Chilled-water plants are major contributors of total energy consumption for facilities. Various energy-efficiency measures have been proposed to improve plant performance in retro-commissioning projects. This paper introduces a method to estimate the savings potential of some popular measures by building a forward simulating model for a chilled-water plant without storage. This model is based on a wire-to-water efficiency concept to simulate the plant power for producing cooling. The wire-to-water efficiency of each type of equipment is calculated with selected models or equations. The fluctuations of the chilled-water loop supply and return temperature difference are also considered to reflect their impacts on the chiller loading and pumping power. By finding the optimal reset schedule of some controlled variables, the utility billing cost of a chiller plant can be minimized. The variables to be optimized are cooling tower approach temperature, chiller chilled-water leaving temperature, and chiller condenser water flow rate. This is a nonlinear programming problem and can be solved with the generalized reduced gradient nonlinear solver. The application of this method is illustrated with an example chilledwater system.
| File Size : | 1
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| Note : | This product is unavailable in Russia, Belarus |
| Number of Pages : | 12 |
| Product Code(s) : | D-SA-12-005 |
| Published : | 2012 |
