This model for combined heat and power device uses empirical data contained within a "performance map" to represent device-specific performance characteristics coupled with thermally massive elements to characterize the device's dynamic thermal performance. It was developed based on the specification described in Beausoleil-Morrison (2007).
The model is primarily intended to predict the energy performance of combustion-based cogeneration devices, such as internal combustion engine and Stirling engine units. However, the general model specification makes it applicable to any device simultaneously producing heat and power from which heat is recovered as hot water, as long as recalibration is undertaken. Fuel cell based micro-cogeneration technology is outside of the modeling scope.
The parameters required to define the governing equations can be determined from bench testing with only non intrusive measurements (e.g. fuel flow rate, cooling water flow rates and temperature, electrical production). The ability to reuse and recalibrate the component models or sub-models ensures that they are applicable to future generations of cogeneration devices.
Three control volumes are used to model the cogeneration unit dynamic thermal characteristics.
Depending on the current mode, control signals and plant boundary conditions, the CHP unit switches between six possible operating modes: off mode, stand-by mode, pump-on mode, warm-up mode, normal operation mode, cool-down mode. The mode switch control is implemented in Buildings.Fluid.CHPs.BaseClasses.Controller.
Beausoleil-Morrison, Ian and Kelly, Nick, 2007. Specifications for modelling fuel cell and combustion-based residential cogeneration device within whole-building simulation programs, Section III. [Report]