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BeardMusic wrote:Source of the postWhat I planning is to have the outlet/inlet grill on the actual boxes themselves, if you imagine on the pic below, as the end of the boxes fall roughly in the center of the room (front and back) this seems to be a good placement for them room-wise. Left one (rear) will be over the sofa at the rear of the room (Setting up the room facing the long dimension) and the right one (front) will be over the mix desk
The end of the boxes falling roughly into the centre of the room is a good plan. Why is the duct from the outer leaf to to those boxes going into the middle of the silencers though? It should enter the silencer at the opposite end to where the silencer vents into the room.
If possible, the silencer inlet should not be on the same plane as the silencer outlet. So if the outlet is going into the room at the bottom of the silencer, having the inlet on a side would give more attenuation than having it on the top of the silencer. The size of your silencer should make this less of an issue though if it can't be done.
What are the boxes on the outer leaf for?
Nominally, yes. It is worth noting that the grilles will only have a certain percentage of their area free for air though, as part of it will be covered with fins or similar. So for example you may need a 200 x 200mm grill to get a free area equivalent to your 150mm diameter duct.
OK. not sure how to calculate this, as I siad I was planning on just having 150mm outlet/inlets on the boxes in the room. I could make them 200mm wide if that helps.
The free area should be specified on the datasheet for the grille. If it's not, ask the supplier if they have it. If they don't I'd look for another grill that has this information. Here's a good example of free areas of various grill sizes:
So for those grilles, the 200mm wide choice would give a free area a bit more than duct with a 150mm diameter. The 150mm wide grill would be less. Alternatively, Glenn has recently posted a good design for an in room plenum with grill that would allow the silencer outlet to be 150mm across. The plenum would then have the 200mm wide grill.
As I said, there will very rarely be more than 2/3 people in the room at one time. I do want it comfortable for the odd time I may have the band in there (4 of us in total). Looking at the specs for the TD 500 (https://www.justfans.co.uk/silent-500150-p-1906.html) That you suggested, I was pretty happy with it. Do you think I should go more powerful?
To answer this we'll first have to estimate the static pressure of your entire ventilation system at the required rate of air flow. Static pressure measures the resistance of the system to having air pushed through it. It's analogous in some ways to sucking water through a straw; easier through a thick straw than a thin one. Same with ducts; thinner ducts have higher static pressure. Longer ducts have higher static pressure, like a long straw would.
You should include the combined static pressure of filter, silencers, ducts, grilles, plenum boxes, and anything else you might have in the air path. Elbow joins and turns in the duct increase the static pressure more than straight runs. Most of this can be found in datasheets for those products. For example, the following shows the static pressure of several different sized G2 filter boxes at certain flow rates. I think the one I have came with a curve of static pressures at different flow rates.
The silencers, well, there is a calculation that approximates it, probably
Get as much of this data as you can and I'll help you with the calculation. Based on my own experience with the 500-150 fan, it might be enough. Or it might not. I would not commit to it without verifying first without estimating the static pressure of your system.
If you'd rather just get on with the job ASAP without all those sums I'd keep the option open for the next fan up the series, just in case.
Cheers,
Jennifer
) is the ability to cross-link the supply and return lines to balance the overall pressure by regulating how much is directly transferred when there are pressure changes or as a general overall adjustment. in a multiple fan system - most times this is not an option. i mention this because in a single system, esp dedicated to a small studio, efficiency is somewhat less important because then you're focused on noise reduction and low speed etc and not just achieving the flow rate and related balance. this is where an HRV/ERV unit with dual fans can benefit because you have essentially a single system to balance and get the desired flow rates, filter maintenance access, and energy efficiencies etc.