Thermal storage and CHP coupling in a smart user case study

Within the currently envisaged spreading of smart micro-grid technologies, small-scale cogeneration can play a fundamental role, contributing to energy saving and emission reduction. In this context, the need to couple different technologies emerges, and thermal storages acquire a great importance, especially if given energy exchange patterns with the power grid are to be achieved. Integrating different technologies in order to obtain a smart handling of energy fluxes falls into the broader definition of "smart user", which generally consists in the coordinate managing of a group of generators and users in order to optimize the overall energy consumption. A solution frequently proposed in the literature involves the use of an internal combustion engine to produce power with the recovery of waste heat. In such context, the presence of a thermal storage is fundamental in order to partially de-couple thermal and electrical loads, allowing a more flexible dimensioning and management of the various interacting pieces of equipment. In this work, a smart user solution involving such technology is investigated, also featuring tri-generation and Renewable Energy Sources (RES) exploitation in an office building. The buildings must be provided with power, space heating and cooling, which are produced by a Combined Heat and Power (CHP) system and an absorption chiller. Auxiliary heater and chiller are included in order to achieve virtual independence from the power grid. Estimated load data for the office district is used in a set of simulations, in order to understand the influence of the thermal storage size on the performance of the different pieces of equipment and on total fuel consumption.