The plant was overly complex, did not heat and cool well, and the economic benefits of thermal storage were in question. WWCC was interested in the feasibility of eliminating thermal storage, simplifying operations, improving performance and the impact, if any, on annual energy expenditures. A secondary objective was to improve the ability to manage the mechanical and electrical systems of the campus by improving instrumentation and control, and obtaining timely and relevant information on energy and off-normal functions.
The theory of existing plant operation was based on generating heating and cooling energy during the evening hours and storing that energy in the tank farm. The energy generated during the evening hours was intended to be used during the day, drawing warm and/or cold water from the tank farm and restricting flow from the primary equipment. This is intended to take advantage of lower evening (off-peak) demand and/or usage charges, and/or limiting daytime demand on primary equipment. Sometimes, theory doesn’t turn out as planned.
As part of the planning effort, EEI compiled a set of “as-built” one-line diagrams of the plant, campus distribution and major loads for heating and cooling. We started with the composite of the original construction documents, field verified actual configurations and determined that the plant layout and piping had little resemblance to the original construction documents. That required compilation of as-built diagrams, from scratch, to determine what exists, how the equipment was piped and controlled, and to conceptualize recommendations.
Recommendations were conversion of the plant to a conventional plant, deleting chiller heat recovery, and thermal storage. Based on the lack of economic incentives, the complication of plant, and lack of performance, EEI did not recommend continuing with or investing in performance improvements relative to heat recovery and thermal storage. The existing plant has now been converted to a conventional plant by removing the majority of piping, pumping, heat exchangers, and controls and reconfiguring the primary equipment, piping, and pumping into industry standard heating and cooling configurations. The plant upgrade is also including repair of the cooling towers, and the addition of tower-free cooling. Energy use is expected to go down substantially, in addition to being able to heat and cool an additional 400,000+ square feet of campus growth without any increase in central plant equipment.