Is it worth to try making peltier based refrigerator?
It would be worth while to try and reduce the temperature of the hot side.  The biggest heat leak into your fridge is going to be through the TEC.  The hotter it is the more heat it leaks.. and the more it has to work to get that heat back out.    The "classic" mistake with TEC coolers is to make the hot side heat sink too small the first time. (Welcome to the club :^)