CHILLERS Multi purpose makes sense


David Evans, Aermec’s


general sales manager, looks at


how a shift to multi- purpose chillers can help decarbonise buildings


D


ecarbonising the economy is a key part of the UK’s commitment to mitigate the effects of climate change and the


decarbonisation of the built environment has a major role to play in helping to deliver the UK’s commitment to reducing carbon emissions by at least 80% by 2050. Decarbonising heat is one of the great challenges faced by all industries. Our use of renewable energy sources is reducing our dependency on carbon intensive electricity supplies. HVAC manufacturers are continually introducing new technologies to help businesses across the country, who are increasingly struggling to dynamically manage their changing requirements whilst addressing sustainability and environmental requirements for the built environment. Costs dominate the procurement and specification processes. A fundamental change in buying behaviour for building owners and end users is required, but they need to see real value in moving towards lower carbon solutions. This presents a number of opportunities throughout the HVAC supply chain. Manufacturers invest heavily in research and development and there are some great examples of technology innovation, building designs, heating and cooling solutions that continue to drive down our reliance on fossil fuels. There’s no secret in meeting the challenges of a net zero future – the HVAC industry needs to deliver what customers want and need, but any solution needs to be affordable, reliable and sustainable. Energy efficient chillers have been available for quite some time, maximising performance levels, offering reliability, redundancy and the use of lower GWP refrigerants. Heat pumps have become mainstream and widely used in numerous applications including such diverse applications as tomato growing where they are helping to increase yields, cut emissions and helping to decarbonise farming. Energy efficient chillers minimising the


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use of refrigerants and integrating the latest technologies drive down costs and tick many of the boxes for optimal performance levels, lower energy consumption, robustness and longevity as well as minimal environmental impact. Regularly specified, energy efficient chillers can be a differentiator, highlighting how ‘going green’ is good for the planet as well as the bottom line. But what if you could combine the advantages


and benefits of a chiller with a heat pump? Well now you can. It’s called a multi-purpose chiller which combines the benefits of both and, depending on the manufacturer, uses a non-ozone depleting and thermodynamically high efficiency refrigerant. But what is a multi- purpose unit?


It’s a chiller with a heat pump


that is able to satisfy the demands for cooling and heating simultaneously and independently, producing hot and cold water in a versatile and efficient way, all year round generating significant energy savings.


Available as a two or four-pipe system the


operating principle is based on the removal of heat from the ambient to cool and then transferring it to the ambience to heat. These units offer an alternative to the traditional combination of a chiller with a boiler in 4-pipe plants and saves both running and installation costs. Cooling and heating capacities vary amongst manufacturers and can range from 43kW-960kW for cooling and 46kW-987kW heating capacity.


Multi-purpose chillers are not a new


technology. They have been available for a number of years; the urgency to decarbonise the economy is providing a new platform and is drawing the attention of thermal engineering designers, installers and building owners keen to use heat that would otherwise be rejected to the external ambient. Energy savings of up to 40% can be achieved compared to traditional chillers and boiler installations, a 35% reduction in installation costs and up to 40% reduction in CO2


emissions. Features offered vary by manufacturer but


in addition to simultaneous and independent production of hot water and cold water, they can offer high energy efficiencies particularly at part load, through a multi-purpose logic and the MultiScroll Technology. A multi-circuit system offers maximum reliability units are fitted with axial fans Inverter EC – Motors. Multi-purpose chillers can simplify plants and reduce the time and costs associated with installation


Multi-purpose units are ideal for managing


energy consumption, reduce carbon emissions and running costs. They offer an energy efficient solution for, hospitals, hotel and leisure industries, office buildings, shopping centres as well as process cooling and any other market segment where there is a need for simultaneous and independent heating and cooling. Multi-purpose chillers offer a rational and


efficient solution for all buildings, but typically those that have heating capacity and cooling capacity demands not directly linked with seasonal variations and are required year-round, such as: hospitals, hotels, and buildings for residential use. They can be used with fan coil units ranging from small systems up to large office complexes. When there is a simultaneous demand for


heating and cooling, the unit reaches maximum efficiency by simply transferring energy from the spaces to be cooled to the spaces to be heated or to the domestic hot water. Multi-scroll technology can further increase the energy efficiency especially at part load The energy efficiency of traditional heat pump units is measured using EER for cooling mode and COP for heating mode. But, for the multi-purpose type of heat pump, a parameter is required that takes into account the simultaneous production of hot water and chilled water - the TER (Total Efficiency Ratio), which is defined as the ratio between the total capacity produced simultaneously (heating and cooling) and the electrical power input to the unit: TER = (Heating Capacity + Cooling Capacity) Electrical Power Input.


The technical data for hybrid chillers shows that TER values are significantly higher than the values for COP and EER: this demonstrates the overall very high efficiency that a hybrid chiller and heat pump unit can achieve compared to a traditional heat pump without heat recovery. Project designers working in close collaboration with the architects can, depending on the requirements, achieve the maximum energy savings, optimally balancing the heating and cooling needs for the system installation. Greater awareness and increased supply to the market of this type of product can be a differentiator and improve competitiveness. But, more importantly, multi-purpose chillers can help re-shape our approach to cooling and heating and make a significant contribution towards the net zero future of buildings.


August 2020 13


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