The Client –
A Global Plastic Component Manufacturer
The Challenge –
Process Struggling During Summer Period
The Solution –
A Retrofit Adiabatic and Free Cooling Operation
As a global plastic component manufacturer, minimising downtime and operating costs is key. When our client found their process struggling to keep temperature during the warmer months, Aqua upgraded their existing equipment to include a retrofit adiabatic and free cooling operation.
Situation
A combination of chillers and dry air coolers were being used to cool the injection moulding tools and hydraulics. The moulding line, operating at 15°C, incorporated 4 water chillers, with a weir tank and set of duplex process pumps. The hydraulic line was separate and cooled by 2 dry air coolers.
In summer months, the dry air coolers were unable to maintain temperature. As a last resort, they created a makeshift adiabatic system by using a garden hose, however this would cause scale build up and damage the air blast coolers longer term.
Our client had already highlighted their dependency on mechanical refrigeration and had concerns over rising energy costs. They did consider a free cooling upgrade, but space on site had proved prohibitive. They were also hesitant on adding glycol into the mould cooling circuit because of the frequency with which the tools are changed.
Solution
After a site visit and full review of production requirements, Aqua proposed two changes to the existing system which would add resilience as well as significantly lowering running costs.
The issue over the warmer summer months was addressed by fitting an Aqua retrofit adiabatic system to the air blast cooler. Then, when ambient temperature is over 22°C, the unit can be used as an adiabatic cooler.
The retrofit involved installing a 10-bar spray system to the cooler. The spray is constructed from 304l thin-walled stainless steel. An adiabatic box with a speed driven spray pump regulates the water spray dependent on ambient temperature. An industrial UV filter treat the mains water used in the spray and the system fully drains and runs a flush cycle before use to ensure no risk of standing water and fully compliant with health & safety regulations. A salt free water softener on the mains water inlet protects coils from calcium deposit and risk of blockage over the longer term.
Our Engineers also determined that, outside of the summer months, the hydraulic circuit could be cooled by utilising just one of the existing air blast coolers. The second cooler would be separated and modified to become a free cooler, which would then sit on the refrigerated mould cooling circuit.
In addition, a heat exchanger fitted to the return line of the mould circuit would give the air blast cooler antifreeze protection over winter, whilst still allowing the mould circuit to run glycol free. A filter basket was added to improve filter quality, with a differential alarm alert if the filter becomes blocked.
Free cooling would be utilised when the ambient temperature is below 18°C, rather than mechanical cooling, dramatically reducing energy consumption, reducing carbon impact and operational costs.
Results
By adding adiabatic facility, the hydraulic circuit will now function correctly during the summer months. Utilising free cooling on the mould circuit is estimated to save the customer up to £70,000 per annum. From a payback perspective, total investment was £60,000. In addition, free cooling operation means the chillers will last longer as running hours reduce on the mechanical components for a significant period each year.
For more information on retro fit adiabatic and free cooling call the team on 0333 004 4433 or email sales@aquacooling.co.uk
