42 ms·

Ventilation Made Easy

47 points by Tomte 2y ago

lihli 2y ago
[flagged]
constantcrying 2y ago
What a time that was... Really glad it is over and that it never got the point of me ever seeing such a thing.
- redrove 2y ago
  Are you actually insinuating there still isn’t a pandemic going on or am I misreading your comment? I don’t see how this couldn’t possible be anything but beneficial in public places.
  - baggy_trough 2y ago
    I mean, there isn't? Just endemic viruses, as we always have had, and always will have.
    - redrove 2y ago
      Putting that aside, don’t you then agree ventilation in public spaces is useful for obvious health reasons?
      - constantcrying 2y ago
        Hilariously Air conditioning is very common in the US but very uncommon in Europe. Is there actually any evidence of a positive effect?
        eep_social 2y ago
        The Minergie (Swiss) folks probably have a 90 page application guide that goes into those kinds of details: https://www.minergie.com/media/guia_de_aplicacion_latam_v2023_1_en.pdf https://www.minergie.com/media/guia_de_aplicacion_latam_v202...
        constantcrying 2y ago
        Why are you just sending me a 90 page PDF about housing regulation. Obviously that does not contain a shred of scientific evidence that filtering certain particles reduces transmission of infectious diseases. Genuinely no idea what you are thinking with this or what the point of that PDF is.
        eep_social 2y ago
        > housing regulation is it? I think you may want to do some research of your own.
        constantcrying 2y ago
        Your document contains zero relevant information and you refused to point to any specific part of its 90 pages. Obviously you have no evidence for your claims and you made stuff up by linking to an irrelevant document and then being extremely obtuse and annoying when being asked to substantiate what you are saying or even to specify why the document contains relevant information. If you have zero evidence of a claim being true, stop making it.
        eep_social 2y ago
        Great discussion thanks!
        Vegemeister 2y ago
        Clown if you want, but he's absolutely right. There is exactly one sentence in that entire damn thing that comes close to touching on the question of why ventilation is desirable, and it is: >Pleasant, healthy air to breathe is the most important food for human beings.
      - baggy_trough 2y ago
        That case would have to be made scientifically by credible researchers, which is a lot to ask these days.
  - _def 2y ago
    Maybe they are referencing that the article is from Dec 2020. I agree, it still seems highly useful.
  - constantcrying 2y ago
    Not a pandemic that has any relevance to me, above the prevalence of the common cold.
- nequo 2y ago
  This is about more than pandemics, it is about indoor air quality in crowded spaces: “Our system also solves the long-standing problem of CO2 in classrooms, because it not only transports aerosols outside. It also cuts CO2 accumulation, helping students to concentrate better on their lessons.”
  - constantcrying 2y ago
    Oh, so Europeans have finally invented air conditioning? Of course when I was in school we opened the windows to solve this massive issue, but times change I guess. Hopefully they also have an app, for the kids.
    - pixelfarmer 2y ago
      This whole system was aimed at minimizing the infection rates between students which you won't solve by just opening the windows. Imagine you have some smoker indoors: How do you transport off that cancer inducing poisonous cloud without distributing it in the whole place? Plus in Germany there are quite a few schools located directly at heavily used streets, so just opening windows will not exactly give you really fresh air (I mean, it will lower the CO2, but otherwise its going from one bad state into another), plus it increases the noise levels considerably. And yes, ACs are still uncommon in Germany. In return, most buildings, including suburb style homes, are not just made from cardboard. This means the buildings have a lot of thermal inertia which can be used to manage heat during hotter phases.
    - jimkleiber 2y ago
      I'm not sure if you've ever lived in a place where you're not supposed to drink the tap water because it can bring a lot of disease. I think we as humans realized that water carried a lot of disease and in many places started treating water much better to protect our health. To me it seems very logical that we should also treat the air to protect our health from diseases carried in the air.
      - constantcrying 2y ago
hedgehog 2y ago
This is a pretty cool project, it's basically a retrofit approach to what in industry is known as "displacement ventilation" or "stratification ventilation". In the US our typical approach is "mixing ventilation" where you try to mix and equalize the air everywhere within a space, then cycle a portion of the air through an air conditioner to get the temperature and humidity to the desired level. This is mechanically intensive, needs big ducts, and has the downside that contaminants in the air tend to get spread everywhere. Displacement ventilation uses the fact that hot and humid air rise, instead of mixing everything together it removes the most stale air at the top of the room and replaces it. Trickier to get right, but quieter and more effective in many cases. Here's a blog post with illustrations: https://blog.hoffman-hoffman.com/blog/the-basics-of-displacement-ventilation https://blog.hoffman-hoffman.com/blog/the-basics-of-displace...
- kurthr 2y ago
  For efficiency you need to minimize leakage of outside conditions, but you also really need a heat/energy exchanger (HRV/ERV) at the fresh air input so that you're not recirculating stale air.
  - toast0 2y ago
    School buildings with operable windows often don't condition the air. This design collects / guides air from around the pupils towards an exhaust window and suggests leaving a door or opposite site window to get fresh air in. It's not a solution for highly conditioned spaces.
    - kurthr 2y ago
      Just thinking about Germany, I'm wondering when peak infections occur. I'd guess that it's during the winter? I have not heard that Germany's winters have become particularly mild. In fact Mainz, where this was developed, often has high temperatures below freezing during the winter months. Having significant airflow without an HRV might make people a bit chilly in the morning. Or would this still require the expensive filtration system in the winter?
adolph 2y ago
Due to its low material and operating costs, it could turn out to be a clever alternative to expensive filter systems and ventilation by shortly wide opening the windows. This is a neat idea that seems penny smart and pound foolish. For one, the article does not address overall system reliability and maintenance tempo. Given a low material to install cost ratio this is an important factor since repeated re-installation or rework will moot any cost savings from materials. For two, ejecting the gases that have been expensively conditioned for thermal and humidity properties will drive up operating costs since replacement gasses will be required. For three, hopefully they carefully plan for where the system exhausts since they have made something that concentrates contaminants as well as it evacuates them. To the extent that it uses tragedy of the commons to get better odds for people indoors by worsening odds for people outside that building, the primary innovation of the system is statistical arbitrage based on a larger outdoor volume.
- toast0 2y ago
  > For two, ejecting the gases that have been expensively conditioned for thermal and humidity properties will drive up operating costs since replacement gasses will be required. This application optimizes exhaust in rooms with operable, high mounted windows for exhaust. Most rooms with expensive conditioning don't have operable windows, so it's not really an option to use this design for those anyway. In a heavily conditioned space, the expectation would be external air ventilation would be managed near the centralized air handlers. Plenty of options there, like HRV/ERV depending on climate specifics. It might be possible to use a similar design to augment air returns from a conditioning system, but it's going to depends on the system if it would be useful or reasonable.
danjc 2y ago
(2020)
aaron695 2y ago
[dead]
jkljl 2y ago
[flagged]

