Heating Options for 500L Vat

[LakeThomas]

Hi guys, I am about to take the plunge on a 500L vat that I am having made local to me. Everything is pretty much set with the design but my only concern is the heating. Unfortunately I do not have a three phase electricity supply and will not be able to get one. My plan was to purchase a tankless gas geyser that is capable of a maximum output temperature of 85C (185F) and use that to circulate water through the jacket with a circulating pump and a small reservoir tank. In the past I have only made raw milk cheeses but would like the option of pasteurising in the vat, do you think that will be possible in a reasonable time frame? The vat does have a lid and agitator but is double, not triple skinned.

Really appreciate any input!

[mikekchar]

To raise 1 kg of water 1 degree C takes about 4 kJ of energy.  Let's assume your jacket is 100% efficient (so all of the energy in the jacket is transferred to the milk).  Let's say (to keep the math simple) that you need to raise the temp of the vat 50 degrees C.  That means you need 200 kJ per kg.  For 500 L, that's about 100,000 kJ. Let's say you want to raise the temp in about 30 minutes (half an hour), which means you need 200,000 kJ/h of heat.  A kJ/h is very clost to a BTU/h.  That will give you the absolute minimum rating you're going to need.  I don't know how well the exchange will work or how big a reservoir you're going to need.  All of the similar equipment I'm familiar with is steam jacketed (brewing equipment), so I'm not exactly sure...