OT-HVAC and Covid

[Leeshouldveflanked]

It sounds like one the biggest contributors of Covid in the south since the hot miserable summer has set in, everyone going to Memaw’s house and it is too hot and everyone is sitting inside under the AC, parents going to work and Grandparents are keeping the kids and sitting inside or 30 under crowd is all up on each other at the bar... this is resulting in a moist environment in the 70 degree range that the virus is thriving in... could there be something from a HVAC standpoint that could somewhat economic standpoint help decrease the virus? I think the Virus is too small to filter residentially (.3 microns)....

 

[engie]

It sounds like one the biggest contributors of Covid in the south since the hot miserable summer has set in, everyone going to Memaw’s house and it is too hot and everyone is sitting inside under the AC, parents going to work and Grandparents are keeping the kids and sitting inside or 30 under crowd is all up on each other at the bar... this is resulting in a moist environment in the 70 degree range that the virus is thriving in... could there be something from a HVAC standpoint that could somewhat economic standpoint help decrease the virus? I think the Virus is too small to filter residentially (.3 microns)....

Infrared in air returns is believed to kill it dead and is reasonably inexpensive.

 

[johnson86-1]

Infrared in air returns is believed to kill it dead and is reasonably inexpensive.

INfrared? Do you mean maybe UV? Pretty much everything radiates heat in the infrared spectrum, right? Can you do concentrated infrared that sterilizes?

 

[engie]

Can you do concentrated infrared that sterilizes?

Yes. UV. You can even do it aerially in a room and it naturally sterilize any surface the light can hit and the air in between.

For our purposes, it goes just in front of the filters of the package units we are always shipping all over the country and sterilizes the return air. It’s old tech that they’ve always known worked very well, just never really institutionalized on a high level out in the world. I’m sure it’s going in everywhere now. Is a stipulation for us with Churchill Downs this year

 

[L4Dawg]

Yes. UV. You can even do it aerially in a room and it naturally sterilize any surface the light can hit and the air in between.

For our purposes, it goes just in front of the filters of the package units we are always shipping all over the country and sterilizes the return air. It’s old tech that they’ve always known worked very well, just never really institutionalized on a high level out in the world. I’m sure it’s going in everywhere now. Is a stipulation for us with Churchill Downs this year

Infrared? Are you sure you don't mean UV?

 

[Jeffreauxdawg]

I have been posting about this for weeks. House parties are part of the problem, but Commercial HVAC (bars and restaurants) are the biggest contributor.

With a central HVAC system, you usually are moving air around quite a bit before it goes gets filtered anyway. (10 vents for every return.) A lot of other countries use ductless mini splits that move air right near the unit. Plus they have really good multi stage filtration.

Any HVAC experts on here? Is there an opportunity to move the US more in the ductless direction? From my understanding they are much more efficient and it's easier to control climate in individual spaces. If it proves out to also slow virus, pollen, and bacteria spread. I'm in.

By I'm in, I literally want to get into that business... If it's not a bunch of ******** I am making up in my own mind.

 

[Leeshouldveflanked]

You figure with MSU being an engineering school.... we would have someone working on this....

 

[My Bru]

Common sense would tell you that a droplet leaving someone's mouth, circulating up through a filter and all the way through an HVAC system, then coming out and being gobbled up by someone, is probably not the pure driver of this thing. It's person to person close contact.

I see people saying that airplanes spread it through their air system. Not true. They have some of the most state of the art filters on the planet. But if you sit by someone who has it, you are at risk.

It's an either/or situation with distancing or a mask. Either of those will pretty much stop the virus in all practicality. The notion that an AC system is spreading it to any type of real effect is kinda laughable.

 

[johnson86-1]

Common sense would tell you that a droplet leaving someone's mouth, circulating up through a filter and all the way through an HVAC system, then coming out and being gobbled up by someone, is probably not the pure driver of this thing. It's person to person close contact.

I see people saying that airplanes spread it through their air system. Not true. They have some of the most state of the art filters on the planet. But if you sit by someone who has it, you are at risk.

