How small can an inverter air conditioner be?

Question

I am making a small temperature controlled environment in a 35x35x16cm plastic box. The ambient temperature of the room will be around 25° C, but I want to see how my electronics behave/shift their outputs on a range of 25° C to 35°C, maybe 40° C tops.

I already have a hotplate and a heater controller PCB for the project, so I can heat the box to the temperatures I want.

As a bonus for my project and outside of my requirements, I would like to cool it a bit below 25° C, maybe 20° C minimum.

I was wondering what would be the easiest and most silent way to achieve this. One idea is to use Peltiers, but thinking about alternatives, I am wondering how small an inverter for such a small space could be. The, I started looking for similar solutions on the web.

I found these products:

ACT-HSC-22 HEAT SINK COOLER

ACT-HPC-15 HEAT PIPE COOLER

ACT-TEC-90 (90 WATT THERMOELECTRIC COOLER)

I wonder what the technology is behind such coolers. They are labeled as "Heat sink cooler", "Heat pipe cooler" and "Thermoelectric cooler."

From what I understand:

1. Thermoelectric cooler uses a Peltier.
2. Heat sink cooler cannot cool below the ambient temperature because it just heats the heatsink from the inside of the device and cools it down by sucking that heat to the outside.
3. I do not understand what a heat pipe cooler is. Is it a heatsink cooler, but the heatsink fins also have heat pipes like in some PC heatsinks?

Questions (in the concept of bringing temperature from 25° C to ~20° C):

• Are some of them, or are any small factor heat exchangers (I'm talking about maybe 15x15x15cm sizes,) or there are only Peltier ones?
• What is the determinantal factor of the size of a small inverter? From what I understand I believe it is the compressor.
• What is a heat pipe cooler?

Answer 1

Do you understand how a heat pipe works? By itself, all it does is transfer heat from one place to another by making use of the heat gained and released by the phase change in the working medium - the refrigerant. Think of a heat pipe as like an AC or refrigerator (although a heat pipe cannot cool below the ambient, as   user253751 pointed out), only without the compressor.

So to be an effective cooler, you have to 1) attach the heat source to the heat pipe at the proper end and 2) attach the other end of the heat pipe to a radiating, convection, or conductive cooled surface.

If you do an internet search for "heat pipe", you'll find lots of information on how they work.

A couple of more things. Some heat pipes need to be oriented in a particular manner in order for them to work in a gravity (earth's surface) application. Other types that are designed for zero-g (space) applications do not care about orientation. And heat pipes are very popular in satellite and other space applications because they, since they contain no moving parts, are extremely reliable.