Chilled Water System Analysis
Using a ClimaCheck Performance Analyzer System, baseline data was collected including temperature and refrigerant pressure sensors on the two (2) 450 ton Trane Chillers and through electrical metering on the Compressors. Additional data was collected using electrical sub-metering on auxiliary Pumps and Fans.
Through the identification of deviations between Manufacturer Specifications and current System operation, low cost/no cost measures with less than 2 years payback were recommended and these were implemented by the Client. Capital measures with a longer payback were also implemented to increase System efficiency and savings.
Chilled Water Supply Temperatures
During the Monitoring Period both Chillers operated with constant Chilled Water Supply Temperatures. As there is no floating Evaporator setpoints for either Chiller configured in the Control System, a Chilled Water Set point reset strategy was implemented.
Condenser Water Return Temperatures
The Condenser Water Return Temperature Setpoint was too low on both Chillers. A Condenser Water Return Temperature reset strategy was implemented based on outdoor Wet Bulb Temperature. This reduced Head Pressures and resulted in decreased energy consumption.
Low ΔT across the Evaporator – Chiller 2
Low Temperature Differentials across the Evaporator on Chiller 2 was found. This was likely caused by excessive flow across the Evaporator due to incorrect VFD operation. To verify and correct this, flow around the Chiller 2 Evaporator was measured and verified. VFD operation for the Distribution Pumps were also evaluated and reset to lower values.
Low ΔT across the Condenser – Chiller 2
As a result of a dirty Condenser and potential high flow rate, low Temperature differential was noted across the Condenser on Chiller 2. Cleanliness was verified and flow around the Chiller 2 Condenser was measured. Cleaning improved the heat transfer between the refrigerant and the water loop.
Capital measures were also recommended and implemented on the Chilled Water System. These included Adaptive Frequency Drive (AFD) retrofit, Cooling Tower refurbishment and Chiller Overhaul.
The Cooling Tower refurbishment reduced Chiller power consumption, achieving 10% energy savings in the Chillers’ Compressor power and Cooling Tower Fans. With the Installation of the AFD on the Chiller’s Compressors, more efficient part load was achieved resulting in approximately 28% energy saving in Compressor power. Performing the overhaul services also achieved energy savings on Compressor power and ensured that the Chillers gained optimal efficiency.
The measures implemented on the Chilled Water System have achieved measured electricity consumption savings of 31% and 48% electricity demand savings. The ClimaCheck System remains in place as an ongoing “commissioning tool” to maintain the baseline of savings and efficiency already achieved as a Continual Monitoring System.