Energy efficient refrigerated container operation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Refrigerated storage containers on ships and in yards face inefficiencies due to heat recirculation and impingement, leading to increased power consumption and potential cargo degradation, as exhaust air from one container can heat adjacent containers, raising condensing pressures and temperatures.
Innovation Solution
The implementation of adjustable louvers on refrigerated storage containers to direct air exhaust at an angle, reducing direct impingement and recirculation, combined with a decentralized control algorithm that cycles air conditioners based on waste heat ingestion from neighboring containers, using local controllers to manage on-off operations within predefined time windows and temperature variability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If refrigerated storage containers are placed in close proximity on ships and in yards, then space utilization is improved, but waste heat from one container impinges on adjacent containers causing increased power consumption and temperature control issues
Solution Approach 1:
The patent extracts the harmful waste heat exhaust air from the recirculation path by directing it away from adjacent containers through adjustable louvers. The exhaust air is separated from the ambient air intake path, preventing it from being drawn back into the condenser of neighboring containers. This extraction of the harmful element (heated exhaust air) from the system resolves the contradiction by allowing close container placement while avoiding heat impingement and the associated increased power consumption.
2Temperature
If exhaust air is discharged directly from refrigerated storage containers, then cooling function is maintained, but waste heat ingestion from neighboring containers raises condensing pressures and temperatures
Solution Approach 1:
The patent introduces spatial dimensionality to the air flow management by using adjustable louvers that can direct exhaust air at various angles away from adjacent containers. Instead of simple linear exhaust, the system utilizes angular adjustment in multiple directions to create three-dimensional air flow patterns. This dimensional approach allows the exhaust air to be dispersed in directions that avoid impingement on neighboring containers, thereby maintaining cooling function while eliminating waste heat ingestion.
Solution Approach 2:
The adjustable louvers provide dynamic control over the direction of exhaust air discharge. The louvers can be adjusted in real-time to optimize exhaust direction based on the relative positions of adjacent containers and ambient air flow conditions. This dynamic adjustment capability allows the system to adapt to different operational scenarios, maintaining effective waste heat dispersion while preserving the cooling function under varying conditions.
3Measurement precision
If air conditioners are cycled frequently to maintain temperature, then temperature control precision is improved, but energy efficiency deteriorates due to increased cycling frequency
Solution Approach 1:
The patent implements a feedback control system that monitors ambient air temperature, condenser inlet air temperature, and container interior temperature. The local controller uses this feedback information to determine the optimal timing for cycling the air conditioner on and off. By considering the temperature difference between ambient and condenser inlet air, along with the interior temperature and allowable variability, the system can delay or advance cycling decisions to avoid frequent short-cycling. This feedback mechanism maintains temperature control precision while reducing energy consumption associated with excessive cycling.
4Adaptability or versatility
If decentralized control algorithm is implemented for each container, then operational autonomy is improved, but system complexity increases due to coordination requirements
Solution Approach 1:
The patent enables each refrigerated storage container to operate autonomously through a local controller that independently manages air conditioner cycling decisions. Each container's controller uses locally available temperature data and pre-programmed control logic to determine when to cycle the air conditioner, without requiring constant communication or coordination with other containers or a central controller. This self-service approach grants operational autonomy to each unit while actually reducing system complexity by eliminating the need for complex inter-container coordination protocols and centralized control infrastructure.
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 reduces energy consumption, minimizes waste heat ingestion, and maintains cargo quality by optimizing air flow and temperature control, enhancing the energy efficiency and operational performance of refrigerated storage containers.
Implementation Method 1
an air conditioner comprising a condenser supportively disposed on an end wall of the container housing, the air conditioner being operable to maintain control of temperatures within the interior
Implementation Method 2
a sensor operably disposed to sense a temperature of the interior and transmit data reflective of the temperature to the local controller
Data Source
AI summary
A refrigerated storage container is provided and includes a container housing defining an interior, an air conditioner operable to maintain control of temperatures within the interior and a local controller configured to cycle the air conditioner on and off within a time window based on waste heat ingestion from neighboring refrigerated storage containers.