Saving the environment and reducing soaring energy costs for building managers could be as easy as opening windows at night time, according to a Griffith University researcher.
In research conducted over a two-year period led by Griffith School of Engineering and Built Environment lecturer Dr Henry Skates, it was found that simply opening windows or pushing hot air using ventilation systems through unoccupied buildings at night was enough to reduce the heavy reliance on airconditioning to cool buildings down the following day.
Dr Skates, who specialises in architecture technology, and his team of researchers recently published the findings in a first-ever comprehensive review of night ventilation strategies in Energy and Buildings.
He said these strategies in Australia, while known of, were not commonly practised, but the benefits for cutting building running costs and reducing greenhouse gas emissions was clearly evident in the findings.
“There are some buildings designed to allow for night ventilation, but one of the things that seems to be accepted knowledge is that it’s only suitable in certain circumstances; for instance, it’s only good where you have a very high difference in temperature between daytime and night time,” Dr Skates said.
“Whilst that is important, in actual fact in the work that we’ve done it’s not the only factor involved.”
The research also includes a review of the use of phase change materials (PCMs) which store many times more heat than normal building materials and are effective in many different building types and all climate types throughout the world.
Dr Skates said the use of these materials can further reduce the reliance on daytime airconditioning and significantly reduce energy costs associated with both cooling and heating; in some cases, by up to 40%.
“PCMs melt at a very low temperature and as they melt they absorb lots of heat then release that heat the following day. So PSMs are smart materials in that they can maintain steady temperatures in a building, even though the outside temperature might be climbing rapidly,” he said.
“These materials can be retrofitted, are becoming lower in cost and a company in Australia is now producing them. That’s a big consideration because the majority of our building stock is already in existence.
“We looked at all the major cities in Australia and discovered that PCMs are effective in every climate type within certain parameters, so this research could have a significant effect on energy use in buildings.”
The research also uncovered the main parameters and the effectiveness of night ventilation along with its limitations, control systems used and the use of supplementary cooling when used in conjunction with night ventilation.
Dr Skates said this comprehensive review of night ventilation strategies will provide building designers, developers, facility managers and other researchers with the tools to make buildings more energy efficient and reduce running costs.
“Building managers and developers will find it extremely beneficial because if buildings are more energy efficient then there’s more likelihood of attracting a sale or a lease,” he said.
“As energy prices increase – and they will – it becomes a significant part of the running cost of a business, so it can cut your bottom line significantly.”