Suction Tube Heat Exchanger for Parallel Evaporator Flow Control
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Solution Overview
Problem
Existing refrigeration devices with parallel evaporators face challenges in accurately determining the mass flow distribution between evaporator groups due to the complexity of gas proportion and subcooling, which are not accessible for device control, making precise temperature control difficult.
Innovation Solution
A refrigeration device with a refrigerant circuit featuring two parallel evaporator groups and a suction pipe heat exchanger, equipped with temperature sensors at strategic positions, uses thermodynamic principles to determine the mass flow ratio by measuring temperatures at inlets and outlets, allowing for independent control of each evaporator group's temperature and mass flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If parallel evaporator groups are used to enable different temperature control for storage compartments, then temperature control flexibility is improved, but mass flow distribution measurement becomes difficult
Solution Approach 1:
The patent introduces a suction pipe heat exchanger as an intermediary device between the parallel evaporator groups and the compressor. This heat exchanger enables indirect measurement of mass flow distribution by measuring temperature differences across its pipe sections, rather than directly measuring mass flow in each evaporator group. The heat exchanger acts as a mediator that converts difficult-to-measure mass flow parameters into easily measurable temperature parameters.
2Measurement precision
If gas proportion and subcooling parameters are used to determine mass flow distribution, then measurement accuracy could be improved, but device complexity increases due to inaccessibility of these parameters
Solution Approach 1:
The patent extracts the measurement function from the complex internal parameters (gas proportion and subcooling) and relocates it to the suction pipe heat exchanger where temperature can be directly measured. By taking out the measurement requirement from the difficult-to-access evaporator groups and placing it in the accessible suction pipe heat exchanger, the system achieves accurate mass flow distribution measurement without increasing control system complexity.
3Measurement precision
If temperature sensors are placed at all four positions of the suction pipe heat exchanger, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
Instead of placing temperature sensors at all four positions (inlet and outlet of both high-pressure and low-pressure pipe sections), the patent inverts the approach by using only three positions. It leverages the known relationship between the high-pressure and low-pressure sides of the heat exchanger to calculate the fourth temperature value, thereby reducing sensor quantity while maintaining measurement accuracy.
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 solution enables accurate determination of mass flow ratios and improved temperature control across evaporator groups, enhancing energy efficiency and flexibility in maintaining different temperature settings for storage compartments.
Implementation Method 1
a suction pipe heat exchanger (50, 50') in which a high-pressure pipe section (52, 52') of the high-pressure pipe (48) and a low-pressure pipe section (54, 54') of the low-pressure pipe (49) are thermally coupled
Data Source
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AI summary
The invention relates to a cooling device (10) with a coolant circuit (20, 80, 90) comprising a compressor (22), a first evaporator assembly (26) having at least one first evaporator (28) and having a high-pressure tube (48) connected upstream of the first evaporator assembly (26), a second evaporator assembly (32) connected in parallel with the first evaporator assembly (26) and having at least one second evaporator (34), a low-pressure tube (49, 49') connected downstream of the first evaporator assembly (26) and the second evaporator assembly (32), and a suction tube heat exchanger (50, 50') in which a high-pressure tube section (52, 52') of the high-pressure tube (48) and a low-pressure tube section (54, 54') of the low-pressure tube (49, 49') are heat-conductingly coupled. The suction tube heat exchanger (50, 50') has three temperature sensors in three positions from a group of positions (60, 60'; 62, 62'; 56, 56'; 58, 58') at the inlet and outlet of the low-pressure tube section (54, 54'), and at the inlet and outlet of the high-pressure tube section (52, 52'). The cooling device and the associated method allow for a ratio of the mass flow of coolant to the first evaporator assembly relative to the total mass flow of the coolant to be determined.