Method for dehumidifying a refrigeration system
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Solution Overview
Problem
Existing dehumidification methods in refrigeration systems often result in surface temperatures that are too low, leading to economic inefficiencies and disturbances in the refrigeration process, particularly affecting the cooling of goods in refrigerated transportation containers.
Innovation Solution
A method that dynamically shifts between dehumidification and re-establish modes, using a control unit to regulate the evaporator surface temperature based on air moisture and temperature readings, ensuring the temperature remains within acceptable limits and optimizing energy use by maintaining the evaporator surface temperature just below the dew-point temperature, with heating elements placed downstream to enhance moisture condensation and air reheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the evaporator surface temperature is maintained below the frost point to dehumidify air, then moisture deposition on the evaporator coils is improved, but the temperature in the cooling compartment drops too low causing damage to goods
Solution Approach 1:
The system dynamically switches between dehumidification mode and cooling mode based on real-time temperature and humidity sensor readings. In dehumidification mode, the evaporator operates at low temperature to condense moisture, while in cooling mode, it operates at higher temperature to prevent goods damage. This dynamic operation resolves the contradiction between effective dehumidification and goods protection.
Solution Approach 2:
The control unit implements periodic cycling between dehumidification and cooling modes. The system alternates between running the compressor at high capacity (dehumidification mode) and reduced capacity (cooling mode), creating a periodic action that achieves both moisture removal and temperature maintenance, preventing continuous low-temperature exposure that would damage goods.
2Productivity
If the evaporator surface temperature is lowered to remove moisture efficiently, then dehumidification speed is improved, but energy consumption increases due to excessive cooling
Solution Approach 1:
The control unit continuously monitors temperature and humidity levels via sensors and adjusts compressor operation accordingly. When humidity reaches target levels or temperature approaches critical thresholds, the system reduces compressor capacity or switches modes. This feedback mechanism prevents excessive energy consumption by avoiding unnecessary low-temperature operation once dehumidification goals are achieved.
Solution Approach 2:
The system changes operating parameters (compressor capacity, evaporator temperature) based on real-time conditions. Instead of maintaining constantly low evaporator temperature, the system adjusts temperature parameters dynamically - using lower temperatures only when needed for moisture condensation, then raising temperatures to reduce energy consumption while maintaining acceptable dehumidification levels.
3Temperature
If the refrigeration system operates continuously at high capacity to maintain low temperatures, then cooling effectiveness is improved, but the dehumidifying process causes disturbances and economic inefficiencies
Solution Approach 1:
The refrigeration system operates dynamically with variable compressor capacity rather than continuously at high capacity. The control unit adjusts compressor speed and refrigerant flow based on actual cooling and dehumidification needs, using high capacity only when required for rapid cooling or moisture removal, then reducing to lower capacity for maintenance operation, thereby improving economic efficiency while maintaining cooling effectiveness.
Solution Approach 2:
The refrigeration system performs multiple functions through a single integrated control strategy - both cooling and dehumidification are achieved using the same evaporator and refrigeration circuit, but with different operating modes. This multi-functionality eliminates the need for separate high-capacity continuous operation, allowing the system to switch between cooling-priority and dehumidification-priority modes, reducing energy loss while maintaining both temperature and humidity control.
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 efficient dehumidification while maintaining optimal refrigeration system parameters, preventing damage to goods and reducing energy wastage by controlling the evaporator surface temperature effectively, thereby achieving economical and effective dehumidification.
Implementation Method 1
blow air over a cold evaporator with the temperature of the evaporator surface maintained below the frost point so the moisture in the air will deposit on the evaporator coils and freeze to ice
Implementation Method 2
heating elements arranged downstream of the evaporator
Implementation Method 3
a temperature sensor placed close to the surface of the evaporator
Implementation Method 4
a moisture sensor arranged upstream of the evaporator
Data Source
AI summary
A method for dehumidifying a refrigeration system especially to dehumidify a refrigerated transporting container is disclosed. The refrigeration system includes a refrigeration circuit including an evaporator, a compressor, an expansion valve and a condenser. The refrigeration system also includes a control unit and a cooling space, the evaporator is placed in the cooling space and air blows over the evaporator to be cooled down. The dehumidification method is stepwise, and the method includes a dehumidification mode and a re-establish mode. During the dehumidifying process the system shifts between the dehumidification mode and a re-establish mode stepwise dehumidifying the air in the container in such a way that the measured parameters especially the compartment temperature stays within acceptable limits.