AN ELEMENTARY APPROACH TO EVALUATING THE THERMAL SELF-SUFFICIENCY OF RESIDENTIAL BUILDINGS WITH THERMAL ENERGY STORAGE

Abstract

Thermal energy storage (TES) plays a pivotal role in integrating renewable energy. Nevertheless, there are major challenges in the diffusion of TES such as selection of the optimum system size, system integration, and optimization. A key target for using TES is to increase the thermal self-sufficiency of a building or an entire district. Thermal self-sufficiency, unlike total energy self-sufficiency, concerns heating exclusively. Thus, thermal self-sufficiency measures the ability of a system to meet its heating demand from local renewable energy sources. Thermal self-sufficiency is an important metric for practitioners and researchers in the design, optimization, and evaluation of energy systems, especially when considering TES. Unfortunately, no comprehensive method exists in literature for determining thermal self-sufficiency with TES. Energy profiles and simulations are required to determine thermal self-sufficiency. This article aims to close this gap and presents a new method for evaluating thermal self-sufficiency for a building with a TES. Using this approach, the upper and lower limits of the building thermal self-sufficiency are derived for various heat storage capacities and annual heat demands, demonstrating the impact of a TES on the system. In addition, the approach is largely technology agnostic. The new approach helps to quantify the effects of integrating TES on the share of renewable energies and the degree of self-sufficiency that can be achieved, thereby supporting the design of efficient heating/energy systems.