2O
and two more within the scope of the program
5. Outdoor Air Correction Factor (OACF) at three pressure differentials, 0.00 in
H2O and two more within the scope of the program
AHRI Standard 1060
for Air-to-Air ERVs
Exhaust Air Transfer Ratio
per AHRI 1060
EATR: The tracer gas concentration
difference between the Leaving Supply
Airflow and the Entering Supply Airflow
divided by the tracer gas concentration
difference between the Entering
Exhaust Airflow and the Entering
Supply Airflow at the 100% rated
Airflows.
Expressed as a percentage.
Outdoor Air Correction Factor
per AHRI 1060
OACF: The ratio of the Entering Supply
Airflow to the measured (gross) Leaving
Supply
Accordingly, OACF is used to size the
fans.
Customer Benefit:
Energy Efficiency & Code Compliance
• “Energy Standard for Buildings” -
ASHRAE Standard 90.1 • Except Low-Rise (3 stories or fewer) Residential Buildings
• Covers Efficiency Standards for Windows, Lighting, Water
Heating, Power Distribution, and HVAC
• ASHRAE 90.1 2010 = Minimum 50%
• ASHRAE 189 = Minimum 60%
What is ASHRAE 189? • Stretch Standard for Energy Efficiency
• Currently Being Specified for Some Government
Buildings
• Requires Even More Energy Recovery
– As Low as 10% Outside Air Requires Energy Recovery
in Some Cases
Minimum Effectiveness Requirements
Widespread Adoption of ASHRAE 90.1
http://www.energycodes.gov/adoption/states
ASHRAE 90.1 2010 Zones
Climate Zones and ERV Requirements
ASHRAE 90.1 2007: Requires energy
recovery if system air is greater than 5,000
CFM (12.5 tons) and outside air is more than
70%.
ASHRAE 90.1 2010: Significantly expands
requirement as shown below:
5 X the
requirement
of previous
standard
Type of ERVs
Primary ERV Configuration Types
Unitized (Bolt-On) Stand-Alone
Compact ERV
Outdoor
Down Discharge
Side-By-Side
Over / Under
Types of Stand Alone ERVs
OVER
X
UNDER
S
I
D
E
X
S
I
D
E
OVER
X
UNDER
S
I
D
E
X
S
I
D
E
Indoor
Side-By-Side
Over / Under
Compact ERV
Configuration: Stand Alone Ducted
A/C Unit ERV
Supply Duct
ERV Return Duct Balancing Dampers
Stand Alone ERVs - Ducting
Configuration: Ducted into RTU
Balancing
Damper
A/C Unit ERV
ERV Supply Duct
ERV Return Duct RTU
Return
Stand Alone ERVs - Ducting
Compact ERV Installation
Alternate Outside Air Entry
Alternate Room
Air Entry
Typical ERV Selling Proposal
Current Scenario
(11) 25-ton High Efficiency RTUs $150,000
Total 1st Cost $150,000
With ERVs and High Efficiency Equipment
(11) 20-ton High Efficiency RTUs $125,000
(4) ERVs $39,000
Total 1st Cost $164,000
ERV Electricity Savings $23,000
•
Total Annual Savings $23,000
Payback 7 Months
*Based on ERV operation in Kansas City, MO
ERV Case Study: Creative Solution for VRF
Systems
• This four-story building (43,000 sq. ft) specified a Variable
Refrigerant Flow (VRF) system within the building’s
heating and cooling system.
Tahlequah City Hospital - Medical Office Building in Oklahoma
ERV Case Study: Jobsite Problems
• High temperature and high humidity in the
summer
Taxed VRF System May Cause Uncomfortable
Conditions
Due to low winter temperatures, additional
heaters might be required to supplement VRF
units
Limited Installation Space for Conventional Large ERVs
ERV Case Study: Solution – Compact Indoor ERV
2 Compact ERVs Per Floor - 8 Total in
Building
Reduced Incoming Temperature and
Humidity Enough to Ensure Comfortable
Conditions in the Summer
• Raised Incoming Temperature Enough to Prevent Need for Supplemental
Heat
• Low Profile, So It Fit in Available Ceiling Space
ERV Case Study: Results
Initial Equipment Cost Savings - $22,400
Estimated Cost Of Purchase and
Installation Assuming that each of the
64 VRF Units Needed Supplemental Heat
Energy Savings Delivered Directly From the
ERVs Pre-Conditioning the Fresh Air - $8,500
/ Annually
8 ERVs Cost Less Than $30k Installed
Examples of ERV Options
• Low Ambient Kit - By Means of Temperature
Sensors the Intake Blower is De-energized
Momentarily When Frost Conditions are Sensed,
and the Blower is Re-energized After the
Exhaust Air Has Warmed the Wheel
• Motorized OA Damper - Closes the Outside Air
Damper When the ERV Is Not Operational (Outdoor
models only)
ERV Options
• Airflow Measurement – Electronic
Fan-inlet Air Measurement Station
Utilizes Thermal Dispersion
Technology Combined with Low-
Pressure Drop Aerodynamic
Sensors to Measure the Airflow
ERV Options
• Pressure Sensor - Provides a Static
Reading Across the Intake Air Side of
the ERV Wheel So Airflow Can Be
Measured
“Economizer Mode” -
Stop, Start, Jog –
When the Fixed Wheel ERV
is Used This Option Stops
the Wheel When Outside
Conditions Exist Where
Recovery is Not Desired,
and the Wheel is “Jogged”
on a Timer to Prevent Dust
Buildup on the Wheel.
Standard ERV Options
Utilizes a Controller that Will
Control the Unit Based on
Temperature and Humidity.
• VFD Control – ERV Blower Speed is Controlled by
VFDs, Which Allows the Building Pressure to be
Control Based on a Variety of Inputs
• Sensible Only Wheel – Allows Moisture To Pass
Through Energy Wheel
• BACnet Controls – Allows Real Time Monitoring and
Controls of Some Functions of ERV
ERV Options
• Disconnect with GFCI (Ground Fault Circuit
Interrupter)
• – ERV is Equipped with a Properly Sized
Disconnect, and a GFCI Plug is Provided (Must Be
Field Wired)
• Filters – Located at Intake and/or Exhaust Air
• Dirty Filter Sensor – Sends 24 Volt Signal When
Filters Need Replacement
ERV Options
• Hinged Access Panels – Easy Access to Inside of
ERV.
• Rotation Sensor – Sensor Provides a 24 Volt
Feedback Signal Should the Wheel Not Rotate as
Required, and Signals Both a Motor Failure and a
Belt Failure
ERV Options
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