ᐅ Automation of a Mechanical Ventilation with Heat Recovery (MVHR) System
Created on: 23 May 2018 17:44
H
Hausbauer1
Hello everyone,
I’m currently struggling again with the warm indoor temperatures (unfortunately, there is no mechanical ventilation with heat recovery). When I am at home, I try to ventilate vigorously whenever it is cooler outside than inside, even if the temperature difference is only 1-2°C (34-36°F). And when it’s warmer outside, everything is shaded and the windows stay closed.
This obviously pushes comfort limits. If you want to stay in a room, ventilating at the same time is not always very comfortable. Also, you don’t want to leave the windows open all day when you’re not at home or when it gets warmer as the day goes on.
My question to all experts and owners of centralized ventilation systems is: can a mechanical ventilation system be programmed to operate exactly like the rational ventilation behavior you would do manually? So, no ventilation when it’s warmer outside and strong ventilation when it’s cooler outside. Of course, without heat recovery in this case. In winter, it would be different, with ventilation mainly during the day when temperature differences are smaller, and less or no ventilation at night when it’s very cold outside.
I think it’s clear what I’m getting at. Can these systems be automated to that extent, or is that too much to expect?
Thanks.
I’m currently struggling again with the warm indoor temperatures (unfortunately, there is no mechanical ventilation with heat recovery). When I am at home, I try to ventilate vigorously whenever it is cooler outside than inside, even if the temperature difference is only 1-2°C (34-36°F). And when it’s warmer outside, everything is shaded and the windows stay closed.
This obviously pushes comfort limits. If you want to stay in a room, ventilating at the same time is not always very comfortable. Also, you don’t want to leave the windows open all day when you’re not at home or when it gets warmer as the day goes on.
My question to all experts and owners of centralized ventilation systems is: can a mechanical ventilation system be programmed to operate exactly like the rational ventilation behavior you would do manually? So, no ventilation when it’s warmer outside and strong ventilation when it’s cooler outside. Of course, without heat recovery in this case. In winter, it would be different, with ventilation mainly during the day when temperature differences are smaller, and less or no ventilation at night when it’s very cold outside.
I think it’s clear what I’m getting at. Can these systems be automated to that extent, or is that too much to expect?
Thanks.
C
cybergnom25 May 2018 12:57Because a controlled residential ventilation system is designed to remove old, used air to the outside rather than circulate it within the house.
The idea is to distribute the heat from the fireplace throughout the house using the mechanical ventilation system. This would be achieved partly through air circulation and partly by heat recovery from the exhaust air. Steffen thinks this won’t work or that the effect is not noticeable.
Hmm, in winter my supply air is always only about 2-3 degrees cooler than the exhaust air. So, I wouldn’t say it’s ineffective.
The heat recovery actually works quite well, in my opinion.
However, you can’t cool with the controlled ventilation system... that’s what air conditioners are for. And as mentioned, maintaining the temperature at a certain level is only partially possible.
Once the heat is inside, it stays inside.
The heat recovery actually works quite well, in my opinion.
However, you can’t cool with the controlled ventilation system... that’s what air conditioners are for. And as mentioned, maintaining the temperature at a certain level is only partially possible.
Once the heat is inside, it stays inside.
H
Hausbauer128 May 2018 22:27My assumption is not that I can cool the house down from 28 to 21 degrees. That no longer really works with the current intense heat, even with ventilation at night.
What I do believe, however, is that I can at least slow down and reduce the heating of the apartment/house. That is what experience with evening, nighttime, and morning ventilation tells me. It may only be about 0.1 to 0.3 degrees per day, but that already results in a few more days with bearable temperatures.
And with a well-automated controlled residential ventilation system, I would expect this to be even more optimizable. With a heat exchanger, it should work even better.
What I do believe, however, is that I can at least slow down and reduce the heating of the apartment/house. That is what experience with evening, nighttime, and morning ventilation tells me. It may only be about 0.1 to 0.3 degrees per day, but that already results in a few more days with bearable temperatures.
And with a well-automated controlled residential ventilation system, I would expect this to be even more optimizable. With a heat exchanger, it should work even better.
A ventilation system is designed solely to eliminate the need for manual airing.
Just as a ventilation system does not bring heat into the house during summer, it does not lose heat in winter either. The "heat is retained in the walls," not in the air (which is why heat recovery is basically more of a gimmick). Air generally holds very little potential heat. Therefore, you don’t really lose much heat if you briefly ventilate by opening windows in winter and then wait 2-3 minutes. The temperature inside remains practically the same as before. The same applies in summer. Modern houses primarily prevent heat from entering in the first place. But once heat is inside, it’s difficult to get rid of it. The only real solutions are opening windows fully to create a strong draft or using an actual air conditioning system.
A ventilation system circulates a relatively small amount of air per hour. It is sufficient to dry out a bathroom after showering and generally prevents mold from forming, but it doesn’t do much more than that. A tilted window already provides more ventilation than the system...
Automating the ventilation system is as pointless as constantly adjusting underfloor heating: completely senseless. The only thing that makes some sense is increased ventilation in the morning after showering, if you choose to do so. Our system has been running constantly on level 2 (standard setting) for three years, and there has never been a situation where this was fundamentally wrong.
We are very frustrated that we did not prepare for or order an air conditioning system back then. We even asked about it, but it was dismissed as nonsense because the ventilation system was supposed to handle it. And, of course, that’s nonsense. In reality, the site supervisor probably had no idea about air conditioning…
Just as a ventilation system does not bring heat into the house during summer, it does not lose heat in winter either. The "heat is retained in the walls," not in the air (which is why heat recovery is basically more of a gimmick). Air generally holds very little potential heat. Therefore, you don’t really lose much heat if you briefly ventilate by opening windows in winter and then wait 2-3 minutes. The temperature inside remains practically the same as before. The same applies in summer. Modern houses primarily prevent heat from entering in the first place. But once heat is inside, it’s difficult to get rid of it. The only real solutions are opening windows fully to create a strong draft or using an actual air conditioning system.
A ventilation system circulates a relatively small amount of air per hour. It is sufficient to dry out a bathroom after showering and generally prevents mold from forming, but it doesn’t do much more than that. A tilted window already provides more ventilation than the system...
Automating the ventilation system is as pointless as constantly adjusting underfloor heating: completely senseless. The only thing that makes some sense is increased ventilation in the morning after showering, if you choose to do so. Our system has been running constantly on level 2 (standard setting) for three years, and there has never been a situation where this was fundamentally wrong.
We are very frustrated that we did not prepare for or order an air conditioning system back then. We even asked about it, but it was dismissed as nonsense because the ventilation system was supposed to handle it. And, of course, that’s nonsense. In reality, the site supervisor probably had no idea about air conditioning…
Our system has a summer mode. When it’s warm, it stops supplying fresh air to the house and resumes once the outdoor temperature drops below the indoor temperature in the evening. In summer mode, there is no heat recovery.
This afternoon, we had a comfortable 22°C (72°F) inside the house. It was warmer over the weekend, as the terrace door was open at midday.
I’m curious to see how things will develop during the summer. These systems are not air conditioners; they can only delay temperature changes.
This afternoon, we had a comfortable 22°C (72°F) inside the house. It was warmer over the weekend, as the terrace door was open at midday.
I’m curious to see how things will develop during the summer. These systems are not air conditioners; they can only delay temperature changes.
Similar topics