Thermal mass - has anybody toyed with this

[ratdog]

@Larry Badgeley that reminds me i had some off cuts of porcelain in the van for this very reason, should spread the warmth a bit better in the cupboard

[Larry Badgeley]

@ratdog. Do it man. It really is a great way of doing it.

[ratdog]

Just now, Larry Badgeley said:

Do it man

 

 

already done mate, i think i underestimated how much i would need, i have enough for at least two spaces

[RUFUS HOUND]

because I just so happen to have my temperature gun handy and just because I can, I took the temps of the blocks - a very chilly 3 to 4'C

 

they may take a bit longer to warm up than I thought - might have to resort to stacking on the radiator 

[RUFUS HOUND]

Ive been thinking about the laying the blocks in a slab covering the base. As its only 60x60 it wont take that many, but then I had a thought about how the bricks are used in a Russian stove.

 

For those that have a life, its simple but genius way of collecting heat from a fire/stove by heating thermal mass.

 

essentially its a massive brick fireplace that funnels the exhaust gases through a maze of bends, heating the thermal mass of  the brick. This heat is then released long after the fire is out

 

Sorry got carried away there - anyway Ive decided instead of laying the blocks in a slab, Im going to create a maze to channel my "rad box" heated air through, so it picks up the max heat possible by exposing as much surface area of the bricks, to the heated air as possible. very deep  breath 

Edited April 2, 2022 by RUFUS HOUND

[BilgePump]

@RUFUS HOUND the Romans did what yer describing , have a Google of hypocausts 

 

[RUFUS HOUND]

cheers for that @BilgePump thats exactly the same principle - bloody romans what did they ever do for us

[somelad]

Some firebricks from a old electric storage heater would work better, might be worth asking in your local fireplace shop if they have got any in their skip, we used to skip loads of them when I used to fit fireplaces 

[RUFUS HOUND]

@somelad they would be perfect but rare nowadays, the greenhouse owners have snaffled them all.

 

The driveway blocks are free and a decent substitute, very dense and heavy for their size, should store a good amount of heat.

They are now nice and warm at 23'C

 

heres the plan 

 

Im going to insulate the floor of the tent with 3 layers of green fibre laminate underlay boards (again free) put

Heat mat on the insulation and lay 20 blocks on top of this.

Over the blocks a layer of green fibre insulation, then the catch tray and finally the pots.

I need to fashion a bit of ducting to direct the air under the false floor.

Edited April 3, 2022 by RUFUS HOUND

[RUFUS HOUND]

heres a photo of the thermal mass / heatsink on the floor of my tent 

Ive lost about 4 inch in headroom but so far never needed the height.

I have already knocked off the oil radiator and it running just the heat mat currently but it not thaat cold to be fair.

4

[MindSoup]

Looks good man, be keen to see how well it works. 

[botanics]

I used a similar system when rigging my my veg box to flower box set up.  The hot air was ducted via the veg box underneath the floor of the flower box and into that room before being exhausted from the top.  This negated me having to use any supplemental heating when the lights were off in the flower room (veg lights always on during flower room off period), but requires light proofing of course. 

 

Technically, especially if you're running LED systems because the heat is not directed downwards an intercooler system whereby the heat is transferred into a radiator of liquid (oil or water) on the top of the light unit and then pumped into a thermal mass for heat transference within an underfloor setup, would catch some of that waste heat for when lights are off and slow release of course.  Efficiency wise I don't know the numbers but makes use of that heat that would otherwise be going out of the exhaust duct and would serve to cool the room more efficiently when the lights are on of course.

[RUFUS HOUND]

@botanics I had near the same set up with my vegbox exhaust, feeding the flower tent and like you found it gave very consistent temps, the vegbox acting like a preheater, the key thing was like yon was the veg light was on 24hrs - which helped steady things out and gave some supplemental heat while the flower light was out.

 

At the minute, Im using the flower tent only, so it should help slow down the temp fall at lights out.

 

I like the idea of a heatsink on the light but need to find something not to heavy that will realease heat slowly - not keen on water / light combo

[botanics]

1 hour ago, RUFUS HOUND said:

not keen on water / light combo

 

Would be fine enough mate provided you pressure test it all first for leaks.  You get water cooled computers for instance, plus they're a good source of inspiration regarding heatsink designs and the utilisation of thermal paste etc. for chip cooling purposes  

[RUFUS HOUND]

hummmmmmmm, I do have a heat sealer, it might be time to see if the bags are waterproof - they're vacuum bags, so are airtight, so should be ok