On the majority of hydronic heating radiators we install thermostatic valves. These valves automatically adjust the heat of the panel to the temperature you select. So you could have the study at 21 deg, bed 1 and 19 deg and so forth…
The other interesting thing with this picture is the flow and return pipes are on the same side of the panel. Access under the floor was not possible and the client was happy to have the pipes come through the wall. So the hot water enters from the top of the panel (which has the thermostatic valve) and the water then returns to the system out the bottom – simple!
