ᐅ Using a geothermal basket to precondition the air for a mechanical ventilation with heat recovery system?
Created on: 22 Aug 2022 18:14
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Nixwill2
Hello everyone,
From the beginning, I’ve been thinking about how to keep the temperature at a comfortable level (24° to 25°C (75°F to 77°F)) in our new house during the summer. We will have underfloor heating with a heat pump and cooling function. At least, we want to have air conditioning provisioned.
Since we will have a mechanical ventilation system with heat recovery, I’m also wondering if it’s really ideal to have warm outdoor air blown into the house.
Today, by pure chance, I came across something called a ground heat exchanger.
Does anyone have any experience with whether this is effective for pre-cooling the air? Of course, it should also have the positive effect of pre-warming the air in winter.
It doesn’t seem very complex and is supposedly relatively uncomplicated even in a water protection area.
I have no knowledge about heating or anything like that, so I’m just asking openly…
Best regards,
Nixwill2
From the beginning, I’ve been thinking about how to keep the temperature at a comfortable level (24° to 25°C (75°F to 77°F)) in our new house during the summer. We will have underfloor heating with a heat pump and cooling function. At least, we want to have air conditioning provisioned.
Since we will have a mechanical ventilation system with heat recovery, I’m also wondering if it’s really ideal to have warm outdoor air blown into the house.
Today, by pure chance, I came across something called a ground heat exchanger.
Does anyone have any experience with whether this is effective for pre-cooling the air? Of course, it should also have the positive effect of pre-warming the air in winter.
It doesn’t seem very complex and is supposedly relatively uncomplicated even in a water protection area.
I have no knowledge about heating or anything like that, so I’m just asking openly…
Best regards,
Nixwill2
S
SaniererNRW12322 Aug 2022 18:22Nixwill2 schrieb:
Since we will have a mechanical ventilation system with heat recovery, I’ve been wondering if it’s really ideal that it blows warm outdoor air into the house.
Today, I happened to come across something called a ground heat exchanger online. This is actually a very old "invention" (in fact, known and used for thousands of years, but seriously applied about 50-60 years ago, as you mentioned). You can search for air wells or earth-air heat exchangers. You will find plenty of information including videos, construction guides, and more.
It helps in both summer and winter because the air for the mechanical ventilation system is preheated.
Thank you for your keywords!
I’ve done some reading, and it seems that an earth air tunnel is more difficult to implement in soils with a high clay content. Does a ground heat exchanger work on the same principle? Does it also have a similar snorkel?
How should I imagine this? Currently, we have planned supply and exhaust ducts on the house for the heat pump (air-to-water) and the mechanical ventilation with heat recovery. How would planning for such an earth air tunnel change the existing design? I am also interested in the cost factor here (earthworks should be less of an issue since we have a very reliable excavation contractor). Is the technology for a "standard" mechanical ventilation system easy to modify? Do you need a different mechanical ventilation system? And importantly, our building permit / planning permission has finally been approved; would such a change require a new application to the district authority, or can the municipality simply approve it?
Maybe someone can give me a few more tips here...
I’ve done some reading, and it seems that an earth air tunnel is more difficult to implement in soils with a high clay content. Does a ground heat exchanger work on the same principle? Does it also have a similar snorkel?
How should I imagine this? Currently, we have planned supply and exhaust ducts on the house for the heat pump (air-to-water) and the mechanical ventilation with heat recovery. How would planning for such an earth air tunnel change the existing design? I am also interested in the cost factor here (earthworks should be less of an issue since we have a very reliable excavation contractor). Is the technology for a "standard" mechanical ventilation system easy to modify? Do you need a different mechanical ventilation system? And importantly, our building permit / planning permission has finally been approved; would such a change require a new application to the district authority, or can the municipality simply approve it?
Maybe someone can give me a few more tips here...
In principle, this is a good idea, and if there is an opportunity to implement it, I would go for it.
Although the solution by @rick2018 might not be comparable, at least he has expertise and possibly useful tips for execution.
I have never looked into it in depth myself, since it wasn’t feasible for us, and at that time I also heard about potential drawbacks and risks such as possible condensation, mold growth, etc. I don’t want to cause any concern, but I do think proper installation is very important here.
Otherwise, I can say that with underfloor cooling you are already well prepared to keep the temperature within a comfortable range. Even better would be the air conditioning system, which you have also already considered! So everything will be fine 🙂
Although the solution by @rick2018 might not be comparable, at least he has expertise and possibly useful tips for execution.
I have never looked into it in depth myself, since it wasn’t feasible for us, and at that time I also heard about potential drawbacks and risks such as possible condensation, mold growth, etc. I don’t want to cause any concern, but I do think proper installation is very important here.
Otherwise, I can say that with underfloor cooling you are already well prepared to keep the temperature within a comfortable range. Even better would be the air conditioning system, which you have also already considered! So everything will be fine 🙂
@Nixwill just keep in mind that air is a poor heat carrier with low capacity. This means you need a high airflow for effective cooling.
This year, the indoor temperature has not exceeded 22.5°C (72.5°F). When building with solid construction, the mass acts like a good shock absorber in a car.
It effectively smooths out temperature peaks.
This year, the indoor temperature has not exceeded 22.5°C (72.5°F). When building with solid construction, the mass acts like a good shock absorber in a car.
It effectively smooths out temperature peaks.
@netuser
The pre-installation for the air conditioning is intended only as a last resort to provide some relief if needed in the future. The actual goal is to achieve as much as possible through simpler passive methods. I find the idea of ventilating with pre-cooled air quite convincing. Since our planning is already finalized, the question is how complex it would be to change it now. I don’t want any shortcuts; everything should be done properly and correctly.
@TmMike_2
We are building a KfW40 house using timber frame construction. Since we will ensure good shading and generally pay close attention to other factors (keeping windows closed, etc.), my main concern right now is the warm outside air being drawn in. This is precisely the point: if the outside air could be pre-cooled with little effort, that sounds at least like THE solution for this... But I have no idea how much work that would involve.
The pre-installation for the air conditioning is intended only as a last resort to provide some relief if needed in the future. The actual goal is to achieve as much as possible through simpler passive methods. I find the idea of ventilating with pre-cooled air quite convincing. Since our planning is already finalized, the question is how complex it would be to change it now. I don’t want any shortcuts; everything should be done properly and correctly.
@TmMike_2
We are building a KfW40 house using timber frame construction. Since we will ensure good shading and generally pay close attention to other factors (keeping windows closed, etc.), my main concern right now is the warm outside air being drawn in. This is precisely the point: if the outside air could be pre-cooled with little effort, that sounds at least like THE solution for this... But I have no idea how much work that would involve.
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