Very basic design question - from 'the other side'.

[mharries1]

Hi and thanks for reading. I am from the electricians forum but try to be as helpful as possible, Chris Murphy can vouch for me!
I live in an old property. My walls are made from anything that was available be it beach pebble, cob, or stone. One corner of my living room is particularly cold, often 2-3 deg C cooler than the rest of the room. Some of this is down to the fact that I have cold walls (which I am able to take steps to improve but do not expect spectacular results), some of this is bound to be down to radiator positioning. I currently have two radiators, the main one has to be moved.
In this cold corner my wife wants / insists on a corner setee. As I do not have a true 90 deg corner I am having to make this myself and it will extend roughly 2.4m each way . The problem is that this is going to fully enclose a section of one wall which is particularly prone to condensation so, as a minimum, ventilation will be required. My design for the setee means that I will effectively have a 4" wide shelf running the whole length (approx 6" below cushion level and therefore not visible) in which I can place vents. However, to my mind, these vents will not be effective as there will be little reason for there to be any natural convection.
I am pretty certain that my reasoning so far will stand up to scrutiny but from now on I might be going off the rails!! I am thinking of bringing a flow and return down the corner, then running these on the surface under the setee and exiting out the side of the setee to a new radiator position on the coldest wall. My thinking being that the heat from the 15mm pipes will be enough to a) give me a little bit of ambient heat in this area and b) be enough to provide some natural convection when the ch is on. This will be supplemented by two computer case fans (one at each end of the setee) powered by tiny solar panels to give a trickle of air movement when the ch is not on.
When you have finished laughing, I would appreciate any constructive comments or different solutions to this problem.
I am thick skinned enough to take any ridicule coming my way!
It is a gas fired system boiler if this is relevant.
Many thanks,
Mike

 

[mharries1]

Well, doing a quick google search for daisy unit, it comes up full of mental health institutions. Is this daisy unit similar to long waits that apprentices are sent to get from the wholesalers?

 

[mharries1]

Thanks for that. Perhaps I should have mentioned that I intend to fit a heat recovery ventilation system in the house. However I don't see that this will have any major effect on either my 'cold spot' or the area of wall that is going to become enclosed.

 

[chris watkins]

Sounds good to me, 15mm will give you around 28-30 W/m of pipe but why not increase the pipe diameter along the select under the corner / shelve to 22mm (38-43W/m) or even 28mm (47-53W/m) you may not even need the fans but may be useful for when heating is not on & will increase the outputs listed above.
PS don't forget as with any pipe coil you will need an air vent on to to remove the trapped air when filling & drain off to drain completely.

 

[mharries1]

Thank you. And some figures so I can be a bit more scientific working out my requirements!
No I hadn't considered drain off and vents but I am doing so now!
Mike

 

[AWheating]

fit the heat recovery in that corner of the room.

 

[Nostrum]

Have you considered changing the wife for one who is happy with a normal settee? :angel_smile:

Do you really want computer fans humming away while you watch t.v? I know I wouldn't and they get noiser as the dust sticks to them. You could stick a very small radiator behind there, with a thermostatic valve set low to prevent damage to the settee timber? I would think the vents high and low would provide enough movement of air for what you require?

 

[Chalked]

I would just fit a 450 x 450 single radiator with a trv. Then fit grilles to the top of the corner sofa and vents or a cut out to the bottom.

 

[Killy Bing]

Small rad, vents on the top shelf.
fully enclose/ seal the rest and fit a small vent to outside.
natural air flow and no fans buzzing away

 

[Ermintrude]

Nope nope nope. From the sounds of it walls are pours and of low insulating valve.

Hot moisture laden air inside, cold air outside. Think of the wall cross section as a graph.


Left hand side is inside and right hand side is outside


Top is high temp and bottom is low temp.


There is a gradient going from top left to bottom right. This is called the thermal gradient . If you plot on opposite axis humidity, where they cross is the dew point. ( where vapour condenses) sounds like it's in the wall.
Interstitial condensation is the issue.

Insulate and provide a vapour barrier and cold ventilate.