Two gradient failure and repair events as experienced at the El Paso solar pond

Two salinity gradient failure and repair events at the El Paso solar pond are described in this paper. These breakdowns, though unplanned and undesirable in so far as sustaining thermal performance, yielded several significant findings. An inappropriate operating strategy coupled with the lack of adequate salt recycling facilities was found to be the root of the gradient problem. The stability margin number limits allowable for sustained pond operations was confirmed from the stability analysis of the gradient breakdowns. Scanning injections with proper injection flow rates were determined to be the key factors for successful gradient repair. The two gradient failure and repair events described herein demonstrate that a gradient breakdown can be repaired in a short period of time without a significant operating loss and that operating strategy must focus on maintaining the SMN within an operating limit of >2.5 and allowing the temperature to follow.