ᐅ Centralized mechanical ventilation with heat recovery: Are individual rooms controllable?
Created on: 23 Apr 2015 11:59
L
LuciferSam
Hello community,
while researching central systems for controlled residential ventilation (controlled ventilation) with heat recovery (heat recovery), I noticed something: nobody seems to build systems where the ventilation of individual rooms can be comfortably adjusted on an ongoing basis (not just once for balancing but continuously, daily). I can neither find testimonials nor see such systems being advertised.
Why do I want this? – A central controlled ventilation system with heat recovery equalizes the temperature of all connected rooms over time. (Air is extracted from all rooms, mixed, passed through the heat exchanger; warmed fresh air reaches every room.) However, this is not always desirable. At night, I want to sleep in a cold room but still use controlled ventilation to be able to sleep with windows and doors closed. The living room, heated by underfloor heating, I do not want or need to cool down every evening. If I could turn off the ventilation in the living room at night and in the bedroom at least temporarily during the day, the problem would be solved.
Would this be difficult? – Air dampers in all pipes from the central manifold to the rooms, controlled by very expensive actuators or simple, inexpensive servos from the model building sector, could regulate the airflow. Sound attenuators would probably be needed behind them (?). Between the fan and the first central manifold, a pressure sensor could be installed to control the fan continuously. If the air pressure before the control dampers is kept constant, adjusting one damper should not significantly affect the airflow through another.
As I see it, this would be a huge advantage with reasonable extra effort. Why does nobody do this? I am still quite a beginner in this field. Have I overlooked something?
Thanks!
while researching central systems for controlled residential ventilation (controlled ventilation) with heat recovery (heat recovery), I noticed something: nobody seems to build systems where the ventilation of individual rooms can be comfortably adjusted on an ongoing basis (not just once for balancing but continuously, daily). I can neither find testimonials nor see such systems being advertised.
Why do I want this? – A central controlled ventilation system with heat recovery equalizes the temperature of all connected rooms over time. (Air is extracted from all rooms, mixed, passed through the heat exchanger; warmed fresh air reaches every room.) However, this is not always desirable. At night, I want to sleep in a cold room but still use controlled ventilation to be able to sleep with windows and doors closed. The living room, heated by underfloor heating, I do not want or need to cool down every evening. If I could turn off the ventilation in the living room at night and in the bedroom at least temporarily during the day, the problem would be solved.
Would this be difficult? – Air dampers in all pipes from the central manifold to the rooms, controlled by very expensive actuators or simple, inexpensive servos from the model building sector, could regulate the airflow. Sound attenuators would probably be needed behind them (?). Between the fan and the first central manifold, a pressure sensor could be installed to control the fan continuously. If the air pressure before the control dampers is kept constant, adjusting one damper should not significantly affect the airflow through another.
As I see it, this would be a huge advantage with reasonable extra effort. Why does nobody do this? I am still quite a beginner in this field. Have I overlooked something?
Thanks!
I connected and programmed this to my DDC system for house control. However, it could also work with a simple E4 or Logo controller.
P.S. The fan speeds adjust according to different scenarios. For example, when the bathroom light is turned on, the exhaust fan increases with a 5-minute delay and continues running for 10 minutes after the light is turned off. Or, if the fireplace is on, the range hood switches from exhaust to recirculation mode and the house’s overpressure is increased (in addition to the usual slight overpressure). These are just a few examples.
P.S. The fan speeds adjust according to different scenarios. For example, when the bathroom light is turned on, the exhaust fan increases with a 5-minute delay and continues running for 10 minutes after the light is turned off. Or, if the fireplace is on, the range hood switches from exhaust to recirculation mode and the house’s overpressure is increased (in addition to the usual slight overpressure). These are just a few examples.
I find this really interesting, even though I don’t currently need it. What disadvantages would there be in installing the measurement and control options at the air distributor instead of at the outlet or inlet? There is only a defined length (meter) of controlled residential ventilation ducting between them.
I’m thinking about it now and realize that some challenges need to be overcome. The total volume flow always remains the same. If I throttle one branch, the others will automatically get more. So I would have to reduce them accordingly depending on the throttling (position of the throttle valve).
I’m thinking about it now and realize that some challenges need to be overcome. The total volume flow always remains the same. If I throttle one branch, the others will automatically get more. So I would have to reduce them accordingly depending on the throttling (position of the throttle valve).
@i_b_n_a_n Installing the throttle valves directly at the distributor is also fine and generally does not bring any disadvantages or advantages. Since I don't have an air distribution box myself and instead have the supply and exhaust outlets arranged in series, that was the only way possible for me.
You are right about the total airflow. It always remains the same because the air follows the path of least resistance. I have three options for this.
1. I reduce the airflow using a PID controller when I change the air volume in a room and do not want supply or exhaust air anywhere else.
2. I use my insulated attic as a buffer (which is always ventilated anyway).
3. A combination of options 1 and 2.
You are right about the total airflow. It always remains the same because the air follows the path of least resistance. I have three options for this.
1. I reduce the airflow using a PID controller when I change the air volume in a room and do not want supply or exhaust air anywhere else.
2. I use my insulated attic as a buffer (which is always ventilated anyway).
3. A combination of options 1 and 2.
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