Plate Heat Exchanger Flow-Channel Sensing for Freeze Control
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Solution Overview
Problem
Existing plate heat exchanger systems lack effective monitoring and control mechanisms, leading to inefficient operation and potential issues such as overheating and freezing damage, particularly in refrigeration cycles using combustible hydrocarbons like propane and propene.
Innovation Solution
Incorporating temperature measuring points within the flow channels of the plate heat exchanger stack to monitor refrigerant temperature conditions, allowing for precise control of components like expansion valves and compressors, and providing additional temperature measurements to prevent freezing and optimize evaporator usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature monitoring is added to the plate heat exchanger, then operational safety and control precision are improved, but device complexity increases
Solution Approach 1:
The temperature sensor is integrated into the flow channel structure itself, with the sensor being arranged in the flow channel of the refrigerant between the second and third heat exchangers. This nesting approach allows the monitoring function to be embedded within the existing heat exchanger structure rather than adding separate external monitoring components, thereby improving reliability while minimizing increases in device complexity.
2Measurement precision
If more temperature measuring points are added, then measurement precision and control capability are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
Temperature monitoring is implemented at specific critical locations within the heat exchanger structure rather than uniformly throughout. The sensor is positioned in the flow channel between the second and third heat exchangers where temperature monitoring provides maximum control benefit for the expansion valve and compressor operation, achieving high measurement precision where needed without unnecessarily increasing device complexity across the entire system.
3Ease of operation
If integrated temperature monitoring in flow channels is implemented, then operational control is improved, but manufacturing complexity increases
Solution Approach 1:
The temperature sensor integration is combined with the flow channel structure during the manufacturing process. The sensor is arranged within the flow channel of the refrigerant between the second and third heat exchangers, merging the monitoring function with the heat exchanger body. This integration allows operational control improvements while managing manufacturing complexity by implementing the sensor during the stacking and sealing process rather than as a separate post-manufacturing step.
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 improved monitoring and control of refrigeration cycles, preventing overheating and freezing damage, optimizing the use of evaporator surfaces, and ensuring efficient operation with reduced refrigerant usage.
Implementation Method 1
heat can flow between the fluids flowing through the heat exchanger plates is transferrable
Implementation Method 2
one of the fluids being in heat exchange in one heat exchanger section initially with the second fluid and in another heat exchanger section with the third fluid
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a plate heat exchanger with a stack of heat exchanger plates having surface structures and between which sealed flow spaces are formed for the separate transport of several media, a first heat exchanger (4) formed in the stack of heat exchanger plates and in which an inlet (4a) and an outlet (4b) are connected on the connection side to first connections through which a hot liquid can be supplied and discharged, such that the first heat exchanger (4) can be operated as a condenser, a second heat exchanger (5) formed in the stack of heat exchanger plates and in which an inlet (5a) and an outlet (5b) are connected on the connection side to second connections through which a cold liquid can be supplied and discharged, such that the second heat exchanger (5) can be operated as an evaporator, a third heat exchanger (6),which is formed in the stack of heat exchanger plates and is connected in a refrigeration circuit (7), which is formed at least sectionally in the stack of heat exchanger plates and is traversed by a refrigerant during operation, to non-connection-side inlets (4c, 5c) and outlets (4d, 5d) of the first and second heat exchangers (4, 5), a flow channel (10), which as part of the refrigeration circuit (7) connects a non-connection-side outlet (5d) of the second heat exchanger (5) and an inlet (6c) of the third heat exchanger (6), and a temperature measuring point (12), which is arranged on the stack of heat exchanger plates in the area of the flow channel (10) or adjacent thereto and is configured to accommodate a temperature measuring device (13),with which an operating temperature can be measured for the refrigerant in the flow channel (10). Furthermore, a method for operating an arrangement with a plate heat exchanger has been provided.