A tropical take: smart cooling in the tropics

Glenn Evans reading the electricity meter with clients John and Lea Mungbando

A Northern Territory program that works with low-income residents to reduce their energy bills and improve their comfort is starting to see results. Robyn Deed talks to one of the energy assessors about his approach and how the project is progressing.

ReNew first reported on COOLmob’s Smart Cooling in the Tropics project in December 2014, when the project was just starting. Since then, 480 households have had initial home visits and many have had upgrades applied to their homes.

Data is also being collected. This is the first large-scale project to identify and measure the best approaches to cooling, comfort and energy efficiency in tropical Australia. The outcomes will be used to inform national energy policy, and to influence building codes and rating systems to make them appropriate for the tropics.
The research findings will consider a range of factors including which treatments produced the biggest energy cost savings, which households achieved improvements in comfort levels, and which participants gained better awareness of energy consumption issues and opportunities.

While the evaluation phase is only just starting some early anecdotal observations are giving a flavour of the evidence to come, says Project Manager Jessica Steinborner: “The two primary issues identified through the home visits are heat gain and air flow.”

Heat gain

  • Many homes have no or inadequate shading and a number have dark roofs.
  • A high proportion of homes assessed have outside walls of high thermal mass.

By the end of the project, nearly a quarter of participating homes will have had a heat prevention solution such as shading or reflective roof paint.

“Shading has been a really popular treatment. In addition to preventing heat gain, shading creates a protected outdoor living space away from the hot concrete interiors of their homes,” says Jessica.

Air flow

  • Ventilation is often restricted either as a result of the orientation or because of the design, with windows and doors poorly located to capture a prevailing breeze.
  • Many homes have fly screens in disrepair and consequently not in use, leading to houses being shut up with the air conditioner on.

Half of the households will have received a treatment addressing air flow including upgrades to their doors and windows to facilitate passive cooling and upgrades to their fans (ceiling, wall and floor).

Other observations and some surprises

  • The majority of participants are home during the day and, despite reporting the highest discomfort in the afternoon, they were opting to not use the air conditioner until the evening.
  • Average number of air conditioners was three and average temperature setting was 24 °C.
  • On average, participants were using 26 kWh/day, the average usage for Darwin.

Until more data is available, it’s great to hear comments like this: “I have lived in Darwin for 15 years and this is the first time I’ve felt cool and comfortable during the wet season,” says Mieme, one of the participants.

Read the interview with one of the energy assessors in ReNew 134.

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