Hybrid Solar PV-THERMAL SYSTEM 

Solar collectors represent the major cost component of a solar system and require sizable space. In the near future, successful strategies to maximize the return on investment and land use efficiency in solar energy systems will be a combination of high-efficiency solar collectors with energy storage and cogeneration/polygeneration concepts. Solar “poly-generation” aims to combine multiple products (e.g. electricity, air conditioning and desalinated water) from the one solar resource. Polygeneration is an attractive solution for many applications in residential, commercial, touristic, sport and industrial sectors, as they can satisfy almost all energy and water needs, with numerous cost and performance benefits. However these benefits can only be realized if a simple, reliable, efficient and cost effective solar collector and energy storage components can be developed.

As almost all the applications and polygeneration systems require simultaneous supply of both electrical and thermal energy, a robust solar energy portfolio is likely to include photovoltaic (PV) and solar thermal systems with complementary roles. Hybrid Photovoltaic- Thermal (PV-T) solar collectors holds a great promise for realization of the targeted solution, as electrical and thermal energy can be generated simultaneously in the same collector with no additional land footprint and minimum incurred costs.

On the other side, operation of PV systems under extremely high
temperatures in hot climates represents one of the major challenges for all PV applications. As the efficiency of PV cells drops significantly at high temperatures when the demand for cooling and water desalination, as major consumers of energy in hot arid climates, is also high, maintaining the temperature of PV modules at a lower level is highly desirable and offers two additional advantages: an increase of the life expectancy of PV modules and stabilization of the output power characteristics.

While cooling PV modules requires a temperature level of the cooling medium as low as possible below 40 °C, most of polygeneration applications require thermal energy at higher temperatures in the range from 80 °C up to 250-300 °C. On the other side, solar thermal collectors for medium temperature applications in the same range are underdeveloped although potential market and applications are huge. In 2013, solar thermal engineering applications accounted for 30% of the solar thermal market, with an increase of more than 50%. It is expected that the solar thermal engineering application market will further expand with the development of solar thermal technology for industrial and agricultural applications, as well as solar district heating and cooling applications.

This patent introduces a simple, yet robust hybrid Photovoltaic-Thermal (PV-T) Solar Collector Integrated with/or without Ground-Based thermal energy storage to deliver electricity and thermal energy at low and medium temperatures to drive polygeneration systems in many applications in hot countries and all over the world. It rigorously addresses challenges of operation of PV systems in hot dusty countries and proposes an extremely efficient, yet simple, design. The present invention will help in maximization of solar energy conversion and land use efficiency in hot sunny countries to promote solar energy applications for sustainable development. This paves the way to put solar PV energy on the fast track.

Although the innovative Hybird Collector is a stationary, non-evacuated, and low-technology, it is a promising alternative to supply heat at intermediate temperature thermal needs between 100 °C to 200 °C. The yearly energy delivery of the Hybid Collector is 75-80% compared to less than 20% for most efficient PV panels available in the market. The thermal efficiency of the Hybrid Collector is comparable to that of the evacuated collectors. The has a great potential for reducing the land foot print by almost 50% and energy production cost by 50-60%, with a real possibility to deliver energy round the clock due to integration with thermal energy storage and solid waste reactors.