How can rooftop solar photovoltaic (PV) arrays reduce building energy use?

Building rooftop solar photovoltaic (PV) arrays coupled with electrical storage are a demonstrated means for addressing building energy use since roof areas are often unobstructed to solar radiation and freely available for such utilization , .

How does energy cost affect the insulation level of a PV system?

The 100 €/t increase in energy cost increased the optimal insulation level by a single increment at the time of installing PV. As example, the very high insulation was selected in the apartment complex building, the extra high insulation level (6.32 RSI, with 240 mm of insulation) in the multi-family and single-family prototypes.

Are energy savings from roof insulation and PV generation equivalent?

The authors recognise that energy savings deriving from roof insulation and those from PV generation are not equivalent due to timing. Insulation ensures uniform savings throughout the day, while savings deriving from PV depend on solar radiation and day-hour.

Can combining insulation with PV reduce energy use in residential buildings?

We found combining appropriate insulation with PV can provide a cost-effective option to reduce net primary energy use in residential buildings. Savings from insulation alone varied from 3% (apartment complex) to 17% (single-family).

Do raised stand-off PV arrays affect heat gains and insulation performance?

Secondly, starting conditions (e.g. no/low insulation, arbitrary roof improvement/roof in need of refurbishment) are defined. Finally, the optimal intervention with savings and related costs, are obtained in each situation. Shading from raised stand-off PV arrays is examined and how this influences heat gains and insulation performance.

How much does a PV system save if insulated?

Savings from insulation alone varied from 3% (apartment complex) to 17% (single-family). When adding PV systems with the roof initially uninsulated, net savings range from 55% (apartment complex) to 80% (single-family).