Production Facilities
The district cooling system operates year round with no seasonal or scheduled shutdowns. Prior to Lake Source Cooling, the Cornell District Cooling System has been extremely reliable due to the distributed nature of the production facilities and use of the Thermal Storage Tank. This distributed production capability allows Cornell to make equipment and piping repairs within the plants themselves without interruptions to the customers. Individual equipment failures or trips are countered by quickly shifting load to the Thermal Storage Tank.
Lake Source Cooling continues the very high reliability of the central cooling plants, due to the inherent simplicity of the system. This facility has been carefully designed so that given any single equipment failure (pump, motor, VFD, transformer, etc), there will always be >80% of the total plant capacity available. This is possible because LSC is essentially a pumping facility and total power is proportional to the total flow cubed. The power transmission lines that feed the facility are fed from two separate substations and they have also been partitioned with motorized switches and fault detection. Chilled Water Plant 3 and the Thermal Storage Tank remain on line as additional back-up to LSC (50-60% of current campus peak load).
Distribution System
The district cooling distribution system has proven extremely reliable over its life. Cornell has maintained this reliability with an aggressive program of installing and maintaining a cathodic protection system for exterior corrosion protection. Interior corrosion protection is maintained with an extensive corrosion protection and monitoring program, which has resulted in an average corrosion rate of less than one mil per year on average over the last ten years. In the past two years leading up to the startup of LSC, that corrosion rate was reduced to .25 mil per year by stripping iron (corrosion byproducts) from the circulating water. In addition, the system is "looped" and "segmented" using high performance butterfly valves installed in vaults. This allows sections of the distribution system to be shut down for maintenance, repairs or upgrades without affecting the customer base.
District Cooling Availability and Reliability
The normal operating criteria for the district cooling system is to maintain a minimum differential pressure at the furthest point in the distribution system (2-4 psid) and also maintain an acceptable leaving chilled water temperature at the production facilities.
