I'm designing a beer fridge that's built into a cabinet, I plan to line the cabinet with an insulating foam and pass a thermoelectric cooler through a hole in the foam.
To calculate the required cooling load do I just take the K value for the foam, multiply it by the surface area, thickness and required temperature gradient and then pick a cooler that offers at least that wattage at the required temperature gradient or is it more complicated? I'm not looking to exactly calculate the maximum temperature differential achievable, I just want to get an idea of the required cooling power to give a minimum required cooling wattage.
>>995396
>thickness
*divide by the thickness
You might as well rip the guts out of a bar fridge. Using peltier devices is incredibly inefficient and you will end up with something that doesn't cool stuff very well while spending a fortune on electricity.
>>995404
Fair enough, but is the calculation method for required cooling power valid?
>>995396
>Designing a cooler from scratch
God damn dude are you trying to summon HVACaholic?!
>>995431
That might well be helpful, is he the equivalent to Oppenheimer on /k/? Basically, my question is, is the thermal conductivity information on all the walls of a cooled enclosure enough to calculate the required cooling power to maintain a specific internal/external temperature gradient?
>>995443
Yes, no, kind of.
Using the insulator R value and desired temp gradient between inside and outside you can calculate the heat gain and choose a cooler to counteract it... BUT that is based on the assumption of a perfectly sealed system and doesn't take practical factors into consideration. In reality air will leak in from cracks, people will open the door, fresh drinks will be added and the minimum load cooler will take forever to cool the new drinks.
A better starting point would be to set a desired time to cool an entire fridge full of new drinks and calculate the cooling load for that. To keep things simple you can ignore the heat transfer rate from the drinks to the glass bottles, glass bottles to the air etc. and assume the cooler is embedded in the beer with perfect heat transfer.
Calculate how many beers your fridge can hold, calculate the total volume of that beer, calculate the energy that must be removed using the specific heat and the temperature difference from hot to cold, divide that energy by your desired cooling time to get cooling power and multiply by an efficiency factor like 1.25 to account for the little details you skipped over.
>>995459
Thank you, spherical cow * fudge factor is fine by me. I'll do some separate calculations for beer cooling time, pick something acceptable and heap it on top of gradient maintenance.
