DIY Heat Exchanger Idea

Since converting my room to water cooled LEDs iv managed to get my room temp this summer to stay below 32C which has been the highest recorded temp. (Compared to last years 38C)

I want to improve this slightly so have been researching DIY AC and dehimidifer conversions. But none of them have been what Iv been looking for awhile still keeping humidity down with out major work.

So I have come up with this Idea using parts of got laying around.


Basically using a intake pump iv got left over from RDWC setup.
A car alloy radiator and running some copper coils after the air flow of the dehumidifier and oscillating fan.

The radiator ill be mounting on a window frame so it pulls cooler outside air in.

Has any one tried something along the same lines or have any extra tips?
My water pump should be enough being 50W.

Proof of concept using a old rubbish radiator since I dont want to run tap water though my new alloy one.
Defiantly more flow then I need with pump set on lowest setting.
https://vid.me/LW5s

I was thinking a similar thing just yesterday, but not the DIY way.

Was gona put a small AC in a small room in the house, put the radiator and fan in that room - and leave the door closed.

Can you think of any downsides to that?

What 50W pump are you using? 2000L/ph?

Found a condenser radiator in my scrap bin from a car which looks like it would fit on my Dehumidifier exhaust vent perfectly.
So have ditched the idea of coiling up some copper.
Going over my tent with a IR heat gun the main thing heating up the room is the dehumidifier so just cooling its exhaust should be enough to get me down 4C cooler.
Vid of leak testing and flushing.
https://vid.me/lrjN

Joe34 said:

I was thinking a similar thing just yesterday, but not the DIY way.

Was gona put a small AC in a small room in the house, put the radiator and fan in that room - and leave the door closed.

Can you think of any downsides to that?

What 50W pump are you using? 2000L/ph?

Click to expand...

4000L/PH
Running a AC is very expensive.
My tent is all about efficiency since I aim for 1G per Watt.
Running this heat exchange will put my tents total draw up to 650W, If I had to run a AC that would be closer to 800W
Not that iv had any issues with the high temps for my strain. Hitting 32C vs 38C made only a slight difference to density of the buds so Im hoping keeping it under 30c will make enough difference to justify 50W more.

Had it running this afternoon and its working too good.
Max temp for today in the tent 22C, Min temp 20C
----- Edit -----
Switching off the pump the temp comes back up quickly.
So im going to have to look into getting a temperature control timer since I only wanted to drop the tent to around 25C.
The fan on the radiator never reached the 30C switch on point so ill remove it.
Im thinking I may also be able to remove the radiator since the bucket of water on its own is 0.2c cooler then the radiator anyway.

majins said:

Since converting my room to water cooled LEDs iv managed to get my room temp this summer to stay below 32C which has been the highest recorded temp. (Compared to last years 38C)

I want to improve this slightly so have been researching DIY AC and dehimidifer conversions. But none of them have been what Iv been looking for awhile still keeping humidity down with out major work.

So I have come up with this Idea using parts of got laying around.

Basically using a intake pump iv got left over from RDWC setup.
A car alloy radiator and running some copper coils after the air flow of the dehumidifier and oscillating fan.

The radiator ill be mounting on a window frame so it pulls cooler outside air in.

Has any one tried something along the same lines or have any extra tips?
My water pump should be enough being 50W.

Click to expand...

Yes;

I'd recommend an stc 1000 temp control unit off ebay.

It would be better to submerge the heating coils of the dehuey in the water. Using air as the exchanging medium is never ideal.

I'm assuming the main purpose of this is so your dehumidifier doesn't heat your room so much?

@ttystikk is that fan pushing air into the radiator?

majins said:

4000L/PH

Click to expand...

What pump is that? Iv never seen a 50W pump at 4000lph, most 50w I seen are in the 2500 lph range.

Also how many cobs are you pushing water over with that sort of lph?

Joe34 said:

@ttystikk is that fan pushing air into the radiator?

Click to expand...

NO, and an excellent question; PULL air through to cool, PUSH to heat it.

It makes a big difference in performance.

ttystikk said:

NO, and an excellent question; PULL air through to cool, PUSH to heat it.

It makes a big difference in performance.

Click to expand...

Yeah, was gona suggest the same,

Also regarding your pic, why dont you make the shroud bigger?

ttystikk said:

Yes;
View attachment 3909619

Click to expand...

Cooling down the babies with monsters like that must be noisy and expensive.
How many KWH / year is that ?

I was just laying around in my bathtube. Previously i was used to take showers only.
But since my coolmac-300 serves plenty of hot water, i accustomed to use no more cold water and use hot water more generously - because it`s free.
My bathtube is ~30ft away from my heat exchanger and my grow room.
When i put my ear under water and telephone with the hot water hose - i can hear my little 2,3W pump and in the background the swinging led drivers.

Too much hot water - when I think in summer. ~300W lamp is where a DIYer starts to think about,
and when i look to you guys i read about wattages > 5000W.
Then i understand why you have to use these noisy monsters.

So for me some nice, smart idea of what to do with bigger quantities of needless hot water
is highly appreciated. - Specially in summer season.
O.K. there is always the ~ personal need - even in summer - and swimming pools, greenhouses, aquariums, fish ponds, kitchen,
hairdresser, car wash ... and ... ???

- where do you see HOT WATER NEED in summer. ???

Hope to get a good collection of ideas here... ... every answer is a good answer.

mahiluana said:

Cooling down the babies with monsters like that must be noisy and expensive.
How many KWH / year is that ?

I was just laying around in my bathtube. Previously i was used to take showers only.

Click to expand...

xDDD hahaha

mahiluana said:

But since my coolmac-300 serves plenty of hot water, i accustomed to use no more cold water and use hot water more generously - because it`s free.
My bathtube is ~30ft away from my heat exchanger and my grow room.
When i put my ear under water and telephone with the hot water hose - i can hear my little 2,3W pump and in the background the swinging led drivers.

Click to expand...

Next improvment you can put switch route on the pump pipe and divert it to make a mini wave machine in the bath? when your LEDS are off ofcourse...

mahiluana said:

So for me some nice, smart idea of what to do with bigger quantities of needless hot water
is highly appreciated. - Specially in summer season.

- where do you see HOT WATER NEED in summer. ???

Hope to get a good collection of ideas here... ... every answer is a good answer.

Click to expand...

Hmm, its a good question...

mahiluana said:

Cooling down the babies with monsters like that must be noisy and expensive.
How many KWH / year is that ?

I was just laying around in my bathtube. Previously i was used to take showers only.
But since my coolmac-300 serves plenty of hot water, i accustomed to use no more cold water and use hot water more generously - because it`s free.
My bathtube is ~30ft away from my heat exchanger and my grow room.
When i put my ear under water and telephone with the hot water hose - i can hear my little 2,3W pump and in the background the swinging led drivers.

Too much hot water - when I think in summer. ~300W lamp is where a DIYer starts to think about,
and when i look to you guys i read about wattages > 5000W.
Then i understand why you have to use these noisy monsters.

So for me some nice, smart idea of what to do with bigger quantities of needless hot water
is highly appreciated. - Specially in summer season.
O.K. there is always the ~ personal need - even in summer - and swimming pools, greenhouses, aquariums, fish ponds, kitchen,
hairdresser, car wash ... and ... ???

- where do you see HOT WATER NEED in summer. ???

Hope to get a good collection of ideas here... ... every answer is a good answer.

Click to expand...

It is just a 60W fan. I used it when outside temperatures were low enough to aid in cooling the working fluid. It's a lot less expensive than running an AC compressor! At an ambient temperature of freezing, my tough calculations showed it was good for 2 Tons of cooling capacity. By way of comparison, a chiller doing the same thing needs 2000W.

A good use for hot water would be to heat your grow room at night. This is useful to control RH and thus reduce potential for powdery mildew and related problems.

Joe34 said:

Yeah, was gona suggest the same,

Also regarding your pic, why dont you make the shroud bigger?

Click to expand...

This was the only big radiator I used. The rest of them came from mid 80s Volvo cars, ones the shroud was made for.

ah right, makes sense.

Joe34 said:

What pump is that? Iv never seen a 50W pump at 4000lph, most 50w I seen are in the 2500 lph range.

Also how many cobs are you pushing water over with that sort of lph?

Click to expand...

Label on it says 50-80W Im running it on lowest setting and pulls 51W from the kill-a-watt reading.
Cobs are on there own closed loop that they been running for 5 months now.
200W of Cree 3070 (4X)
250W of Cit 058 (1X)
That radiator vents straight out of the tent.

This heat exchange is just for cooling the air coming out of the dehumidifier since thats all thats dumping heat into the room.
Sure submerging the hot side coils in water would be more effective but then I lose the 9 year warranty on this dehumidifier which is only 6 months old after my original one failed after 5 years with 5 years warranty still on it so got the new one free.

hey guys - i found my washing machine as a great heat exchanger and my coffee and pasta need less energy to be prepared.

Looking to the professionals in watercooling i remember a midnight walk in a cooling tower of a coal-fired power station.
A cooling tower is a very simple system of pumping water up and let it fall down through the air. They are sometimes 300ft high and cause a passive convection to pull out wet air the whole year. The huge amount of heat energy they are able to sink is a result of the
evaporation energy of water 2441J / g
This is 0,68 KW*h for 1 L.
A 2000W of lamp heat *15h/day can vaporize @ 25°C a daily quantity of ~45L.
So adding 45L of tap water a day to the cooling water is the cheapest way.
I loose in my 300W system about 5L/day with only 1 wet socket (my size is 45) hanging it in the windy growroom




i think a good place for such a cooling tower in my case - would be after the carbon filter to enrich the outgoing air with heat and humidity.

I will see if i can find a cheap way to do it - as i also like to run things simple and cheap.

This thread looked really interesting to me, based on the title. Unfortunately I got stoned and the engineering is beyond me. Real bummer. Oh well, maybe someday.

I hope you cool the hell outta stuff. Just make it affordable when you sell it.