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Articolo RSE 14009433

Technical and economic analysis of two existing installations in the caloregeotermica pump, through the use of qualified calculation tools


AICARR Journal, vol. 6, pp. 38-42, Aprile-2015.

A. Capozza (RSE SpA) , M. De Carli (Università degli Studi di Padova), A. Zarrella (Università degli Studi di Padova)

SMART CITIES 2015 - Smart cities e smart communities

In order to ensure a high energy efficiency of geothermal heat pumps over the years, it should be analysed the persistence of a balance between heat and cooling load to the ground. The present memory shows two examples of such analyses, applied to existing systems, designated as office buildings and laboratory, sites in Padua and Bergamo. Results were performed by using two integrated simulation programs LENGTH and CARM, developed by RSE in collaboration with University of Padua (DII).

A key issue connected to ground source heat pump systems is to assure these high energy efficiency featuresthrough the years. To this purpose, multi-year analyses are fundamental in order to evaluate the seasonaloscillations of the ground temperature and their possible drift in long-term.Unluckily, a very limited number of results in real cases are profitably available. This paper is aimed atovercoming this drawback. Seasonal and long-term computer simulations are conducted in order toinvestigate the thermal performance of two Italian office buildings with unbalanced load profile.

The workfocuses the evaluation of the ground thermal drift, substantially due to the imbalance of the building loadprofile. The analysis was carried out with a detailed numerical model, which was also compared with two analyticalapproaches available in literature.

The effects on the seasonal oscillations and on the thermal drift wereinvestigated of the rebalancing of the ground load profile and of an increase of the number of boreholes. Theresults showed that rebalancing the ratio between the heat extracted from and injected into the ground bringsto the best results from the energetic viewpoint. Moreover, this action is also expected to comply withrequirement finalized to economic optimization.