Air-soil heat exchangers for heating and cooling of buildings: Design guidelines, potentials and constraints, system integration and global energy balance

Air-soil heat exchangers for heating and cooling of buildings are analyzed under various aspects. Based on the analytically resolved case of a constant airflow subject to sinusoidal temperature input, we start by deriving climate independent design guidelines, for dampening of the daily and/or the yearly temperature oscillation. In a second step, constraints and potential of buried pipe systems are analyzed for the case of a typical Central European climate, for which the constraint between climate and comfort threshold induces a fundamental asymmetry between preheating and cooling potential. Finally, it is shown that the net yield of an air-soil heat exchanger has to take into account more than the mere input-output temperature differential.