What is an Energy Recovery Ventilator (ERV)?

The COVID-19 pandemic has made indoor air quality (IAQ) and ventilation household words. Balanced ventilation strategies are indeed on the rise. The most efficient method is to use Energy Recovery Ventilator (ERV), a way to supply air tempered, filtered and controlled. You may wonder what an ERV is, I would be more than happy to talk about ERV science and how they work.

• Components of Energy Recovery Ventilator

• What are Energy Recovery Ventilators?

• How does an Energy Recovery Ventilator work?

• When to Use Energy Recovery Ventilator

1. Components of Energy Recovery Ventilator

An ERV system consists of the following parts:

1. Fans to bring fresh air indoors and to exhaust stale air to the outdoors.

2. High efficiency brushless DC motors

3. A heat-exchange core, where energy is transferred from one air stream to the other

4. Filters to keep dirt out of the heat-exchange core

2. What are Energy Recovery Ventilators?  

- A balanced mechanical ventilation system designed with fans that exhaust and supply equal quantities of air, to pull stale air out of the building and to bring fresh air into the building.

-  An air-to-air heat exchanger that pretreats incoming outside air by transferring the heat and moisture between incoming fresh outside air and exhausted stale air. The two air streams is blocked by plates so they do not mix.

3. How does an Energy Recovery Ventilator work?

An ERV works on the principle that air moves from hot to cold, and moisture from more to less.  

There are two mechanisms in the process of energy recovery.

- 1st is heat conduction.

When the two air streams pass over the surface of the plate between them, the plate absorbs the temperature differential. So heat will move from the warmer airstream to the cooler airstream through the plate.  

- 2nd is capillarity.

The water vapor moves though the capillaries from the warmer airstream to the cooler airstream.

The capillary hole are small enough that actual liquid does not flow through, only the moisture grains will pass as they seek balance between the two air streams.  

4. When to Use Energy Recovery Ventilator

• When indoor air quality an issue for you

• When constanst humidity control is an issue.

• When large quantities of ventilation air are desired

• When long-term energy cost are more important then first cost

• When energy efficiency a high priority for you

If your answer is yes to any of these questions then an ERV could be of assistance.

What are your thoughts on ERVs and Indoor Air quality generally? What are your top questions? We'd love to hear.