Sciencemadness Discussion Board - Device that heats at around 40 degrees C?

Device that heats at around 40 degrees C?

khourygeo77 - 17-5-2020 at 03:26

Hello,

I need to make some experiments while having a temperature at around 40 degrees C. The experiments may take a few months of continous heat and I dont want the temperature to be interrupted. (dont want the device to stop working after 1 or 2 months)

Can I do this without paying much?

I bought the following terrarium heater but it doesn't seem to work well

https://www.miscota.com/reptiles/lucky/rep-thermo-socket-can...

Any ideas?

Thanks!!

[Edited on 17-5-2020 by khourygeo77]

j_sum1 - 17-5-2020 at 03:55

Temperature is going to depend on the energy demand of your system and heat loss both of the system and the heat source. (I other words, insulation and ambient temperature.)

Incandescent light bulbs are commonly used for hatching chickens. My thoughts would be to play around with a simple resistance heater: maybe cannibalise an electric blanket and experiment with a variable power supply and an equipment mock-up. You might also have some success with a water bath and a submersible element with thermostat. That would give a bit of thermal mass which might be good. See suppliers fot tropical aquariums.

In NZ it is common for domestic water heaters to be located inside a cupboard. Often there are exposed copper pipes that stay warm. With a bit of insulation ripping and some imagination you might already have a solution.

Like I said, depends on the demands of your setup.

Sulaiman - 17-5-2020 at 04:42

A well insulated large thermal mass helps to maintain a constant temperature.
Using a heater of just enough power also helps by minimising rate of change of temperature.
Some basic information on your requirements may help
e. g. Air or liquid, volume, allowable temperature range etc.

monolithic - 17-5-2020 at 05:20

https://www.briskheat.com/products/heaters/heating-tapes-and...

You can get knockoff versions of this on various websites. Connect it to a variac and dial in your temperature.

Ubya - 17-5-2020 at 06:06

everything depends on your experiment, do you need to keep at 40°C a 250ml beaker or an entire complex apparatus?
if it is something small you can use a styrofoam box, they insulate quite nicely, the thicker the walls the better, i use one for recrystallizations and it takes many hours for a 250ml beaker to go from 100c to room temperature.
if you don't want to pay much in electricity you need a well insulated container, even 5w of heating can be more than enough if you got the right insulation

khourygeo77 - 17-5-2020 at 06:18

I am going to make a closed system and experiment with a thermometer to see at what distance I get the 40 degrees C then insert tiny flasks there. The heater will be the center of the circle and several flasks all around it. So you dont have to worry about the system. I just need a device that gives off a heat of 40-45 degrees C without getting corrupted after continual use of a few months. I can take care of the rest.

[Edited on 17-5-2020 by khourygeo77]

Tsjerk - 17-5-2020 at 06:21

I used stackable plastic boxes in the past. I would put an aquarium heater between two boxes and fill the space with water. I would insulate the whole thing with blankets.

khourygeo77 - 17-5-2020 at 06:26

Quote: Originally posted by j_sum1

Temperature is going to depend on the energy demand of your system and heat loss both of the system and the heat source. (I other words, insulation and ambient temperature.)

Incandescent light bulbs are commonly used for hatching chickens. My thoughts would be to play around with a simple resistance heater: maybe cannibalise an electric blanket and experiment with a variable power supply and an equipment mock-up. You might also have some success with a water bath and a submersible element with thermostat. That would give a bit of thermal mass which might be good. See suppliers fot tropical aquariums.

In NZ it is common for domestic water heaters to be located inside a cupboard. Often there are exposed copper pipes that stay warm. With a bit of insulation ripping and some imagination you might already have a solution.

Like I said, depends on the demands of your setup.

About the light bulb, I tried working with them once however they stop working after a few weeks maximum. I can always put 2 in case 1 stops working so I replace it while the temperature keeps going, but the problem is that installing 2 lamps will cause a temperature change whenever one stops working and this isn't what I want..

j_sum1 - 17-5-2020 at 06:26

40-45°C is not heat. It is a temperature.

The temperature you attain will be a function of the rate of heat input and heat loss from your system. The former is the wattage of your heating element. The latter is related to insulation.

It still is not clear what you hope to accomplish. But one thing is certain, it will not be a closed system -- you are asking about heat input and you will also have heat being lost.

Ubya - 17-5-2020 at 06:47

Quote: Originally posted by khourygeo77

I am going to make a closed system and experiment with a thermometer to see at what distance I get the 40 degrees C then insert tiny flasks there. The heater will be the center of the circle and several flasks all around it. So you dont have to worry about the system. I just need a device that gives off a heat of 40-45 degrees C without getting corrupted after continual use of a few months. I can take care of the rest.

