The ability of the wind towers, particularly the leeward wind tower, to ventilate the space below was determined for a set occupancy against current guidelines for air supply rates. Furthermore, the effect of the spacing and arrangement on CO 2 concentration within rooms ventilated by the leeward wind tower was investigated (re-entry of exhaust air pollutants into fresh supply).It was found that a parallel arrangement of wind towers was not effective for ventilating an occupied volume, regardless of the spacing between the two wind towers when incident wind direction was parallel to the arrangement. The maximum supply rate for the leeward wind tower in parallel arrangement at a spacing of 5 m was just over 50% of the regulation rate (10 L/s/occupant) and 40% of the supply rate of an isolated wind tower. Decreasing the spacing between the parallel wind towers to 3 m further reduces the supply rate to 2.4 L/s/occupant and the device was observed to be operating in reverse (airflow entering from leeward opening). As the angle of wind increased, an improvement of air supply rates was seen. For a staggered arrangement of wind towers, the leeward wind tower was capable of supplying the recommended ventilation rates at all tested spacing lengths.The average indoor CO 2 concentration of the space with the leeward wind tower was higher in the parallel arrangement than the staggered arrangement at 0˚ wind angle. For the parallel arrangement, the average CO 2 concentration was 28-50 ppm higher than the outdoor air. The staggered arrangement effectively minimised the re-entry of pollutants, with the indoor CO 2 concentration 1-3 ppm higher than the outdoor.

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The aim of this investigation is to evaluate the recent advances in the field of solar absorption cooling systems from the viewpoint of solar collector types. A review in the area of photovoltaic thermal (PVT) absorption cooling systems is conducted. This review includes experimental and computational work focusing on collector types and their efficiencies and performance indicators. Compared to vapour compression air conditioning systems, 50% of primary energy was saved by using solar absorption cooling systems and 10-35% maximum electrical efficiency of PVT was achieved. This review shows that Coefficient of Performance (COP) for solar cooling systems is in the range of 0.1-0.91 while the thermal collector efficiencies are in the range of 0.06-0.64. The average area to produce cooling for single effect absorption chillers for experimental and computational projects is 4.95 m 2 /kW c and 5.61 m 2 /kW c respectively. The specific area for flat plat collector (FPC) is in the range of 2.18-9.4 m 2 /kW c , while for evacuated tube collector (ETC) is in the range of 1.27-12.5 m 2 /kW c. For concentrated photovoltaic thermal collector (CPVT) and PVT, the average area to produce cooling for solar absorption chillers are 2.72 m 2 /kW c and 3.1 m 2 /kW c respectively.

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This investigation focused on the research undertaken on solar photovoltaic (PV) and solar thermal technologies for pumping water generally for irrigation of remote rural farms specifically considering the Sub-Saharan African region. Solar PV systems have been researched extensively for irrigation purposes due to the rise in Oil prices and the upscaling in commercialisation of PV technology. Based on the literature the most effective PV system is presented for the irrigation of a small scare remote rural farm with respect to the cost, pumping capacity and system efficiency. Similarly, solar thermal systems are reviewed and the most effective system described. Unlike PV technology, solar thermal technology for water pumping is lacking especially in small scale operations. However, with the possibility of local production, low investment cost, easy maintenance and lower carbon footprint, solar thermal water pumping technologies may be able to overcome the shortcomings of the PV technology that has stopped widespread use of the technology for irrigation applications. Taking into consideration recent developments in concentrated solar technologies using the Stirling engine, novel solar thermal water pumping systems may be developed. This review also highlighted the different methodologies such as modelling, used to investigate and optimise the performance of solar powered systems.

Mechanical Heating Ventilation and Air-Conditioning (HVAC) systems account for 60% of the total energy consumption of buildings. As a sector, buildings contributes about 40% of the total global energy demand. By using passive technology coupled with natural ventilation from wind towers, significant amounts of energy can be saved, reducing the emissions of greenhouse gases. In this study, the development of Computational Fluid Dynamics (CFD) analysis in aiding the development of wind towers was explored. Initial concepts of simple wind tower mechanics to detailed design of wind towers which integrate modifications specifically to improve the efficiency of wind towers were detailed. From this, using CFD analysis, heat transfer devices were integrated into a wind tower to provide cooling for incoming air, thus negating the reliance on mechanical HVAC systems. A commercial CFD code Fluent was used in this study to simulate the airflow inside the wind tower model with the heat transfer devices. Scaled wind tunnel testing was used to validate the computational model. The airflow supply velocity was measured and compared with the numerical results and good correlation was observed. Additionally, the spacing between the heat transfer devices was varied to optimise the performance. The technology presented here is subject to a patent application (PCT/GB2014/052263).

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