A Methodological Framework for Calculating the Levelized Cost of Heat for Solar Thermal Applications in Residential Buildings
Abstract
The levelized cost of heat (LCoH) is becoming an important economic metric for economic assessment of heating systems in the thermal engineering literature. Yet published values are hardly comparable because studies adopt different – and often implicit – system boundaries for both energy and costs. This paper reports about a methodological framework that resolves this deficiency for heating systems in residential buildings. Starting from the energy balance defined in building standards, boundaries for the reference energy are identified along the supply chain, from primary energy to end-use heat demand. Similarly, four nested “levels of analysis” are specified for costs. As a result of the investigations, a nomenclature is proposed to differentiate the LCoH values from each other. The influence of boundary choices is illustrated with an example, with the heat supply of a multi-family house as application. Depending on the selected boundaries, the ranking of the technical solutions compared can reverse, and absolute LCoH values vary significantly. The study therefore recommends (i) adopting heat demand as the default reference energy, (ii) selecting the level ofES of analysis that captures only those components that differ between technical solutions, and (iii) reporting the chosen boundaries explicitly using the proposed nomenclature. The framework lays the foundation for harmonised techno-economic assessments within the wider scientific community.
Keywords
Solar thermal systems, Levelized cost of heat, Domestic applications