[Edited on 17-5-2020 by khourygeo77]

so your idea is to put a heat source in a room, and flaks all around it at the distance where you can measure 40°C?
1) we are not in a vacuum, convection is a thing, temperature in a room is not a function of the distance from the heater.
2) your system is not closed, it's totally open lol, if it was closed every point in the system should reach a thermal equilibrium, that's why pretty much everyone is telling you to use an insulated box, small volume with same temperature instead of infinite open system with a radial temperature gradient.

ps https://www.ebay.com/itm/W1209-DC-12V-Digital-thermostat-Tem...
here you are, take a small 12v 5w incandescent tube, an insulated box and this thermostat (the cheapest thing china has to offer) and your problem is solved.

[Edited on 17-5-2020 by Ubya]

khourygeo77 - 17-5-2020 at 07:18

Quote: Originally posted by Ubya

Quote: Originally posted by khourygeo77

No, it is not about putting them in a room, but in something small. I don't care if heat escapes, I just need the heat to remain the same at the same points.

For example, I used to put a terrarium heater before in an empty small gallon of water and cover it. The temperature was ~39 degrees all the time inside the gallon whenever I tried to measure it except at the beginning.

Ok. I will buy a thermostat.
About the incandescent tube, it can remain functional for several months straight?

Ubya - 17-5-2020 at 07:39

Quote:

Can I do this without paying much?

Quote:

I don't care if heat escapes

these two things are opposite of eachother, that's why i was heavily suggesting insulating the container. if you want to keep an open fish tank at 40°C you are going to need at least a 25w heating element, if you insulate it, 5w will suffice, cheaper on the electrical bill.
about the life span of an incandescent light bulb, they usually live 1000 hours give or take, so if you keep it on 24/7 it should last you 1 month.
something you could do is using a 24V light bulb and run it on 12V (remember to pick a higher wattage bulb in that case) so the filament won't be so hot, it should last longer.

khourygeo77 - 17-5-2020 at 10:38

yeah I didn't specify. I am not paying electricity and I can use it all the time while having a fixed price to pay for it every month.

But isn't it common for a light bulb to stop working sometimes after a week if turned on permanently? Sometimes I used lamps that were supposed to last 1000 hours but they lasted 100 hours instead and other times they would last more...

And how is it possible to use 24V light bulb and run it on 12V? You mean the socket should be on 12V?

mackolol - 17-5-2020 at 11:03

You can buy the cheapest electric kitchen hotplate. The stuff is super cheap and you can get variety of temperatures up to 500C. At the lowest setting it should be like 40C.
Also, you can use terrarium heating pad, it should be around 40C and it works by emitting infra red radiation, here is an example:
https://www.wish.com/product/5e7c4b787303c03973181412?hide_l...

Dr.Bob - 17-5-2020 at 16:42

Try an easy bake oven... or just a 40 watt bulb in a box.

Ubya - 17-5-2020 at 22:20

Quote: Originally posted by khourygeo77

And how is it possible to use 24V light bulb and run it on 12V? You mean the socket should be on 12V?

buy a bulb rated for 24v, and connect it to a 12v power supply.
the 24v bulb should have a wattage 4 times the amount you need, if you were using a 12v 5w bulb, you need a 24v 20w bulb, so you get the same power output at half the voltage while running the filament colder, aka it lasts longer.

clearly_not_atara - 17-5-2020 at 22:31

I know it's not a real answer but when I saw the thread title my first thought was "a cat"

IIRC they make therapeutic heating pads that will hold themselves to around 40 C though if you look at the specs. A typical hot tub is also kept at 40 C but that seems like too much expense.

Ubya - 17-5-2020 at 23:29

Quote: Originally posted by clearly_not_atara

I know it's not a real answer but when I saw the thread title my first thought was "a cat"

IIRC they make therapeutic heating pads that will hold themselves to around 40 C though if you look at the specs. A typical hot tub is also kept at 40 C but that seems like too much expense.

oh you reminded me of constant temperature PTC heating elements, but i don't know if there are ones for 40°C

unionised - 17-5-2020 at 23:54

Apparently this is cheep.

https://www.youtube.com/watch?v=3Y0ROuPGaxw

[Edited on 18-5-20 by unionised]

Heptylene - 18-5-2020 at 00:51

A fan, an electric heater and a PID controller in an insulated box could do the trick. Even styrofoam would withstand the heat. For safety, pick a heating element that only gets warm when run at 100 % duty cycle.

A safe, low power heating element can be a kitchen appliance which is run on 12 volts instead of 120 volts. E.g. a waffle mold. You would put the waffle mold in the box, connect it to 12 V via relay controlled by the PID. The power at 12 volts will be 100 times less than at 120 volts.

Herr Haber - 18-5-2020 at 07:05

Got nothing to add except if you are looking for decent sized styrofoam boxes for free make friends with your local sushi shop.

