Method for optimizing the energetic consumption of a refrigerating machine and refrigerating machine implementing said method

A method for optimizing the energy consumption of a refrigeration machine (10) which includes:

• a cold exchanger (11) and a hot exchanger (12);
• a variable speed Fcomp compressor (13) having a driving device (14) and an electrical consumption Ecomp, variable according to said speed Fcomp;
• a controller (15) connected to said driving device (14) to regulate said operative speed Fcomp on the basis of a thermodynamic optimization algorithm;
• at least one auxiliary member with variable speed Faux, apt to force a flow of fluid and having an electrical consumption Eaux, variable according to said speed Faux;
• wherein one of said auxiliary member is associated with said cold exchanger (11) and/or said hot exchanger (12) to promote heat exchange;
• wherein said driving device (14) comprises:
• a connector (16) to an electrical network having a single-phase or three-phase Vac power supply;
• an AC/DC converter (17) converting said supply voltage Vac into a bus voltage Vdc;
• an inverter (18) converting said bus voltage Vdc into a driving voltage Vout at which said compressor (13) is powered;
• said method providing:
• a step A of thermodynamic optimization providing activate said driving device (14) by modulating said driving voltage Vout to an optimized value Vout* apt to drive said compressor (13) at an optimized speed Fcomp* determined by means of said thermodynamic optimization algorithm;
• a step B of regulating said driving device (14) providing drive said AC/DC converter (17) so that said bus voltage Vdc is equal to the greater of a first threshold Vdc1 and a second threshold Vdc2;
• wherein said first threshold Vdc1 is equal to the product of √2 by the effective value of said supply voltage Vac and said second threshold Vdc2 is equal to the product of √2 by the value of said driving voltage Vout;
• a step C of regulating said at least one auxiliary member providing modify the speed Faux of each of said at least one auxiliary member so as to minimize the value of an overall electrical consumption Etot which is equal to the sum of the electrical consumption Ecomp of said compressor (13) and the electrical consumption Eaux of said at least one auxiliary member.