Bill McCullough Director ERV Products Dallas, TX
TOPICS 1. ERV Definition & Benefit 2. Indoor Air Quality 3. Energy Efficiency 4. ERV Technology & Operation 5. Stand-Alone ERVs 6. Compact ERVs
What is an ERV? 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. In Twenty-One Words
ERV Operation A Picture Is Worth a Thousand Words 96º F Outside Air for Ventilation 89º F Exhaust Air from Building 81º F Tempered Air Into Building 75º F Exhaust Air from Building Incoming Ventilation Air Temperature Reduced by 15º
ERV Operation A Picture Is Worth a Thousand Words -1º F Outside Air for Ventilation 47º F Tempered Air Into Building 22º F Exhaust Air from Building 72º F Exhaust Air from Building Incoming Ventilation Air Temperature Increased by 48º
Benefit of ERVs Energy Savings Improved Indoor Air Quality Code Compliance Utility Rebates
70% Energy Recovery ERVs Typically Recover About 70% of the Energy Exhausted from Buildings
25% HVAC Load Reduction ERVs Reduce HVAC Load by Up To 25% on New Construction On new construction, ERVs can typically reduce the
Schools Energy Recovery Frequently Used Here 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 Wheel Pie Segment Adjustable Motor Support
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 CO 2 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 3 Significant Significant Offensive 5% 4 High High High 0% 10%
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
Minimum Effectiveness Requirements 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
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
Types of Stand Alone ERVs Outdoor Down Discharge Side-By-Side Indoor S I D E X S I D E Side-By-Side Over / Under Over / Under S I D E X S I D E OVER X UNDER OVER X UNDER Compact ERV
Stand Alone ERVs - Ducting ERV A/C Unit Supply Duct ERV Return Duct Balancing Dampers Configuration: Stand Alone Ducted
Stand Alone ERVs - Ducting ERV A/C Unit ERV Supply Duct ERV Return Duct Balancing Damper RTU Return Configuration: Ducted into RTU
Compact ERV Installation Alternate Room Air Entry Alternate Outside Air Entry
Typical ERV Selling Proposal Current Scenario (11) 25-ton High Efficiency RTUs $150,000 Total 1 st Cost $150,000 With ERVs and High Efficiency Equipment (11) 20-ton High Efficiency RTUs $125,000 (4) ERVs $39,000 Total 1 st 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 Tahlequah City Hospital - Medical Office Building in Oklahoma This four-story building (43,000 sq. ft) specified a Variable Refrigerant Flow (VRF) system within the building s heating and cooling system.
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
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 Pressure Sensor - Provides a Static Reading Across the Intake Air Side of the ERV Wheel So Airflow Can Be Measured
Standard ERV Options 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. Utilizes a Controller that Will Control the Unit Based on Temperature and Humidity.
ERV Options 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