**1. Introduction**

Over the years, building design, occupants' behaviour, choice of technology usage, and manufacturing and construction processes have resulted in the increasing energy consumption as well as the release of greenhouse gases (GHG) in the building sector [1]. Globally the building sector consumes over 30% of total final energy, having increased by more than 35% since 1990 and, at the same time, accounting for 30% of CO2 gas emission. The building sector also accounts for half of the world electricity demand, with some region electricity consumption increased by 500% [2]. In the residential sector, energy is consumed for space heating, cooling, domestic activities, and lighting, among others.

However, the use of improved thermal building envelope, bioclimatic design, and energy-efficient appliance, as well as light fittings, has seen the offset of energy demand from floor and population growth in the building sector [3]. Thus, final energy demand in the building sector only rose by 5% between 2010 and 2017. Within the above specified period, a significant decline in space heating was observed, while improvement in space heating is not visible [4].

In South Africa, the housing shortage in most rural communities resulted in the mass construction of houses (low-cost) in the Reconstruction Development Program (RDP) in 1994. Since the inception of low-cost housing (LCH), more than 4.9 million households have been accommodated with over 2.3 million backlogs [5, 6]. According to Klunne, LCH are designed with no consideration of thermal energy efficiency, as they cannot utilise solar energy for space heating. He further indicated that uncontrollable heat exchange between the inner and outer space of the house due to openings and cracks on the building envelope leaves the inner space extremely cold in winter [7]. In 2005, Overy also found that the quality of LCH is poor with 90% of newly built houses not conforming to the national norms and standards. In his report, he also eluded that corruption and the use of unqualified contractors (builders) are at the forefront of the nature of the houses [8]. However, LCH dwellers tend to bear the burden as they spend a significant amount of their income to achieve thermal comfort indoors [9]. Most households that cannot afford electrical energy resort to the use of firewood, coal, paraffin heaters, or thick clothing as alternative sources of energy for heating. This results in poor indoor air quality, cold-related illness, early child motility, respiratory diseases, etc. [10, 11]. Needless to say, the provision of LCH is a positive approach to rural development in the country, but incorporating passive solar design will improve the welfare of occupants and energy consumed in space heating as well as cooling, creating sustainable rural development.

The ambient weather of a house possesses a significant amount of energy required to naturally heat or cool the inner space at little or no expense. At the same time, the uncomfortable thermal condition indoors is due to the uncontrollable interaction between the indoor and ambient weather factors [12]. Hence, to efficiently utilise the ambient weather energy indoors, a selective thermal exchange between the inner and outer environment is required; this process is known as passive solar or bioclimatic design [13]. A passive solar design uses heat movement such as conduction, convection, and radiation to admit and distribute heat in the inner space of a house.

On a typical sunny day, heat is transmitted through the windows due to radiation and conduction. The transmitted heat is stored and distributed by furniture and indoor air due to conduction and convection, respectively. Minimum infiltration air heat transfer through enhanced airtightness and controlled ventilation components are among the strategies of passive solar design. Conductive heat transfer through the perimeter walls of a passive solar house is also avoided as it is uncontrollable [14]. Regarding cooling, strategic locating and sizing of windows are used to achieve various airflow indoors. Windows at the windward and leeward side of the house create pressure difference indoors, resulting in a cross-ventilation [15, 16]. Also, locating windows or vents at significant height results in another form of airflow known as stack effect. Stack effect occurs due to vertical air temperature variation indoor. Therefore, the rate of airflow increases with an increase in the height between the upper and lower windows or vents [17].

In both aspects of passive solar design mentioned above, the windows play a vital role, considering the building envelope components, whereas the sun and wind constitute the ambient weather influencing factors. The windows in a passive solar house are strategically located and sized to take advantage of the

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**Figure 1.**

windows [16].

*Towards Sustainable Rural Development in South Africa through Passive Solar Housing Design*

ambient climate condition effectively. A prototype rural LCH energy-efficient house was design and constructed in SolarWatt Park based on the principle of a passive solar house. The aim of this study is to analyse the thermal performance of the house. In the context of this study, the thermal performance of the house is analysed based on the indoor weather condition relative to the outdoor ambient

SolarWatt Park is located at the University of Fort Hare, Alice, in the Eastern Cape, South Africa. Alice is classified in the temperate interior (zone 2) climate of South Africa [18]. Typical annual season of Alice is characterised by a hot summer and mild (no snow) winter, with an average dry bulb temperature of 29 and 15°C, respectively. The east wind is predominant in summer, while the winter is dominated by the west wind. An average wind speed of 2.5 m/s is experienced in Alice throughout the year [19]. A climatic map of South Africa [20], the Google earth map of SolarWatt Park and the passive solar house are presented in **Figure 1**.

The site was found suitable for the design and construction of the passive solar house due to its clear north side with no sunrays' obstacle such as tall trees, mountains and high-rise buildings. Therefore, the house was designed with its major glazing area facing north which is by the energy-efficient building design recommendation in South Africa [18, 20]. A simulated daily sun path of the house with

In the northern hemisphere, north-orientated housing design guarantees optimum sunray penetration in the winter season due to the low-angle sun. The penetrated sunrays, therefore, provide heating and daylighting indoors. However, the 44-cm long eaves are used to prevent overheating indoors during the summer season by blocking direct sunrays. To this effect, the two large north-facing windows (see **Figure 2**) distribute solar radiation to the northern floor area of the house, while the clerestory windows channel solar radiance to the southern floor

Meanwhile, the clerestory windows enhance indoor passive cooling due to convectional current and various wind effects through effective operations of the

*Climatic map of South Africa indicating the location of the SolarWatt Park and a photo of the passive solar house.*

area. Hence, even solar radiation distribution is achieved indoors.

*DOI: http://dx.doi.org/10.5772/intechopen.85997*

**2. SolarWatt Park and the passive solar house**

respect to its orientation is shown in **Figure 2**.

weather and the windows.

*Towards Sustainable Rural Development in South Africa through Passive Solar Housing Design DOI: http://dx.doi.org/10.5772/intechopen.85997*

ambient climate condition effectively. A prototype rural LCH energy-efficient house was design and constructed in SolarWatt Park based on the principle of a passive solar house. The aim of this study is to analyse the thermal performance of the house. In the context of this study, the thermal performance of the house is analysed based on the indoor weather condition relative to the outdoor ambient weather and the windows.
