Development of Valley View University, Accra, Ghana
Saving Energy by Passive Cooling
Due to increasing student numbers the demand for electricity
supply will increase. At the present a reliable electricity supply cannot
be guaranteed on campus. This results in repeated interruptions in supply
and voltage fluctuations. It is to be expected that costs will rise
in future. Alternative sources of electricity should be therefore explored.
Energy saving programs should be given priority over energy
production. The aim is to reduce energy consumption across the entire
campus and to utilise the potential offered by the sun.
Significant energy savings can be made by using energy saving electric
devices and lighting as well as through more conscious user behaviour.
Buildings can be planned to maximise natural lighting by appropriate
window size and position.
Expensive air conditioning equipment is avoided by careful building
planning, orientation and structure. Natural air circulation is used
to keep rooms at a comfortable temperature by arranging new buildings
perpendicular to the main wind direction, with a relatively narrow building
depth and sufficiently large windows and high ceilings. Rooms, which
easily heat up, such as computer labs and other labs will have air conditioners.
The use of horizontal and vertical shading
elements arranged according to the sun's position and of natural shading,
such as trees, can significantly help to maintain a comfortable indoor
room temperature. Plants evaporate moisture and help to reduce the temperature.
Saving Energy by Solar Collectors
Solar energy is available all year round in Ghana, almost
without interruption. The use of solar energy was examined with a simple
solar collector for the new cafeteria.
The viability of solar energy depends partly on the global development
of energy prices. But, regardless of energy prices, such systems are
more economical when one installation serves several parties rather
than lots of individual systems. The use of a thermo-siphon plant is
proposed after the testing phase for buildings with a large demand for
hot water such as student hostels and cafeteria. These compact and economical
plants work in a closed cycle utilising gravity rather than a pump and
Prof. Dr.-Ing. D.
Glücklich Dipl. Ing. Nicola Fries
Bauhaus-Universität Weimar 99421
Biogas Plant - Waste Water Treatment and Renewable
The biogas plant on campus was completed in January 2005
. Its location is next to the new cafeteria and the sanitary block,
which are the main “waste” providers and biogas users. Since
the decentralised sanitary concept suggests a separation of different
flow streams of waste water such as urine, grey and black water, the
process can be optimized and at the same time the size of the biogas
digesters can be reduced.
The simple and robust dome system is a continuous flow plant. Several
have been built in Ghana with Ghanaian engineers by local companies.
Within the research project, the solid and liquid matters, after a certain
treatment time, will be analysed and tested on their suitability as
fertiliser for agriculture.
Black water of the sanitary facilities is treated anaerobic in the biogas
digester together with organic waste from kitchen and farms. Biogas
is the product of putrefaction bacteria that can biologically degrade
organic material under anaerobic conditions (i.e. under sealed conditions
without air). The biogas is collected in a PE sack and used for cooking
in the cafeteria. The sludge on the ground of the digester can be used
as fertiliser in agricultural areas of the campus.
The outflow of the digesters discharge into three expansion chambers.
From here the treated waste water goes into a septic tank where the
wastewater is treated again. From the last filtration chamber purified
water is pumped into an elevated tank and used under gravity for irrigation
and as fertiliser on the farmland. The main purpose of the digesters
is the treatment of black water. The production of biogas is just a