My team is doing a senior project that involves using polymerase chain reaction to analyze DNA. From what we know, most modern thermal cyclers uses the Peltier thermoelectric modules for active heating and cooling. For those who aren't aware, a thermoelectric effect creates a voltage when there is a temperature difference on each side of the involved surface.
Our research indicates that while Peltier thermoelectric modules are simple, accurate and do not involve any moving parts. However, they are very energy inefficient. Most input energy into the thermal cycler is lost as heat.
Our team then tried to propose other alternative methods for active heating and cooling. Below are some of our ideas (heat sink is out of the question).
1.) Cooling the thermal cycler with fan modules, while heating the thermal cycler with wires.
2.) Cooling the thermal cycler with a custom water cooling system (like those used in car engines and computers).
3.) Using a mixture of the fan and water cooling system.
Cost is not the biggest constraint here (although it can be touched upon). Does anyone here have any experience with doing heating and cooling system with electronics? If so, could anyone explain the ups and downs of the methods I've suggested? If there are any better alternatives, please do suggest them so we could do further research. Thanks.
Best Answer
Its not about efficiency, its about choice of application. If I am making an air conditioner of 1000 watts, I will still choose conventional vapor compression ( even though it has thousand times more global warming potential than carbon dioxide itself, and high efficiency thermoelectric materials ZT > 2, are still in development).
But for smaller loads 10 watts, 20 watts, 100 watts etc. ,to actually cool them, or cooling/heating/thermal cycling, thermoelectric systems are better, nor will I get a 20 watts air conditioner in market. The best part about thermoelectric systems is the response time from heating temperature to cooling temperature and vice versa, its very quick in seconds especially in your case, where cooling load is generally small in PCR.
Now, I do not know the response time and what is required in your test, but you should check that whether your above proposed systems will respond quickly to required temperature in the desired time, as you want them.
You can make thermoelectric cooling heating system yourself, its quite simple.