universal terrarium energy-saving with peltier cell

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this is my new project of universal terrarium.

I want to share my very positive experience with the construction of multi-purpose terrarium, all controlled by electronic thermostat.

For the refrigerant I used a Peltier cell, for the warm part, we used a heating cable.

For the walls of the terrarium I used extruded polystyrene panels and front with double sheet of plexiglass.

I will update the topic step by step, to be lighter on the initial topic.


My project schema :









cooling assembly diagram 



A) tank with pump

B) water cooler

C) cooling fan

D) rubber tube

E) Peltier cell block: peltier + heatsink + water block

F) internal fan

G) double glazing plexiglass

H) polystyrene slab


Edited by Prompt
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Sounds like an interesting setup. I don't think I would use the phrase energy-saving with regards to Peltier thermoelectric cooling though. From recollection they are approximately 1/4 the efficiency of a conventional compressor refrigerator.

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Peltier cells if properly dissipated, have an efficiency of 50-60%, this means that approximately 40-50% of the energy consumed is wasted. Now do not know the efficiency of a compressor type that used in refrigerators.

The term energy savings, refers to the entire realization of the terrarium and not to the single cell Peltier.

With 80 watts of consumption can refrigerate well a terrarium of 90 liters, reducing the temperature by more than 9 degrees Celsius, the equivalent of less than one watt per liter.

To make understandable my project, I put the measurements done and reported on the graph.


cool system






Warm system



By analyzing the performance of the chart, and taking as reference a range of 2 degrees, we can easily derive the phases on and off. Taking the reference of 17.5 degrees we can see the cooling phase that lasts about 40 minutes and the resting phase of 5 minutes. Certainly a compressor refrigerator with gas is more efficient, but also more noisy and cumbersome, not to mention the installation and the cost.

However, my project is based on obtaining the maximum energy savings by using an electronic solid-state, with the least possible noise .

Edited by Prompt
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  • 3 weeks later...

Zoom view internal cool system, group: peltier (hidden from polystyrene panel), heatsink, silent fan, basket lock (red element).

The polystyrene panel is covered by an adhesive sheet mirror




Large view in terrarium, group: peltier, heatsink, silent fan






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Here is the cool devices, since the outer side, the components are all of the highest quality, this choice allows you to have a background noise imperceptible and flawless operation.

The choice of components was long and laborious, the cost of the components is not negligible, around 150 euro. 

Consumption when turned on is about 80 watts and if the terrarium is well insulated it is possible to determine the power consumption per liter, for this project is approximately 0.89 watts per liter.





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  • 2 weeks later...

Hello Gubbtjuven,


For the thermostat, follow the link:




I connected the thermostat on the green wire (power) of the power supply, see figure: 
When the green wire is connected to ground, the power supply is turned on, when the green wire is disconnected from the ground, the power supply shuts down.
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