Approximately 50 % of EU energy consumption is used for heating and cooling of buildings and industry, the majority of that still powered by fossil fuels as of 2018 despite increasing interest in renewable energy resources. Solar technologies to harness the Sun’s practically limitless supply of energy are poised to play a critical role in reducing dependence on fossil fuels, and thus decreasing the impact of human activity on global climate change. The EU-funded FOCALSTREAM project focused its energy on optimising a configuration already among the best, patenting technology along the way, while generating interest among international stakeholders.
Turning up the heat
Conventional photovoltaic (PV) panels have relatively low efficiencies and a lot of thermal energy is wasted. Hybrid high-concentration PV thermal (HCPVT) systems give PVs a boost in two ways. Solar collectors supply concentrated light onto the PV cells using optics much as a child uses a mirror to burn a piece of paper with sunlight. Concentrating PVs therefore use less materials and space and also substitute expensive PV materials with inexpensive mirrors. Secondly, high-efficiency multi-junction PV cells require active cooling to prevent damage. The heat harvested in this process can be used to heat hot water or provide air conditioning.
Challenges present opportunities
FOCALSTREAM’s HCPVT development faced a number of roadblocks. There were delays in the availability of multi-junction cells and direct bonded copper (DBC) power modules. Then, researchers discovered that dense-array cells with welded connections would no longer be produced and a completely new design was needed. Project coordinator Ugo Manfredi explains, “During the project, we designed a different FOCALSTREAM system using standard rather than dense-array multi-junction cells. In addition, we invented the patented ‘parabolic cline collector’ shape that concentrates light more than 500 times with uniform flow. With smaller mirrors and short focal length, we will improve performance with systems that are also easier and less expensive to produce.” According to Manfredi, “The best silicon PV panels on the market today have an electric module efficiency of 22 %. The FOCALSTREAM prototype with manually realised long-focus mirrors achieved a system electric efficiency beyond 25 %. The commercial FOCALSTREAM system, with higher precision short-focus mirrors, will reach 40 % module and 33 % system efficiency, with 82 % of incoming solar energy harnessed.”
International patent and international interest to match
The patented short-focus HCPVT system is light yet powerful and will be an excellent option for rooftops and urban applications. FOCALSTREAM is pursuing opportunities with energy service companies (ESCOs) and utilities’ organisations, and the Patent Cooperation Treaty (PCT) patent has been extended to include China, EU, India, Italy and United States. EU-funded FOCALSTREAM HCPVT technology is poised to make a global contribution to addressing one of the greatest global challenges of our time. As Manfredi summarises, “We are proud of our resilience and ability to introduce radical changes to overcome challenges and adapt to market requests. The short-focus version of FOCALSTREAM was instrumental in attracting the attention of utilities and investors. We are launching a seed fundraising to get the financial resources needed to realise the improved FOCALSTREAM short-focus version. A pan-European electricity stakeholder and utilities provider are also interested, as are several academic and research organisations.”
FOCALSTREAM, photovoltaic (PV), energy, patent, high-concentration photovoltaic thermal (HCPVT), heat, light, cooling, solar, utilities, thermal, PV panel, PV cell, multi-junction cell, hybrid