I'm running an 1 1/2" Cu. atmospheric pressure heat transfer loop from a eight gallon water pot sitting on my hot wood stove to an eight gallon heat exchanger on the floor. The conducted heat is transferred to upstairs bedrooms by thermostatically controlled zoned forced hydronics (20 psi). Should I have a high or low theta pattern heat exchanger since half is at atmospheric pressure?
I'm a little confused , in your example in side 1 the outlet temperature is 40C, in side 2 the outlet temperature is 50C, the outlet temperature in side 1 shouldn't be higher than the temperature outlet in side 2?
In their example the flow type is set to counter-current. In this case it is possible that side 1 outlet is colder than side 2 outlet. It's explained at 15:28 . Counter-current is way more efficient, that's why there's hardly any application where you want to use co-current flow.