Simulated Performance of Earthtube for Cooling of Office Buildings in the Southeast of UK

Using the ground-air heat exchanger to reduce the temperature fluctuations of the outdoor air supply to a building is a potential sustainable low carbon emissions building design option where suitable site conditions exist. Although the basic concept of this technology is simple and some thermal models already exist, there is no integrated design tool or published data that can be used directly to predict their dynamic thermal performance. This research reviewed the current state of the art on the thermal models of earthtubes and thermal performance prediction tools. Available soil temperature profiles and earthtube thermal models were evaluated, selected and adopted in component based dynamic thermal simulation software Transient System Simulation Environment (TRNSYS). A system network representing the configuration of a proposed system can be establish which enables parametric and system study of the dynamic thermal behaviour. This computer simulation tool was applied to study the application of earthtube to maintain the summer thermal comfort of an office located at the southeast of UK. The results showed an optimized system configuration with the appropriate pipe diameter, pipe length and airflow rates are necessary to maintain the comfort conditions in the summer.