Hey Everybody! For those who attended yesterday’s (10/24) PPD workshop, toward the end someone (I apologize I didn’t catch your name!) asked for some more specifics about how I thought about cost, scope, and scale to help me categorize mechanical systems. (What I had shared in the ‘How I Struggled with this Topic’ section). Below is a bit more of a specific breakdown of what I meant by that.
Mechanical systems can be super complex but trying to come up with parameters that help distinguish the pros and cons of each system was helpful for me. The three I went with were cost, scope, and scale, but you could really choose any that work best for you! These are not complicated but just helped me wrap my mind around what the options were for mechanical systems and how they related to each other.
Cost: In looking at the various mechanical systems I created a linear scale from cheapest to most expensive. This is a bit over simplified as the systems depend so heavily on the types and sizes of spaces, but it was helpful for me to know roughly how they related to each other from an equipment cost standpoint. This LINK provides a non-exhaustive example.
Scope: The question I asked myself here was, what does the system need to accomplish? Is it only cooling? Does it require 100% fresh air? Does it need individual control for different spaces? (Just like in our workshop scenarios!) Simply aligning the various systems to a yes/no answer for questions like this gives an understanding of the benefits and capabilities of each system.
Scale: Knowing the rough footprint of a system was helpful for me. Like the scenarios in our workshop, if we weren’t able to put units on the roof and only had a small mechanical closet available that would greatly impact what systems could be utilized. It is also helpful to consider general output of a system. As an example a CAV system may be great for a large assembly space where a PTAC would be more appropriate in a hotel room.
Overall, chapters 9 and 10 of Mechanical and Electrical Equipment for Buildings are a good place to skim through. We looked at pages 393-394 during the workshop to discuss the single vs. multi zone systems. Those are included in chapter 10.
Some other references that may help your search and organization of the different systems may include VRF vs Mini-Split and Section 4 of the Architect’s Studio Companion.
Hope this is helpful!
- Heidi