They receive their fish in very neat boxes that close very well and if you break then you can just come the next day !

I'd have used an aquarium heater / mat too.

khourygeo77 - 18-5-2020 at 14:31

I thought aquarium heaters would be a good idea, but they dont get above 35 degrees C unfortunately... Or at least this is the case with those I saw...

And Thanks everyone for the tips, I finally have many cheap & simple & effective options to choose between..

Twospoons - 18-5-2020 at 14:48

Quote: Originally posted by Heptylene

A fan, an electric heater and a PID controller in an insulated box

I've done exactly this -- and it turned out the heat input from the fan alone was enough to heat the box to 40C.

j_sum1 - 18-5-2020 at 15:03

Quote: Originally posted by khourygeo77

I thought aquarium heaters would be a good idea, but they dont get above 35 degrees C unfortunately... Or at least this is the case with those I saw...

And Thanks everyone for the tips, I finally have many cheap & simple & effective options to choose between..

Again, the temperature you get to is a function of insulation and ambient temperature.

Your aquarium heater might be rated to 35° but you won't get anywhere near that if you are heating up a gymnasium or an igloo.
On the other hand, if you stuff your heater in a shoebox and surround that thing with space-shuttle tiles you will get much higher than 35° because you have input of heat energy and no easy way for that heat to go anywhere.

Mateo_swe - 18-5-2020 at 23:55

You could use one of those heating pads 120x120mm made for 3D-printer and use a temp controller.
They have the temp sensor already inside.
https://www.ebay.com/itm/120x120mm-120W-12V-KEENOVO-Silicone...

Or you can use one of those seedling heatmats that are used when sprouting stubborn seeds.
They usually go to about 30°C but if you put it in an enclosure you probably can get 40°C at least.
They are made to run 24/7 ie. all the time.
Or just a lamp. If in an enclosure it will get warm, you need to make outside air cool it a little.
Or just some nicrome/kanthal heating wire with a controller, or heating cable for outside drainage to prevent freezing.
So many possibilities.

khourygeo77 - 25-5-2020 at 11:45

So I bought 50W spot and installed it on a 150V socket. I put it in a cardboard and my thermometer measures 39-40 degrees C.
It is the same temperature on all points in the cardboard except right in front of the spot. I covered the few openings of the cardboard with old cotton clothes.

Let's say I want to lower the temperature a few degrees just for the science. All I need to do is decrease the thickness of the cotton layer, correct? Or maybe I can cover the openings with something that is more heat conductive. Or maybe it is possible to make new openings in the cardboard and put something more conductive to heat?

Belowzero - 25-5-2020 at 22:43

The question reminded me of something called heating mats , they are used for growing plants and various other things.

https://www.amazon.co.uk/s?k=heating+mat&i=outdoor&r...

The ones for plants usually go just a few degrees above ambient, there are probably ones that go above that.
The fancy ones come with controllers.

If a constant temperature isn't required one could place the reactor on top of the central heating system , I used this in the past to artificially age distilled wine.It's a very cheap way at least.

Ubya - 26-5-2020 at 01:05

Quote: Originally posted by khourygeo77

So I bought 50W spot and installed it on a 150V socket. I put it in a cardboard and my thermometer measures 39-40 degrees C.
It is the same temperature on all points in the cardboard except right in front of the spot. I covered the few openings of the cardboard with old cotton clothes.

Let's say I want to lower the temperature a few degrees just for the science. All I need to do is decrease the thickness of the cotton layer, correct? Or maybe I can cover the openings with something that is more heat conductive. Or maybe it is possible to make new openings in the cardboard and put something more conductive to heat?

or add a trimmer and pump less heat in the system

brubei - 26-5-2020 at 12:46

common yahurt cooker have a heat temperature around 40°C

khourygeo77 - 29-5-2020 at 01:00

Quote: Originally posted by Ubya

Quote: Originally posted by khourygeo77

or add a trimmer and pump less heat in the system

Thanks. I have a last question. A 50W spot installed on a 150W thermo socket can last for a long time if not turned off?
I brought a backup lamp to switch 1 lamp every 12hrs, but I may go on a vacation for about 2 weeks and may not manage to switch them..

beerwiz - 29-5-2020 at 01:12

I would use a vacuum oven similar to this one in the picture, it can maintain the preset temperature for months or years on end. I bought a similar one brand new with shipping for $500.

But remember, what takes years to do, can be cut down to months, what takes months, can be cut down to weeks, what takes weeks, down to days, what takes days, down to a few hours, etc ad infinitum.

[Edited on 29-5-2020 by beerwiz]

pneumatician - 14-6-2020 at 14:52

I use this:

https://www.theimagingwarehouse.com/ProductGrp/Novatronic-su...

or this more acurate?

https://www.theimagingwarehouse.com/ProductGrp/Protronic-Hea...