Development Bank of South Africa, Visitors centre, South Africa. Holms and Friends: 25,6m2 Vacuum tube system for domestic warm water and under floor heating.


Holms and Friends completed a solar water heating (SWH) project for the Development Bank of South Africa in 2009.  The company specializes in integrated energy strategies and EPC for large scale, commercial solar water heating and photovoltaic systems. They are known for the training they offer in the renewable energy and energy efficiency sector as well as education for sustainable development.  One of the energy-efficient measures is the heating of the buildings’ domestic water supply through thermal solar water heating.  This system additionally heats water for under floor heating during winter time.


The low temperature (30° C) required for the UFH system creates the opportunity for very high SWH system efficiency. Both the collector and domestic water system are direct and connected to the fresh water. This in itself leads to high energy transfer efficiencies. The UFH system (300m2) has a heat exchanger of 12kWth. A peak demand of 40Watt/m2 floor area is only required in extreme cold weather, as the building as excellent solar passive performance. The building is also ventilated by a pre-heated earth tube system. As the UFH system warms the well-insulated structure (which has a high energy capacity), the continuous opening and closing of doors has very little effect on the thermal comfort.

The domestic hot water system is circulated through a well-insulated circulation pipe loop, which avails hot water instantaneously  when the water efficient taps are opened.

The water heated by the solar panels is stored in the 2 500 litre high pressure steel vessel with enamel coating.

Holms and Friends can individually tailor an energy building plan specifically suited to the client. Especially new (and existing) office constructions have so much potential for energy efficiency that just needs to be harnessed through professional design.
“This building brings us closer to our quest for energy and carbon neutrality”, says Graham Tate, Divisional executive facility management at DBSA “and it is a pleasure to welcome guests to the DBSA with this eco-friendly building.”