Page 115 - ISES SWC50

Ioannis Tsipouridis
Country: Greece
Year Started Research: 1977
Title of Research: Enhancement of solar cell efficiency by infra-red
absorption
University: Fuel and Energy Dept., Houldsworth School of Applied
Sciences, The University of Leeds, UK.
Still Active in Research: Yes

A new approach to the photoelectrochemical conversion of solar energy has been investigated. A new cell
configuration was tested in an attempt to enhance the efficiency of a solar cell by infra-red absorption. The
cell designs tested succeeded in utilizing the thermal effect of the infra-red region of the incident radiation
to further improve the cell’s operational characteristics. The advantages of this novel cell design are twofold.
Firstly, it achieves power output enhancement by infra-red absorption and secondly it simplifies cell design since
previously, means had to be provided for the filtering out of infra-red radiation in order to spare the solar cell
of its harmful thermal effect. Therefore, the new cell utilises both the photo and thermal effects of the incident
radiation and can be thus termed a Thermophotoelectrochemical cell. The use of this configuration increased
the cell’s efficiency energy conversion by 130%. It was further attempted to investigate the electrochemistry
of a photogalvanic and a photovoltaic cell in an effort to improve the cells operational characteristics, and to
ultimately combine the photogalvanic and photovoltaic responses in order to create a Thermophotogalvanovoltaic
electrochemical cell, which was expected to have improved characteristics. This novel cell was expected to be
responsive to the infra-red (thermal), the visible (galvanic) and the ultra-violet (voltaic) regions of the incident
radiation. The present work failed to add the two photo responses, but the investigation produced results upon
which further research could be based for the eventual creation of the photogalvanovoltaic cell which could store
as well directly convert light energy to electrical energy. The reproducibility of results, the cell’s stability, and the
lack of time degradation of the cell’s response were also investigated and were found to be very good.
The efficiency of conversion was found to be 0.45%, while the maximum photovoltage obtained was 0.75V,
both values comparing very well with those found in literature.

John Twidell
Country: United Kingdom
Year Started Research: 1976
Title of Research: Appropriate technology and renewable energy
University: Universities of the South Pacific (Suva, Fiji) and Strathclyde
(Glasgow, UK)
Still Active in Research: No

John Twidell’s research started for benefits in appropriate technology. Early topics with graduate PhD and MSc
students included solar crop drying, microhydro power, wind power, combined heat and power and energy surveys.
Major projects with EU and UK funding for equipment and research fellows included (i) monitoring passive-solar,
low-energy buildings fitted with transparent insulation to accommodate 300 students in Glasgow; (ii) using large
scale test-cells to monitor and model solar building fitments; (iii) installing and operating wind turbines for island
communities; (iv) operating an innovative 3 MW wind turbine, and; (v) arranging conferences for ‘Energy for Rural
and Island Communities’. A textbook ‘Renewable Energy Resources’ was written with colleague A.D. (Tony) Weir,
and is now in its 4th edition.

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