Hello Harshul,
1. How can I model heat recovery bypass dampers that can be opened during air-side economizer mode?
a. Set the ERV Operation to "When Minimum OA".
" WHEN-MIN-OA specifies that the ERV operates only when the outside air dampers are at their minimum position (i.e., the economizer is inactive). If the building has no economizer, then WHEN-MIN-OA is equivalent to WHEN-FANS-ON."
2. I have 2 systems in my model. ACB (active chilled beam) for 2 floors & VAV system for another 2 floors. I am recovering 10,000 CFM (ERV) through ACB system and now I want to recover 20,000 CFM from dedicated exhaust. For dedicated exhaust, I have created a dummy zone which assigned 20,000 at exhaust side. Now how can I recover heat from this dedicated exhaust. I tried to create a PSZ system just for this dummy zone and tried to recover heat through that but instead it's giving me high penalty. Minimum Outdoor air for this system is kept one. Is there any other way to do this heat recovery? How does it differ from glycol run around from dedicated exhaust to Outside air intake mixing unit?
a. This is a tough one and will take a lot of judgment on your part. eQUEST will not allow you to model multiple systems for one zone so you will have to combine your systems into a combined system for each unique HVAC system. Based on your description above DOAS w/HRX + ACB = System Type A and VAV = System Type B
b. I would assign all your zone exhaust to the system ERV exhaust, and remove the dummy zone (dummy zones do not work for heat recovery), you will need to select a system type that allows an ERV that most closely matches your designed system.
3. How can I model wrap around heat pipe for chilled beam exhaust for my ACB system?
a. Set the ERV Device Type to "Heat Pipe"
"HEAT-PIPE specifies an ERV utilizing a heat pipe. The air streams are typically arranged in a counterflow configuration."
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Byron D. Burns, EIT, BEMP
Energy Engineer, Building Sciences Studio
H&A Architects & Engineers | www.ha-inc.com
d: (804) 420-1622 p: (804) 285-4171 f: (804) 217-8520
