Second life for chilled water air handling system

Avoiding a $300,000 investment, saving more than $100,000 annually in energy and maintenance costs plus protecting the environment: The Global Business Unit Heraeus Conamic has impressively demonstrated how this can be done with the clever re-functioning of an existing chilled water air handling system as the main cooling system for the entire site in Chandler, Arizona.

chilled warer air handling system
Aaon 170 Ton Chilled Water - Air Handling Unit

In 2018, Heraeus Conamic took over a production building in Chandler previously used by the Global Business Unit Heraeus Precious Metals to produce a new generation of materials for Heraeus Conamic customers. "However, when we examined the building and its infrastructure, it quickly became apparent that the technology of the existing air conditioning system on the roof was now unfortunately outdated," says Rob McIntyre, Facilities Manager at Heraeus Conamic in Chandler. Previously, 41 air conditioning units provided cooling for the 3,070-square-meter production area. All of them operated with refrigerant R-22, i.e., with chlorodifluoromethane, also known as Freon.

The problem: 27 of 41 units would have required costly replacement – an investment of about $240,000 plus installation costs estimated at another $60,000. "In addition, the refrigerant R22 is currently being phased out worldwide due to its harmful effects on the ozone layer," Rob McIntyre explains. Thus, an alternative was needed that would be as cost-effective as possible and avoid the use of R-22 refrigerant.

Real added value for people and the climate

Facility Manager Rob McIntyre
Facility Manager Rob McIntyre

While reviewing the on-site infrastructure, 2019 Rob McIntyre noticed a 170-ton industrial chilled water air conditioning system from Aaon that was previously used to cool the high-temperature induction melters. The system uses a very large copper coil tied into the chilled water plant which is technically capable of cooling down an area of more than 8,200 square meters by up to 45 degrees Celsius compared to the current outside temperature. "So instead of disposing of the system, we decided to repurpose the existing Aaon cooling unit as the main cooling system for the entire site," says Christoph Riederle, Site Manager of Chandler. It was a smart move; after all, in addition to Aaon's equipment, all the spare parts needed were available on site. "With only 120 internal labor hours and a $13,700 investment for natural light with new skylights, we were able to upgrade the entire building system." With extraordinary success: compared to the old cooling system, the system consumes only two percent of the previous amount of electricity to cool the production area.

The carbon footprint is also impressive: Currently, 27 of the old air conditioning systems have already been switched off and removed. Seven more are to be replaced by the chilled water air handling system by 2022. The rest will remain as backups. The elimination of the 27 cooling units has improved the efficiency of the building services for the entire site by more than 60 percent, which already results in annual energy savings of approximately $63,000.

The installation of skylights in the locations of the dismantled air conditioning units alone has reduced the use of LED lighting in the production area by around 65 percent. In addition, the amount of waste has also been reduced because there is no longer a need to dispose of cooling system components such as motors or filters. Also, occupational safety has also improved, as maintenance of the cooling system can now be carried out at ground level rather than on the roof surface. The project is successful all round enabling us to avoid the use of a banned hazardous refrigerant, as well as significantly reducing the site carbon footprint in addition to a reduction of consumption of spare parts.