Evaluation of earth-to-air heat exchangers with a standardised method to calculate energy efficiency

In designing an earth-to-air heat exchanger (EAHX), a decision on design goals has to be made. If the air flow is given by the ventilation system and the construction site is known, the question is: is it more important to achieve a high specific energy performance based on the surface area of an EAHX, a high adoption of air temperature to ground temperature or a very small pressure loss? This paper deals with the performance of three EAHXs for mid European office buildings in service, with the aim of characterising their efficiency. A general method to compare EAHXs in operation will be introduced. First, the temperature behaviour is described by plots over time and characteristic lines, and compared by standardised duration curves. Second, the energy gain is illustrated by standardised graphs. Third, a parametric model is used to provide general efficiency criteria. Thermal efficiency should be defined by both the dynamic temperature behaviour and energy performance.

[1]  D. N. Asimakopoulos,et al.  Modelling the thermal performance of earth-to-air heat exchangers , 1994 .

[2]  G. Mihalakakou,et al.  The influence of different ground covers on the heating potential of earth-to-air heat exchangers , 1996 .

[3]  G. Mihalakakou,et al.  On the coupling of thermostatically controlled buildings with ground and night ventilation passive dissipation techniques , 1997 .

[4]  G. Mihalakakou,et al.  On estimating soil surface temperature profiles , 2002 .

[5]  D. N. Asimakopoulos,et al.  Parametric prediction of the buried pipes cooling potential for passive cooling applications , 1995 .

[6]  Athanassios A. Argiriou,et al.  Analysis of the accuracy and sensitivity of eight models to predict the performance of earth-to-air heat exchangers , 1992 .

[7]  Miroslav Bojic,et al.  Numerical simulation, technical and economic evaluation of air-to-earth heat exchanger coupled to a building , 1997 .

[8]  G. Mihalakakou,et al.  On the heating potential of a single buried pipe using deterministic and intelligent techniques , 2003 .

[9]  Luftleitungs-Erdwärmeübertrager: Grundlegendes zum Betrieb , 1999 .

[10]  G. Mihalakakou,et al.  On the heating potential of buried pipes techniques — application in Ireland , 1996 .

[11]  George Papadakis,et al.  Energy from a two-pipe, earth-to-air heat exchanger , 1999 .

[12]  M. Evers,et al.  Simulation und Optimierung von Luftleitungs-Erdwärmeübertragern , 1999 .

[13]  G. Mihalakakou,et al.  On the application of the energy balance equation to predict ground temperature profiles , 1997 .

[14]  OFTHERMOFORMINGM. K. Warby,et al.  Numerical simulation , 1990 .

[15]  Pierre Hollmuller,et al.  Cooling and preheating with buried pipe systems: monitoring, simulation and economic aspects , 2001 .

[16]  Arnold Janssens,et al.  Thermo-hydraulic design of earth-air heat exchangers , 2003 .