Thermal mass - has anybody toyed with this

[inceywinceyspider]

I dont understand where the duct is coming from into the labyrinth, is it moving hot air from the top of the tent into it?, 

[RUFUS HOUND]

@inceywinceyspiderAir coming from the house, through a boxed in oil rad to the base of the tent and the labyrinth.

I have 2x80mm pc fans in the ducting, one on inlet to rad box, one at the inlet to the tent base (labyrinth) 

so there is heat available but hoping to keep the oil rad off and only use the 20W heat mat in the centre of the maze 

Edited April 5, 2022 by RUFUS HOUND

[RUFUS HOUND]

quickly knocked up these water filled jackets using the heat sealer - will test on radiator over night to see if the melt pop leak before going near my lights 

 

to much air in top one , so will need to redo 

 

Edited April 5, 2022 by RUFUS HOUND

[somelad]

You can cook in them so they should be fine, sous vide google, it should give you a idea of temps they can handle 

[RUFUS HOUND]

@somelad cheers - of course they are, I was forgetting that, short term memory not the best

well, good job I tested them as one sprung a leak.

It had a tiny break in the heat seal, operator error - anyway I knocked up another and that seems water tight putting them in a black plastic tray on top of the light to soak up that wasted heat.

 

[RUFUS HOUND]

Tonight, Ive put the water bags with trays, on top on the lights and also exposed the blocks by removing the top layer of insulation

Im hoping the bricks will absorb more heat and emit it faster as its getting to low at 19'C, and I could do with a couple of degrees

if it works I think I will go back to the original slab idea

[RUFUS HOUND]

Been struggling with temps since the rad went off, I changed the labyrinth back to a "slab" where all the blocks are placed flat (giving me back about 2" back in headroom) on top of the insulation and heat mat, as some of the blocks are on the heat mat, heat is spread across all the blocks, which works well but it still wasnt enough. 

 

I had to admit defeat due to the cold weather and turned the radiator onto minimum and backed the heat mat off to 50% and temps are between 21'C and 28 'C with lights on 24/0 - once settled I will try a few days at 20/4 to see how the temps fair.

 

 

 

 

[RUFUS HOUND]

Forgot to mention, I've put a few more blocks inside to increase the mass, currently at 25

[RUFUS HOUND]

While I was up there, I thought I better get some temps 

Water bags = 31'C

Blocks = 30'C in centre (over the heat mat) 

          = 26'C on edges 

Tent = 28'C at canopy 

also made a few small changes

Lined the sides in 10" high fibre underlay

added the blocks as mention 

moved my circ. fan to above the lights blow downwards

[RUFUS HOUND]

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Edited April 14, 2022 by RUFUS HOUND
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[RUFUS HOUND]

apologies for the lack of updates - finished tinkering and have been letting things stabilise.

 

Ive increased the total blocks to 30 and with the 20W heat mat on approx 75%, this has slowed the rate of temperature fall during lights off time 11am to 5pm (18 on/6 off).

 

The root temps are ranging between a max temp of 26'C ( at lights off 11am ) and a low 6 hrs later of 20'C when lights come back on (5pm). 

During this time, I have been converted to monitoring and maintaining root temps, rather than canopy air temp and the girls seem to like it!

[J.C]

Really interesting thread, have you thought about using the same materials found in storage heaters? From what I understand they use either ceramic or clay bricks due to their heat retention?

[RUFUS HOUND]

they would be nice to have but rare to find in large quantities - I find these work well as a replacement.

 

I currentlly have a single layer of blocks over a 20W and 14W heat mats - these heat the mass and it slows temp fall down to about 1'C hour over lights off

 

PS dont try the water bags, water and electricity is always a bad idea 

Edited May 29, 2022 by RUFUS HOUND

[Puffdiddy]

Really interesting  - makes so much sense to try and capture and store heat