CO2 Refrigerating Plant With Recovered Coolant Load Control
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Solution Overview
Problem
Prior natural coolant refrigerating plants for pasteurizing and confectionery production face inefficiencies due to inadequate coolant load control, leading to reduced overall efficiency during both heating and cooling cycles, as they are designed for greater coolant loads during heating, resulting in unused coolant during cooling and reduced efficiency.
Innovation Solution
A natural coolant refrigerating plant with a reversible transcritical carbon dioxide cycle, utilizing a motor-driven compressor with two compression stages, an intercooler, and a gas-cooler, along with electronically controlled valves and branches to recover and manage coolant load, allowing for efficient use of coolant during both heating and cooling cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the plant is designed for greater coolant load during heating cycle, then heating performance is improved, but coolant efficiency deteriorates during cooling cycle due to unused coolant
Solution Approach 1:
The patent implements dynamic coolant load adjustment by controlling the expansion valve to vary the refrigerant flow rate according to the actual thermal load requirements. During heating cycle, the expansion valve opens wider to allow greater coolant flow, while during cooling cycle it restricts flow to match the lower cooling demand, preventing both overheating and coolant waste
Solution Approach 2:
The system changes operational parameters by adjusting the degree of opening of the expansion valve based on the operating mode (heating or cooling). This parameter adjustment allows the same refrigeration plant to optimize coolant flow rate for different thermal requirements, improving both heating performance and cooling efficiency
2Device complexity
If the plant uses a fixed coolant load design, then system simplicity is maintained, but overall efficiency deteriorates due to unused coolant during cooling and insufficient coolant during heating
Solution Approach 1:
The patent incorporates a control system that monitors the operating mode (heating or cooling) and automatically adjusts the expansion valve position accordingly. This feedback mechanism ensures the coolant load matches the actual thermal demand without requiring complex manual intervention or oversimplified fixed designs
Solution Approach 2:
The expansion valve serves multiple functions: it controls coolant flow during both heating and cooling cycles, adapts to different thermal loads, and prevents coolant entrapment in the intercooler. This single component handles what would otherwise require multiple specialized devices, maintaining simplicity while improving efficiency
3Quantity of substance
If greater coolant quantity is used during heating cycle, then heating capacity is improved, but coolant availability deteriorates during cooling cycle due to coolant entrapment in intercooler
Solution Approach 1:
The expansion valve dynamically adjusts the coolant flow rate based on the operating cycle. During heating, it allows greater coolant quantity to pass through the intercooler to maximize heating capacity. During cooling, it restricts flow to prevent coolant entrapment, ensuring adequate coolant availability for the cooling cycle
Solution Approach 2:
The system changes the coolant flow rate parameter by adjusting the expansion valve opening degree. This parameter change allows the plant to optimize coolant quantity for heating operations while preventing excessive coolant accumulation that would hinder cooling cycle performance
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
The plant achieves maximized efficiency by optimizing coolant usage, allowing a single coolant load for both cycles, reducing cycle times and enhancing overall performance by recovering unused coolant and controlling pressure effectively.
Implementation Method 1
a motor-driven compressor (2) with two compression stages
Implementation Method 2
an intercooler (8) located upstream of the second compression stage... for cooling the coolant flowing out from the first compression stage
Implementation Method 3
a gas-cooler (10) located downstream of the outlet from the second compression stage... for cooling the coolant flowing out from the second compression stage
Implementation Method 4
at least one heat exchanger (6) in fluid communication with the motor-driven compressor (2) and with jacket (4)
Data Source
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AI summary
A natural coolant refrigerating plant comprising a motor-driven compressor with two compression stages, at least one jacket for heating and/or cooling a product being processed, an intercooler located upstream of the second compression stage and a gas-cooler located downstream of the outlet from the second compression stage. Moreover, the plant comprises a first branch, connecting the outlet of the gas-cooler with the inlet of the first stage of the motor-driven compressor for recovering a predetermined quantity of coolant.