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.
Every saving program should be given priority over energy production. The aim is to reduce energy consumption across the entire campus and to utilize the potential offered by the sun.


Significant energy savings can be made by using energy saving electric devices and lighting as well as adopting more conscious user behavior. Buildings can be planned to maximize 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.

Solar collector near cafeteria


The use 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 utilizing gravity rather than a pump and circulation controlling.


Biogas Plant – Waste Water Treatment and Renewable Energy
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 decentralized 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.

Biogas plant

sludge digester


The simple and robust dome system is a continuous flow plant. Local companies, through Ghanaian engineers, have built several dome systems in Ghana. Within the research project, the solid and liquid matters, after a certain treatment time, will be analyzed and tested on their suitability as fertilizer for agriculture.

Black water of the sanitary facilities is treated anaerobically 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 fertilizer in agricultural areas of the campus.

The out-flow of the digesters discharge into three expansion chambers. Form here the treated waste water goes into 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 fertilizer on the farmland. The main purpose of the digesters is the treatment of black water. The production of biogas is just a secondary benefit.

 

 

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