In a bid to contribute to market transformation geared towards sustainability in the Western Cape tourism and construction industries, the environment-friendly Hotel Verde, in Cape Town, is installing geothermal heating and cooling designs worth R26.6-million. The construction of the hotel itself, which is operated by hotel management company BON Hotels, started more than a year ago and is about 400 m away from Cape Town International Airport. Built environment consultant Ecolution Consulting engineer Andre Harms says Hotel Verde intends to reduce heating and cooling loads by installing shading, energy efficient lighting, double-glazed performance windows that reduce solar heat gain and by switching off unnecessary equipment.
“The strategy is to cover, as efficiently and effectively as possible, the remaining heating and cooling load required by the building, while still providing a comfortable indoor environment for guests and staff,” Harms says. Guests will also be encouraged through credit notes and bar tabs, to refrain from using air conditioning in their rooms, which will be supplied with preconditioned fresh air from central systems. The hotel has sunk 100 boreholes, each 70 m deep, containing a high-density polyethylene U-bend pipe that will be coupled into six headers to form the hotel’s geothermal field, which will heat water using a constant ground temperature of about 19.4 oC.
The hotel will also feature ground-source heat pumps, variable-speed drives on pumps and fans, inverter-type fan coil units and intelligent control that switches off unoccupied zones. The building products are energy efficient and Harms says the design of the geothermal field and the ground-source heat pumps installation are novel in Africa and are used on a larger scale than usual. Harms explains that a ground-source heat pump is a type of water-source heat pump that uses water circulating through the geothermal field as a heat source or heat sink, depending on a building’s heating and cooling demands. “The heat pumps transfer heat from one closed system to another, heating the one while cooling the other. The hot and cold water are used in the building and any excess is circulated through the geothermal field, which absorbs excess heat in summer and is a heat source in winter. The geothermal field, therefore, acts as a huge thermal battery,” he says. Meanwhile, Hotel Verde will also use a grey water recycling plant, which will help reduce potable water use by 37%. A network of pipes in the building, will reticulate, collect and supply the grey water to the hotel’s toilets. The hotel will also use a rainwater filtering and capturing system to provide water for irrigation and to wash cars.
Further, photovoltaic panels will be mounted on the north facade and northfacing roof sheeting of the building to generate electricity and to create shading for windows that are most exposed to the sun. Hotel Verde owners Mario Delicio and Annemarie Delicio say they have transformed a business proposition into a showcase for some of the most advanced, environmentally conscious technological installations in the world, as well as for construction and operation practices. Local suppliers were sourced and sustainable on-site practices were used, which reduced waste to landfill to almost zero, during the construction of the hotel. Waste is reused and recylced where possible, says Harms. “There is no other hotel in Africa that has gone to this extent. But going green is not just about the building, it’s about every aspect of the operation; for example, zero waste to landfill. We might never reach that, but with the ideas we have in mind we will come pretty close,” say the owners.
BON Hotels CEO Guy Stehlik says the prospect of implementing green practices into every facet of the hotel’s operation is a challenge that the hotel group is relishing. He says it gives the group an opportunity to revolutionise many conventional ways of managing its hotels. Hotel Verde is set to open in mid-2013 and Harms says the owners want to share their convictions and show the continent what can be achieved by using sustainable technologies and practices, and they challenge the construction industry to do the same.