Harare — GOLDEN MAKAKA -- a Zimbabwean PhD student at Fort Hare University -- lifted the country's academic profile high after winning the prize for the best poster presentation on the design and performance of a low-cost passive solar house at the annual South African Institute of Physics (SAIP) conference.

His poster presentation, entitled: "The design and performance of the low-cost passive solar house in the Eastern Cape, South Africa", attracted a lot of interest from specialists and other academics who attended the high profile annual scientific showcase.

Makaka's presentation was part of his PhD study. Fort Hare University and the local community hailed Makaka for his achievements.

The Somerset East Municipality has already indicated that it would adopt the design to build low-cost housing.

"My poster presentation at the 2005 SAIP conference held in Pretoria attracted a lot of attention as it clearly revealed how physics can be applied in buildings for the benefit of the local community," he said.

There were a number of PhD presentations and competition for the most creative research that benefits local communities was stiff.

"People were able to see the beauty of physics in action at this conference. I felt I must do more to put physics in action and I also felt that with the ongoing land reforms in Zimbabwe and the increasing energy demand, the Government needs to put in place an instrument which will compel house designers to focus on passive solar energy-efficient design," Makaka said.

This, he said, would go a long way in improving the health of the people and reduce load-shedding in winter when much heating is needed.

Makaka spoke strongly on the growing need for low-cost passive solar energy-efficient houses.

He pointed out that only about 7 percent of Africa's enormous hydroelectric potential has been harnessed.

A significant proportion of current electricity generation in Africa can be met by renewable energy.

"Based on the limited initiatives that have been undertaken to date, renewable energy technologies could contribute significantly to the development of the energy sector in eastern and southern Africa," Makaka added.

In Zimbabwe, he said, a number of energy sources need to be exploited and this can help the country to reduce the importation of electricity from neighbouring countries, which is proving to be very costly.

Makaka said a passive house is one that heats and cools itself in a purely passive way. To significantly reduce the total energy use in buildings, he says, it is necessary to use several technologies, such as energy conservation, day-lighting, passive solar, active solar, and photovoltaics, in combination.

The designers of these buildings, he suggests, need to find the optimum combinations of technologies for each specific case.

"This requires an integrated design approach, where the different low energy and solar technologies to be used are considered integral parts of the whole," he said.

"A comfortable indoor environment is one of the main requirements of a well-designed house yet most of the low-cost houses in Africa are characterised by poor thermal performance."

He attributed poor performance to poor design, sub-standard building materials and poor craftsmanship.

Wall material that forms almost 70 percent of building needs to meet certain specifications, and cement blocks commonly used have high thermal conductivity, high water absorption, low compressive strength and low sound damping, Makaka said.

This, he said, creates houses with an uncomfortable indoor thermal environment (high temperature swings), resulting in high energy consumption in heating/cooling the indoor environment yet the beneficiaries of these low-cost houses are in the low income groups and cannot afford to pay the energy consumption bills.

"The low income groups cannot afford to build their own houses as the cost of building materials has gone beyond the reach of the majority, and house rentals in urban areas are out of the reach of many," Makaka said.

The result, he added, has been an increase in shacks that are unsuitable for human habitation.

In modern buildings, significant amounts of energy are consumed to keep the building environment comfortable.

On a global scale, he said, the residential, commercial and institutional building sector consumed 31 percent of global energy and emitted 1 900 mega-tonnes of carbon in 1990.

By 2050, the proportion is expected to rise to 38 percent and 3 800 mega-tonnes respectively.

"This calls for housing designers to come up with new, affordable passive solar designs that use locally available materials in specific regions," Makaka suggested.

The introduction of the concept of low-cost energy efficient passive solar housing, he said, can offer immediate and long-term solutions to the problem of housing and energy in Africa.

The Fort Hare University post-graduate student said the inclusion of energy-efficient passive solar design features in the construction of affordable housing offers many benefits to low-income people.

