In the industrial sector, medium, low and ultra-low temperature waste heat represents a significant source of energy loss as well as constitutes a harmful environmental effect, which must be avoided. Nonetheless, waste heat could represent a free and vast potential when a technology to recover effectively energy at low temperatures is utilized. In this context, the Organic Rankine Cycle (ORC) technology is a proven solution because, being the working fluid an organic substance with low boiling temperature, it is more suitable than water when low grade heat needs to be recovered. The identification of a working fluid, performing significantly better than the others, is still far from being achieved, due to difficulty in the maximization of the heat transfer from low grade heat sources. To achieve higher heat transfer efficiencies, unconventional working fluids with enhanced thermal properties should also be investigated. Regarding this topic, nanofluids, suspensions of nanoparticles in a base fluid, synthesized intentionally to have enhanced thermal properties, might have the potential to increase ORCs efficiency. This paper presents an in-depth investigation of the applications of an innovative nanofluid, based on a new class of nanoparticles – termed Metal-Organic Heat Carriers (MOHCs) - in the ORC field, developing a numerical model for assessing the nanofluid gain in terms of net power production. In particular, the possible combination of the base fluid R245fa with the nanoparticle MIL101, a robust Metal Organic Heat Carrier, is considered. To properly model the reversible adsorption/desorption process, typical of the MOHC nanoparticles, experimental analyses were carried out for studying the uptake of the R245fa in MIL101 at different operating conditions and, starting from the experimental results, proper semi-empirical correlations were defined and adopted within the numerical model. The resulting performance of the MIL101/R245fa were compared with those of the pure R245fa, whose cycle was optimized in order to maximize the net power output. Promising results were achieved in terms of system efficiency increase and heat exchanger area reduction.

Influence of the Use of a Nanonfluid on Net Power Production in ORCs for Low-grade Waste Heat Recovery Applications

Cavazzini G.
;
Bari S.;Pavesi G.;Ardizzon G.
2019

Abstract

In the industrial sector, medium, low and ultra-low temperature waste heat represents a significant source of energy loss as well as constitutes a harmful environmental effect, which must be avoided. Nonetheless, waste heat could represent a free and vast potential when a technology to recover effectively energy at low temperatures is utilized. In this context, the Organic Rankine Cycle (ORC) technology is a proven solution because, being the working fluid an organic substance with low boiling temperature, it is more suitable than water when low grade heat needs to be recovered. The identification of a working fluid, performing significantly better than the others, is still far from being achieved, due to difficulty in the maximization of the heat transfer from low grade heat sources. To achieve higher heat transfer efficiencies, unconventional working fluids with enhanced thermal properties should also be investigated. Regarding this topic, nanofluids, suspensions of nanoparticles in a base fluid, synthesized intentionally to have enhanced thermal properties, might have the potential to increase ORCs efficiency. This paper presents an in-depth investigation of the applications of an innovative nanofluid, based on a new class of nanoparticles – termed Metal-Organic Heat Carriers (MOHCs) - in the ORC field, developing a numerical model for assessing the nanofluid gain in terms of net power production. In particular, the possible combination of the base fluid R245fa with the nanoparticle MIL101, a robust Metal Organic Heat Carrier, is considered. To properly model the reversible adsorption/desorption process, typical of the MOHC nanoparticles, experimental analyses were carried out for studying the uptake of the R245fa in MIL101 at different operating conditions and, starting from the experimental results, proper semi-empirical correlations were defined and adopted within the numerical model. The resulting performance of the MIL101/R245fa were compared with those of the pure R245fa, whose cycle was optimized in order to maximize the net power output. Promising results were achieved in terms of system efficiency increase and heat exchanger area reduction.
2019
Proceedings of the 5th International Seminar on ORC Power Systems
978-90-9032038-0
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/3309629
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact