There are papers that do thermodynamic analysis of similar systems finding something like ~65% efficiency. So 75% might be a bit fluffed up, but not outrageousl

There are papers that do thermodynamic analysis of similar systems finding something like ~65% efficiency. So 75% might be a bit fluffed up, but not outrageously so. E.g. if they can use the waste heat for district heating and count that as useful work.