30 July 2019
Modular chillers offer a new way of solving space, performance and noise issues for our changing buildings, says Arnav Maini of Mitsubishi Electric.
In the past, there were very clear lines between what was considered a commercial zone, full of commercial buildings, offices and factories, and what was residential.
Over the years, the boundaries have blurred as an ongoing urban migration has led to people living and working in buildings, particularly in towns and cities, side by side.
This change has required us to think differently about the approach we take when it comes to our heating, ventilation and cooling systems.
Traditional chillers were often the popular choice historically, and still have a place in the market in the right situation.
However, with a rising urban population, and shifting working and living practices emerging, it’s time to revisit some of the unique benefits that a modular approach can bring to building owners and managers.
Modular chillers have been designed to use variable speed fans and compressors, and the Mitsubishi e-Series chiller operates with a two-stage cooling circuit. By modulating temperatures individually, the e-Series increases overall system efficiencies by 4% compared to chillers with a single refrigeration cycle.
As a result of this level of control, modular chillers are able to closely meet the efficiency requirements of projects where the need for cooling is particularly changeable, resulting in significant energy savings over time.
Modular chillers also offer significant part-load efficiencies, and higher capacity models have been designed with more advanced controls, making them easier to operate in a more flexible manner.
Designed for the urban environment
In the increasingly dense urban parts of the UK, in areas with space restraints, modular chillers can readily be fitted onto rooftops to offer flexibility in both installation and positioning. Overall, modular systems can save up to 35% of space compared to traditional chillers.
The 90kW e-Series modular chillers also use a U-shaped heat exchanger, the design of which allows the units to be narrower than conventional chillers, making the units perfect for sites with restricted space or access – often found in a busy city!
As residential areas continue to be built alongside hotels, office and restaurants, sound levels become a greater concern for the managers of multi-purpose buildings. Modular chillers, by their nature, are particularly quiet. A conventional large capacity chiller operates at over 100db; while the 90kW eSeries modular chiller, for example, runs at 77db. In practice, 20 eSeries modular chillers on a rooftop would still produce less noise than a single conventional chiller.
A chiller system with multiple modules can also offer high levels of reliability, as there will be a limited impact in the event of module failure. If one module fails, the others will continue to function, and only a small proportion of capacity will be lost. For example, in an installation of six modular chillers of 180kW each, if one compressor breaks down, only 8% of capacity will be lost. On the other hand, if the compressor in a large traditional chiller fails for any reason, the system will lose 50% of its capacity.
The durability and energy efficiency of modular chillers can also offer significant cost savings. Upgrading an old, out-of-date system with new equipment inevitably brings better and more reliable performance for end users, which can result both in more efficient operation and less need for maintenance calls outs.
They are also an ‘off-the-shelf’ product, delivered to site pre-packaged, pre-piped and pre-wired, only needing to be connected to a power supply, in comparison to traditional chillers, which usually take six to eight weeks to be delivered and deployed. In time-sensitive projects, this can be particularly beneficial, substantially reducing time-on-site for installers.
The Mitsubishi e-Series modular chillers are also designed with an in-built internal header pipe, which simplifies installation and maintenance, as well as a digital indicator which shows pressure levels and water temperature to make servicing the systems more efficient. These factors, as well as lower lifetime energy use, are also likely to improve overall cost-savings.
Modular chiller technology is advancing all the time, as engineering knowledge develops and the market demands more sophisticated approaches to installing and managing chillers. They are easy to source, quick and simple to install, and meet the demands of government legislation around energy efficiency. For end users, they are a quiet and flexible product that can adapt to changing building requirements and environments. Traditional chillers aren’t going anywhere, but for noise-sensitive, outage-sensitive, urban, space-restricted environments, it’s time to embrace the benefits of modular chillers.
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