I need to asses the power (W/m2) entering an concrete structure from the ground surrounding it. But I don't know exactly which of the rate resulted I need to check. Using masking domain (Subdomain Boundary Rate Budget) is it the correct way of assessing it (see the picture)?

I am studying moulded walls equipped with pipes through which a fluid circulates in order to transform the moulded walls into heat exchangers that supply a heat pump. The pipes are caught to the reinforcement cage. However, in the numerical model, I replace the physical pipes with nodes acting like a source or sink of heat. The power set at the nodes represents the power demand during a season (by example 5 W/node in the hottest day of summer). I need to find out how much of the energy can be exchanged with the ground and how much of it is lost within the concrete and the excavation.