To cite this version:Paola Bombarda, Costante Invernizzi, Claudio Pietra. Heat recovery from Diesel engines: a thermodynamic comparison between Kalina and ORC cycles. Applied Thermal Engineering, Elsevier, 2009, 30 (2-3) This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Although the obtained useful powers are actually equal in value, the Kalina cycle requires a very high maximum pressure in order to obtain high thermodynamic performances (in our case, 100 bar against about 10 bar for the ORC cycle). So, the adoption of Kalina cycle, at least for low power level and medium-high temperature thermal 2 ACCEPTED MANUSCRIPT sources, seems not to be justified because the gain in performance with respect to a properly optimized ORC is very small and must be obtained with a complicated plant scheme, large surface heat exchangers and particular high pressure resistant and no-corrosion materials. ACCEPTED MANUSCRIPT

No abstract

No abstract

Among the renewable energy sources, ocean energy is encountering an increasing interest. Several technologies can be applied in order to convert the ocean energy into electric power: among these, ocean thermal energy conversion (OTEC) is an interesting technology in the equatorial and tropical belt, where the temperature difference between surface warm water and deep cold water allows one to implement a power cycle. Although the idea is very old (it was first proposed in the late nineteenth century), no commercial plant has ever been built. Nevertheless, a large number of studies are being conducted at the present time, and several prototypes are under construction. A few studies concern hybrid solar-ocean energy plants: in this case, the ocean thermal gradient, which is usually comprised in the range 20–25 °C in the favorable belt, can be increased during daytime, thanks to the solar contribution. This paper addresses topics that are crucial in order to make OTEC viable, and some technical solutions are suggested and evaluated. The closed cycle option is selected and implemented by means of an organic Rankine cycle (ORC) power plant, featuring multiple ORC modules in series on the warm water flow; with a three-level cycle, the performance is approximately 30% better if compared to the single-level cycle. In addition, the hybrid solar-OTEC plant is considered in order to investigate the obtainable performance during both day and night operation; this option could provide efficiency benefit, allowing one to almost triplicate the energy produced during daytime for the same prescribed water flow

No abstract