Analysis of the integration of micro-cogeneration units in space heating and domestic hot water plants

Abstract

Micro-cogeneration has been recognized as an efficient technology that can contribute to European Union's energy and climate objectives with respect to delivering low-carbon heat and power to citizens and small businesses. For improving the performance of this technology and so take as much advantage as possible of its potential, thermal energy storage plays a key role. This paper presents a techno-economic evaluation and optimization procedure focused on properly sizing and designing a micro-cogeneration residential installation, emphasizing how thermal energy storage is arranged and the different thermal loads prioritized within the plant. Therefore, the proposed methodology can be easily applied to buildings with different conditions and constraints. The methodology is then applied to a representative case study that consists of a detached house with a 1 kWe micro-cogeneration plant. Results of the case study show that in small installations DHW accumulation does not provide any significant improvement but a worsening of efficiency. Additionally, it is also proved that the layout of the distribution loop has an importance on the final performance of the plant that must be kept in mind. Moreover, results show that TES systems coupled with micro-cogeneration engines are traditionally highly oversized, thus worsening economic viability of these facilities