2019
Cavazzini, Giovanna; Bari, Serena; Benedetti, Vittoria; Mcgrail, Peter; Pavesi, Giorgio; Ardizzon, Guido
Influence of the Use of an Innovative Nanofluid on Net Power Production in ORCs for low grade waste heat recovery applications Proceedings Article
In: 5th International Seminar on ORC power Systems, pp. 1-8, 2019.
Abstract | BibTeX | Tags: Nanofluid, ORC, Waste heat recovery
@inproceedings{Cavazzini2019a,
title = {Influence of the Use of an Innovative Nanofluid on Net Power Production in ORCs for low grade waste heat recovery applications},
author = {Giovanna Cavazzini and Serena Bari and Vittoria Benedetti and Peter Mcgrail and Giorgio Pavesi and Guido Ardizzon},
year = {2019},
date = {2019-01-01},
booktitle = {5th International Seminar on ORC power Systems},
pages = {1-8},
abstract = {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.},
keywords = {Nanofluid, ORC, Waste heat recovery},
pubstate = {published},
tppubtype = {inproceedings}
}
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.
2015
Cavazzini, Giovanna; Toso, Paolo Dal
Techno-economic feasibility study of the integration of a commercial small-scale ORC in a real case study Journal Article
In: Energy Conversion and Management, vol. 99, pp. 161-175, 2015, ISSN: 01968904.
Abstract | Links | BibTeX | Tags: Business model, Energy efficiency, Organic Rankine Cycles, Real case study, Simulation model, Waste heat recovery
@article{Cavazzini2015a,
title = {Techno-economic feasibility study of the integration of a commercial small-scale ORC in a real case study},
author = {Giovanna Cavazzini and Paolo Dal Toso},
url = {http://linkinghub.elsevier.com/retrieve/pii/S0196890415003970},
doi = {10.1016/j.enconman.2015.04.043},
issn = {01968904},
year = {2015},
date = {2015-01-01},
journal = {Energy Conversion and Management},
volume = {99},
pages = {161-175},
abstract = {© 2015 Elsevier Ltd. The ORC certainly represents a promising solution for recovering low-grade waste heat in industries. However, the efficiency of commercial small-scale ORC solutions is still too low in comparison with the high initial costs of the machine and the lack of simulation models specifically developed for commercial ORC systems prevents industries from defining an accurate business model to correctly evaluate the ORC integration in real industrial processes. This paper presents a techno-economic feasibility analysis of the integration of a small-scale commercial ORC in a real case study, represented by a highly-efficient industrial distillery. The integration is aimed at maximizing the electricity auto-production by exploiting the heat produced by an internal combustion engine, already partially recovered in internal thermal processes. To analyze the influence of the ORC integration on the industrial processes, a semi-empirical steady-state model of the commercial small scale ORC was created. The model made it possible to simulate the performance of the commercial ORC within a hypothetical scenario involving the use of the heat from the cooling water and from the exhaust gases of the internal combustion engine. A detailed thermo-dynamic analysis has been carried out to study the effects of the ORC integration on the plant's energy system with particular focus on the two processes directly affected by ORC integration, namely vapor production and the drying process of the grape marc. The analysis highlighted the great importance in the business model of considering not only the direct costs (unit costs, engineering, etc.), but mainly the indirect ones and hence the need of an appropriate business model, based on the simulation of the commercial ORC behavior, to evaluate its introduction in real industrial processes. In particular, in the specific case of a highly-efficient distillery plant, the ORC integration resulted to cause an increase in inner fuel consumption, represented by dried grape marc, with a consequent economic loss not offset by a significant increase in electricity auto-production. As a consequence, the ORC integration was not economically feasible in the considered case study due to the great value in the market of the dried grape marc.},
keywords = {Business model, Energy efficiency, Organic Rankine Cycles, Real case study, Simulation model, Waste heat recovery},
pubstate = {published},
tppubtype = {article}
}
© 2015 Elsevier Ltd. The ORC certainly represents a promising solution for recovering low-grade waste heat in industries. However, the efficiency of commercial small-scale ORC solutions is still too low in comparison with the high initial costs of the machine and the lack of simulation models specifically developed for commercial ORC systems prevents industries from defining an accurate business model to correctly evaluate the ORC integration in real industrial processes. This paper presents a techno-economic feasibility analysis of the integration of a small-scale commercial ORC in a real case study, represented by a highly-efficient industrial distillery. The integration is aimed at maximizing the electricity auto-production by exploiting the heat produced by an internal combustion engine, already partially recovered in internal thermal processes. To analyze the influence of the ORC integration on the industrial processes, a semi-empirical steady-state model of the commercial small scale ORC was created. The model made it possible to simulate the performance of the commercial ORC within a hypothetical scenario involving the use of the heat from the cooling water and from the exhaust gases of the internal combustion engine. A detailed thermo-dynamic analysis has been carried out to study the effects of the ORC integration on the plant's energy system with particular focus on the two processes directly affected by ORC integration, namely vapor production and the drying process of the grape marc. The analysis highlighted the great importance in the business model of considering not only the direct costs (unit costs, engineering, etc.), but mainly the indirect ones and hence the need of an appropriate business model, based on the simulation of the commercial ORC behavior, to evaluate its introduction in real industrial processes. In particular, in the specific case of a highly-efficient distillery plant, the ORC integration resulted to cause an increase in inner fuel consumption, represented by dried grape marc, with a consequent economic loss not offset by a significant increase in electricity auto-production. As a consequence, the ORC integration was not economically feasible in the considered case study due to the great value in the market of the dried grape marc.
