Pre filter between MVHR vents and MVHR unit

[Russdl]

And then there were two. External joints taped with left over airtight tape. 

[Russdl]

So, the over engineered MVHR pre filters are ready to go, along with the over engineered attenuators. I still need to tape and paint the wall before I fit it all properly but it’s gone together well so here’s hoping it all works ??
 

 

[tanneja]

This is inspirational @Russdl, can I ask, with the distribution boxes, did you use the restrictor rings for balancing?  Presumably these required cutting as appropriate for each run to achieve your  balancing?  Do you expect to need access to the internals of the distribution boxes in future as they seem to be behind your home made silencers?

[Russdl]

@tanneja I will be using the restrictor rings for balancing and they will require cutting, I'll also be using air valves that have a small amount of adjustment on them as well. It's not commissioned yet for several reasons, not least of which is that there is no power up there yet.

 

The front face of the home made silencers will be screwed on and then taped so if I do need access at a later date (bound to!) then I'll just have to cut the tape and undo the screws and the silencer will be removable, in fact everything will be easily removable should the need arise.

[Onoff]

On 04/12/2020 at 13:31, Russdl said:

And then there were two. External joints taped with left over airtight tape. 

 

Wouldn't a continuous bead of wood glue have achieved the same (better even), air tightness as the tape?

 

Ref inspection windows, I've salvaged a number of non functioning, Enlite flat panel LEDs from the bin at work. They strip down to leave a nice, insertable (157mm cut out) bezel. Made from a light, white painted alloy, they'd sit nice in a cabinet with a bead of silicone. I think the diffuser is too opaque to see through for condensation so another acrylic/polycarbonate disc would be needed (it might polish up clear with compound). Just ever more crap I've collected but you're welcome to a couple or more. Originally got for my lad's 3D printer enclosure until we went with full glass sides. (Of course 3D printing inspection window bezels is an option):

 

 

 

 

 

Edited January 2, 2021 by Onoff

[Russdl]

1 hour ago, Onoff said:

Wouldn't a continuous bead of wood glue have achieved the same (better even), air tightness as the tape?

It may well have done but I had some airtight tape left over so I used it. I had MDF left over as well hence they are made of MDF and not ply, we’ll see what happens. 
 

Thanks for the offer of the old light fittings as inspection thingies, a great idea, I won’t need them however as the fronts come off with a few flicks of levers for inspection/cleaning. The fronts are sealed with closed cell foam, I’m guessing that’ll be as close to airtight as I’ll need. 

(They’re still not fitted properly yet)

[tanneja]

@Russdl, would you please confirm (as seems to be the case based on your picture above), have you used the same foam ducting for duct length that punctures the building wall? Is there any fall / gradient on that length?

[Russdl]

@tanneja yep, it's the Ubbink 180mm insulated duct and both runs have a slight fall from inside to out.

[Russdl]

Finally the MVHR with added bits is properly fitted and the loft space in which it resides is taped and painted. 
 

The spiders are already on the advance through the grills on the intake and exhaust vents so hopefully my MVHR pre filter will keep them out of the MVHR itself.  The pre filters are airtight so should be spider proof as well.
 

The home made attenuators are easy to remove, which I’ll need to do to fit the restrictor rings to the manifolds and I haven’t airtight taped the fronts on yet. Not sure if I need to? The boxes are lined with acoustic foam, would that be airtight enough I wonder, and how would I know if it wasn’t?

 

Just need some electricity to see if it all works as I hope ?? 

 

 

Edited January 17, 2021 by Russdl

[SteamyTea]

13 hours ago, Russdl said:

Just need some electricity to see if it all works as I hope

Just turn the crank, Mousetrap.

 

[Russdl]

@SteamyTea it may just come to that!

[SteamyTea]

8 minutes ago, Russdl said:

it may just come to that

Small windturbine and a solar panel.

But don't site a small generator next to the inlet.

Edited January 18, 2021 by SteamyTea

[Russdl]

Well it’s early days as the MVHR has only been on for a little under a month but my pre filters seem to be doing the trick

 

 

 

But not perfectly, some of the little rascals are getting through, I think I’ve got a ladder in me tights. 
 

