Existing chiller was a Trane 400 ton air cooled chiller.
Existing chiller was a Trane 400 ton air cooled chiller.
Entech was called out to replace this existing chiller and suggest options. Currently the existing chiller had failed, and Entech had provided a 400 ton rental air cooled chiller.
At that time Entech just added a dedicated engineer to the construction team. During a preliminary walk through Entech’s Engineering team discovered existing evaporative tower system that had excess capacity and redundancy from an older process system that was no longer in operation. Luckily piping into this system was not too difficult or cost prohibitive.
The option to utilize a water cooled chiller system vs. air cooled system would provide a much better Return on Investment (ROI). Entech utilized Trane System Analyzer to model the system and provide a payback analysis to the ownership financial department. Based on the energy savings the project funding was approved for final design
During further study of the system operation and some control sequencing changes suggested by Entech’s engineering department, the option to utilize a water side economizer (Free Cooling) was added to the scope of work. This plate and frame heat exchanger was utilized to lower both cost and footprint.
To add a plate & frame heat exchanger would require clean condenser water, and at a steel factory this can prove difficult. Entech’s engineering team designed a full flow filtration system with by-pass and redundancy. The redundancy was designed to allow for continued operation during filter change out service. The by-pass piping was installed for normal operation for chiller mechanical cooling operation.
To add a plate & frame heat exchanger would require clean condenser water, and at a steel factory this can prove difficult. Entech’s engineering team designed a full flow filtration system with by-pass and redundancy. The redundancy was designed to allow for continued operation during filter change out service. The by-pass piping was installed for normal operation for chiller mechanical cooling operation.
Overall the central plant was able to pay-back in less than 2 years after additional programming and sequence changes were suggested on the process side by Entech Engineers. Currently the water side economizer is able to carry the process load for 4 – 5 months each year requiring chiller operation only 7-8 months each year. Additionally with added sequence & programming changes the chilled water temperature set point was raised increasing the chiller efficiency and required chilled water capacity. Currently the system only requires one 200 ton water cooled chiller vs. the old system which required 400 tons to catch the process load when the ambient temperature was over 90 degrees.
Entech also installed a central plant automation system. We have continued the expansion of the automation system to tie in the monitoring and additional central plants within this factory so the remote maintenance and operational staff can access alarms and equipment remotely.
A great win-win for Entech & Nucor, and the beginning of a great relationship with the Engineering team of Entech, as since this project we have redesigned and renovated the main central plant chiller, tower, and pumping system along with the latest project renovating the hot water system within the central plant with new boiler design, new boilers, and associate pumping systems.
