Enthalpy and exergy analysis in the framework of a district scale energy balance

This report presents a study of an enthalpy and exergy analysis in the framework of a district scale energy balance. Energy demand (heating, cooling and lighting) for buildings represents more than 30 % of the total worlds energy use. Main efforts have been made on increasing performances of new building envelop and on the use of low temperature processes in order to increase the exergy efficiency. On a district scale, different temperature and energy flow levels are present, meaning a great potential to make use of synergetic effects by rationally managing energy flow interactions between buildings as synergies by enhanced energy management and the usability of waste heat source. An optimisation of exergy flows for the heating systems allows to identify the temperatures levels according to the energy demand, which helps to implement the best choice of available technologies. A number of connection cases will be described and studied to show the potential gain in terms of thermal and economical performances, where the thermal performances are defined by both the energy and the exergy efficiency. This study shows an improvement of the thermal performances of connection cases where in all scenarios the heat losses are lower than the waste heat recovery. These gains on thermal performances may increase further by the integration of appropriate technologies such as heat pumps. The use of primary resource like gas can also be decreased.

Maréchal, François

Note: The status of this file is: Involved Laboratories Only

 Record created 2012-11-15, last modified 2018-03-17

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