It's an either/or situation with distancing or a mask. Either of those will pretty much stop the virus in all practicality. The notion that an AC system is spreading it to any type of real effect is kinda laughable.

I would have thought going through an AC system might tend to keep it airborn and concentrate the virus over time if it is just recirculating indoor air?

 

[PapaDawg]

We have had a Honeywell (UV100A) UV light & filtration system installed in the return duct of our home HVAC system for a couple of years now. Our AC company installed it. The bulb has to be replaced yearly ($125) and the filter is changed every 6 months. It was installed to help prevent mold since the wife is very allergic to mold. Hearing all of this I am glad we have it already installed.

 

[My Bru]

I would have thought going through an AC system might tend to keep it airborn and concentrate the virus over time if it is just recirculating indoor air?

That's a long way to travel, with a lot of obstacles. Seems impractical to me.

 

[missouridawg]

https://www.ksat.com/news/local/202...r-filter-designed-to-catch-and-kill-covid-19/

 

[JML105]

Mini splits have their advantages, but they just don't make economical sense in a home (or business) with 10-15 rooms because you would need 3 or 4 separate systems to keep each space conditioned effectively. So your installation cost would be 2 to 3 times as high, and if all units were operating regularly your heating and cooling cost would be greater. The reason you see more of them in European countries and larger cities in the US is because of the way their spaces are set up. If you have a small one or two bedroom apartment, a mini split with maybe one duct from it to the bathroom is a great way to go, but keep in mind it is recirculating its own air with no way to get fresh air in most cases.

I am installing a mini split in my bonus room since it's only one room that will be a much different environment than downstairs (heat rises, doors being open/shut downstairs, etc.), but I am installing a fresh air central unit in my home due to using foam insulation. A central unit in a home with traditional insulation types has the opportunity to get some positive fresh air return from the attic, but in my case the roof is sealed air tight with foam so the unit needs a source of fresh air which I bring in with secondary plumbing from a location in the soffit. This type of system has a ton of efficiency benefits, but also gives the home the fresh air that it needs to prevent the environment from becoming stagnant like in cases that this thread is addressing.

I'm a big fan of mini splits and try to incorporate them as much as I can, but more times than not a central system is what gets installed.

 

[GloryDawg]

I had to dig deep for this one.

http://ncirs.org.au/sites/default/f... COVID_Summary_FINAL public_26 April 2020.pdf


Easier to understand version.

https://www.theguardian.com/world/2...ays-study-cited-in-pms-push-to-reopen-schools

 

[Jeffreauxdawg]

That's a long way to travel, with a lot of obstacles. Seems impractical to me.

A lot of the air just circulates for a while without ever actually getting drawn into the return. Also, the air patterns themselves put people in the way of a spreader and where the air is going.

 

[ckDOG]

Good article.

https://english.elpais.com/spanish_...ed-and-how-they-can-be-avoided.html?ssm=FB_CC

 

[MtPigsmore]

I have been posting about this for weeks. House parties are part of the problem, but Commercial HVAC (bars and restaurants) are the biggest contributor.

With a central HVAC system, you usually are moving air around quite a bit before it goes gets filtered anyway. (10 vents for every return.) A lot of other countries use ductless mini splits that move air right near the unit. Plus they have really good multi stage filtration.

Any HVAC experts on here? Is there an opportunity to move the US more in the ductless direction? From my understanding they are much more efficient and it's easier to control climate in individual spaces. If it proves out to also slow virus, pollen, and bacteria spread. I'm in.

By I'm in, I literally want to get into that business... If it's not a bunch of ******** I am making up in my own mind.

HVAC licenced.... Ductless units are awesome, but the big hurdle for most places is where to drain the condensation. They work best when mounted on an exterior wall so the drain can feed downward outside. If you install on an interior wall you have to incorporate a pump to pitch it high enough to connect to a drain in the attic.

They are great though. I just installed 6 - 1 ton units in a business and it is awesome watching the DC condenser ramp up to speed to manage the demand from the units.

