1 HVACR416 – Design Principles Air Exchange

2 HRV’s (Heat Recovery Ventilators)

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4 1.Heat Recovery Ventilators brings in fresh air while expelling stale air. 2.Recommended for colder climates (longer heating season) 3.HRV's air exchange core transfers heat from outgoing household air to the incoming fresh air (pre-heats) 4.Works opposite way in the cooling season 1.Heat Recovery Ventilators brings in fresh air while expelling stale air. 2.Recommended for colder climates (longer heating season) 3.HRV's air exchange core transfers heat from outgoing household air to the incoming fresh air (pre-heats) 4.Works opposite way in the cooling season

5 ERV’s (Energy Recovery Ventilators) ERV’s (Energy Recovery Ventilators)

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7 1.Brings in fresh air, expels stale air from the home 2.Recommended for warm humid climates (long cooling season) 3.Uses enthalpic "core" to transfer heat and moisture 4.Reduces indoor humidity in the A/C season 5.Maintains comfortable humidity level in the heating season. 1.Brings in fresh air, expels stale air from the home 2.Recommended for warm humid climates (long cooling season) 3.Uses enthalpic "core" to transfer heat and moisture 4.Reduces indoor humidity in the A/C season 5.Maintains comfortable humidity level in the heating season.

8 Why use an HRV or ERV? 1.The natural exchange of air between the indoors and outdoors through air infiltration and exfiltration is not satisfactory for good moisture control and IAQ 2.Traditional venting methods (opening a window or use of a bath vent fan) do not providing adequate ventilation. 3.A properly designed ventilation system provides moisture control and helps ensure healthy IAQ for the occupant. 1.The natural exchange of air between the indoors and outdoors through air infiltration and exfiltration is not satisfactory for good moisture control and IAQ 2.Traditional venting methods (opening a window or use of a bath vent fan) do not providing adequate ventilation. 3.A properly designed ventilation system provides moisture control and helps ensure healthy IAQ for the occupant.

9 1.The system uses a fan to maintain a low velocity flow of fresh outdoor air into the house (incoming air stream) while exhausting out stale indoor air (exhaust air stream) 2.Fresh air is supplied to all levels of the house as stale air is removed 1.The system uses a fan to maintain a low velocity flow of fresh outdoor air into the house (incoming air stream) while exhausting out stale indoor air (exhaust air stream) 2.Fresh air is supplied to all levels of the house as stale air is removed How It Works

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12 Common Questions about HRV’s and ERV’s

13 Who needs an HRV/ERV? 1.Every home needs ventilation to bring in fresh air, to remove stale air, and provide moisture control 2.An HRV/ERV offers convenience, comfort and durability 3.In new construction connections should be roughed in if, for budget reasons, an HRV/ERV is not installed during construction. 1.Every home needs ventilation to bring in fresh air, to remove stale air, and provide moisture control 2.An HRV/ERV offers convenience, comfort and durability 3.In new construction connections should be roughed in if, for budget reasons, an HRV/ERV is not installed during construction.

14 How much does it cost? 1.Costs vary depending on the type and complexity of the installation 2.Size and features of the HRV/ERV also effect cost 3.For new construction costs run from $1,000 to $2,500 and up 4.Retrofits generally cost more due to difficulty running ductwork to the source points 1.Costs vary depending on the type and complexity of the installation 2.Size and features of the HRV/ERV also effect cost 3.For new construction costs run from $1,000 to $2,500 and up 4.Retrofits generally cost more due to difficulty running ductwork to the source points

15 Do operating costs increase electric, heating or cooling bills? 1.An HRV/ERV requires service and electricity to run the fan but provides for heat recovery 2.On average the cost is approximately $42 annually to run an HRV/ERV fan 1.An HRV/ERV requires service and electricity to run the fan but provides for heat recovery 2.On average the cost is approximately $42 annually to run an HRV/ERV fan

16 How does the heat and moisture transfer work? 1.The incoming fresh air is tempered with a heat or energy recovery core 2.Heat is exchanged through a core made of multiple plates of aluminum or plastic 3.Water vapor is transferred through a rotating wheel with desiccant material or permeable plates 1.The incoming fresh air is tempered with a heat or energy recovery core 2.Heat is exchanged through a core made of multiple plates of aluminum or plastic 3.Water vapor is transferred through a rotating wheel with desiccant material or permeable plates

17 Enthalpy Wheel

18 1. HRV’s transfer heat from the exhaust air to the incoming air in the heating season and from the incoming air to the exhaust air in the A/C season 2. HRV’s with heat recovery and moisture recovery transfer heat and moisture from the exhaust air to the incoming air during the heating season 3. During the A/C season heat and water vapor from the incoming air transfers to the exhaust air 1. HRV’s transfer heat from the exhaust air to the incoming air in the heating season and from the incoming air to the exhaust air in the A/C season 2. HRV’s with heat recovery and moisture recovery transfer heat and moisture from the exhaust air to the incoming air during the heating season 3. During the A/C season heat and water vapor from the incoming air transfers to the exhaust air

19 Heat Exchange Plates

20 How to size HRV/ERV Manufacturers have guidelines for sizing (many states do not have standards at this time). The following is a Minnesota new home construction standard: The total number of bedrooms with a minimum airflow of 15 CFM/bedroom + 15 CFM and a total ventilation capacity equal to 0.05 CFM/square foot. NOTE: Additional ventilation may be required for special needs such as crafts/hobbies and excessive moisture situations Manufacturers have guidelines for sizing (many states do not have standards at this time). The following is a Minnesota new home construction standard: The total number of bedrooms with a minimum airflow of 15 CFM/bedroom + 15 CFM and a total ventilation capacity equal to 0.05 CFM/square foot. NOTE: Additional ventilation may be required for special needs such as crafts/hobbies and excessive moisture situations

21 How to maintain a system? Typical maintenance can be done by the homeowner and includes the following: Clean or replace air filters every 1-3 months. Clean or unblock outside hoods and screens every 13 months Clean the energy recovery core every 6 months Clean condensate drain and pans every 6 months Clean(oil if needed) fans every 3-6 months Annually clean grills and inspect ductwork for leaks or obstructions A professional should annually check the system to verify proper balance Typical maintenance can be done by the homeowner and includes the following: Clean or replace air filters every 1-3 months. Clean or unblock outside hoods and screens every 13 months Clean the energy recovery core every 6 months Clean condensate drain and pans every 6 months Clean(oil if needed) fans every 3-6 months Annually clean grills and inspect ductwork for leaks or obstructions A professional should annually check the system to verify proper balance

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24 Enthalpy Wheel

25 HRV Installed

26 HRV Installed

27 Honeywell ERV

28 Commercial Units