Efficient heat engines locally slow entropy increase. If they could reverse entropy, they would (to get more energy out of things). They can also export high entropy (e.g. medium-temperature water) while intaking low entropy (e.g. un-mixed high and low temperature water) to locally reduce entropy. Entropy is waste from the perspective of a heat engine. Likewise, animals intake low-entropy food and excrete high-entropy waste.
Efficient heat engines locally slow entropy increase. If they could reverse entropy, they would (to get more energy out of things). They can also export high entropy (e.g. medium-temperature water) while intaking low entropy (e.g. un-mixed high and low temperature water) to locally reduce entropy. Entropy is waste from the perspective of a heat engine. Likewise, animals intake low-entropy food and excrete high-entropy waste.