The design of a field of geothermal probes coupled to a heat pump of the water/water type supporting the air conditioning plant of the Rectory of the University of Calabria, is presented. The convenience of a geothermal plant is linked to the prevailing weather conditions, i.e. it is of greater benefit when the location temperatures are harsh. Although the location of the installation is not characterized by a very low project external temperature (-3.2 °C), the heat exchange gradient generated in both Cooling seasons is enough at the ground to carry out the task of a hot/cold well. For the sizing of geothermal heat pump systems, reference is made to the UNI 11466: 2012 and ASHRAE recommendations. The water/water heat pumps are designed for specific values of the outlet water and in return reaching COP values next to 4.4. Their coupling with a properly sized SGV system keeps the value of the COP constant for the entire cooling season. By sizing performed for the object of the case study, the building was achieved with a total length of variable probes between 4200 m and 4800 m according to the theorized wheelbase. Taking into consideration the cost items and the long-term system performance, it can be said that the optimal solution is the use of 28 probes each 150 m in length. This result was later validated by the simulations conducted with the TRNSYS software from which was found a water return temperature to the HPs always below the 30 °C required, resulting in further improvement of performance of the machine. In the paper we present the calculation results according to the standards and their comparison with those obtained with the TRNSYS 17 software.
PERFORMANCE OF A FIELD OF GEOTHERMAL PROBES TO SUPPORT THE AIR CONDITIONING PLANT OF A PUBLIC BUILDING POWERED BY WATER/WATER HEAT PUMPS
CUCUMO, Mario Antonio;FERRARO V.;KALIAKATSOS D.;
2016-01-01
Abstract
The design of a field of geothermal probes coupled to a heat pump of the water/water type supporting the air conditioning plant of the Rectory of the University of Calabria, is presented. The convenience of a geothermal plant is linked to the prevailing weather conditions, i.e. it is of greater benefit when the location temperatures are harsh. Although the location of the installation is not characterized by a very low project external temperature (-3.2 °C), the heat exchange gradient generated in both Cooling seasons is enough at the ground to carry out the task of a hot/cold well. For the sizing of geothermal heat pump systems, reference is made to the UNI 11466: 2012 and ASHRAE recommendations. The water/water heat pumps are designed for specific values of the outlet water and in return reaching COP values next to 4.4. Their coupling with a properly sized SGV system keeps the value of the COP constant for the entire cooling season. By sizing performed for the object of the case study, the building was achieved with a total length of variable probes between 4200 m and 4800 m according to the theorized wheelbase. Taking into consideration the cost items and the long-term system performance, it can be said that the optimal solution is the use of 28 probes each 150 m in length. This result was later validated by the simulations conducted with the TRNSYS software from which was found a water return temperature to the HPs always below the 30 °C required, resulting in further improvement of performance of the machine. In the paper we present the calculation results according to the standards and their comparison with those obtained with the TRNSYS 17 software.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
