Saving energy needn’t cost the earth 

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Paul Lawrence, managing director of Aermec UK, outlines how the HVAC plant (and equipment) is becoming more efficient, reducing energy costs and delivering more sustainable solutions.

The HVAC industry has made intensive efforts to improve the efficiency of equipment and is rapidly embracing the Internet of Things (IoT) to enable equipment to work harder, smarter and maximise the lifespan of plant and equipment. Every sector is under pressure to minimise its environmental impact, and boost efficiencies whilst addressing reductions in the overall costs of ownership. It’s a tall order, but one that the HVAC industry has embraced enthusiastically, with many of the key players leading the way. 

For many, the environment has always played an important role and underpinned many companies’ philosophies long before climate change became a hot topic. HVAC manufacturers are continually investing in R&D and looking for solutions that are environmentally benign, affordable but also offer efficiencies that reduce dependence on natural resources and offer a more sustainable approach.

Chillers, air handlers (AHUs) heat pumps, compressors, fans and associated peripherals can be found in many industries and in an equally wide variety of applications. From heating and cooling commercial buildings to cooling for injection moulding, precision-controlled environments in the pharmaceutical industry to heat management in mission critical data centres, the HVAC industry serves them all. 

The HVAC landscape is changing faster than at any other time. Encouraged by legislation and greater environmental awareness, end-users are looking to maximise their investments and expect equipment to perform optimally, boost their businesses green credentials and offer a good ROI. 

Taking an holistic approach and changing the way machines operate, upgrading them to maximise efficiencies, (for example switching from fixed speed to variable speed compressors) and even changing the water temperature – increasing the water temperature can be more energy efficient – can have a considerable impact on how HVAC plant and equipment are used across a wide range of applications and the savings that can be achieved in energy and costs.

Replace or repair?

Replacement of plant is not always the right route to take. Investing in an appropriate BMS (Building Management System), having a good planned preventative maintenance (PPM) strategy  and exploiting advances in components can all have a positive impact. But for aged equipment that is no longer cost effective to maintain and can’t reach the efficiencies required, investing in new plant offers an opportunity to invest in the latest technologies. 

Modular AHUs and chillers are increasing in popularity as they can offer the flexibility to increase the capacities as businesses expand. Often height, width and weight restraints require an alternative solution to standard unit. Modular systems that can be built in modules and assembled on-site offer excellent performance levels and flexibility as customers can upscale (when it comes to increasing capacity, the modular approach offers significant partial load efficiencies) reconfigure or downscale according to their requirements. 

Modular AHUs and chillers offer a factory tested and proved solution, with the added benefit of being able to ‘pull’ components from the system to fix it and then ‘plug’ it back without the entire system shutting down. This gives the degree of redundancy that standard units lack. 

Depending on the manufacturer, the configurations can be extensive. Some modular chillers offer capacities from 90 kW up to 3,500 kW, achieved with numerous arrays, shapes, sizes and refrigerants. Energy efficiencies are enhanced with the potential of free cooling and the use of HFO refrigerants helps to minimise the environmental impact.

A choice of air-to-water and water-to-water models offer an attractive ESEER of up to 6.5. This has raised the bar and offers an innovative mechanical design solution for businesses looking for a scalable approach.

A PPM strategy in place can help reduce energy wastage but can also prevent shutdowns and high repair bills. Paying closer attention to how buildings and their energy systems are being used can also have a significant impact on HVAC costs. 

Investing in remote diagnostics for service and maintenance, fully integrated BMS, simulators and Computational Fluid Dynamics (CFD) services give facilities managers greater control of their plant and in mission critical sites such as data centres, any tool that delivers a greater understanding of air flows and helps with the design of optimised heating and cooling solutions adds considerable value.

There are many technologies in the pipeline and some still on the drawing board, but we are already taking advantage of magnetic levitation chillers, compressor-less cooling, particularly in data centre environments, variable speed drives, multiple scroll compressors, VRF (Variable Refrigerant Flow) systems and EC (Electronically Commutated) motors.

Compressor technology has also rapidly advanced; inverter driven screw and scroll compressors are now commonplace and new highspeed centrifugal compressors and Turbocor have gained considerable traction.

Heat exchanger technologies have also helped drive down HVAC energy consumption with improved micro channel heat exchangers (MCHX) and spray evaporating technology, which maximises heat exchange effectiveness, lowers working pressures and increases overall chiller/heat pump efficiencies, whilst also reducing refrigerant charge by 50% 

Free cooling technology is also being applied more widely to further maximise the energy saving benefits. 

Predictive control and maintenance strategies are also being deployed with autonomous monitoring of operating parameters and adaption of operating envelopes with maintenance alerts that can sustain original design efficiency levels.

Building energy preservation particularly in high rise offices and commercial buildings is a must for all countries and the latest heat pumps (four and six-pipe) are designed to redistribute building heat energy where previously it was rejected to ambient air and wasted.

Refrigerant manufacturers are promoting a shift towards HFOs or natural refrigerants like hydrocarbons such as 1234ZE, R32, Carbon Dioxide and Ammonia and the F-Gas Regulations, Enhanced Capital Allowance (ECA) schemes, CRC Energy Efficiency Scheme and Energy Performance of Buildings Directive (EPBD), all help to drive change and improve our environments. 

Collaborative working can deliver energy efficiencies too. System design now includes end-users and design contractors collaborating to ensure optimum system efficiency levels are achieved, as opposed to the old school ‘Silo’ approach where each party was kept at arm’s length and operated within their individual silos focusing on erosion of margins and breaches of confidentiality. BIM (Building Information Modelling) has opened the process, and injected transparency whilst offering a greater insight into the planning, design and management of buildings and their infrastructures. 

The days of over specifying have also been replaced with a more holistic approach, that factors in the impact on the environment. Solutions are no longer geared toward cost cutting, but focus on minimising wastage, reducing carbon emissions, PUEs, promoting longevity, reliability and delivering more sustainable outcomes that are better for the customer, for business and the planet.