Housing in Southern Africa October-November 2016

Thermal comfort of Innovativebuilding technologies (IBTs) demonstrate significant value-adding attributes to construction products and building systems, whichcouldplay amore significant role in thedelivery of subsidised houses in South Africa.

A ccording to IBT fundi, Dr Jeff Mahachi from the National Home Builders Registration Council (NHBRC), one of the funda- mental reasons for erecting buildings is to create a shelter against the varia- tions of the outdoor climate. He highlights that innovation in the building system in terms of mate- rials or methods of construction has the potential to be able to achieve improved thermal performance due to its integratednature of the technol- ogy components for relevant climatic zones. There has been little research on the performance of IBT envelopes in the South African low-income and gap housing market. More atten- tion should be paid when designing and constructing homes to address comfort temperatures and energy efficiency savings that will induce benefits in the longer term. Due to the shortfall of housing for the poor, more efficient ways of delivering homes are being sought through the use of IBT. To contrib- ute to wider development goals of sustainability, it is critical to create a shelter against the vicissitudes of the outdoor climate that simulta- neously addresses environmental concerns such as energy efficiency. The aim of climate conscious design is thermal comfort, on which this research is based. Thermal comfort or thermal neutrality is the series of conditions in which householders feel neither too hot nor too cold. The research includes whether the indoor temperatures of the constructed IBTs fall within acceptable comfort temperature ranges. The NHBRC

of artificial heating or cooling is an energy-efficient building. It is also likely to be the buildingwith themini- mumnegative environmental impact and the lowest running energy cost. A fundamental reason for erecting buildings is to protect householders against extreme climate changes and create indoor environmental condi- tions that are better than outdoors and within the comfort range. International standards com- monly used to evaluate thermal environments include ISO 7730 (2005), ASHRAE 55 (2013) and EN 15251(2007). ASHRAE Standard 55 (Thermal Environmental Conditions for Human Occupancy). These stan- dard that providesminimum require- ments for acceptable thermal indoor environments. The study aims to monitor the thermal comfort of 25 different IBT houses at Eric Molobi Innovation Hub to establish the live-ability of houses in terms of comfortable internal temperatures. It therefore estab- lishes whether the IBT houses are thermally comfortable in terms of the indoor temperatures versus outdoor temperatures. Bearing in mind that the IBT houses are show units, the performance of the envelope of the building becomes relevant in the exercise. To obtain optimal results

logged data for summer and winter including minimum and maximum, average temperatures and humidity at 25 IBT houses at the NHBRC Eric Molobi Housing Innovation Hub in Soshanguve, Pretoria. Temperature and humidity loggers were set up in IBT houses ranging in size from 30 m² and 110 m² and the data collected was to ascertain whether the indoor temperatures werewithinAmericanSociety of Heat- ing, Refrigerating, Air-conditioning Engineers (ASHRAE) 55-2013 adaptive method comfort ranges of naturally ventilated buildings. The adaptive chart relates indoor comfort tem- perature to prevailing outdoor tem- perature and defines zones of 80% and 90% satisfaction. The results indicated that only a marginal per- centage of the maximum and mini- mum dry-bulb temperatures, over a one month period, complied with ASHRAE standard 55-2013. However, the average dry-bulb temperatures for all the IBT homes in summer complied, whereas most IBT houses in winter did not comply. This is the temperature of air measured by a thermometer freely exposed to the air but shielded from radiation and moisture. HolmandEngelbrecht state that building design that achieves thermal comfort with a minimum

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