[Russdl]

On 15/11/2020 at 22:17, Russdl said:

I wonder if my little wooden box pre-filter will cause me condensation issues????

I can answer my own question here. 
 

My ‘pre-filter’ MDF boxes are in a warm loft and work a treat at pre-filtering however I am getting plenty of condensation on the outside of my ‘supply side’ pre-filter box, the ‘exhaust’ side is fine. 
 

I’m thinking the easiest fix will be to insulate the inside of it. any suggestions as to what would be best to use?

[PeterW]

Cheap yoga mat or camping mat cut to fit and stuck on with carpet glue

[Onoff]

36 minutes ago, Russdl said:

I can answer my own question here. 
 

My ‘pre-filter’ MDF boxes are in a warm loft and work a treat at pre-filtering however I am getting plenty of condensation on the outside of my ‘supply side’ pre-filter box, the ‘exhaust’ side is fine. 
 

I’m thinking the easiest fix will be to insulate the inside of it. any suggestions as to what would be best to use?

 

Could you have built it turned through 45 degrees and had a condensate drain?

[Russdl]

31 minutes ago, Onoff said:

Could you have built it turned through 45 degrees and had a condensate drain?

I guess that may have helped but the condensation is on the outside the box. Mainly on the top and down the back of the box.
 

My aim now is to make the problem go away by insulating the inside of the box.

 

@PeterW’s suggestion of a cut up yoga mat sounds like a good idea because I don’t want to restrict the flow and that should be thin enough to achieve that. 
 

I wonder if it’ll be too thin to be effective? I guess I could always do two layers. 

[Onoff]

29 minutes ago, Russdl said:

I guess that may have helped but the condensation is on the outside the box. Mainly on the top and down the back of the box.
 

My aim now is to make the problem go away by insulating the inside of the box.

 

@PeterW’s suggestion of a cut up yoga mat sounds like a good idea because I don’t want to restrict the flow and that should be thin enough to achieve that. 
 

I wonder if it’ll be too thin to be effective? I guess I could always do two layers. 

 

Sorry, didn't read 'outside", saw the black bits inside I thought were the dreaded black mould.

[Russdl]

15 minutes ago, Onoff said:

saw the black bits inside

I’m pleased to report that is not mould, just crud (flies, seeds, dust etc). 
 

 

[Russdl]

It’s 45 days since I cleaned the MVHR filters and whilst I’ve not had a ‘message’ telling me to clean them the MVHR did seem a bit noisier, nothing excessive but as it’s normally pretty much inaudible the fact that I could hear it sent me to the loft to investigate. 
 

The intake filter is quite bogging after a month and a half, the extract is not too bad at all considering doors and windows have been opened as required to off load unwanted heat. 
 

 

The pre-filter seems to be doing its job, this was a brand new pair of tights a month and a half ago!

 

I wonder if the pre filter housing is actually enticing critters in? Again, this was cleaned out a month and a half ago.
 

 

The coarse mesh of the intake grill is covered in cobwebs, as is the duct into the house though they don’t show up too well in the photos. 
 

the joys of living in the countryside, spitting distance to the wheat field that was just recently harvested I suppose. I opted to replace the intake filter as vacuuming it achieved the square root of bugger all. 
 

I didn’t think to check the MVHR fan speeds before and after the service but it seems quieter again so I’m assuming the crud was restricting the airflow enough to  cause the fan speeds to increase to maintain the selected airflow. 

[jack]

15 minutes ago, Russdl said:

the joys of living in the countryside, spitting distance to the wheat field that was just recently harvested I suppose. I opted to replace the intake filter as vacuuming it achieved the square root of bugger all. 

 

I drove past a wheat field being harvested on Sunday. The dust cloud it generated was visible a mile away!

[SteamyTea]

2 hours ago, jack said:

 

I drove past a wheat field being harvested on Sunday. The dust cloud it generated was visible a mile away!

Don't tell the vegans they are chocking the planet.

