Case Study: Somerville House – Solar Hot Water

Solar Hot Water – South Brisbane, Qld

Project Overview

Somerville House girls school in South Brisbane built a new Junior Boarding House in late 2009 that was opened in early 2010.

A key aspect of the project was installation of a solar / gas hybrid hot water system to supply the almost 100 teenage residents of the boarding house.

High performance evacuated tube solar collectors were chosen to supply solar heated water in a two stage Rotex hot water delivery system. The first stage is a solar pre-heat and the second stage is a gas finishing plant powered by two commercial grade Bosch 32 series instantaneous gas burners.

The Solar Guys working with Rotex designed and supplied the system, which was installed by the major plumbing contractor on the project. The system was designed to deliver an annual solar contribution of over 60% so as to minimise natural gas usage on the site.

Solar Hot Water

Eight x Hills Solar 30 tube collecters were installed flush-mount onto the north-facing roof at a pitch of 20°. These are connected in one back of three and one bank of five back to the Rotex hot water delivery system.

The solar heated water keeps the three x Rotex 500L Storage Heat Exchanger pre-heat tanks hot, with cold mains water picking up this heat as it runs through heat exchange coils inside each tank. Any additional heat required to meet the temperature requirements is provided by the three x Rotex 500L Storage Heat Exchanger gas finishing plant tanks before the mains water proceeds to the point of use.