Assesment of Emerging Renewable Energy-based Cogeneration Systems for nZEB Residential Buildings

Net Zero Energy Buildings (nZEB) imply reduced consumption by means of good insulation, passive strategies and highly efficient energy supply systems. Among others, micro cogeneration systems are considered as one of the system solutions with the highest potential to enable nZEB.
These systems entail production of electricity and usable thermal energy (heat and/or cooling) to cover the energy demands of residential buildings, high energy efficiency levels and proximity of the energy source to the building. The concept of cogeneration is not new but the interest in small scale cogeneration technologies based on renewable energy sources has increased tremendously
in the last decade. A significant amount of experimental and modelling research has recently been presented on emerging technologies. In this paper, four main technologies are assessed: Fuel Cells (FC), Photovoltaic thermal (PV/T), solar thermal reversible heat pump /organic Rankine cycle (HP/ORC) and cogeneration solar Thermoelectric generators (TEG). This paper aims to give an overview of the state-of-the-art developments, discuss the fundamental
and technical challenges facing commercial adoption and prospects of these technologies for use in single-family houses. A schematic of each technology, a graph comparing the technical characteristics and a radar chart contrasting the strengths and weaknesses of each technology in market diffusion are provided.