PvPro: Powering the Future of Domestic Heating with the Sun

Imagine using the sun’s energy not only to generate electricity, but also to provide hot water in a smart, efficient, and self-contained way.

This is the vision behind the PvPro project, funded through the Energy and Water Agency’s 2022 Research and Innovation Scheme (Project No. EWA/37/23/1).

PvPro has developed an innovative system that converts solar energy directly into hot water using intelligent electronics. Unlike conventional solar thermal systems, which rely on rooftop tanks, fluid circulation loops, and extensive plumbing, PvPro uses photovoltaic (PV) panels and solid-state electronics to control standard electric water heaters based on available solar energy.

The result is a simple, safe, and maintenance-free solution that can be installed in homes where traditional solar water heating systems are impractical.

The project is a collaboration between Abertax and the UM. At its core is a low-voltage smart controller that activates water heaters when sufficient solar energy is available.

The system can manage multiple water heaters according to user-defined priorities and can also direct surplus energy to a battery storage system once water heating requirements have been met. Stored energy can then be used to power low-consumption household loads, such as lighting circuits.

This approach addresses a common limitation of conventional solar thermal systems, which often produce excess hot water during summer months when demand is lower. Instead of wasting this energy, PvPro can redirect surplus solar generation to other useful applications, improving overall energy utilisation and household efficiency.

The project team has designed, built and tested two hardware prototypes. The latest version supports multiple water heaters, provides real-time temperature monitoring and communicates wirelessly with a remote server for data logging and analysis. The system also incorporates several safety features, including thermal cut-off protection, overcurrent fusing and photovoltaic fault detection, making it suitable for residential deployment.

Extensive testing has been carried out using rooftop PV installations in Maltese homes. Trials involving two electric water heaters were conducted over several weeks under real operating conditions.

Results demonstrated significant reductions in auxiliary electricity consumption while maintaining safe and reliable water temperatures despite changing weather conditions. Combined with adequate insulation, the heated water remained warm well into the evening, covering most household hot water needs.

Beyond its technical achievements, PvPro supports a broader vision of decentralised and accessible renewable energy. By delivering hot water directly from rooftop solar panels, the system reduces installation complexity and lowers barriers to solar adoption. Its modular design allows it to accommodate different water tank capacities, while its ability to operate independently of the electricity grid makes it particularly attractive for rural areas and energy-resilient communities.

Further household trials resulted in extremely positive results in terms of heating performance, energy efficiency and battery integration. The project team has now refined the system, pursuing safety certification and identifying pilot partners for larger-scale deployment.

PvPro demonstrates how innovative engineering can help households make better use of Malta’s abundant sunshine, delivering a practical, affordable and sustainable solution for solar-powered water heating.