Hybrid PV & Solar Chimney (HPVSC) Technology


"Electricity & Hydroponic Food & Water"

Undoubtedly PV parks are one of the most suitable renewable energy system to solve the planet's energy problem without the side effects of climate change due to the use of fossil fuels.
PVs, however, have the following disadvantages in particular for large scale application in countries with strong solar irradiation such as the Arab countries:

  • Strong solar irradiation increases PV productivity, but as increasing their temperature reduces their efficiency by up to 50%.
  • Dust in these sandy countries lands sitting on the surface of PV panels is further reducing their performance.
    So PV panels in these countries need cooling and removing of dust.
  • In several countries as well as in several Arabic countries land is valuable and PV solar parks occupy soils that could be used for agriculture for food production.
    In these countries, solar PVs must be suspended high above the ground to leave the arable land. [1]
  • In all countries, electricity is also needed after the sunset, and solar PV plants must be able to operate after the sunset. Storage energy for sunset operation in solar PV parks will gradually become necessary and PV plants with batteries will be the ultimate solution of Energy Problem. 
    With current data, however, Lithium-Ion batteries are expensive and a method should be found to reduce the required amount of batteries for operation after sunset.

​​The HPVSC technology gives satisfactory answers to all previous problems as described below:

  • The PV panels on the roof rest on water tubes where they transfer part of their thermal load, and these water tubes are cooled by the moving air stream that is continuously escaping from the chimney. The water in the tubes can be continuously be circulated in an underground tank on the ground for cooling.
  • Roof PV panel rows can be dust-cleaned with special automatic brushes as many times as needed per day.
  • Translucent glasses that complement the roof can also act as mirrors, further increasing the performance of PV panels. [2]
  • The PVs are suspended on the roof and leave the space beneath them, protected inside the closed greenhouse from outside winds and cooled by the air stream generated by the solar chimney for hydroponic green-housing [3]
  • The solar chimney creates a huge air stream [4] which, when needed during the day, can only be used to cool the PV panels and the hydroponic plants. 
  • While the Solar Chimney air stream can be used, after the Sunset, to generate electricity through the Power Plant Air-Turbines. It should be noted that the external winds enhance the operation of the solar chimney.
  • The generation of electricity after sunset from Air Turbines obviously reduces the amount of batteries required to operate the station after sunset.
  • Water for cooling and cleaning of PV panels can be collected from rainfall (with a proper roof gutter system).
  • If the power Plant is within a reasonable distance from the sea or from a brackish source, water for the hydroponics and PV panel cleaning (2,000m3 / year / MW) can be produced by a reverse osmosis desalination unit. 
  • Of course, if required, the desalination unit can be boosted to produce the required water in the area.
  • We believe that large scale application of HPVSC technology with the accompaniment of batteries, for uninterrupted electricity generation, can become, in a few years, cost competitive with any fossil fuel electricity generation technology.

The ​​ HPVSC technology 

1.1   Greenhouse roof made o PV and Glass panels
1.2   Peripheral wall
1.3   Air Turbines
1.4   Greenhouse side door
1.5   Roof of the connecting  tunnel of Solar Chimney with the Greenhouse
1.6   Solar Chimney

Especially for Arab countries the choice and development of HPVSC technology is not simply useful it is necessary.

Publications List:
Papageorgiou C., Hybrid PV/Solar Chimney Technology
Papageorgiou C. (2016). Enclosed Solar Chimney Power Plants with Thermal Storage
Papageorgiou C., Floating Solar Chimney Technology
Papageorgiou C., Psalidas M., Katopodis P., Solar chimney technology without solar collectors
View More
[1] Research, Discovery & Innovation, What is Agrivoltaics? View More 
[2] The Conversation, Can mirrors boost solar panel output - and help overcome Trump’s tariffs? View More 
[3] Sahara Forest Project View More 
[4] South China Morning Post, China builds ‘world’s biggest air purifier’, View More 
Green Chimney Technologies


Prof Christos D. Papageorgiou
National Technical University of Athens
E-mail: chrpapag@gmail.com
Mobile: +30 6937 377 998