use of phase change materials for thermal control in building integrated photovoltaic systems
Buildings play a significant role in the global energy balance. Typically they account for 20-30% of the total primary energy requirements of industrialised countries (46% in Ireland). Photovoltaics (PV) convert solar energy directly into electricity and building integrated PV (BIPV) is widely recognised as the most cost effective form of PV power generation that can be connected to the national grid. However, as only ~16% of the solar energy incident on a PV device is converted to electricity; the remaining insolation absorbed is transformed into heat. For silicon solar cells, the associated elevation of temperature reduces solar to electrical energy conversion efficiency by 0.4-0.5%K-1. The most common approach to heat dissipation uses a duct behind the PV panel which allows for natural convection. Accrual of airborne dust in inlet grilles and on duct surfaces reduces the rate of heat transfer from the PV. As a novel method to regulate the rise in BIPV temperature, the student will investigate the use of phase change materials (PCM) which absorb energy as latent heat at a constant phase transition temperature. The outcome of the project will be an integrated PV/PCM system enabling the PV to operate with improved solar to electrical conversion efficiency.
The strategic objectives of the research programme are to:
- Assess the feasibility of utilising commercially available PCMs integrated into a system with photovoltaic (PV) cells to minimise the PV cells’ temperature rise and maintain them at, or close to, the PVs’ characterising temperature (25oC), and store thermal energy in the PCM for a potential use in another application.
- Provide a rigorous understanding of the behaviour of PCM in this novel application for BIPV.
- Obtain detailed experimental data on performance and develop and validate experimentally a detailed dynamic system simulation model.
- Conduct parametric analyses to optimise system configurations and provide a systematic basis for experimental design using modelling techniques.
DIT - School of Physics
Dr Sarah McCormack
Prof Brian Norton
Collaboration with Dr Mingjun Huang - University of Exeter