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Improving chillers’ cooling efficiency with VSD technology

31 August 2023

When manufacturers look at how to improve the efficiency of their cooling systems, it’s important to consider technologies that maximise part-load efficiency, says Dave Palmer

REDUCING ENERGY consumption in process cooling is on the agenda for manufacturers looking to save money on their energy bills. The same can also help them improve the reliability and resilience of their operations and remain competitive in the local and global marketplace.

The UK manufacturing sector is also subject to a wide range of environmental and sustainability regulations, which impact how they operate, their carbon footprint and their sustainability goals. The Net Zero by 2050 target to achieve net-zero greenhouse gas emissions by 2050 requires significant reductions in emissions across all sectors, including manufacturing.

With Heating and cooling accounting for UK’s and Europe’s biggest energy use and industry as the second largest energy user after residential sector, implementing energy efficiency strategies to temperature control applications offers significant potential to reduce that demand.

Importance of part-load performance

As manufacturers think about improving the efficiency of their cooling systems and lowering their energy bills, it’s important to consider technologies that maximize part-load efficiency. Controlling the flow of air and water in process temperature control systems is an effective, permanent way to meet the ever-changing demands put on a system and enhance its efficiency.

Constant volume cooling systems operate at one speed, regardless of the cooling load. This means that they consume the same amount of energy, whether the cooling load is high or low. By contrast, installing a Variable Speed Drive (VSD) - an electrical/electronic system that provides infinitely variable speed control of AC induction motors - you can meet varying system flow rate requirements or just increase energy efficiency.

Variable speed components meet the actual load required during any given time over a wide operational range, meaning their speed and output varies to reflect the conditions and demands. By precisely matching output to the cooling demands, compressors and fans operate at their fastest levels when demand is high, and modulate to slower levels when demand is lower, for a high Seasonal Energy Efficiency Ratio (SEER), a measurement of part–load performance. The result is lower annual energy use and typically smaller annual energy bills.

For example, a cooling system with a fixed speed motor may consume 100 kW of energy, regardless of the cooling load. In contrast, a cooling system with a VSD motor may consume only 60 kW of energy when the cooling load is low, and up to 90 kW of energy when the cooling load is high. This results in significant energy savings, reducing the overall operating costs and improving the system's efficiency.

In addition to reducing energy consumption and improving performance, VSD technology can also increase the lifespan of the cooling system. Constant volume cooling systems operating at a fixed speed, place a constant strain on the motor and other components. Over time, this can result in wear and tear, leading to breakdowns and increased maintenance costs.

Retrofit to VSD

Variable-speed technologies are applied by chiller manufacturers across product portfolios, but VSD technology can also be retrofitted to existing chillers, making it an excellent option for businesses looking to improve the efficiency and reduce the energy consumption of their cooling systems.

Retrofitting VSD technology to an existing chiller involves installing a VSD drive between the motor and the electrical supply. The VSD drive adjusts the motor speed to match the cooling load, reducing energy consumption and costs. Payback on an installed VSD system can be as little as 4-6 months.

Matching the right VSD requires an understanding of the chiller’s cooling load, including peak and off- peak periods, and the chiller's existing control system to allow for proper communication between the VSD and the chiller's other components. Best to consult with industry professionals to assess the chiller's existing system and make recommendations to retrofitting VSD technology.

Once the VSD is installed, it is essential to monitor and maintain the system to ensure optimal performance. Regular maintenance and monitoring with a qualified and experienced professional can help identify issues before they become problems, reducing downtime and maintenance costs.

Given the process-heavy nature of the UK’s industrial landscape, getting a firm grip of a plant’s temperature control systems can quickly result in a reduction of energy consumption and consequently, utility bills. VSD technology is an excellent option to look at and best way to start is by calling your temperature control partner and undertake an energy analysis audit to get a true picture of all areas that need to be addressed to improve your energy efficiency and reduce your overall costs.

Opting for a subscription model

Today’s market reality very often requires companies to count every penny in their capital budgets to ensure the expenditure will provide the best return on investment. When considering energy efficiency upgrades for your temperature control systems and capex is an issue, there are now flexible options available in form of a membership or subscription type of a long-term rental agreement. This offers access to the latest process temperature control technology, maintenance, and equipment upgrades - all with the flexibility of an operating expense.

This subscription model allows manufacturers to transform their process temperature control system from a fixed asset into a dynamic solution that will be up to date with their changing business and process needs. They receive new equipment vs. existing rental stock units, preventive and 24/7 emergency maintenance, replacements, and upgrades. The elements of the all-inclusive, monthly rate contract are tailored to the process’ needs and based on a detailed assessment by the service provider’s engineers.

Manufacturers receive the right temperature control solutions for their process with the flexibility to adapt their capacity according to changing seasonal and operational requirements. They get bespoke systems installed with no upfront cost and capital investment. Additionally, unlike in the case of a traditional long-term hire, they benefit from the flexibility to exchange and upgrade the equipment as their requirements change or technology improves. All this with the peace of mind of complete maintenance and contingency plans.

Dave Palmer is general manager for the UK and Ireland at ICS Cool Energy

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