Method of defrosting a multiple heat absorption heat exchanger refrigeration system
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Solution Overview
Problem
Conventional refrigeration systems in refrigerated trucks and trailers face challenges in maintaining a consistent temperature and moisture environment due to frequent access, leading to temperature and moisture variations in the cargo space, which can affect the quality of perishable goods.
Innovation Solution
A multi-temperature refrigeration system with multiple heat absorption heat exchangers that can be operated in a single temperature mode, with a controller managing the defrosting process by isolating and heating individual heat exchangers as needed, allowing the system to continue operating without interruption even when only one heat exchanger requires defrosting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional refrigeration systems operate with multiple heat absorption heat exchangers in a single temperature mode, then the system can maintain temperature in the cargo space, but when one heat exchanger requires defrosting, the entire system must be shut down for defrosting, causing loss of productivity
Solution Approach 1:
The system divides the heat absorption heat exchangers into independent, separately controllable units. Each heat exchanger can be monitored and defrosted individually through its own expansion device control, allowing one unit to be taken offline for defrosting while others continue operating. This segmentation resolves the contradiction by enabling selective maintenance without system-wide shutdown.
Solution Approach 2:
The system dynamically adjusts the operational state of individual heat exchangers based on real-time defrost requirements. The controller monitors each heat exchanger's condition and dynamically switches between cooling and defrost modes for specific units while maintaining overall system operation. This dynamic control allows the system to adapt to partial defrost needs without complete shutdown.
2Reliability
If the refrigeration system shuts down the entire system for defrosting when one heat exchanger requires it, then defrosting can be performed, but the system experiences frequent interruptions and extended defrost time
Solution Approach 1:
By segmenting the defrost control to individual heat exchangers rather than system-wide shutdown, the system performs defrosting in isolated units. This allows continuous operation of other heat exchangers and minimizes the time the overall system is interrupted, while still achieving effective defrosting of the specific unit that needs it.
Solution Approach 2:
The system applies defrost action only to the specific heat exchanger that requires it, rather than defrosting the entire system. This partial action approach reduces the total defrost time and minimizes operational interruptions while ensuring the necessary defrosting is performed on the affected unit.
3Adaptability or versatility
If multiple heat absorption heat exchangers are used in a multi-temperature system, then temperature control flexibility is improved, but the complexity of managing defrosting across multiple units increases
Solution Approach 1:
The controller is designed with universal control logic that can manage multiple heat exchangers in different operational modes (single temperature or multi-temperature) using the same defrost management approach. Each heat exchanger responds to standardized control signals for defrost initiation and monitoring, simplifying the control architecture despite the system's versatility.
Solution Approach 2:
The system segments defrost control into independent, modular units that can be managed separately. Each heat exchanger has its own defrost control pathway through its expansion device, allowing the controller to manage multiple units independently without requiring complex interdependent control logic. This modular approach reduces overall system complexity.
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 ensures consistent temperature maintenance and extended operation without frequent interruptions for defrosting, reducing the impact of moisture and temperature variations on perishable goods, thereby improving the efficiency and reliability of cold chain distribution.
Implementation Method 1
Each of the plurality of heat absorption heat exchangers is heated with a resistance heater
Data Source
AI summary
A method of operating a refrigeration system. The method includes operating a multi-temperature refrigeration system that has a plurality of heat absorption heat exchangers in a single temperature mode. A number of the plurality of heat absorption heat exchangers are determined that require defrosting a single heat absorption heat exchanger is directed into a different operational state when the number of heat absorption heat exchangers that require defrosting is equal to one. E of the plurality of heat absorption heat exchangers is directed into a defrost mode when the number of heat absorption heat exchangers that requires defrosting is more than one.