Including EAHX (earth-to-air heat exchanger) in early-design phases considering local bioclimatic potential and specific technological requirements

Abstract

Horizontal ground systems for ventilative cooling/heating, such as earth-to-air heat exchangers (EAHX), are a valid pre-heating and pre-cooling low-energy techniques to reduce the building energy consumptions for space heating and cooling. Nevertheless, the potential of these systems, such as others passive solutions, is local specific and need for devoted design methodologies. In particular, EAHXs need to be included in the design process as soon as possible in order to maximise the potentiality and allow for their integration – operational, technological and environmental issues. The paper will introduce a design methodology to define the local climatic potential of EAHX since the building programming phase by defining specific boundary conditions in well-known bioclimatic chart instruments. The effect of different design choices will be analysed for a set of three representative Italian locations. Furthermore, main functional, operational and environmental requirements will be discussed for this technical system. This analysis is based on the performance-drive approach to environmental and technological design – see for example UNI 8290-2:1983 – and is hence compatible with the technological-design practice and early-design consolidated methodologies.