Purdue University

Reducing 1 MW at no cost: Chilled Water Evaluation

The challenge 

Purdue University was pursuing the path of sustainable development with a desire to reduce their carbon footprint.  An initial site visit completed by WM Group revealed substantial areas of improvement in the chilled water system.  With great emphasis on Energy Savings and the potential opportunities in the chilled water system, Purdue University was eager to explore the inefficiencies in their system and improve with great strides.

The smart solution 

1.  Pumping Imbalance

Initially it was established that Purdue had a major pumping imbalance on their campus.  WM Group completed a hydraulic analysis of the university campus to determine all losses within the system.  With minor control changes, WM Group reduced the electric load by 1 MW as a result of minimizing all losses and shutting down over 100 building pumps.

2.  Chilled Water Quality

High short temperatures were identified on every chiller on campus.  With further investigation, it was found that the chilled water quality was causing poor heat exchange and tube fouling in the system.  Improving the chilled water quality would result in a payback of months.

3.  Plant Re-engineering

By identifying more efficient strategies and controls, WM Group could optimize the 40,000 ton chilled water system by reconfiguring and sequencing the current equipment.  The proposed recommendations consisted of Condenser Water System Optimization, conversion to Variable Primary Pumping, Near Optimal Chiller Staging, re-piping, and additional valve automation.  The recommendations would results in hundreds of thousands in annual savings.

4.  Water Side Pre/Free-Cooling

A substantial amount of savings on energy and equipment lifetime was recognized through the proposed addition of water side free cooling.  Through the utilization of cooler ambient conditions, the substantial winter time load of 5000 tons would be maintained without running chiller equipment.  Not only does this extend the lifetime of chiller assets, but it reduces energy cost by a half of million dollars.

5.  Building Controls: Reduction in Simultaneous Heating and Cooling

It was found that major building control imperfections were causing a high simultaneous heating and cooling load in the buildings.  Even reducing the concurrent campus load by 25% resulted in millions of dollars.  An additional study of a small sample of buildings completed by WM Group resulted in major savings as well as improved comfort for occupants.