HVAC Design for Unoccupied Spaces - Tools & Resources

[AgsMyDude]

Good evening Steve,

I’m wondering if anyone could point me in a direction for resources in sizing/specifying or reviewing packaged HVAC units for unoccupied spaces. Our office is increasingly responsible for sizing and/or procuring these units. Having enough competence to properly specify or review vendor proposals would be helpful.

An example would be a wall-mounted unit used to cool a 14’x25’ motor control center. Another example would be a unit designed for a pre-engineered metal building used to house chemical pumps and tanks; this example might include a minimal amount of ductwork.

Is there a reference book or calculation software/guide that would be particularly applicable?

I found the two courses below from ASHRAE which I thought might be relevant.

https://myelearning.ashrae.org/local/catalog/view/product.php?productid=75

https://myelearning.ashrae.org/local/catalog/view/product.php?productid=56

Thanks in advance

 

[HVAC-Novice]

Any load calculation you use for occupied spaces should work. So any resource for load calculations will work. ASHRAE books have a chapter or 2 about load calculation. Obviously knowing thermodynamics and heat transfer also helps. You need to consider that required humidity may differ, loads are more likely to be sensible, and the need to condition might be 24/7.

After you have the load, think about what equipment may work best. For specific equipment, manufacturers can help.

If those courses are good, I don't know and depends on your prior knowledge.

 

[AgsMyDude]

Thanks HVAC-Novice,

We have access to ashrae guidelines so that will be a good resource. Our area of competency is process equipment and piping specification and design. We run into HVAC systems generally for small buildings housing chemical feed pumps or electrical enclosures and have historically allowed others to design/review HVAC design for these systems, we would likely not attempt HVAC design for occupied spaces.

If there are any software packages that are regularly used and could be appropriate for the above applications, we would investigate their use.

 

[HVAC-Novice]

Is this cooling and heating? Enclosure exposed to lot of sun? You know the ventilation requirements? if it isn't too complex, you could do it in a spreadsheet based on ASHRAE. A software really come sin handy when you have multiple zones, lots of solar load etc. If most cooling is determined by the equipment (and not solar) this can be simplified. Although, ASHRAE ahs some guidelines how to deal with solar manually.

But you really should know a bit and have some experience. And you should know the legal requirements for who can design in your area.