Solar Cogeneration for Access to Energy in Off-grid Rural Households in Developing Countries (DCs)

  • Ronald Muhumuza

Student thesis: Doctoral Thesis


Off-grid households in developing countries require low cost solar energy technologies that maximise the available solar radiation resources. This doctoral thesis develops a Solar Energy Cogeneration (SEC) concept for increased solar radiation conversion potential, access to modern energy and displacement of unsustainable traditional fuels. The concept utilises readily available photovoltaic (PV), Integrated Collector Storage Solar Water Heater (ICSSWH) and concentrator technologies to fabricate a novel, modular and affordable prototype described as Asymmetric Formed Reflector Integrated Collector and Storage (AFRICaS) SEC prototype. The thesis studied the performance behaviour of the PV subsystem and the AFRICaS ICSSWH subsystem of the AFRICaS SEC prototype through extensive experimental work and theoretical modelling. Indoor experiments estimated the daily solar energy yield (electrical and thermal) to enable the prediction of the techno-economic potential of the SEC prototype in Sub-Saharan Africa. The AFRICaS ICSSWH subsystem is applicable in equatorial latitudes of −30◦ ≤ θi ≤ 30◦ due to the beneficial technical features of
its construction. With no-drawoffs, the AFRICaS ICSSWH could produce hot water
at 55 ◦C with ambient air temperature of 28 ◦C at an average 6 h collection efficiency of ηcol = 30.3±1.0%. The night-time retention efficiency for different storage water starting temperatures ranges from 33.4% to 40.8%. The thermal losses coefficient per unit aperture area over an 18 h cooling period ranges from 2.124WK−1m−2 to 2.840WK−1m−2. The predicted annual thermal energy output under typical utilisable irradiance of 730Wm−2 ranges from 311 MJyear−1 to 518 MJyear−1 whilst the annual yield of direct current electricity is 1129.7 kWh/kWp. For a solar saving fraction of 48.47% consisting of thermal energy demand for water heating only, the discounted payback period is at most 7.8 years to displace fuelwood. This research increases our practical understanding by designing and analysing modular SEC technology and exploring the techno-economic potential of displacing traditional fuels in off-grid Sub-Saharan Africa households.
Date of AwardFeb 2020
Original languageEnglish
SponsorsDepartment of Education, Northern Ireland
SupervisorAggelos Zacharopoulos (Supervisor), Mervyn Smyth (Supervisor) & Jayanta Mondol (Supervisor)


  • Renewable energy
  • Optical efficiency
  • Flux distribution
  • PV cells
  • Technoeconomics
  • Ray tracing

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