Three’s company for hot water

Three’s company for hot water

At a time when climate change and population growth are placing increased pressure on water resources, South East Water has developed a new rain-to-hot water system that will reduce reliance on potable water and allow homes to be plumbed with three types of water. Adelle King explains.

A new housing development in Melbourne’s south east will incorporate a range of unprecedented water saving features as part of a collaboration between South East Water and residential land developer Villawood Properties.

Known as Aquarevo, the 460-home development is being built at the site of a decommissioned water purification plant owned by South East Water and will have built-in energy efficiency and water saving features in each property.

It’s on track to become what has been described as Australia’s most sustainable urban residential development that will push the boundaries in eco-friendly living.

“We wanted to reduce the reliance on drinking water without losing the liveability we enjoy today, which is why Aquarevo homes will be plumbed with three types of water – rainwater, drinking and recycled,” says South East Water Aquarevo group manager Terry Dalgleish.

The main water-efficient feature is a rain to hot water system that will directly supply hot water services in the bathroom and laundry.

Terry says South East Water designed this rain to hot water system as a way to focus on using sources of water for their most appropriate purpose.

“At the moment, in most towns and cities, reticulated mains drinking water is used for a variety of purposes – drinking, cleaning, flushing toilets, watering gardens and washing clothes. In rural communities, the opposite is often the case, with rainwater usually the sole source for the household and often untreated and unmonitored for quality.”

This is the first rain to hot water system to be developed to deliver water of this quality and on this scale. Terry says designing the system into a new home rather than an existing one is not only much easier but also more practical.

“Considerations such as ongoing ownership, maintenance and monitoring of the equipment make precinct-scale implementation much more viable.”

South East Water has designed and developed a system that will treat rainwater for safe supply as hot water for the shower, bath, laundry trough and washing machine. In addition, heated drinking water for food preparation or other human consumption will be supplied to all sinks, basins, fridges and dishwasher appliances via a normal water system.

Every home will have a 2,400L rainwater tank to feed the heat-pump hot water system, which will draw its energy from the warmth in the air.

“We all need to reduce our reliance on drinking water as we deal with the challenges of population growth and climate at change. That’s why innovative projects like the Aquarevo development are key to putting people first by making our communities more liveable and sustainable for the future,” said Victorian Minister for Water Lisa Neville in a 2016 press release.

Rainwater is collected on the roof of each home within the Aquarevo development and screened through a gutter guard to remove debris that might be on the roof or in the gutters. The water then passes into the downpipe where it is screened a second time through a leaf diverter. A third screening is done via the initial flow of 17L of rainwater being diverted away from the rainwater tank by a first flush device.

The screened water flowing into the tank is filtered through a fi ve micron filter and exposed to UV light before being heated to 60°C to remove bugs or pathogens to be safe for non-drinking purposes.

An air source heat pump fitted on the tank uses a refrigerant fluid to absorb warmth from the outside air and transfer it to the water stored inside, using up to 60% less electricity than a conventional electric storage hot water system.

Drinking water will be automatically supplied to the hot water system as a back-up if no rain water is available or if the system detects any variations in quality.

“South East Water will monitor individual systems throughout the estate to ensure all components are maintained and in good working order. We will also supply, install and maintain all components of the system installed on individual homes for 10 years at no cost to the property owner,” says Terry.

South East Water has a patent pending on this technology, which has undergone extensive testing and monitoring.

“Several test sites have been established with full monitoring and South East Water has established a formal test environment at Holmesglen Institute to create scenarios and drive the system beyond expected real-life situations. The facility is also being used in the curriculum for the education of future plumbers,” says Terry.

As part of this collaboration between South East Water and Holmesglen Institute, a test rig has been constructed within the Chadstone campus workshop with an assembly of water tanks, pumps, filtration systems and fixtures attached to a two-storey simulated domestic home. This simulated home can be monitored remotely from a South East Water facility to test the performance and viability of the heating of rainwater.

Terry says independent testing is also being undertaken by Monash University to further push the system’s performance.

Each property will have South East Water’s OneBox technology installed to intelligently manage water use and monitor energy consumption within the home.

OneBox is a small, wall-mounted, remote controlled telemetry system that can control and monitor the hot water system at a property, as well as the temperature of hot water leaving the hot water unit. It allows South East Water to remotely monitor and control the Aquarevo estate’s pressure sewer network, regulate sewer flow and enable Tank Talk.

Tank Talk is a system that enables the rainwater tank on each home to serve as a retention system through which South East Water can control stormwater discharge.

“Each tank has a transducer device installed within it that measures the water level and a motorised valve on the outlet of the tank. Both are connected to South East Water’s OneBox device, which integrates data from the Bureau of Meteorology with a predetermined formula and discharges water to stormwater prior to a significant rain event,” explains Terry.

“The benefit is that flows to our waterways can be better controlled and water quality within the tank improved.”

Additionally, South East Water has developed an app that aggregates data from the technologies in the system to provide customers with near real-time data on their water and energy use.

As part of the three plumbed system, waste water will be recycled to a Class A standard at an on-site treatment plant.

A pressure sewer is being used throughout the development instead of the traditional gravity system. This allows flows to the onsite water recycling plant to be controlled without diurnal peaks, resulting in a smaller treatment plant footprint. The plant will then return Class A recycled water to homes for use in toilets, gardens and optionally for washing machines.

Terry says these systems and technology, making use of rainwater and recycled water, will enable Aquarevo residents to cut drinking water demand by up to 70%, which is the equivalent of 1.2 million showers. They will also reduce stormwater run-off by 25%.

“These outcomes are unprecedented in a greenfields residential development,” says Terry.

South East Water’s use of innovation was recognised in 2017 when South East Water was inaugurated as a member of the Leading Utilities of the World (LUOW), an organisation that aims to promote innovation within utilities and communication between utilities.

It seems home owners are also impressed by the range of advanced environmental initiatives on offer at Aquarevo, with some lots selling out within hours of their release.

Land sales at Aquarevo commenced in November 2016 and all 167 lots released as of August 2017 have been sold. House construction will begin in 2018 and the development is expected to be completed by 2022.

Once completed, South East Water hopes Aquarevo will demonstrate there is a better way to use water at home that doesn’t compromise quality or liveability. If successful this could then result in more residential developments plumbed with three types of water to deliver sustainable, waterefficient homes.

“We’re excited about the opportunities this rain to hot water system presents for developments in urban and rural environments, and in Australia and beyond,” says Terry.

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