An evaluation of ground pipe ventilation and overnight radiant cooling to displace air conditioning in Nigeria

  • Iheanyichukwu Onyeabo OGBONNAYA

Student thesis: Doctoral Thesis


Stimulating minimal energy use and a consequential reduction in CO2 emissions to curb global warming has been a great challenge for mankind particularly when more than half of all prime energy supplied is consumed by the built environment. In Nigeria, 44% of primary energy consumption is used by the built environment with 75% of this used for air conditioning. To compensate for regular power outages in the Nigerian electricity supply system, 80% of households also operate independent electricity generators, primarily to maintain mechanical cooling and food preservation. Energy consumption is expected to rise as most new buildings don ot incorporate any significant energy saving techniques that could reduce cooling demands. Providing a solution to this becomes a major challenge for architects and the building industry in Nigeria.Factors such as pollution, insects, high dust levels and home security, negatively impact on the use of natural ventilation techniques which is a common practice, with most home owners keeping windows permanently closed, increasing their dependence on mechanical means of cooling to maintain indoor comfort. The task is therefore to develop sustainable cooling strategies for buildings in this region without compromising indoor air quality and security. The research assessed and analysed the thermo physical properties and energy performance of existing building types and developed an enhanced 'fabric first' solution followed by a synergised application of ground pipe supply ventilation and cool air supply due to clear night sky radiation from roof mounted black body as passive cooling techniques for buildings in South Eastern Nigeria.Despite the thermal interfaces being less than optimal, the results suggest that the application of such passive cooling strategies in combination with enhanced building fabric using thermal inertia and external insulation, can displace circa 83.5% of energy demand for domestic air conditioning. This could - in the long term - reduce energy consumption in the building sector from 44% to 16.45 %, with a commensurate reduction in the carbon footprint. The energy saving costs in use, were calculated to offset the additional capital costs, in under 8 years. These strategies and techniques are therefore worth further investigation as they represent both an economic and environmental gain.
Date of Award16 Aug 2019
Original languageEnglish
Awarding Institution
  • University Of Strathclyde
SupervisorStirling Howieson (Supervisor) & Andrew Agapiou (Supervisor)

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