Gas flow rate by pass as well as other
Hence, three suitable values of the refrigerant mass flow rate have been detected in order to introduce the need of controlling the working fluid flow rate: for the first range of working points (#1 to #4) it ANA 12 was reduced by 50%, for the second range (#4 to #8) it was kept as it was designed and, finally, for the third range (#9 to #14) it was increased by 50%. This flow rate, on the other hand, can be easily changed because it is imposed by the pump which is of a rotary volumetric type so linearly correlated to the pump speed. Table 7 summarizes the results with these three different flow rates: fluid degradation is always avoided and working fluid at the outlet of the evaporator is almost always superheated, so suitable for expansions. Only for the tests #1 and #2 (at very low engine speed) refrigerant quality is too low for a good expansion: an even lower flow rate should be considered but the thermal power recovered by the gas would be really low.
Finally, results obtained demonstrate lymph hearts a model based control strategy applied to the working fluid flow rate is indeed suitable to manage the recovery unit.