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Modular chillers offer a new way of solving space, performance and noise issues for our changing buildings

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.

In addition, with increasing pressure from government legislation to drive energy efficiency and meet environmental standards, we must consider an option that can tick all of these boxes.

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.

Arnav Maini Arnav Maini Product Marketing Executive

Championing energy efficiency

Tackling ongoing requirements to reduce energy usage in buildings can result in a huge amount of pressure on HVAC installers. From Minimum Energy Efficiency Standards (MEES), which require a minimum EPC rating (Energy Performance Certificate), to taxes aimed at driving down emissions from UK businesses, installers must opt for products which champion efficiency and sustainability.

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. In comparison, 90% of traditional chillers operate at fixed speeds, ‘on’ or ‘off’.

This style of cooling is likely to be appropriate in environments which have more static requirements, such as an office building in a business park, where a fixed level of cooling is required during set working hours, and where there’s little variance to this load.

In contrast, modular chillers also offer significant part-load efficiencies, and newer models have been designed with more advanced controls, making them easier to operate in a more flexible manner. For example, in an office building where one day a week the population falls significantly, for example on a Friday when many people opt to work from home, the cooling requirements will be lower during this time.

As such, advanced scheduling would allow for the load to be reduced during these off-peak hours, driving significant energy savings. In contrast, the fixed output of a traditional chiller might be better suited in a building where there is little variability in cooling requirements, for example a factory or industrial facility that operated shift rotas and is ‘always on’.

Designed for the urban environment

In Japan, around 90% of the chiller market is modular; virtually the opposite of the UK. This is because the small, light, units of a modular chiller allow for the flexible, scalable installation needed to meet the demands of densely populated urban spaces.

 In the increasingly dense urban parts of the UK, it may be time to follow Japan’s example. In areas with space restraints, modular chillers can readily be fitted onto rooftops to offer flexibility in both installation and positioning. End users are provided with the flexibility to arrange them in any number of positions, fixing multiple units together in whatever layout best fits the space available.  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!

In areas with more available space, such as on a business park or at an industrial site, where units can be installed at ground level and cranes aren’t required, or where there is more flexibility around when units can be installed or serviced, a traditional chiller system can still provide an appropriate solution.

As houses 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 practise, 20 eSeries modular chillers on a rooftop would still produce less noise than a single conventional chiller.

Modular redundancy

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.

Lifetime value

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.

Arnav Maini is Product Marketing Executive for the advanced range of modular and traditional chillers