Control device for pumping one-pipe hydronic systems

Abstract

The article presents the development and algorithms behind an active control device for pumping one-pipe (or primary-secondary pumping) systems. The main feature of such a system is the series connection of thermal loads/sources and a small pump by each load/source, as opposed to classical two-pipe systems with a parallel connection and throttling valves. Our main contribution is an integration of all necessary components into one device and the ability to infer mass flow in a secondary circuit without a flowmeter. By also measuring a temperature drop, we can estimate and control a heat flow and provide remote thermal and hydraulic diagnostics of a connected heat terminal via the device. It is powered and communicates through the Ethernet and contains a wet-rotor BLDC pump controlled by the field-oriented control method. A Kalman filter provides a mass flow estimate, and a robust distributed parameter system controller regulates the heat flow.