Heat exchanger measurements in a mass flow controlled consumer substation connected to a ring network

The contribution of this paper is to demonstrate experimentally the feasibility of a novel district heating (DH) system that uses a new low-temperature technology based on ring network topology and a mass flow control system. The study is based on several previous works: a theoretical approach to the new concept, an optimization case study and a simulation of a heat exchanger in a consumer substation. The central part of the work is the analysis of a laboratory-scale system with the purpose of proving the usability of the new technology. Series of experimental measurements were conducted with the aid of a simulation model, getting a mean heat exchanger effectiveness of 0.88 as a result. Additionally, non-linear supply and return temperature curves were obtained, which implies higher temperature difference (ΔT) and lower return temperatures. Furthermore, the new mass flow control enables equal flow rates on both sides of the heat exchanger, which improves the heat transfer and allows lower flow rates. These improvements led to the main findings of the research: substantial increase of the overall system efficiency and important savings in operational costs.