Conclusions
This study has been focused on the dynamic simulation of an air conditioning system which employs thermal solar flat plate collectors as heat source in a water-lithium bromide vapor absorption chiller , showing an increment of the heating energy gained by using nanofluids ( colloidal dispersion of 3.0 volume % of Al2O3 nanoparticles in bi-distilled water ) as working fluid in the solar thermal field , compared with conventional water based one . It follows that the hot fluid stream headed to the chiller ’ s generator needs a lower external auxiliary heating , to reach the hot inlet temperature of about 85 ° C required by the absorption chiller , which means energy and cost savings .
In June the simulation presents an energy rate deriving from the solar collectors with nanofluids and stored in the tank , increased by about 6.76 %, with a saving of 29.06 % on the auxiliary heating ; in July 6.42 % more stored energy is recorded , with a saving of about 22.10 % on the heater ’ s energy consumption ; in August 7.26 % more stored energy is calculated , with a saving of 17.21 % on the auxiliary heating and in September energy rate increased by 7.79 % with a saving of 14.80 % on the heater ’ s energy consumption .
In conclusion , according to the need to increase the efficiency of renewable energy systems and the general necessity to increase energy savings for a country like Italy which depends in large part by third parties with regard to energy supplies , these results suggest the possibility to use nanofluids in several systems characterized by closed loop working fluids , in order to improve their energy efficiency .
Acknowledgements
This work has been possible thanks to the financial support of the “ Innovasol ” project ( Pon02 _ 00323 _ 3588246 ), funded by the Italian Government .
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