ᐅ Mechanical ventilation with heat recovery – Is setting level 7 out of 9 a reasonable configuration?
Created on: 3 Jan 2018 21:30
S
stefanc84
Hi everyone,
We installed our mechanical ventilation system ourselves, which was planned by a trading representative of H******.
They calculated the nominal ventilation rate at 147 m³/h (147 cubic meters per hour) and selected a device with a maximum capacity of 300 m³/h (300 cubic meters per hour). My own calculations resulted in a slightly higher nominal ventilation rate, partly because we have an insulated, unoccupied attic without windows that I think should be included (?). Also, they didn’t include stairwell areas and assumed a slightly lower ceiling height. This isn’t a big issue, as the difference is not substantial and the valves can still be adjusted during commissioning.
However, I came across the pressure loss calculation in the planning manual. No calculation like this was done previously, and even though it seems obvious now, I hadn’t thought about it before. I realize that a professional installation company would probably have done this calculation properly, rather than just a trading agent.
Anyway, I calculated a pressure loss of about 94 Pa (Pascal) for the longest duct run. According to this, the device would need to run continuously at level 7 out of 9. This obviously results in more noise and power consumption compared to using a more powerful device running only at level 5, according to the technical specifications.
We could possibly replace the unit with a larger one. But it’s not that simple, since larger diameter ducts would also need to be used between the distribution boxes and outside. These ducts are not yet installed, but have already been purchased.
How critical do you consider this situation? Is operating at level 7 out of 9 an acceptable design? After all, the example calculation in the planning manual uses the same device for similar data.
Do you have any comparable data from your systems that you could share with me?
We installed our mechanical ventilation system ourselves, which was planned by a trading representative of H******.
They calculated the nominal ventilation rate at 147 m³/h (147 cubic meters per hour) and selected a device with a maximum capacity of 300 m³/h (300 cubic meters per hour). My own calculations resulted in a slightly higher nominal ventilation rate, partly because we have an insulated, unoccupied attic without windows that I think should be included (?). Also, they didn’t include stairwell areas and assumed a slightly lower ceiling height. This isn’t a big issue, as the difference is not substantial and the valves can still be adjusted during commissioning.
However, I came across the pressure loss calculation in the planning manual. No calculation like this was done previously, and even though it seems obvious now, I hadn’t thought about it before. I realize that a professional installation company would probably have done this calculation properly, rather than just a trading agent.
Anyway, I calculated a pressure loss of about 94 Pa (Pascal) for the longest duct run. According to this, the device would need to run continuously at level 7 out of 9. This obviously results in more noise and power consumption compared to using a more powerful device running only at level 5, according to the technical specifications.
We could possibly replace the unit with a larger one. But it’s not that simple, since larger diameter ducts would also need to be used between the distribution boxes and outside. These ducts are not yet installed, but have already been purchased.
How critical do you consider this situation? Is operating at level 7 out of 9 an acceptable design? After all, the example calculation in the planning manual uses the same device for similar data.
Do you have any comparable data from your systems that you could share with me?
U
UpperEast31 May 2019 20:42That doesn’t make sense to me; it should make a difference whether 2 people or 6 people with 2 dogs are living in a house.
U
UpperEast31 May 2019 21:02I don’t understand the connection. Apparently, I’m too stupid.
As far as I understand, you should try to keep the CO2 level low. If a lot of CO2 is produced, more fresh air needs to be supplied.
As far as I understand, you should try to keep the CO2 level low. If a lot of CO2 is produced, more fresh air needs to be supplied.