 

These are the UK supermarket items with the worst environmental impact

Researchers trained an algorithm to estimate the environmental impact of 57,000 products sold in the UK and Ireland to help consumers make eco-friendly choices

 

ENVIRONMENT 8 August 2022

By Adam Vaughan

 

Meat has a bigger environmental impact than most other products in the supermarket

E W Brown/Alamy

 

Avoid the supermarket aisles piled with cheese, quiches and pies. That’s the message of an analysis that found they fare worst for nutritional quality and environmental impacts among thousands of food and drink products sold in the UK. And if your priority is curbing carbon emissions and water use, avoid the meat and fish shelves too.

So far, most studies assessing the environmental footprint of food have focused on the impact of agricultural commodities such as beef or soya, rather than the lasagnes, tofu and other products that shoppers often buy. Where research has focused on consumer products, it has usually been for a small number of them.

In a bid to bridge the gap, Michael Clark at the University of Oxford and his colleagues analysed more than 57,000 food and drink products sold in the UK and Ireland. The team took the ingredients data from eight retailers, including major supermarkets Tesco and Sainsbury’s.

 

However, precise figures on how much of each ingredient is in each product were only available for around a tenth of them. To estimate the rest, Clark and his colleagues trained an algorithm on the known products and used it to predict the composition of the unknown ones, helped by the fact that UK regulations mean ingredients must be listed in descending order of quantity. Finally, the team linked all the ingredients to an existing database of environmental impacts, including emissions, land use and water stress.

The results may come as no surprise: meat, fish and cheese products had the highest environmental impact. Desserts, pastries and savoury pies came next. Fruit, vegetables, bread and sugary beverages had the lowest burden. For the most part, there was an overlap between low environmental impact and good nutrition, a further analysis showed.

Solving the world’s problems Rowan Hooper at New Scientist Live this October

Clark concedes that none of this is mind-blowing, given what we already knew from past research. “The major advance is not that beef has high impacts, fish has high impacts, cheese has high impacts. It’s the fact that you can start getting these impact estimates for products that people are purchasing, which then has a lot of knock-on implications,” he says.

 

One of those is eco labels, which a growing body of evidence shows can steer consumers to make greener choices. However, retailers have struggled in the past with the scale of the challenge. In 2012, Tesco stopped trying to add carbon labels to all its products because it would take centuries to assess them all at the rate it was managing.

Clark’s approach points the way to doing such labelling at scale. He is thinking about how to eventually turn the data into an app that could be used either by shoppers or by retailers wanting to reduce their environmental impact. “We’ve made that information available in a way that means people can start making informed decisions,” he adds.

The main limitation of the new research is that it doesn’t account for different sources of the same ingredients, such as beef produced in the UK or imported. For example, according to the UK Climate Change Committee, UK beef emissions are 14 per cent lower than the European Union average.

“The paper provides a lot of value by making the environmental impacts of foods more tangible and applicable for consumers,” says Hannah Ritchie at Our World in Data. “Previous studies mostly focus on the impacts of broad food categories – such as maize, wheat or legumes.” She thinks the study is a step towards eco labels in supermarkets.

 

Journal reference: PNAS, DOI: 10.1073/pnas.2120584119

[Russdl]

I think I may have neglected my pre-filters the last time I cleaned the MVHR filters.
 

Once again the MVHR Seemed to be getting noisier, initially I put it down to me just always listening out for any noises but this morning when it did it’s morning switch from 100m3/hr to 200m3/hr it sounded like it was on boost. I went to have a look and this time remembered my pre-filter!

 

🤮🤮🤮

 

 

not the best photo but you can probably see that it is absolutely bogging. Almost completely blocked by all sorts of detritus. 
 

I don’t think it’s been neglected for more than 6 months so I’m surprised how bad it is. The only thing I can think of is that we seem to have had many more days of northerly/easterly winds of late (according to my gut feeling) and we have cultivated fields that side. 
 

I measured the noise with an app on my phone up against a supply terminal before and after replacing the pre filter. 41db before 33db after. 
 

Also the power draw 67W before 34W after. 
 

I must remember to keep an eye on those pre filters. 

[Temp]

I fitted a pre filter to the air inlet of our system so it's visible without removing any covers. Saves a lot of effort.