Prof Richard Aynsley – Correspondence to Tim Renouf Dec 2010
FULL SCALE THERMAL FIELD STUDIES
The roof is usually the most critical part of a house with respect to heat gain and heat loss. As you will know when NatHERS was being developed I conducted field studies of heat transfer in house roofs in Townsville for the Queensland Government. Angelo Delsante at CSIRO took an interest in this work as the computer modelling of roof spaces at that time was very primitive. We submitted a joint research study in 2000 to the AGO to determine critical heat flow mechanisms in roof spaces but it was not funded.
It is still my view that there is an urgent need to conduct full scale thermal studies on Australian houses to ensure that computer models reflect reality before many more millions of dollars are wasted on get rich quick programs for the bulk insulation industry.
Such studies were conducted at Oak Ridge National Laboratories in the USA from the 1960s to get above the influence and hot air from the fibreglass industry in the USA. It is way past time that such studies are done in Australia. Australian Standard 4859.1 rates fibreglass insulation R-values at an average temperature of 23ºC and summer metal roof temperatures can reach close to 100ºC with air in roof spaces around 55ºC and average of 77.5ºC.
As UNESCO Professor of Tropical Architecture and Director of Australian Institute of Tropical Architecture the postgraduate research institute at James Cook University I supervised a number of doctoral research field studies on energy efficiency in houses. Some of this work demonstrated the enormous heat transfer reduction benefits to be gained from aluminium foil radiant barriers in roofing as has been endorsed by the US Dept of Energy for decades. How long will it take for Australia to learn?
Professor Richard Aynsley
B.Arch(Hons I), MS(Arch.Eng), Ph.D.
FRAIA, FAIRAH, M.ASHRAE, Af.M.ASCE
(22 Dec, 2010 ***correspondence to Tim Renouf)
SPECIAL NOTES BY TIM RENOUF as at May2011
The CSIRO-Aynsley collaborative research proposal (2000) was co-ordinated by myself as Secretary of AFIA, the independent foil insulation association (I held this position from 1996-2010). The proposal was submitted to the AGO, under a funding program for national “greenhouse gas abatement”. The study is available on request. The reason given to me at the time why the proposal was rejected from the AGO was that “other proposals were considered to produce faster greenhouse gas abatement”.
I found the reasons completely implausible and my disappointment was an understatement. If this early work had been done (for about $200,000) AccuRate might not be in the mess that it is today.