A study of the benefits of including thermal energy stores in district heating networks

Abstract

A model to simulate district heating networks (DHN) was applied to a hypothetical DHN in Loughborough, UK. The model includes different thermal energy storage (TES) systems: i) short-term water-based stores and phase-change material-based stores and ii) a seasonal thermal energy storage (STES) system. Heat pumps (HP) and evacuated-tube solar thermal collectors (ETSTC) are considered to both provide heat for dwellings and charge the TES systems. The model assumes that the HPs can only be used to charge TES at those times when the electricity is produced by zero-carbon sources. To assess this real CO2 emissions data per kWh of electricity produced in UK was used. The effect of both 1) the STES volume and 2) the half-hourly maximum amount of zero-emissions electricity available to charge TES on a) cost, b) efficiency and c) CO2 emissions was studied. The results showed that CO2 emissions and electricity cost can be reduced to 83.4 % and 12.3 %, respectively, using TES, when comparing with the scenario with no TES. Savings of 41.7 % can be achieved when comparing the cost of electricity used in the proposed DHN with TES with the current cost of the gas.