How to use the ThermaSize tool?

The ThermaSize tool is used to determine the size of pipe that is necessary in your network. This is done by a calculation and a graph to complement the calculation. The power loss to the surroundings through the insulation (determined in section A and B) can also be calculated (A & B) for your network or part of the network. With the desired power (section C) and the medium temperature drop between flow and return (C), the flow of the system can be determined (section D) and with this flow suggestions for the pipe size are given in (D). These sizes and flow values can be set in the graph (E) to determine the pressure loss of the different sizes. Usually you will have demands on this pressure loss to be within limits. The best choice of pipe size will now become more obvious, usually the smallest size that has acceptable pressure loss. The ThermaSize tool will give you a good way to choose a pipe size and lets you calculate heat loss of the pipe to surroundings.

With the demanded power (that is necessary for all users in your part of the network, including heat losses) for a heating situation and the medium temperature drop (C) between flow and return, the volume flow (F) and the necessary pipe (d) size for flow with appropriate flow speed are calculated with F=P/(4.19*DT).
As an example, in Picture 2: With a desired power of 500 kW and a temperature drop of the medium of 10°C, we get ~11 L/s. At this flow, we could select a pipe size of 110 or 125 mm.

Picture 2