SMART BUILDINGS & BUILDING CONTROLS Maximising chiller efficiency I
Smarter compressor controllers can boost efficiencies and can provide smarter cooling explains Aermec’s Andy Hawes
s it possible to reduce carbon emissions from a chiller by up to 50%? Aermec’s Aersave, a next generation compressor controller brings this possibility closer, whilst tangibly demonstrating how smart compressors can play a part in unlocking energy savings to minimise the use of fossil fuels in cooling solutions. Last year’s COP 28 delivered an agreement to transition away from fossil fuels and laid down a route for every country and industry to follow. Over 60 countries additionally signed up to a Global Cooling Pledge the objectives are to slash cooling emissions across the cooling sector as part of a strategy aimed at minimising pressure on energy grids but also reducing costs so that lifesaving cooling can be accessible to countries at risk of extreme heat. The European Commission agreement ensures member states outline plans for reducing the use of fossil fuels in heating and cooling solutions. As a result, the Energy Performance of Buildings Directive (EPBD) revisions have been proposed with 2028 the target for publicly owned buildings followed by all buildings in 2030. Traditional cooling such as air conditioning is accountable for over seven per cent of greenhouse gas emissions. The United Nations Energy Programme (UNEP) recognises that cooling is essential in many critical areas and services particularly for food security and the storage and delivery of vaccines, both depend on cooling. With the cooling industry developing more efficient products and adopting measures that can reduce power consumption, reliance on fossils fuels, minimising use of refrigerants and by maximising the Energy Efficiency Ratio (EER) of equipment, the HVAC industry can effect change across the globe. Harnessing technologies and improving cooling efficiencies not only saves money but also reduces CO2 emissions. One of the latest developments in compressor technologies is doing exactly that. Compressor efficiencies have dramatically
improved as chiller manufacturers are aware that increasing energy efficiencies further is the best approach in helping energy users reduce emissions and reach their sustainability goals. In alignment with the Global Cooling Pledge,
Aermec works closely with universities and invests heavily in research and development. It’s founding principles - delivering sustainable solutions and technologies that have minimal environmental impact is even more applicable 60 years later. The company’s latest product focuses on compressor technology and controls. Chillers are already high-performance workhorses and the Aersave smart
compressor technology enables any manufacturer’s chiller to work hard but a lot smarter. It raises the bar in smart technology. Aersave is a smart controller that can convert any 3-phase fixed speed compressor to a variable speed compressor and deliver up to 50% energy savings. A fixed speed compressor as the name suggests operates at the same speed whenever it is running and there is a constant demand. They are very effective if they need to be operated on 24/7 year-round production line and can be a lower cost to purchase. However, if a compressor is going to be operated daily, weekly or adjust to seasonal changes a variable speed compressor is a better option. A variable speed compressor can operate anywhere between its minimum and maximum speed and automatically adjusts the speed according to demand which can fluctuate depending on requirements. One of the benefits of replacing a fixed speed with a variable speed compressor is energy saving. But the initial outlay can prove costly and uneconomical particularly if the chiller is relatively new and the building load profile is not known.
Chiller efficiency is a critical factor in assessing the performance of a cooling system. The choice of chiller is pivotal in cooling buildings and processes. Assessing the (Coefficient of Performance) COP and (Energy Efficiency Ratio) EER has an impact, the higher the COP and EER the better the efficiency. In addition to specifying correctly, providing a good power environment, for example not overloading and using more power than is necessary, regular maintenance practices and protocols, matching the output to the actual cooling load are just some of the factors that influence the choice of chiller technology. There are a number of strategies that can be deployed to maximise chiller efficiencies. It may be economical to keep legacy chillers and retrofit Aersave, making it more efficient and reduce CO2 emissions, by running the existing system. Alternatively, modern chillers can often have much improved efficiency and control capabilities, upgrading or retrofitting with newer models maybe a solution. On the controls side, many manufacturers often release software updates for controllers and equipment, and these should be implemented as part of a maintenance programme. In addition to these scenarios, Aersave offers an alternative solution.
By converting any 3-phase fixed speed compressor to a variable speed compressor, the Aersave smart compressor technology enables customers the choice, either replace their chillers or retrofit their existing chillers. Aersave can play a crucial role by helping to
increase the green energy potential for many processes and applications by using their chillers more effectively. Instead of pressure transducers Aersave comprises two sensors. One connects onto the suction line of the compressor, the other to the discharge line. Its unique compressor control gathers the temperature from the two sensors’ points. Data gathered via Modbus from the compressor, is then input into an algorithm. This calculates the speed and compressor capacity that is required for the system to achieve its demand capacity.
While working on a lower frequency for extended periods of time to ensure oil return, a control sequence brings the oil back to the compressor to protect it. Aersave features multiple dip switch settings. These can be switched dependent on the compressor type.
As the technology operates with any type
of refrigerant, there is no need to cut into the refrigerant line.
Key features:
• Converts any 3-phase fixed speed compressor to a variable speed
• Controls and monitors the compressor with temperature sensors
• Protects the compressor from working with abnormally high discharge temperatures
• Voltage optimisation and eliminates inrush current
Aersave optimises a chiller’s performance in real time and delivers significant savings, eases reliance on the electrical grid, increases reliability, offers compressor protection, and can be retrofitted by Aermec authorised engineering partners. The benefits are decreased noise levels,
precise room temperatures and humidity controls, protects the compressor from short cycling and there is no interference with existing controls.
Aersave has been successfully trialled and independently tested by one of the largest fresh food manufacturers in Ireland where the chiller delivered a 41% reduction in electrical consumption. With energy costs fluctuating and global ambitions to reduce our impact on the planet’s resources, heating and cooling products are fundamental to our quality of life and survival in so many ways. Compressor technologies can have a major impact in delivering more sustainable cooling solutions.
30 BUILDING SERVICES & ENVIRONMENTAL ENGINEER FEBRUARY 2024 Read the latest at:
www.bsee.co.uk
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