Heating and cooling systems for a midsize to large building to minimize maintenance expenses


Mock exam #1, question 22/120. The answers were VAV, single duct with CAV, and hydronic convector are the most appropriate.
According to BlackSpectacles, FCU and heat pumps were not appropriate because the maintenance is done in occupied spaces, but isn’t this the case for VAV and hydronic convectors as well?
Both of these systems might need access through occupied spaces.

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Hey @ridlby, can you post a screenshot of the question itself? The mock exams randomize the questions, so 22 for you might not be 22 for me.

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Please see below.

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Thanks for posting the original question. In your original post, you spoke about maintenance accessibility, but the question seems to be asking for a cost comparison. While ease of access should be considered (could be an additional cost to have someone service the systems overnight), we need to really weigh the initial and lifetime costs of all systems.

In response to your question about VAV and hydronic convectors; yes. Both of these systems would require maintenance in occupied spaces as well.

Did I address your question?

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Thanks for getting back to me.
Black Spectacles mentioned that access through occupied spaces is what’s driving the maintenance cost up.
If all of the systems need such access, the explanation as to why hydronic and heat pumps are not appropriate should be different than the one provided, no?

Hmm I see what you’re saying. The explanations could be more specific, for example a hydraulic convector might be able to be serviced in a more timely manner than the closed loop heat pump which could keep costs lower, though I’m not sure. @heatherrivera, do you have any thoughts on this?

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@ridlby I think the explanations are a bit misleading and referencing back to language in The Architect’s Studio Companion. Through-the-wall and packaged terminal units, closed loop heat pumps, and fan-coil terminals all require frequent or routine maintenance. If maintenance is required in occupied spaces, there will be a service increase for timing. Conversely, single duct at constant air volume, VAV and hydronic convectors are simple to maintain and operate and therefore have a lower maintenance cost.

Thank you for your feedback. I think this is one such question where we can do some rework internally. Sorry for the confusion!