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Our ventilation system
Our building has a ventilation system that integrates mechanical ventilation components with moisture control to create an efficient and healthy system for the building. Our system included:
- Energy Recovery Unit (ERU)
- Moisture Control
The sustainability goals for the ventilation system are:
- Meet 20 cfm per person for the building.
- Maintain the indoor relative humidity at 45% +/- 15%.
- Ensure healthy indoor environment.
- The system should be simple to maintain, adapt and control.
Strategy and Conceptual Design
The major elements of our ventilation strategy were:
- The ventilation system at the Green Garage has two main components:
- ERU - Air Exchanger
- Moisture Control
- Reduction in energy usage.
- Select the highest-efficiency methods available.
- Demand controlled ventilation (DCV) adjusts ventilation rates based on actual occupancy at any given time instead of at a fixed rate for full occupancy.
- Make sure we are addressing moisture in every building component.
Ventilation System Diagram
ERU - Air Exchanger Design
The Energy Recovery Unit is an integral part of the the air exchange system. In general, the Energy Recovery Unit provides the year-round foundation for the building's ventilation. During a normal air exchange, the outdoor air will be brought in through the Energy Recovery Unit, where the outbound air will be used to heat/cool the inbound air, as well as dehumidify or humidify the air.
The powerful aspect of this design is that the Energy Recovery Unit takes the heat and humidity out of the exhaust air stream in the winter and transfers it through an energy recovery wheel to the incoming raw outside air. The process is reversed in the summer season.
The above chart shows the relative contributions of each component.
Moisture Control Design
We have designed moisture control through every component of the building systems. The main areas of focus are controlling where the dewpoint occurs in the building envelope and controlling humidity in the occupied space. For more on moisture control please see our Moisture Control pattern page.
Ventilation Sequence of Operations
If you're interested in leaning more detail about how we control our ventilation system, please see our Sequence of Operations Matrix and click on the Ventilation/ERV tab at the bottom.