[Bldg-sim] Car Parking Ventilation Fans

Fred Betz fbetz at aeieng.com
Thu Dec 18 14:37:05 PST 2014


I’ve received credit for this energy conservation measure from LEED reviewers as an exceptional calc, but the schedule you apply to the fan needs to be well thought out.

I’ve taken 50% credit through 95% fan power savings credit depending on the operating schedule. For example, a 24 hour hospital has 3 peak usage periods per day during shift changes.

LEED reviewers will push back on this measure, and have required me to show 3 similar projects nearby that don’t have the technology installed built in the last 5 years.

Good luck on this.


Fred Betz  PhD., LEED AP ®BD+C
Senior Sustainable
Design Consultant

5802 Research Park Blvd. | Madison, WI  53719

P: 608.236.1175 | F: 608.238.2614
fbetz at aeieng.com<mailto:fbetz at aeieng.com>  |  www.aeieng.com<http://www.aeieng.com/>

From: Sherif Farag [mailto:sherif.sabr at gmail.com]
Sent: Thursday, December 18, 2014 11:05 AM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] Car Parking Ventilation Fans

Dear Modellers;
I am modelling a residential building with underground car park, the car parking will be mechanically ventilated via variable speed fans using ducted ventilation system to provide an air-change rate comply with ASHRAE 62.1-2007. Pollutant sensors (PS) are connected to BMS to control fans speed at parking floors to achieve ventilation recommended by ASHRAE 62.1.
Pollutant sensors locations and numbers have been determined to ensure that no part of the car park is located more than 25 meters from a sampling point, monitoring locations selected are considered worst-case within the car park area. And that each area which is serviced by a separate ventilation system has a separate monitoring point. In addition, one sampling point is provided at each of the entrances and exits of the car park. The monitoring will take place within the breathing zone between 1 and 1.8m above the floor and more than 0.1 m from walls or air conditioning equipment.
Based on the occupancy schedule of the project, it is assumed that the number of vehicles moving in the parking area will be minimal between 8:00 pm to 8:00 am, this means that the CO levels in this period will be less than 50 ppm -given the large parking areas and small number of cars using the garage during these hours- and based on the sequence of operation for this system, the fan speed will be reduced at least 50% for 12 hour.
The sequence of operation of this system will be as the following:
a)      Less than 25ppm, fan speed will be 1.5 ACH
b)      At 25ppm, fan speed will be 3 ACH
c)       Between 25ppm to 50 ppm, Fan speed will be 3 ACH to 6 ACH
d)      At 50ppm, fan speed will be 6 ACH

Feedback CO sensors will reduce the fan speed by at least 50% for 12 hours a day and hence the energy consumption will be reduced by at least 45% a day.

My questions are:
1) a)      Does the above sounds as an exceptional calculation (For me it is not standard practice and therefore can be done as an exceptional calculation)
b)    b)f the answer is YES, can I assume the saving is 45%

I will appreciate your feedback


Sherif Farag

Sustainability Consultant

P.O. Box: 127842

Abu Dhabi, UAE

M: +971 55 199 0022 | E: sherif.sabr at gmail.com<mailto:sherif.sabr at gmail.com> | Skype ID: sherif.farag9
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