Method for optimizing the energy consumption of a refrigeration machine and refrigeration machine implementing said method
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Solution Overview
Problem
Refrigeration machines face inefficiencies in energy consumption due to high compressor electrical absorption, especially when operating at reduced cooling capacity, leading to suboptimal energy usage and increased energy costs.
Innovation Solution
A method that optimizes energy consumption by modulating the compressor speed and auxiliary member operations using a thermodynamic optimization algorithm, reducing electrical consumption of fans and pumps while maintaining efficient thermodynamic conditions, through a controller-driven system that adjusts voltage and frequency to minimize overall electrical usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the compressor speed is modulated to adapt cooling capacity to contingent demand, then the cooling capacity adapts to varying requirements, but the energy consumption optimization is insufficient when operating at reduced cooling capacity
Solution Approach 1:
The patent applies dynamics by making the auxiliary member operating regimes adjustable and modifiable based on real-time operating conditions. The controller dynamically changes the operating speed of auxiliary members (fans, pumps) to match the compressor's modulated speed, enabling the system to adapt efficiently to varying cooling demands rather than operating at fixed regimes.
Solution Approach 2:
The patent changes operational parameters by modulating both compressor speed and auxiliary member operating regimes. The controller adjusts parameters such as fan speed, pump flow rate, and valve positions in coordination with compressor modulation, optimizing the overall system energy consumption across different loading conditions.
2Loss of energy
If auxiliary members operate at maximum capacity to maintain maximum mass flow rate of heat transfer fluids, then the thermodynamic efficiency is optimized, but the total electrical consumption increases significantly
Solution Approach 1:
The patent applies partial action by operating auxiliary members at reduced capacity when full capacity is not required. Instead of always running fans and pumps at maximum speed, the controller modulates them to provide just sufficient mass flow rate to maintain adequate thermodynamic efficiency, accepting partial reduction in heat transfer performance when cooling demand is low.
Solution Approach 2:
The system dynamically adjusts auxiliary member operating regimes based on real-time conditions. The controller continuously monitors compressor operation and heat transfer fluid flow requirements, modifying fan speeds, pump rates, and valve positions to optimize the balance between thermodynamic efficiency and electrical consumption.
3Productivity
If the compressor operates at reduced speed to match lower cooling demand, then the cooling capacity is reduced, but the auxiliary members continue to consume high electrical power
Solution Approach 1:
The patent implements feedback control where the controller continuously monitors compressor operating conditions and heat transfer fluid flow rates, then adjusts auxiliary member regimes accordingly. This closed-loop control ensures that fans, pumps, and valves operate at appropriate levels to match the actual cooling demand, preventing excessive energy consumption by auxiliary members.
Solution Approach 2:
The controller serves multiple functions by simultaneously managing compressor operation, auxiliary member regulation, and overall system optimization. The single control unit coordinates all system components, integrating compressor speed modulation with auxiliary member regime adjustment to achieve comprehensive energy optimization.
4Productivity
If multiple compressors are operated in parallel to achieve cumulative compression power, then the cooling capacity is increased, but the device complexity and control requirements increase
Solution Approach 1:
The patent applies segmentation by dividing the compression function across multiple compressors that can be independently controlled. The controller selectively operates individual compressors based on demand, allowing the system to scale cooling capacity in discrete steps while maintaining simplified control logic for each individual compressor unit.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the total electrical consumption of refrigeration machines by minimizing auxiliary member energy use and optimizing compressor operation, enhancing efficiency and reducing electromagnetic emissions and motor stress, thereby lowering energy costs and extending equipment lifespan.
Implementation Method 1
a compressor (13), with variable speed Fcomp, having a driving device (14); a controller (15) connected to the driving device (14) to regulate the operating speed Fcomp of the compressor (13)
Implementation Method 2
This heat transfer fluid is generally put into thermal contact with the said exchangers to exchange heat mainly by forced convection
Implementation Method 3
a compression system that comprises one or more compressors
Implementation Method 4
an expansion member, generally a mechanical or electro-operated valve
Data Source
Figure 1~2
AI summary
Described is a method for optimizing the energy consumption of a refrigeration unit (10) which comprises a cold exchanger (11) and a hot exchanger (12), a compressor (13) having a driving device (14) and fans associated with the exchangers (11, 12). The driving device (14) comprises a connector (16) to an electrical network having a supply voltage Vac, an AC/DC converter (17) which converts the supply voltage Vac into a bus voltage Vdc, an inverter (18) which converts the bus voltage Vdc into a driving voltage Vout at which the compressor (13) is powered. The method comprises: - a thermodynamic optimization step A which activates a driving device (14) of the compressor (13) by modulating the operating voltage Vout of the compressor (13) to an optimized value Vout * designed to activate the compressor (13) at an optimized speed Fcomp * determined by a thermodynamic optimization algorithm; - a step B of regulating the driving device (14) which drives the AC/DC converter (17) so that the bus voltage Vdc is equal to the greater between a first threshold Vdc1 and a second threshold Vdc2; wherein the first threshold Vdc1 is equal to the product of √2 by the value of the supply voltage Vac and the second threshold Vdc2 is equal to the product of √2 by the value of the driving voltage Vout; - a fan regulation step C which envisages modifying the Faux speed of each fan in order to minimize the value of an overall electrical consumption Etot.