Energy Recovery Ventilation & ERV Basics The New Custom Express Tool Presented by: Dinesh Patel dinesh.patel@nationalgrid.com David Gaudet david.gaudet2@nationalgrid.com 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 Minimum Rates 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 Examples: 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 Assumes 8 ceiling for air change per hour comparison Ventilation Required During Occupied Hours ACH Determined by: People (cfm/person) Area (cfm/ft 2 ) Ventilation Rates Should Not be Lowered Below the Area Rate per ASHRAE 62 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% Design Supply Airflow Rate (cfm) >70% and <80% >80% >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
Cooling Coil Heat OA Ventilation and Energy OA 0 F High Grade Energy (Gas & Electric) EA 72 F WASTED Low Grade THERMAL ENERGY 72 F Room Air 80 F Supply Air 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 8
Cooling Coil Heat ERVs Recycle Energy to Preheat Outdoor Air in Winter 0 F OA ERV 57 F AHU 15 F 72 F Heat Exchanger 72 F Room Air Reduces Natural Gas Consumption 80 F Supply Air 9
Poll Question 10
Cooling Coil Heat ERVs Pre-Cool and Dehumidify Outdoor Air in Summer ERV AHU 95 F OA 79 F 91 F 75 F Heat Exchanger 75 F Room Air 55 F Supply Air Reduces Peak Demand and AC System Size 11
Outdoor Air Energy Comparison (Boston Health Club) Location Worcester MA Based on 100 % OA air, $1.X therm, $0.XX/kwh, 70% heating and 75% cooling eff. ERV, 80% efficient gas heat. OUTDOOR AIRFLOW (CFM) 4000 (100%OA) ERV 1 ERV 2 8000 (100%OA) Incremental Cost $ 6000 8000 WINTER Annual Gas Energy savings (therms)) SUMMER 4176 2270 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 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 makeup 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
ERV Component Options Design Trade-Offs Effectiveness Airflow Pressure Drop Run Around Coils Heat Pipe Rotary Wheel 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 Large Office 16% OA Complex Hospitals 55% OA Medium Office 13% OA Primary Schools 75% OA Low Outdoor Air Rates Small Office 23% OA Warehouse 26% OA Secondary Schools 69% OA Outpatient Healthcare 50% OA High Outdoor Air Rates Fast Food 34% Restaurant 36% Simple Retail 65% OA Strip Mall 62% % 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 Dinesh.Patel@nationalgrid.com David Gaudet David.Gaudet2@nationalgrid.com Michael Blaney Michael.Blaney@nationalgrid.com 25