The aim of the project was to develop evidence-based cool roof design and cost-benefit calculation resources, mainly focused on large-footprint buildings, and specifically tuned to the needs of Australian industry, namely covering Australian climate zones, building typologies, construction details, locally produced cool roof products, etc.
Cool roof technology is known to reduce the cooling energy consumption of conditioned buildings during hot periods and widespread implementation of such roofs in a neighbourhood or precinct can mitigate the urban heat island effect. Established building energy modelling techniques are able in principle to predict the benefits of cool roofs due to reduced heat transfer through the roof structure. But several scientific and industry publications have claimed that additional benefits can arise from reducing air temperature above cool roofs. Rooftop heating, ventilation and air-conditioning (HVAC) equipment energy consumption would be reduced by such an effect and the efficiency of rooftop photovoltaic (PV) panels would be improved. This study summarises the work carried out under project RP1037 (an activity carried out under the auspices of the Cooperative Research Centre for Low Carbon Living, under Program 1: Integrated Building Systems), the aim of which was to help overcome a number of barriers that were hindering the wide-scale utilisation of cool roof technology on Australian large-footprint buildings.
The specific aims are:
The evidence base and resources developed will allow designers/owners to easily, but rigorously, quantify the costs and benefits of cool roof products from the point of view of both ‘passive’ reduction of heat load through the roof and from the above-roof temperature field, which may cause HVAC plant located on the roof to consume significantly more energy than when a cool roof is employed.
Figure 1. Comparison of thermal and visible images of PV panels
The project was comprised of four main steps:
Figure 2. Side-by-side comparison of a non-cool (SR = 0.47) and a cool-coated roof (SR = 0.61)
Figure 3. Schematic outline of the project activities
Building Performance Simulations (BPS) were conducted for two case-study large-footprint buildings, in seven Australian climate zones, with four different roof materials and two different HVAC systems. Research case study buildings represented a simplified airport and a shopping centre, and were simulated with and without above-roof temperature model.
Project leader: Scientia Prof. Mattheos Santamouris
Research team: Alan Green, Laia Ledo Gomis, Afroditi Synnefa, Shamila Haddad, Riccardo Paolini, Paul Cooper, Jamie Adams, Mark Eckermann, Greg Johnson, Georgios Kokogiannakis, Zhenjun Ma, Buyung Kosasih and Mattheos Santamouris
Prof. Mattheos Santamouris, email@example.com