 

[Jeffreauxdawg]

HVAC licenced.... Ductless units are awesome, but the big hurdle for most places is where to drain the condensation. They work best when mounted on an exterior wall so the drain can feed downward outside. If you install on an interior wall you have to incorporate a pump to pitch it high enough to connect to a drain in the attic.

They are great though. I just installed 6 - 1 ton units in a business and it is awesome watching the DC condenser ramp up to speed to manage the demand from the units.

Awesome. Have you installed the ducted mini splits? It seems like it would be more likely to gain adoption in the US since you don't see it. How do you drain the condensation line on the ducted if you have messed with them?

Eta. Can you drop the drain into a local plumbing stack on the ductless? Might open up a lot more locations if you can.

 

[MtPigsmore]

Awesome. Have you installed the ducted mini splits? It seems like it would be more likely to gain adoption in the US since you don't see it. How do you drain the condensation line on the ducted if you have messed with them?

Eta. Can you drop the drain into a local plumbing stack on the ductless? Might open up a lot more locations if you can.

Haven't been requested to add one of those yet. The condensation will be easier to manage since the evap is in the attic and not on the wall like the ductless. Your cost will greatly increase since your adding ducts. Also - the ductless evaps are incredibly inexpensive. My cost is roughly $200 per unit so the margins are great.

As long as your local code allows it - or you don't ask... Running through a stack would work. Would require a trap to keep any smell at bay.

 

[memphisbulldog]

Yes. UV. You can even do it aerially in a room and it naturally sterilize any surface the light can hit and the air in between.

For our purposes, it goes just in front of the filters of the package units we are always shipping all over the country and sterilizes the return air. It’s old tech that they’ve always known worked very well, just never really institutionalized on a high level out in the world. I’m sure it’s going in everywhere now. Is a stipulation for us with Churchill Downs this year

Not true. UV is line of sight only. there is an expensive UV version that can go in the duct but not commonly used. Best option is bi polar ionization. I am familiar with the GPS market leader brand. I will post a separate response to the subject also. GPS is the only product that has been successfully tested against Covid-19.

https://globalplasmasolutions.com/

 

[memphisbulldog]

Best bet is bi polar ionization. GPS brand is market leader. My company does lots of those applications. PM if you want detail for using on commercial application. GPS is the only technology that has tested positive against the Covid-19. Cost effective, virus effective and low maintenance. UV is line of sight only (not room effective), more expensive and high maintenance.

https://globalplasmasolutions.com/

 

[greenbean.sixpack]

HVAC licenced.... Ductless units are awesome, but the big hurdle for most places is where to drain the condensation. They work best when mounted on an exterior wall so the drain can feed downward outside. If you install on an interior wall you have to incorporate a pump to pitch it high enough to connect to a drain in the attic.

They are great though. I just installed 6 - 1 ton units in a business and it is awesome watching the DC condenser ramp up to speed to manage the demand from the units.

With a mini split getting the condensation drain right is the biggest struggle for most installers.

 

[RocketDawg]

Aren't the ductless systems noisy? I can't even tell when my current heat pump with round metal duct work is running or not.

 

[MtPigsmore]

Aren't the ductless systems noisy? I can't even tell when my current heat pump with round metal duct work is running or not.

Actually the opposite. You could have a normal conversation 1 ft from the condenser.

 

[engie]

Not true. UV is line of sight only.

What did you take "naturally sterilize any surface the light can hit and the air in between" to mean?

Duct return UV is a couple of hundred bucks. A cheap investment. Churchill is affording them for the sixteen 10 ton package units of ours that will go underneath the finish line suites for the Derby, which as of now is still going on as planned. Our deposit is due in 3 weeks and I'll be headed that way. Fingers crossed.

 

[memphisbulldog]

We have had a Honeywell (UV100A) UV light & filtration system installed in the return duct of our home HVAC system for a couple of years now. Our AC company installed it. The bulb has to be replaced yearly ($125) and the filter is changed every 6 months. It was installed to help prevent mold since the wife is very allergic to mold. Hearing all of this I am glad we have it already installed.

What you have does nothing for virus. Fact.