> If you cycle between 45 C and 55 C water temperature (as mentioned by the press release), you are only getting a 10 C delta.
You are calculating the wrong delta T. To heat a space, you need your working fluid to be warmer that the space you’re heating by an appropriate amount.
55°C is certainly on the cool side to heat a building, but it’s entirely workable with a high-area, highish-thermal-conductivity system. Here’s an actual chart:
https://www.warmboard.com/wp-content/uploads/2022/04/WaterTe...
You don’t actually want an absurdly warm floor.
Even for buildings that need warmer fluid, water at 45-55°C is a fantastic source for a heat pump.
55 C might be enough to heat buildings but it's right on the edge where domestic hot water needs to be to kill Legionella. So traditional DH systems need to run hotter.
There low-temp/cold DH systems out there that rely on heatpumps in the buildings to extract the heat. Less losses in the network and you can even use them for cooling, but needs heat pumps everywhere.
In comparison, a traditional heat exhanger is pretty simple technology; just a hunk of metal with a valve.