Analysing Thermal Energy Storage in Residential Buildings: Towards Decarbonization of the Heating Sector

Abstract

The majority of Dutch homes currently use natural gas boilers to meet their space heating demand. Changes in this significantly large sector are required to achieve the sustainability goals established by the Paris Agreement. Since most renewable energy sources produce electricity, transitioning residential heating systems might cause problems managing national electricity grids. Furthermore, the intermittent nature of renewable energy sources leads to an imbalance between supply and demand.

These challenges can be overcome by combining different storage techniques. An example of such a technique is the thermal energy buffer developed by Borg, which focuses on single-household use. This thesis looks into the feasibility of such a system by comparing different scenarios for residential heating systems.

Three scenarios were modelled using Simscape. In scenario I, a natural gas boiler provided all the heating demand of the house. In scenario II, the heating system consisted of Photovoltaic Thermal (PVT) panels and the thermal energy buffer. In scenario III, the house was heated by PVT panels, the thermal energy buffer, and a heat pump. In all scenarios, the same house was connected to the heating system.

In scenario II, the system sizes were 0, 1, 2, and 3 PVT panels, combined with buffer capacities of 0, 2, 4, and 6 m3. In scenario III, the system sizes were: 3 PVT panels with 6 m3 buffer capacity, 1 PVT panel with 4 m3 buffer capacity, and 3 PVT panels with 2 m3 buffer capacity.

The total yearly heat consumption of the modelled house was 5109 kWh. In scenario I, 378 kg of CO2 was emitted. In scenario II, CO\textsubscript{2} emissions were highly dependent on the sizing of the PVT system and the TESS and ranged from 20 to 405 kg, based on a heating demand of 9444 kWh.

Scenarios I and III maintained a comfortable temperature during the entire year. The heating system of scenario II was insufficient to heat the house throughout the year for all modelled system sizes; however, the scenario could be acceptable with larger PVT and TESS sizing. By comparing CO2 emissions and payback time, the optimal capacity of the thermal energy buffer was found to be 6 m3.

The uncertainty of the future gas price causes a challenge in comparing the cost of electrified heating systems to traditional heating systems. Additionally, it underlines the necessity of decarbonizing residential heating systems to secure comfortable, affordable housing.