Design of an onboard auxiliary power and desalination unit powered by a Stirling engine
Other Research Product
Publication Date:
2014
abstract:
Starting from the increasingly demand of performance and comforts on pleasure boats, this work refers to an innovative integrated system for the simultaneous production of fresh water and electricity onboard.
In particular, a 1 kWe Stirling engine coupled with a thermal desalination plant has been considered for the purpose. The prototype, which refers to the distributed micro cogeneration field, has the final aim of building and testing a single effect distillation plant with a fresh water production of about 150 l/day.
Firstly, the technical and economic feasibility has been evaluated together with the potential plant performance. Then, thermodynamic theories and numerical analysis have been adopted to define the final prototype configuration. Later on, a field test phase has been carried out to evaluate the actual plant performance. Hence, a comparative analysis with a compact reverse osmosis desalination plant has been performed.
In general, the experimental analysis has been in good agreement with the predicted results. In particular, at nominal operating conditions (@50°C) the maximum heat transfer rate was higher than the designed condition (5 kWt). Despite the non-ideal plant thermal insulation, fresh water production reached about 7 l/h at best operating conditions, proving a good process efficiency. Definitively, the experimental phase has provided a significant contribution to confirm and understand most of the mutual interconnections between the different key process parameters. According to the predicted behavior, fresh water production has been strongly dependent on salt content of the treated water and on temperature difference between the heating fluid and the salt water in the evaporator tank. However, even at the most severe operating conditions the thermal desalination plant has shown very interesting performance. Moreover, the apparatus exhibited a very good response to varying in time thermal power input thus confirming the opportunity to operate also powered by different forms of waste heat.
In particular, a 1 kWe Stirling engine coupled with a thermal desalination plant has been considered for the purpose. The prototype, which refers to the distributed micro cogeneration field, has the final aim of building and testing a single effect distillation plant with a fresh water production of about 150 l/day.
Firstly, the technical and economic feasibility has been evaluated together with the potential plant performance. Then, thermodynamic theories and numerical analysis have been adopted to define the final prototype configuration. Later on, a field test phase has been carried out to evaluate the actual plant performance. Hence, a comparative analysis with a compact reverse osmosis desalination plant has been performed.
In general, the experimental analysis has been in good agreement with the predicted results. In particular, at nominal operating conditions (@50°C) the maximum heat transfer rate was higher than the designed condition (5 kWt). Despite the non-ideal plant thermal insulation, fresh water production reached about 7 l/h at best operating conditions, proving a good process efficiency. Definitively, the experimental phase has provided a significant contribution to confirm and understand most of the mutual interconnections between the different key process parameters. According to the predicted behavior, fresh water production has been strongly dependent on salt content of the treated water and on temperature difference between the heating fluid and the salt water in the evaporator tank. However, even at the most severe operating conditions the thermal desalination plant has shown very interesting performance. Moreover, the apparatus exhibited a very good response to varying in time thermal power input thus confirming the opportunity to operate also powered by different forms of waste heat.
Iris type:
5.12 Altro
Keywords:
m-CHP, cogeneration, Stirling engine, thermal desalination, reverse osmosis, waste heat
List of contributors:
Cioccolanti, Luca
Book title:
Doctoral Thesis, Università Politecnica delle Marche,