we had received following comments from GBCI for final design review for IEQP1 credit: Revised documentation has been provided including a response narrative, revised Ventilation Rate Procedure (VRP) calculations, and an updated LEED Prerequisite Form to address the issues outlined in the Preliminary Review. The 62MZCalc spreadsheet has been used which is appropriate for the multiple-zone re-circulating system. The system ventilation efficiency (Ev) has been determined based on the critical zone parameters. However, three issues remain outstanding. Outstanding Issues: 1. Preliminary ReviewComment #1 and ;#2 requested;a separate;VRP calculation be performed for each
ventilation system. However, the VRP calculations provided combining all ventilation systems (AHU1 to AHU12) in one VRP calculation. Additionally, the mechanical schedule;and anarrative describing the ventilation system and system design outdoor airflow for each system has not been provided as requested. It is unclear whether the ventilation requirements have been met at the systemlevel for each system. 2. Preliminary Review Comment #3
requested the VRP calculations be revised to account for the total system population, area, supply air, and outdoor air volumes for systems also serve spaces outside the project scope. However, it appears from the revised VRP calculations, the zone area and zone population for other spaces in the building have not been included, and no justifications have been provided. 3. Preliminary Review Comment #4 requested the VRP calculations be performance based on the worst-case condition, which includes revising the zone air distribution effectiveness (Ez) to 0.8 for zones that are provided with heating and using the terminal box minimum supply flow to zone in the calculations. ;However, the zone air distribution effectiveness (Ez) used in the revised VRP calculations is still 1.0, and the Ds value of 100% has been used, with no justifications provided. Note that Ds is used to calculate the"; percent of total design air flow rate at conditioned analyzed” and shall be determined based on terminal box minimum supply flow to zone to represent the worst case condition. Failure to adjust Ds results in an inaccurate value of system ventilation efficiency Ev value. The documentation dose not demonstrate prerequisite compliance.
Please help us on the comment, we are unable to understand comments received, please let us know how can we reply to GBCI.
Roger Chang
Principal, Energy and Engineering LeaderDLR Group | Westlake Reed Leskosky
LEEDuser Expert
398 thumbs up
August 31, 2012 - 1:53 pm
I recommend working with your mechanical engineering consultant to resolve these issues. Overall, a separate calculation needs to be performed for each air-handling unit system, so you'll end up with 12 spreadsheets. The Ez value needs to be selected carefully - the value of 0.8 is typical for a heating condition for most air distribution systems. The adjustment of Ds allows you to simulate turndown of the system in heating mode.