Session: 02-01: Building Energy Efficiency Technologies

Paper Number: 126235

126235 - An Elementary Approach to Evaluating the Thermal Self-Sufficiency of Residential Buildings With Thermal Energy Storage 

Abstract: 

The thermal energy storage (TES) is a corner stone for the global energy transition helping to improve the integration of renewable energy. Nevertheless, there are major challenges in the diffusion of TES such as selection of the optimum system size, system integration, control, and optimization.

A key target for using TES is to increase the thermal self-sufficiency of a building or an entire district. Unlike the usual definition of total energy self-sufficiency, thermal self-sufficiency focuses only on the heating aspect/sector of a system. 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, there is no comprehensive method in the scientific literature for determining thermal self-sufficiency based on annual consumption considering TES. Hourly energy profiles and simulations are required to determine thermal self-sufficiency. This paper aims to fill this gap and presents a new method for determining a generic thermal self-sufficiency equation for a building archetype 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 methodology developed in this study evaluates a building's thermal self-sufficiency, considering its solar energy input, ambient temperature, heat demand, and non-heat related residential electricity consumption. A model calculates different levels of thermal self-sufficiency based on different storage capacities. The obtained values of thermal self-sufficiency with different TES capacities allow the formulation of an analytical function that describes thermal self-sufficiency in terms of storage capacity and heat demand. Within the presented model, a system without heat losses and a system with losses are considered as upper and lower bounds, respectively.

As a demonstration of the functionality of the methodology, this paper applies it to a single-family home. In a further step, the methodology will be applied to a large number of archetypes to find generic dependencies.

Presenting Author: Richard Lüchinger Lucerne University of Applied Sciences and Arts Engineering and Architecture

Presenting Author Biography: Mr. Lüchinger is a research associate at the Competence Center Thermal Energy Storage of the Lucerne University of Applied Sciences and Arts. He holds a master's degree in business engineering and is a PhD student at the Vienna University of Technology at the Institute of Energy Systems and Thermodynamics (IET). He has extensive expertise in energy economics, energy systems modeling, innovation research, responsible research and innovation, systems thinking, technology assessment, and seasonal heat storage development. He is involved in an interdisciplinary project investigating design criteria for seasonal thermal storage systems.

Authors:

Richard Lüchinger Lucerne University of Applied Sciences and Arts Engineering and Architecture
Nuria Duran Adroher Lucerne University of Applied Sciences and Arts Engineering and Architecture
Jörg Worlitschek Lucerne University of Applied Sciences and Arts Engineering and Architecture
Heimo Walter TU Wien
Philipp Schütz Lucerne University of Applied Sciences and Arts Engineering and Architecture