Investigating the potential for implementing solar thermal cooling systems and energy efficiency measures for dwellings in Egypt

Global warming presents major challenges to the world and especially to hot climatic countries, as global warming-driven increases in outdoor temperatures consequently increase the demand for cooling energy in buildings. A country like Egypt, whose climate is classified as hot and arid, is facing major challenges to meet the required high demand for energy that is mainly consumed for space cooling purposes in buildings, which will worsen due to global warming. The residential sector in Egypt consumes almost 50% of the energy produced compared to other sectors, and the high demand of air-conditioning systems in the Egyptian residential sector contributes the most to this consumption of energy. Residential buildings in Egypt are built with minimal energy efficiency standards which makes vital the need for space cooling. Thus, the idea of enhancing the thermal behaviour of residential buildings in Egypt is essential to reduce the heavy burden on the energy sector due to cooling needs. Due to the country’s geographical location, Egypt is considered a rich country in terms of availability of solar radiation, and this can encourage the utilisation of solar thermal energy for cooling purposes as a clean and renewable source of energy instead of using fossil fuels as is currently the case.

This thesis addresses the challenge of reducing energy demand for cooling in the residential sector in Egypt alongside meeting that demand through utilisation of solar thermal cooling. A simulation model is developed to evaluate the cooling demand of typical current built dwellings in Egypt as affected by different energy efficiency measures that aim to enhance the thermal behaviour of dwellings and reduce cooling energy consumption. A further simulation model is developed of a solar thermal cooling system for application to Egyptian residences. The simulation models are verified with reference to experimental data gathered and presented in published works from the peer-reviewed literature. The verified models are then used to carry out parametric analyses for investigating the potential of implementing solar absorption cooling systems in typical Egyptian dwellings, the energy performance of which have been enhanced via a range of efficiency measures that include treatments

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to glazing (double, triple, and use of external shutters) and treatments to fabric (application of roof and wall insulation). Focussing on the two most common residential building types in Egypt (five storey houses and villa types), the most effective energy efficiency measures for cooling energy reduction are identified and recommendations are made for energy efficiency design and policy for dwellings in Egypt. The potential for utilising solar energy to thermally powered absorption cooling systems for Egyptian dwellings is also evaluated.

Parametric analyses are conducted to determine suitable sizes of the main components of a solar absorption cooling system (solar collector field area, hot water storage tank volume and hot water flow rate) that is required to deliver cooling demand to a typical villa in Egypt.

The results show that the solar absorption cooling system can offer a practical and feasible technical solution for reducing the high share of electricity consumption in the residential sector that arises from conventional air conditioning units. It is also shown that the proposed energy efficiency measures and the components of the solar absorption cooling system can fit within the free provided areas in these dwellings without the need for any extra land area to locate these components, this finding being important for urban design. The results also show that applying external shutters to windows of dwellings in Egypt offers the highest reduction in cooling energy compared to the base case of dwellings without energy efficiency measures.

Findings from the thesis can be used to aid development of new sustainable communities that are being envisioned in Egypt (the Golden Triangle, the New Administrative Capital City and the Western Desert) away from the Nile River banks to spread-out the dense population. An example is devised and presented to illustrate how the outcomes in the thesis could be utilised to help inform future policy design by the Egyptian Government.