The first thing I thought of: The Hardcore Coffee Machine https://www.youtube.com/watch?v=i5OYQOyceoM

Second thing was:

Dutch startup BlueHeart Energy is testing its thermoacoustic heat pump engine in residential settings, with a limited European launch expected in spring 2027, followed by gradual scaling. The system uses sound waves instead of refrigerants, aiming for quiet, flexible, low-maintenance heating suited especially for retrofits and renewable integration.

https://www.pv-magazine.com/2026/04/23/thermoacoustic-heat-pumps-on-the-verge-of-commercial-breakthrough/

But back to the original article:

Saving up to 75% of energy by not heating the water is a minor benefit for home users or small coffee shops. But for companies making ready-to-drink coffee products at industrial scale, it could be very significant indeed.

I was going to say that my coffee machine runs off solar/battery so no use here but I'm certain a good majority of coffee shops are not running on solar or solar battery and this would be amazing

Here's hoping they can commercialise it