Thermostatic valves are common in institutional water heating installations. There are also quite a few people who use thermal storage with wood fired boilers.

Thermostatic valves are common in institutional water heating installations. There are also quite a few people who use thermal storage with wood fired boilers. The boilers burn the most efficient and cleanest when they are near full output, then hot water is stored in an insulated tank to intermittently supply the house with heat. Description of one such system: https://www.newhorizoncorp.com/PDF/ekomanual.pdf https://www.newhorizoncorp.com/PDF/ekomanual.pdf