Greetings!
The retail building pursuing LEED certification wants to use inverter type split ACs for their heating/cooling. eQuest allows us to model air cooled DX direct air path split systems. There is also Table 6.8.1A in ASHRAE 90.1 2010, that defines the performance requirements for split systems being used. Modeling the systems and adhering to ASHRAE 90.1 isn't therefore an issue.
I'm running into a problem however when filling out the minimum energy performance calculator. The baseline suggestion for a building this size (approximately 20,000 ft2) is PTACs and PTHPs as per ASHRAE 90.1. However, the minimum energy performance calculator has no option for defining split systems. Is there a trick to filling out the calculator with split systems as our proposed system?
Are split systems even allowed as the only HVAC solution for LEED projects? If so, could someone share how to fill out the minimum energy performance calculator in such a case?
Thanks in advance!
I would really appreciate some help on this.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5867 thumbs up
March 1, 2021 - 5:07 pm
In a retail building the baseline system is a System 3 or 4, not a System 1 or 2 those are for residential projects only.
Split systems are allowed. Is there an option for DX systems? What are the options?
Muhammad Asaad Iftikhar
March 2, 2021 - 3:19 am
Yes you're right, I mistakenly wrote PTACs, it's System 3 or 4, PSZ ACs. Regardless, split systems provide recirculated air and not fresh outside air as is the ventilation requirement for ASHRAE 62.1 (goes hand-in-hand with minimum energy performance). One option is to keep the split ACs as the heating/cooling solution and install ductless dedicated ventilation systems on each floor. While the logistics of this are still unclear at the moment, I'm still not sure how that system's performance will be documented in the minimum energy calculation worksheet.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5867 thumbs up
March 2, 2021 - 2:00 pm
What are the options in the calculator?