A combined monitoring and modelling approach to understand cooling loads for residential PV system sizing

Case study of a villa in Jeddah

Abstract

The Kingdom of Saudi Arabia (KSA) is ranked third in the world for electrical cooling demand. Almost half of its currently generated electricity is consumed by the residential sector and around 70% of this is used to support cooling loads. KSA has an aspiration to be net zero carbon by 2060, which will require transitioning its current fossil fuel-based energy supply to renewable resources, such as solar photovoltaic (PV). The Saudi ‘Energy sector transition plan 2030’ includes 40 GWp of PV capacity to be delivered through large scale solar farms but lacks emphasis on the contribution from PV on building roofs.

This research provides evidence on how optimally deployed PV on roofs can contribute to reducing air-conditioning electrical loads. A year-round electricity consumption dataset from a continuously monitored villa  in Jeddah with a floor space of 757m²  was used to provide the basis for modelling optimum PV systems. Results show that daily cooling loads varied between 76 kWh in December and 187 kWh in July. Regardless of seasonality, all cooling peak loads occur in daytime. The highest peak loads which are related to ambient temperature were found to be 18.5 kW in July (summer), and 7.5 kW in December (winter). Analyses of optimised PV sizing to address such loads coupled with economics are presented. All three potential PV systems modelled showed substantial return on investment under the higher tariff of USD 0.08/kWh scenario and not at the lower tariff of USD 0.048/kWh for the same export rate. Therefore, a tariff reform coupled with some kind of financial support towards rooftop PV installation is recommended. The presented methodology is generalisable and projects how PV deployed in domestic sector can contribution to the national low carbon target at the city level.