Hi I deal with power electrical not so much electronics as much.

I am looking to make a device that would serve as a cooling source for an air pumped device. Likely it would be a thermoelectric generator in a small collection chamber, and a fan forcing the cold air out into a 1/2"-3/4" ID hose. I would want it to cool to a temperature I could set to between 50F and 70F when placed in a normal room that may be 65F to 75F. I have several questions:

- How difficult would it be go get just 1 (not 1000) regulator units that could do this? I'm looking for something where I could set the desired output air temperature, and the voltage the the thermo generator would be gradually stepped up or down until the desired air temperature is met.
- If I put 2 thermoelectric generators in series, with one in the cold air collection chamber and the other outside of it, would this make one of them be the hot source and the other the cold source? If not how do you keep the cold and hot sides of the thermo units from cancelling each other out in a scenario like this?

Is this something that already exists? I was looking at beer tower coolers but I think those are way too cold and likely do not have an adjustable setting.

 

You could likely use Peltier Plate Modules. You make no mention of your desired set point temperature(s)? Keep in mind that Peltier cooling uses quite a bit of current to make cold. You will have to design your fixturing. As to control? There are plenty of inexpensive off the boat PID controllers available.


Ron

 

You make no mention of your desired set point temperature(s)?

Hi thanks. I would want it to cool to a temperature I could set to between 50F and 70F when placed in a normal room that may be 65F to 75F.

 

Hi thanks. I would want it to cool to a temperature I could set to between 50F and 70F when placed in a normal room that may be 65F to 75F.

That should be easy enough as you aren't removing much heat from ambient air. I would likely go with Peltier and use a MOSFET for the switching. You can either build or buy an off the shelf controller.

Ron

 

Hi thanks. I would want it to cool to a temperature I could set to between 50F and 70F when placed in a normal room that may be 65F to 75F.

Cooling to 50°F with 75°F ambient requires a 25F° ∆T across the cooling module. That's not trivial and might require two stages. You'll have to look at the specs carefully.

The ∆T across a module depends on supplied current and is limited by the current capacity of the module. That cited maximum current assumes nearly perfect heat exchange, so a good heat sink and forced air. If you have less-than-perfect conditions, the module is at risk of overheating if run to capacity.

All the power supplied to the module, plus the heat moved from the cold side to the hot side, appear on the hot side and must be shed.

 

Is the air flow constant or does it change? If it changes, this is not an easy task. Doubling the airflow would require more than doubling the ΔT. If it changes rapidly, I see no easy way to maintain a constant output temperature.

 

1) How are you planning to stop room heat being replenished from outside the room, e.g. when people go in and out of doorways?
2) I think you'll find a 3/4" diameter tube will have much too great a flow resistance. Most ventilation systems use large cross-section ducts.
3) Have you calculated an energy budget? A room say 3m x 5m x 4m has a volume of 60cu m and the air in it weighs about 60kg. That will need considerable energy to cool it, especially if a door opens frequently.

 

1) How are you planning to stop room heat being replenished from outside the room, e.g. when people go in and out of doorways?
2) I think you'll find a 3/4" diameter tube will have much too great a flow resistance. Most ventilation systems use large cross-section ducts.
3) Have you calculated an energy budget? A room say 3m x 5m x 4m has a volume of 60cu m and the air in it weighs about 60kg. That will need considerable energy to cool it, especially if a door opens frequently.

Hi I’m only wanting to blow a small amount of cool air on something. I’m not attempting to cool an entire room.

 

It might be far simpler to run a tube through a bucket of ice water - or other cold reservoir - and then blend with ambient air if you need to produce air at a specific temperature.

 

Generally speaking, the Peltier may not be cooled with an air in no respect how large is the cooler radiator. The cause is extra high power flux density W/mm2. However there is a certain gap where one may try to squeeze into, that is large sized PC videochart boosted type supercooler or other wording heatpipe. My experience with the 40x40 mm platelet shows the 20x20x20 cm heatpipe with four fans is just just but enough to catch a -40 C 20 W at hot desert obstacles. Normally Peltier is considered be cooled by a water.

 

There are also cooler devices that consume compressed air and produce a stream of cooler air and a stream of much warmer air. Often called "vortex coolers" or even "Hilsch-tube" coolers. They are frequently used for cooling electrical control cabinets, and in locations with explosive fumes, because they are safe.

 

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A conventional mini fridge might be the best choice. They're more efficient, can maintain near-freezing temperatures even in a 90 degree F room, plus you can keep beverages in it.

 

Hi I deal with power electrical not so much electronics as much.

I am looking to make a device that would serve as a cooling source for an air pumped device. Likely it would be a thermoelectric generator in a small collection chamber, and a fan forcing the cold air out into a 1/2"-3/4" ID hose. I would want it to cool to a temperature I could set to between 50F and 70F when placed in a normal room that may be 65F to 75F. I have several questions:

- How difficult would it be go get just 1 (not 1000) regulator units that could do this? I'm looking for something where I could set the desired output air temperature, and the voltage the the thermo generator would be gradually stepped up or down until the desired air temperature is met.
- If I put 2 thermoelectric generators in series, with one in the cold air collection chamber and the other outside of it, would this make one of them be the hot source and the other the cold source? If not how do you keep the cold and hot sides of the thermo units from cancelling each other out in a scenario like this?

Is this something that already exists? I was looking at beer tower coolers but I think those are way too cold and likely do not have an adjustable setting.

Hi J,
From what I remember, the ground temperature just below the surface where I live is more or less a constant 50Deg. Could you heat exchange from a ground source?
C.

 

At this point it becomes clear that whatever the application is, nine of the responses are easily applicable.
Holding a constant temperature of an unknown something, which may, or not, produce heat as it functions, while in an environment with a varying temperature, is not so very simple, because it may require either heating or cooling.
It seems that the item to have the temperature held constant may not be insulated from the ambient temperature, which makes any control more complex.
So is it possible for the TS to supply more information about the details of the application????