Some of the benefits, he said, include reduced operating costs, i.e. reduced appliance running costs and, therefore, low energy bills, reduced energy-related greenhouse emissions, and reduced need for expensive heating and cooling of the house and, above all, an improved comfort.

"Many building practices today are high-cost solutions simply because designers and suppliers make more when houses and their components cost more. Alternative methods exist to design and build effective low-cost houses," Makaka said.

He explained more about the passive solar design houses that use sunshine to heat and light homes without mechanical or electrical devices.

"It is usually part of the design of the building itself, using certain materials and placement of windows. A successful passive solar building needs to be well insulated to make best use of the sun's energy," he explained.

The result is a quiet and comfortable space, free of drafts and cold spots. Passive solar design can also achieve summer cooling through the correct management of ventilation components. This is enhanced by convective air currents, which are created by the natural tendency of hot air to rise.

Makaka shed light about the basic operation principles of the house.

In winter when heating is required, the sun is low in the sky, and north-facing windows allow the solar radiation to penetrate indoor, heating the thermal mass which later on at night radiate thermal radiation, thus heating the indoor environment.

In summer, north-facing windows can be shaded off by roof overhangings or awning to keep out the high hot summer sun. Because much of a building's heat is lost through its windows, the majority of windows in a passive solar building are located on the north wall.

Applying low solar absorptivity paint to the outer roof surface and using aluminium foil on the inside lowers emission, helping to create better thermal performance.

"All these above-mentioned techniques could create better thermal performance. A good house design has to safeguard health and safety by providing sufficient airspace, ventilation, insulation, etc., and, most importantly, to involve the end users in the design process," Makaka said.

Zimbabwe is always in his thoughts. And, with the agrarian reforms, he said passive solar energy-efficient house design is the most ideal as these houses can be located far from electrical power lines.

He said Fly ash bricks are ideal because of their properties of low water absorption capacity, low thermal conductivity, high heat retention capacity, high strength and high sound damping.

"Renewable energy technologies provide attractive environmentally sound technology options for Africa's electricity industry," Makaka says.

"Renewable energy technologies could offset a significant proportion of foreign exchange that is used for importing oil for electricity generation in most countries."

In addition, renewable energy sources are modular and well suited to meeting decentralised rural energy demand.

The modular nature of most renewable energy technologies and the low investment levels makes them particularly suitable for capital-constrained African countries, he added.

Most renewable energy technologies use locally available resources and expertise, and would, therefore, provide employment opportunities for locals.

Makaka noted that the success of renewable energy technologies in Africa is limited by a combination of factors which include: poor institutional framework and infrastructure; inadequate renewable energy technology planning policies, lack of co-ordination and linkage in the renewable energy technology programme; and pricing distortions which have placed renewable energy at a disadvantage.

High initial capital costs, weak dissemination strategies, lack of skilled manpower, poor baseline information and weak maintenance service and infrastructure have also added to the woes.

"There is great need for all stakeholders to refocus and work as a group, but the first stage is to have a strategic plan," Makaka said.

"Zimbabweans are known for academic excellence and we need to take advantage of this human potential. All that is retarding meaningful research in Zimbabwe is funding.

"Zimbabwe has potential students who, with adequate resources, can help develop the country. Industry and Government must play a significant role in funding research. At present research is at a minimum level due poor resources," he said.

He said there is need to mobilise resources for research and to better pay researchers to retain them in key institutions. Makaka, who was born in Chimanimani in eastern Zimbabwe, finished his A-Levels in one year.

He did his first degree in physics in Cuba (1987-1992), then a BSc Honours (Physics) at the University of Zimbabwe in 1996, following which he attained an MSc in Applied Physics (1998-1999).

He is a final year PhD student at Fort Hare.

"I enjoyed science and mathematics from an early age and could read these subjects without getting tired at all," he said. "My mathematics and science teachers at Rusununguko High School played a crucial role in modelling me to appreciate the beauty of science and mathematics."

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