47 points by Tomte 2y ago

lihli 2y ago

[flagged]

constantcrying 2y ago

What a time that was... Really glad it is over and that it never got the point of me ever seeing such a thing.

redrove 2y ago
Are you actually insinuating there still isn’t a pandemic going on or am I misreading your comment? I don’t see how this couldn’t possible be anything but beneficial in public places.
- baggy_trough 2y ago
  I mean, there isn't? Just endemic viruses, as we always have had, and always will have.
  - redrove 2y ago
    Putting that aside, don’t you then agree ventilation in public spaces is useful for obvious health reasons?
    - constantcrying 2y ago
      Hilariously Air conditioning is very common in the US but very uncommon in Europe. Is there actually any evidence of a positive effect?
      - eep_social 2y ago
        The Minergie (Swiss) folks probably have a 90 page application guide that goes into those kinds of details: https://www.minergie.com/media/guia_de_aplicacion_latam_v2023_1_en.pdf https://www.minergie.com/media/guia_de_aplicacion_latam_v202...
        constantcrying 2y ago
        Why are you just sending me a 90 page PDF about housing regulation. Obviously that does not contain a shred of scientific evidence that filtering certain particles reduces transmission of infectious diseases. Genuinely no idea what you are thinking with this or what the point of that PDF is.
        eep_social 2y ago
        > housing regulation is it? I think you may want to do some research of your own.
        constantcrying 2y ago
        Your document contains zero relevant information and you refused to point to any specific part of its 90 pages. Obviously you have no evidence for your claims and you made stuff up by linking to an irrelevant document and then being extremely obtuse and annoying when being asked to substantiate what you are saying or even to specify why the document contains relevant information. If you have zero evidence of a claim being true, stop making it.
        eep_social 2y ago
        Great discussion thanks!
        Vegemeister 2y ago
        Clown if you want, but he's absolutely right. There is exactly one sentence in that entire damn thing that comes close to touching on the question of why ventilation is desirable, and it is: >Pleasant, healthy air to breathe is the most important food for human beings.
    - baggy_trough 2y ago
      That case would have to be made scientifically by credible researchers, which is a lot to ask these days.
- _def 2y ago
  Maybe they are referencing that the article is from Dec 2020. I agree, it still seems highly useful.
- constantcrying 2y ago
  Not a pandemic that has any relevance to me, above the prevalence of the common cold.
nequo 2y ago
This is about more than pandemics, it is about indoor air quality in crowded spaces: “Our system also solves the long-standing problem of CO2 in classrooms, because it not only transports aerosols outside. It also cuts CO2 accumulation, helping students to concentrate better on their lessons.”
- constantcrying 2y ago
  Oh, so Europeans have finally invented air conditioning? Of course when I was in school we opened the windows to solve this massive issue, but times change I guess. Hopefully they also have an app, for the kids.
  - pixelfarmer 2y ago
    This whole system was aimed at minimizing the infection rates between students which you won't solve by just opening the windows. Imagine you have some smoker indoors: How do you transport off that cancer inducing poisonous cloud without distributing it in the whole place? Plus in Germany there are quite a few schools located directly at heavily used streets, so just opening windows will not exactly give you really fresh air (I mean, it will lower the CO2, but otherwise its going from one bad state into another), plus it increases the noise levels considerably. And yes, ACs are still uncommon in Germany. In return, most buildings, including suburb style homes, are not just made from cardboard. This means the buildings have a lot of thermal inertia which can be used to manage heat during hotter phases.
  - jimkleiber 2y ago
    I'm not sure if you've ever lived in a place where you're not supposed to drink the tap water because it can bring a lot of disease. I think we as humans realized that water carried a lot of disease and in many places started treating water much better to protect our health. To me it seems very logical that we should also treat the air to protect our health from diseases carried in the air.
    - constantcrying 2y ago

