i am using a petlier module to heat or cool bevrages in a water bottle using arduino nano
i need a idea whether to use a h brige or mosfet to reverse the polarity to heat or cool the water according to the user preferences
it could be useful if there is any circuit reference and iam new to electronics as its my first project without any knowledge pls guide me through it

 

If you have only a single power source then to have both directions of heat transport you will need to effectively have an "H" bridge of some form to apply either polarity to the Peltier Junction device, unless you choose to have a manual switch to select heating or cooling.
Really, using a manual switch to select will offer a big improvement in efficiency and quite a reduction in cost and complexity. Beverage applications in particular seldom need both heating and cooling and so that should work very well.

 

I built a small warmer/cooler for my shop, at first I considered using the TECs for dual use but after some careful consideration I decided to use a couple of 90-watt TECs overhead and power resistors below.