A multipurpose test rig for district heating substations: domestic hot water preparation and keep-warm function comparison

Jad Al Koussa,Robbe Salenbien,Rutger Baeten,Nico Robeyn,S.I Tanabe,I Nastase,H Zhang,M.C Gameiro Da Silva,J Kurnitski,P Wargocki,G Cao,L Mazzarela,C Inard

doi:10.1051/e3sconf/201911106012

Abstract

A well performing District Heating Substation (DHS) is crucial for the efficiency of the District Heating (DH), especially with the shift towards low temperature 4th generation DH systems. For this reason, testing and characterization of commercially available DHSs becomes important to estimate their effect on the DH network. Within the thermo-technical laboratory of EnergyVille, a multipurpose test rig has been built for testing DHSs. In this setup, different DH conditions and heat demand profiles for space heating and for Domestic Hot Water (DHW) can be emulated. Independent tests have been performed on 4 DHSs from three different manufacturers, focused on the DHW preparation for low DH supply temperature and on the stand-by/keep-warm operation of the substations. The latter maintains a certain temperature within the heat exchanger to avoid delays in the delivery of DHW. The results showed that improvements are needed on DHW production for lower DH supply temperatures. Also, enhancements are needed to reduce losses from the keep-warm function. Given that DH systems can have thousands of substations, this will reduce the overall losses and improve the performance of the DH network.

Highlights

This paper discussed the development of a multipurpose test rig for testing heating equipment, district heating substations
Tests were performed on 4 different substations having different methods of supplying Space Heating (SH) and Domestic Hot Water (DHW)
The tests focused on the DHW operation and on the stand-by losses of those substations for low temperature district heating systems

Summary

Introduction

With the shift towards lower supply temperatures in DH systems, the role of DHSs becomes of great importance because of their direct influence on the return temperature This temperature should be kept as low as possible to help improving the efficiency of renewable energy sources as well as the technology mix that can be coupled to the network, to help increasing the potential of waste heat by for instance better heat recovery from flue gas condensation, or to help reducing the losses in the district and increasing the capacity [2]. To properly understand the behaviour of such control under operational conditions, characterisation of DHSs becomes vital For this reason, a DHS test rig was developed, and a series of tests were performed on 4 substations from 3 different manufacturers. All the data communication from and to the different sensors is performed through a central Programmable Logic Controller (PLC)

Tests performed

DHW tests

Findings

Conclusions