hedgehog 2y ago

This is a pretty cool project, it's basically a retrofit approach to what in industry is known as "displacement ventilation" or "stratification ventilation". In the US our typical approach is "mixing ventilation" where you try to mix and equalize the air everywhere within a space, then cycle a portion of the air through an air conditioner to get the temperature and humidity to the desired level. This is mechanically intensive, needs big ducts, and has the downside that contaminants in the air tend to get spread everywhere. Displacement ventilation uses the fact that hot and humid air rise, instead of mixing everything together it removes the most stale air at the top of the room and replaces it. Trickier to get right, but quieter and more effective in many cases. Here's a blog post with illustrations: https://blog.hoffman-hoffman.com/blog/the-basics-of-displacement-ventilation https://blog.hoffman-hoffman.com/blog/the-basics-of-displace...

kurthr 2y ago
For efficiency you need to minimize leakage of outside conditions, but you also really need a heat/energy exchanger (HRV/ERV) at the fresh air input so that you're not recirculating stale air.
- toast0 2y ago
  School buildings with operable windows often don't condition the air. This design collects / guides air from around the pupils towards an exhaust window and suggests leaving a door or opposite site window to get fresh air in. It's not a solution for highly conditioned spaces.
  - kurthr 2y ago
    Just thinking about Germany, I'm wondering when peak infections occur. I'd guess that it's during the winter? I have not heard that Germany's winters have become particularly mild. In fact Mainz, where this was developed, often has high temperatures below freezing during the winter months. Having significant airflow without an HRV might make people a bit chilly in the morning. Or would this still require the expensive filtration system in the winter?

adolph 2y ago

Due to its low material and operating costs, it could turn out to be a clever alternative to expensive filter systems and ventilation by shortly wide opening the windows. This is a neat idea that seems penny smart and pound foolish. For one, the article does not address overall system reliability and maintenance tempo. Given a low material to install cost ratio this is an important factor since repeated re-installation or rework will moot any cost savings from materials. For two, ejecting the gases that have been expensively conditioned for thermal and humidity properties will drive up operating costs since replacement gasses will be required. For three, hopefully they carefully plan for where the system exhausts since they have made something that concentrates contaminants as well as it evacuates them. To the extent that it uses tragedy of the commons to get better odds for people indoors by worsening odds for people outside that building, the primary innovation of the system is statistical arbitrage based on a larger outdoor volume.

toast0 2y ago
> For two, ejecting the gases that have been expensively conditioned for thermal and humidity properties will drive up operating costs since replacement gasses will be required. This application optimizes exhaust in rooms with operable, high mounted windows for exhaust. Most rooms with expensive conditioning don't have operable windows, so it's not really an option to use this design for those anyway. In a heavily conditioned space, the expectation would be external air ventilation would be managed near the centralized air handlers. Plenty of options there, like HRV/ERV depending on climate specifics. It might be possible to use a similar design to augment air returns from a conditioning system, but it's going to depends on the system if it would be useful or reasonable.

danjc 2y ago

(2020)

aaron695 2y ago

[dead]

jkljl 2y ago

[flagged]