To see deep into space deserts offer the best atmospherics, Temperzone describe how they helped make those atmospherics suitable for human habitation.
By the time you read this article, the decision about the location of one of the world’s most advanced scientific projects of our time, has already been made.
Hopefully, the winner will be the Australia and New Zealand site.
Australia and New Zealand were jointly shortlisted as a potential host of the Square Kilometre Array, or SKA, telescope and are currently working together to establish an SKA site in Western Australia. The SKA will be built in either South Africa or Australia and New Zealand with the final site decision expected in April.
The Square Kilometre Array is a next-generation radio telescope currently planned by institutions from over 20 countries. The SKA will be a revolutionary radio telescope made of thousands of receptors linked together across an area the size of a continent. The total collecting area of all the receptors combined will be approximately one square kilometre, making the SKA the largest and most sensitive radio telescope ever built: it will be able to detect an airport radar on a planet 50 light years away. It will expand our understanding of the universe and drive technological development worldwide.
Temperzone involvement
Temperzone’s involvement in this world first project is the result of a strong relationship between the South Australia office and Robin Johnson Engineering (RJE). RJE is a large electrical engineering, design, project management and construction company.
RJE were asked to look at the cabling for the project which, as you can imagine, involves kilometres of cabling connecting each of the dishes to the compound building. They were also working on the construction of the central building that will house the super computers.
Temperzone’s South Australian branch manager Ryan Wijayasekera received a phone call directly from Robin Johnson, requesting a quote to supply and commission Hitachi chillers to maintain the strict conditions necessary within the compound building for the super computers.
The list of required specifications presented some unique challenges that needed to be overcome.
The whole compound building needed to be a transportable building that could be manufactured offsite in sections and then transported to the site for reassembly. The mechanical services within the compound building had been designed to allow for the majority of the mechanical installation to be incorporated into the transportable building off-site with sections connected together on-site. Given the obvious size constraints the compact foot print of the Hitachi chillers was welcomed by RJE.
The actual location of the site at Murchison, Western Australia (WA), also created other issues because the climate and environmental conditions are extremely harsh. According to Wijayasekera, “many chillers use open system water cooling towers, but the conditions of the site meant we needed to provide a closed system. Because water is so scarce, we needed to use a closed geothermal water cooling system that pumps the water deep underground to cool it. We were able to do this with the Hitachi chiller.”
Unique challenges
The chilled water system incorporates three water cooled chillers serving chilled water to a number of fan coil and rack units within the correlator room. This is critical to enable close control of the temperature and humidity where the electronics equipment is installed. Three chillers were programmed in a lead/lag/standby configuration. The lead chiller is enabled when the lead chilled water pump is enabled once flow is proved. Lead and lag chillers swap monthly. Chillers need to respond to the external building management system (BMS) signal to unload, when the plant is staged up and staged down to meet the building load.
A unique ground-coupled geothermal heat exchanger system was installed to suit the condenser water. Heat rejection was via high density polyethylene pipework buried in trenches and located in vertical boreholes, using the ground as the heat rejection medium. The vertical boreholes were drilled and pipes were inserted, then filled with grout.
This ground is expected to heat up slowly over the years resulting in increased water temperatures back to the water cooled chillers. The chillers, therefore, had to operate under a wide range of entering condenser temperatures (up to 430C as specified by the consulting engineer). Hitachi product manager James Su played a crucial role by researching this issue first with engineers in Japan, looking at the Hitachi chiller factories and then approaching Hitachi Air conditioning Products Europe (HAPE) in Barcelona, Spain. Fortunately, the Samurai water cooled chiller RCUE80WG2 (232kw) was exactly what was needed and available as a standard product.
The Murchison region of WA is sparsely populated and super radio quiet. The whole compound building has two radio frequency interference (RFI) shields, one around the entire perimeter of the building and one around the correlator room. No fixings should penetrate either of the two shields and all penetration associated with mechanical installation had to be RFI approved.
According to Wijayasekera, “it was important that the equipment used does not emit any radio frequencies that could cause interference with the dishes. The Hitachi chiller uses a mechanical variable screw compressor that adjusts the capacity down to 15 per cent by sliding valve and would not cause any distortion or interference.
The client asked for the chiller to be tested at the design specifications. The engineers in Spain set up the exact specifications and ran the tests at their facilities in Spain. These chillers are Eurovent certified and offer excellent performance as well as efficiency.
“The more the engineer and client looked at it,” said Wijayasekera, “they realised that the Hitachi chiller is perfectly suited to this type of application. Obviously something very reliable was needed because this is an unmanned site hundreds of kilometres from Perth. The fact that the chiller was built by Hitachi was an important factor in receiving the job. The client also had confidence in Temperzone’s ability to support this product.”
The chiller was ordered and delivered directly from Spain to Adelaide where it was installed in the central, steel clad building that RJE constructed. The central building was then shipped in modules to the SKA site at Murchison. Temperzone trained technicians from Perth then faced a 14 hour drive (over some very rough roads) to the site. They stayed on site for several days while they commissioned the equipment.
According to Wijayasekera, “we faced a number of challenges from a technical point of view to satisfy the engineers and clients, but because we could rely on the expertise of people like James Su and the engineers in Hitachi, we were able to provide exactly what the client needed. We are just waiting now for the first images to come through and hoping that Australia and New Zealand are chosen as the final site.”
Hitachi Samurai
The latest Samurai AG2 chiller unit from HAPE considers the environment and is highly effective. The improved DC inverter fans achieve market-leading low noise (with a further 4dBA reduction on the low noise model).
The AG2 offers Hitachi reliability due to its twin screw compressors. Hitachi manufactures the compressors itself and claims to be the world’s first supplier of screw chiller units.
The AG2 also enables precise control of the outlet water temperature to within +/-0.5°C, independent of cooling load.
The new Samurai chiller has been carefully designed to be smaller than previous units, for high cooling capacity in less space. It also boasts a number of key improvements for easier servicing and maintenance. The single cycle units are compatible with the hydraulic module.