Mines – which are typically rustic environments in which to operate, requiring robust technology – often work against nature, descending deep underground, where temperatures can rise to between 60º and 70º at the rock face, explains heating, ventilation and air conditioning (HVAC) company Johnson Controls GM Neil Cameron.
These extreme temperatures affect production and should be mitigated through the use of a ventilation and cooling system, he adds.
“Mines need to ensure that they have the best available solution for their operation to ensure that temperatures are kept reasonably low so that operations can continue,” Cameron notes, explaining that this is where the company’s YD dual centrifugal chiller – which ranges in capacity from 5 300 kW to 21 100 kW – plays an important role.
He explains that, while Industry 4.0 may present a challenge in terms of the evolution of technology, mines are continually evolving and adapting. Therefore, he notes that HVAC providers, such as Johnson Controls, need to continually adjust and provide improved cooling capabilities.
These capabilities depend on a mine’s infrastructure availability; however, Cameron explains that the size of the YD chiller reduces the need for expensive modifications on site, as the compact configuration is suitable for operations with space constraints.
“The YD chiller is significantly shorter and narrower than competitive designs, and, therefore, doesn’t require a large area of floor space.”
Cameron explains that the compact configuration of the chiller is created using one evaporator and condenser shells, one refrigerant circuit and two compressors piped in parallel.
“Depending on the site and chiller size, compressors can be shipped completely assembled to reduce shipping, rigging and site-assembly costs.”
For larger chillers, however, the compressors, drivelines, evaporator and condenser can be shipped as modules for easy assembly.
The YD chiller can be installed for commercial and district cooling and central utility plants, as well as high-rise buildings, campuses, medical centres and more applications.
Time Is Money
Another aspect to be considered, Cameron says, is that chillers spend nearly 99% of their operating hours running at less than design capacity.
“That’s when a chiller can often take advantage of lower entering condenser water temperatures that reduce the compressor’s workload to save energy,” he highlights.
Therefore, Cameron notes that the YD chiller motor employs an open-drive design that can be either air- or water-cooled, thereby removing the need for cooling by refrigerant flow, which saves energy and improves reliability.
Performance is further improved by a variable-orifice design that works in conjunction with the company’s OptiView Control Centre and accompanying panel to improve the efficiency of refrigerant flow.
The full-colour OptiView Control Centre provides users with control management that combines advanced control logic, industrial-grade hardware and a fingertip-activated control display designed with the chiller operator in mind.
“Operation is practically foolproof,” Cameron enthuses.
Data and parameters are automatically saved on a memory card and no battery backup is required.
“Data outputs are completely described with illustrations of the appropriate chiller components. Native Metasys (a control interface) compatibility and an e-link communication card simplify the building automation- and control-system integration,” he explains.
OptiView also provides monitoring and trending capabilities, as well as the flexibility to select parameters critical for the mine’s effective operation.
Cameron further highlights that energy efficiency is not only important for a plant but also for the planet.
“A chiller impacts on the climate directly by releasing refrigerant emissions into the atmosphere and indirectly through power plant carbon dioxide (CO2) emissions, which are responsible for 98% of the global warming potential associated with chillers.”
To reduce the direct effect, Cameron notes that the YD chiller uses HFC-134a refrigerant, which has no ozone-depletion potential and no phase-out date. This is in line with the Montreal Protocol, which is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances that are responsible for ozone depletion.
“We also use ‘leak-free’ sealing technology to keep the refrigerant inside the system and leak-tight construction practices, which are validated during the manufacturing process.”
Moreover, regarding the indirect effect, the YD chiller reduces utility CO2 emissions, owing to the easy optimisation to reduce kilowatt consumption. This, Cameron explains, reduces a mining facility’s total climate impact and earns points in the Leadership in Energy and Environmental Design (LEED) building certification programme.
The LEED programme is overseen by the Organisation for Economic Cooperation and Development, which is an intergovernmental economic organisation with 35 member countries, founded in 1960 to stimulate economic progress and world trade.
“Our organisation comprises 5 000 technicians located at 169 branches worldwide. “This helps us to assist in creating buildings and working conditions that offer employees healthier operating environments, save energy and achieves enhanced operations,” he concludes.