The installation of Smart Valves in so-called 'single-pipe loop' systems is not recommended.
It is basically a single pipe that connects all radiators and, as Smart Valves act independently on each radiator, when the first valve is closed all radiators downstream of the first radiator would remain cold.
The installation of Smart Valves in traditional systems with manifolds and 'single-pipe with bypass’ valves, on the other hand, presents no obstacles.