Optimization of the electricity/heat production of a PV/T system based on spectral splitting with Ag nanofluid

The reduced electrical efficiency of PV modules caused by the increase of cell temperature, is a crucial issue for photovoltaic applications in buildings. Traditional solutions focus on passive cooling techniques to achieve heat regulation of PV modules, but cannot use effectively solar radiation not absorbed by solar cells. Therefore, in the current study a spectral splitting PV/T system is developed, which targets to filter part energy with Ag nanofluid and balance the effective heat and electricity harvesting for buildings. For this purpose, an indoor experimental investigation using a solar simulator is carried out to evaluate the performance of spectral-splitting PV/T system with optimal Ag nanofluid. The effects of solar radiation, optical thickness and mass fraction on the heat/electricity yield are discussed to illustrate the potential utilization in buildings. Results indicate that increased solar radiation would have a negligible effect on the electrical efficiency with a cell temperature of 25 °C. Due to the reduced transmittance of the Ag nanofluid caused by the increased optical thickness or mass fraction, electricity yield is decreased but harvest of heat is increased. In addition, adding Ag/water nanofluid above PV modules, would have a positive effect on the heat regulation of cell temperature.