Fresh Air & Heat Recovery in Mechanical Systems

Hi there!

In today’s PPD Workshop with @coachheidimetcalf one of the answer choices mentioned a mechanical system which had 100% fresh air intake and heat recovery. In my limited experience and studying I’ve only come across heat recovery systems which use recycled, pre-conditioned air in order to increase efficiency. What other systems or methods of heat recovery are there which may allow for 100% fresh air?


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Hi @sillscai ,

Was the workshop talking about heat recovery ventilators by chance? Check out the link on “Heat recovery ventilators” below! In the section marked, " Advantages and disadvantages" it lists a few different types of this system and positives and negatives of each.

Hope this helps!

Hi @sillscai
I just wanted to also direct you to another link discussing heat recovery ventilation. Particularly check out the section titled “Choosing between an HRV and an ERV”.

In terms of the hear recovery we were discussing in the workshop, the two systems that are mentioned that may be relevant to your question are, Rooftop-mounted Dedicated Outside Air system (DOAS) with heat recovery; also known as a Single-Zone Variable Air Volume (SZVAV) and then the Variable Refrigerant Flow/Volume (VRF/VRV) heat pump / fan coil system with 100% outside air ventilation.

This LINK has some great graphics that break down with the DOAS with heat recovery is and how it works.

This LINK also has a good breakdown of the VRF and some of its pros and cons.

Hope these additional links are helpful for you!

  • Heidi
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