Abstract
Combined heat and power (CHP) systems in both power stations and large plants are becoming one of the most important tools for reducing energy requirements and consequently the overall carbon footprint of fundamental industrial activities. While power stations employ topping cycles where the heat rejected from the cycle is supplied to domestic and industrial consumers, the plants that produce surplus heat can utilise bottoming cycles to generate electrical power. Traditionally the waste heat available at high temperatures was used to generate electrical power, whereas energy at lower temperatures was either released to the environment or used for commercial or domestic heating. However the introduction of new engines, such as the ones using the organic Rankine cycle, capable of employing condensing temperatures very close to the ambient temperature, has made the generation of electrical power at low temperatures also convenient. On the other hand, district heating is becoming more and more significant since it has been extended to include cooling in the warm months and underground storage of thermal energy to cope with variable demand. These developments imply that electric power generation and district heating/cooling may become alternative and not complementary solutions for waste energy of industrial plants. Therefore the overall energy management requires the introduction of an optimisation algorithm to select the best strategy. In this paper we propose an algorithm for the minimisation of a suitable cost function, for any given variable heat demand from commercial and domestic users, with respect to all independent variables, i.e., temperatures and flowrates of warm fluid streams leaving the plants and volume and nature of underground storage. The results of the preliminary process integration analysis based on pinch technology are used in this algorithm to provide bounds on the values of temperatures.
Highlights
The increasing cost of energy and the continual sharpening of carbon dioxide emission standards in the last decades have urged companies to implement energy saving measures in the design of new industrial processes and when retrofitting existing plants
The introduction of new engines, such as the ones using the organic Rankine cycle, capable of employing condensing temperatures very close to the ambient temperature, has made the generation of electrical power at low temperatures convenient [4]. This may enter into conflict with the use of lower temperature energy for district heating, which is becoming more and more significant since it has been extended to include cooling in the warm months and underground storage of thermal energy to cope with variable demand
In industrial processes cogeneration means production of electrical power by gas turbines or by steam turbines operating in a Rankine cycle using the available surplus heat
Summary
The increasing cost of energy and the continual sharpening of carbon dioxide emission standards in the last decades have urged companies to implement energy saving measures in the design of new industrial processes and when retrofitting existing plants. The introduction of new engines, such as the ones using the organic Rankine cycle, capable of employing condensing temperatures very close to the ambient temperature, has made the generation of electrical power at low temperatures convenient [4] This may enter into conflict with the use of lower temperature energy for district heating, which is becoming more and more significant since it has been extended to include cooling in the warm months and underground storage of thermal energy to cope with variable demand. In this article we examine the options available to both managers and design engineers of industrial plants for the selection of the optimal energy management when territorial integration is taken into account To this purpose we present an optimisation algorithm that considers possible scenarios and the constraints they are subject to for the attainment of technically sound and financially feasible solutions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
