Data Reconciliation and Parameter Estimation of a Double-Effect Absorption Chiller Driven by Exhaust Gases

摘要

Adequate estimation of the state of a process is fundamental for its correct monitoring. Reliable process measurements are necessary in order to obtain adequate performance indicators required for control and optimization. However, process measurements often contain errors. Because of these errors, the mass and energy balances that describe the process are not satisfied when calculated from raw and untreated measurements. Data reconciliation is the procedure used to optimally adjust measurements so that the calculated values obey conservation laws and other constraints. Data Reconciliation (DR) techniques have been successfully applied to the process industry for many years. Nevertheless, not many applications have deal with closed cycles with complex connectivity and recycle loops, as is the case of absorption chillers. This paper presents a methodology for the joint Data Reconciliation and parameter estimation of absorption chillers. The methodology is applied to a double-effect water/LiBr absorption chiller of 5 MW of cooling capacity that is directly fired by the exhaust gases of three reciprocating engines installed in a trigeneration plant near Barcelona (Spain). Four missing parameters of the chiller are estimated from experimental data in order to simulate it properly. Then a DR procedure is applied in order to reconcile the energy balance using the plant measurements. This procedure will be very useful in the future for the calculation of the plant performance, fault detection and plant operation.