Hofmeyr-Cohen Residence

We recently completed a house for Genevieve Hofmeyr and Peter Cohen up in

Devonport road, Tamboerskloof. Some of you might know Peter better as the

drummer for local act Freshly Ground". Genevieve is a director at Moonlighting

Film productions. Please take a look around.

Click on images for a larger view

Solar Installation

The solar installation at the Hofmeyr-Cohen Residence is responsible for all hot water intended for household use, under floor heating and the swimming pool.

The dark blue rectangles which can be seen in the image are solar collectors. Solar collectors collect energy from the sun, which is then transferred to a water glycol mix. This energy(heat) is exchanged via internal heat exchangers to water which is stored in hot water storage cylinders . The flat plate glazed solar collectors which were used at the Hofmeyr-Cohen residence are made in Germany and used throughout the world due to their high efficiency in the low operating temperature range. Compared to other kinds of solar collectors, the flat plate collector is the most durable and cost-effective, and is especially suitable for regions with high solar exposure and frost.

The solar collectors are manufactured from a sturdy anodized aluminium frame

which is covered with tempered glass and sealed with high temperature gaskets

made from EPDM for high endurance in the sun. The rear of the solar collector

absorber is insulated with 30mm thick rock wool and the back cover is made

from aluminium. The blue black colour is due to a coating which is used on the

collector surfaces to optimize energy absorption. In a thermo siphoning system

the heated water is transferred from the collector to the tank through convection.

For this to work the storage tank needs to be installed higher than the solar

collector otherwise natural convection cannot occur. At the Hofmeyr-Cohen

residence it was necessary to consider the sightlines and views of neighbouring

properties which meant that the tanks could not be accommodated on the roof

where the collectors are. Instead the tank is located on the ground floor in a

storage room, which means that a controller and pump was necessary to transfer

the heated water to the tank. The pump and controller are both connected to the

main power supply and have an average consumption of around (250-300 W/day),

which amounts to betweenR6 and R8 a month.

The solar installation was completed by Solarzone in conjunction with

Florad, who were responsible for the under floor heating.