Dr Ashak Gulamali Nathwani’s story is one of overcoming adversities and triumphing over the odds – and now the 72-year-year old has the answer to every building services engineer’s biggest conundrum: which airconditioning system is a cut above the rest.
Dr Nathwani arrived in Australia in 1972 from Uganda with just 20 cents in his pocket. And this week, exactly 50 years later – to the hour – he obtained his PhD at the University of Sydney’s School of Architecture, Design and Planning.
“An unbelievable serendipity,” he said.
Having worked at Norman Disney & Young for 33 years, volunteered in educational services with the Property Council for 25 years, and lectured in facilities management and mechanical services at Sydney University for more than 10 years, Dr Nathwani knows that one of the biggest challenges facing building services engineers is choosing the right airconditioning.
And in times of pandemics and urban heat, it can be life-or-death to get it right.
His research thesis addressed a comparative analysis of airconditioning systems in the commercial built environment – comparing cost, comfort, climate change and Covid. The findings of which will contribute to the ARBS Education and Research Foundation and the Aga Khan Development Network (AKDN).
Dr Nathwani thanked his children for encouraging him to complete his PhD, after he discontinued the research in 2017 to care for his wife Samim, who passed away from motor neurone disease – she was instrumental in much of his research up to that point, assisting in taking temperatures and recording results.
Comfort is subjective
During the study, participants from the built environment industry, including from the City of Sydney, Commonwealth Bank, GBCA, Stockland, and AMP among others, came to spend time in the Environmental Quality Lab (IEQ), which he said was so that the test subjects would be people from real-world office settings.
“Comfort is subjective: what you find comfortable, I might not find comfortable. I wanted to research the practical aspects of comfort and other aspects of airconditioning,” he told The Fifth Estate.
Therefore, in addition to human participants was another unlikely test subject – Laura Palmer, a cutting-edge thermal comfort research mannequin wired to mimic a human body’s skin temperature, equipped with sensors and the ability to breathe. The life-sized mannikin is named after a fictional character from the cult TV series Twin Peaks.
“It’s the only one of its kind used to test comfort,” Dr Nathwani said.
“It created a real understanding of temperature gradients.”
Thermal comfort not so clear cut
For the ideal temperature, “23 degrees appears to be the right temperature,” he said. But this varies depending on the season, with ideal summer temperatures set at 24 degrees Celsius, and ideal winter temperatures set to 21 degrees.
But it’s not so clear cut.
The results found that women percieved the environment to be slightly cooler than men: because women’s clothing generally lacks insulation, and because their metabolism is slightly different (studies show that men have less body fat, and consume more calories than women).
In fact, he said, women are so used to it that many women participants in the study brought a shawl with them in anticipation of just this (take note, ladies: he said the best fabric to choose is pashmina wool due to its high thermal comfort).
He said that to counteract this, in his work helping his community by improving indoor air quality and thermal comfort in Ismaili Muslim prayer centres across the world, he found it is best to set the temperature half a degree higher in women’s areas than in mens area’s – this is based on practical evaluations using tiny temperature sensors installed across the centres which record temperature data every 15 minutes.
There is also research into cultural differences in thermal comfort which points to perceptions of thermal comfort varying significantly between countries and regions.
“In some parts of India, people can live comfortably in temperatures of 35 degrees, while we would find that very hot here in Australia. Climate adaptation is a whole new area of research in adaptive comfort.”
Another finding was that participants generally had relatively cooler heads on the temperature gradient and warmer feet with chilled beam systems particularly, “like when you go into the kitchen and the floor is cold, and you put socks on.”
He found that there were a range of other factors contributing to comfort, which need to be considered by facility managers when fine-tuning HVAC systems, including cold draughts and unwanted air movements.
Cost effectiveness
A big challenge with the research was cost effectiveness, which Dr Nathwani said is often overlooked. Building owners and developers often look to which system is cheaper, rather than which will provide returns over the life cycle of the system, he said.
“It’s difficult to research cost effectiveness,” he said.
“One of the things we created was an excel-based tool that allows you to compare different systems so people can look at the life-cycle costs. Having been in the property industry for a long time, that’s something that’s often overlooked – how the costings are related to energy usage. if you save on energy costs, the ROI period decreases.”
The best airconditioning system overall
The best airconditioning system for cost, comfort, and energy efficiency (depending on central plant configuration) was found to be the chilled beam system, a type of radiation/convection HVAC system with an integral coil that may be installed within a space in order to provide sensible cooling and heating.
This also predicated on the fact that the system has been, installed and maintained appropriately. The system that showed much lower Covid concentrations was Under Floor Air Distribution (UFAD).
“It works on the physics principle of cold air falling and hot air rising,” Dr Nathwani said.
Now that he’s solved that debate, he’s not slowing down yet.
As part of his work with the AKDN, Dr Nathwani is now creating a training program for facility managers on how to manage energy and reduce emissions in buildings, translated into several languages.
He is travelling to Pakistan next month to conduct energy audits and greenhouse gas emissions assessments on a range of buildings, and also looking into geothermal heating in Tajikistan and Northern Pakistan.
He is also working on a book – a technical guide for architects.
“There is a gap of knowledge between aesthetics and the practical, operational side,” he said.