Quantum mechanics

Photovoltaic mounting system

Voltage

Engineering

Hydroxypropyl cellulose

Materials science

Window (computing)

Thermotropic crystal

Systems engineering

Operating system

Rooftop photovoltaic power station

Power (physics)

Computer science

Electricity generation

Maximum power point tracking

Liquid crystalline

Polymer

Physics

Optics

Inverter

Environmental science

Transmittance

Composite material

Architectural engineering

Liquid crystal

Optoelectronics

Photovoltaic system

Electrical engineering

Engineering physics

Solar Energy

Building Integrated Concentrating Photovoltaic (BICPV) window represents a promising alternative approach for improving the electricity generation of photovoltaic cells when integrated into building windows. As a new concept, BICPV smart window consisting of an optically switchable thermotropic layer with integrated PV cells offers the potential to simultaneously generate electricity and control solar heat and visible light into buildings. In this study, a BICPV smart window system with a Hydroxypropyl Cellulose (HPC) based thermotropic hydrogel membrane has been developed and characterised. The system was designed with the aid of a validated wavelength-dependent optical model based on a Monte-Carlo ray-tracing technique, where the thermal and optical properties of the thermotropic layer used for the optical model prediction were obtained from experimental measurement. Subsequently, a prototype of the BICPV smart window system has been fabricated and characterised under controlled indoor conditions. From the experiments, it was found that the maximum power output of the BICPV smart window (6 wt% HPC) increases by 17.1% with the membrane temperature increasing from 40 °C (the transition temperature) to 54 °C; meanwhile, a 70.9% reduction in the light transmittance is observed. This indicated that the BICPC smart window might potentially reduce the solar heat gain in hot periods and therefore reduce the building energy demand. In addition, the effect of different concentrations of HPC polymer (2, 4 and 6 wt%) on the electrical and optical performance of the system has been investigated.

Design, development and characterisation of a Building Integrated Concentrating Photovoltaic (BICPV) smart window system