Smoke problem from neighbours

[Jeremy Harris]

The most reliable sensors I've found are the fine particulate ones, like these: https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=plantower&_sacat=0

 

They bin the number of particles in each size range, and seem to be able to detect smoke particulates OK.

[Savage87]

There's a video about this one

 

[Jeremy Harris]

That's the same sensor I'm using for air quality monitoring.  Nice and easy to use, and not too expensive.

[Savage87]

Do you have it setup in a different way?

[Jeremy Harris]

4 minutes ago, Savage87 said:

Do you have it setup in a different way?

 

Mine's connected to a PIC microcontroller, that reads the serial data, does a bit of simple processing on it, and sends the modified data stream to the house data logging system.

[Dave Jones]

i really dont know how mvhr systems work, but could you relocate the intake to a gable away from the chimney ?

[Savage87]

That would be to much work involved. I'm trying to find a simple fix.

[Gone West]

1 hour ago, Dave Jones said:

i really dont know how mvhr systems work, but could you relocate the intake to a gable away from the chimney ?

Both the intake and extract vents should be on the same elevation so there is no pressure difference between them.

[Temp]

That's probably correct but ive never noticed my ears pop when walking around my house on a windy day so perhaps pressure changes aren't huge?

[Gone West]

11 hours ago, Temp said:

That's probably correct but ive never noticed my ears pop when walking around my house on a windy day so perhaps pressure changes aren't huge?

I doubt the pressure difference is huge but enough to unbalance the intake and extract.

[SteamyTea]

11 hours ago, Temp said:

That's probably correct but ive never noticed my ears pop when walking around my house on a windy day so perhaps pressure changes aren't huge?

Your ears have a very small surface area, and are set up to detect very tiny changes in air pressure, the 'popping' has little to do with the actual ear in isolation.  It is the way it is connected, via the Eustachian tube to the rest of the world, which is very large.

Then there are the 'mechanical' bits of the ear, the malleus bone, which is like a pump to amplify the tiny movement of the ear drum.

The ear was never designed to sense overall pressure differences, and why should it, not as if, 2 million years ago, we rapidly changed altitude.

Those it does serve as a good warning when swimming down into deep water.

Quite a marvel is the ear, probably better,and more useful, that the eye.  Not that I would want to be without either of them.

 

[dpmiller]

I'd be fairly sure that having  the supply fan off or waay too low might unbalance things, but air will still be drawn through the supply.

 

/this is something I haven't yet tested with our system. I can bring the house to a reasonable pressure or vacuum just by running one fan at max and the other at the minimum,  I must try sealing one of themain ducts completely and re-trying...

[ProDave]

This smoke etc on a still day is an interesting problem.

 

We had an odd similar problem.  One morning I came down and thought the house smelled stale, not the normal fresh air we were used to.  It was a dead still spring morning with mist hanging in the valley.  I went outside and the air outside smelled of stale drains.  It was next door taking a shower, they still have a septic tank discharging into the burn (illegal now but no sign of them upgrading it to a treatment plant) and there was just not a breath of wind to take the foul smell away, and that was being drawn in by the mvhr.

[SteamyTea]

Interesting problem, many one here like MVHR because it improves internal air quality, but as soon as the neighbours become antisocial, it all goes wrong.

Someone needs to investigate the best method, be it activated charcoal filters, moving vents and intakes, or an ozone generator, to find out what works.

 

I live about 50 metres from one of the countries worst polluted roads, MVHR could cause me more problems that it saves.

 

 

[Jeremy Harris]

1 minute ago, SteamyTea said:

I live about 50 metres from one of the countries worst polluted roads, MVHR could cause me more problems that it saves.

 

I live about 500 metres from the same road, but up here it carries very little traffic!

[SteamyTea]

29 minutes ago, Jeremy Harris said:

 

I live about 500 metres from the same road, but up here it carries very little traffic!

I think part of the problem here is very local, think it is called the 'canyon effect'.

We also have a higher proportion of older cars, diesel vehicles (industrial estate is near by), no gas from my road upwards, high fraction of solid fuel users, and chronic under investment in housing stock.

You would think the M25 would be worse, but it isn't, well not if you use NOX as a proxy for particulates.

 

I also live about 100 metres uphill from a double mini roundabout, so cars are breaking or accelerating. 

Edited May 6, 2020 by SteamyTea

[dpmiller]

17 minutes ago, SteamyTea said:

I think part of the problem here is very local, think it is called the 'canyon effect'.

We also have a higher proportion of older cars, diesel vehicles (industrial estate is near by), no gas from my road upwards, high fraction of solid fuel users, and chronic under investment in housing stock.

You would think the M25 would be worse, but it isn't, well not if you use NOX as a proxy for particulates.

...which you can't. In diesels, EGR reduces NOx but at the expense of particulates. Hence the DeNOx and AdBlue which scrubs the NOx from a clean burning engine vs the older tech which lowered combustion temps to reduce NOx...

[SteamyTea]

2 minutes ago, dpmiller said:

...which you can't. In diesels, EGR reduces NOx but at the expense of particulates. Hence the DeNOx and AdBlue which scrubs the NOx from a clean burning engine vs the older tech which lowered combustion temps to reduce NOx...

Don't reducing combustion temperature in a diesel engine increase particulates, I thought it did.

Not talking the very latest designs, thinking more around Euro4 standards.

Lowering temperature does cause more visible smoke, but a lot of that is unburnt hydrocarbons.

[dpmiller]

Yes, lower combustion temp = more particulate.

It would be intersting to see the proportion of the current parc that is still older (Furo 3 or 4) diesels,  DPFs have been around for a long time now....

[Ferdinand]

On 04/05/2020 at 18:07, Savage87 said:

Because of wind direction I'm a bit reluctant to do that. My exhaust is almost 3m away for the intake, to the right as you look at the roof. The wind usually blows from the west to east, this means from the intake towards the exhaust. I'm afraid I might get contaminated air back into the intake if I reverse them. ?

 

Would there be benefit in simply putting the intake on the reverse slope?

[Ferdinand]

I'm not sure whether I am being way off beam here, but will there be a glut of the filter type products needed for this in a couple of years time - assuming a Covid-19 vaccine?

[Savage87]

@Ferdinand The reverse slope that you are referring to in facing north onto the front of the house which on a busy main road. When I was designing the system, I have asked the question on which face of the roof to put the intake and exhaust and the answer was south. A couple of people contributed and we councluded that it you be best this way.

[Ferdinand]

1 hour ago, Savage87 said:

@Ferdinand The reverse slope that you are referring to in facing north onto the front of the house which on a busy main road. When I was designing the system, I have asked the question on which face of the roof to put the intake and exhaust and the answer was south. A couple of people contributed and we councluded that it you be best this way.

 

Undoubtedly true, but it may also be the easiest alternative that can be tried in an "easily reversible if it doesn't work" manner.

F

[Roundtuit]

We intake from a north-facing pitch, and exhaust from a south facing pitch.  No issues that I'm aware of, and not uncommon to use different aspects according to the designer.

[Jeremy Harris]

Our intake is on the North wall, exhaust is on the East wall.  Not ideal, as any sort of a breeze when I was trying to balance the system seriously upset the measurements.  One of the things planned for when I eventually get around to extending the intake is to also change it's direction to it also faces East.