Cargo Container Air Distribution Floor for Uniform Rear Cooling
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Solution Overview
Problem
Conventional temperature-controlled cargo containers face challenges in evenly distributing conditioned air throughout the cargo space, leading to overcooling at the front end and undercooling at the rear end, particularly due to the design of the T-bar floor which allows air to flow disproportionately upward, resulting in inadequate air reach to the rear regions.
Innovation Solution
The design incorporates a subfloor and a cargo support floor with a plenum and strategically arranged openings to enhance airflow, along with adjustable side air outlets and ducts with air discharge holes, and vertically extending recesses to direct conditioned air upward along the side walls, ensuring more uniform distribution of conditioned air throughout the cargo space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional T-bar floor design is used, then air can flow through passageways, but air flow becomes disproportionate with excessive upward flow and insufficient reach to rear regions
Solution Approach 1:
The floor is segmented into multiple functional layers: subfloor, cargo support floor, and plenum chamber. This segmentation creates distinct airflow pathways that control air distribution patterns, preventing uncontrolled upward flow through T-bars while directing air systematically through the cargo space.
Solution Approach 2:
Different regions of the floor are designed with different airflow characteristics. The plenum chamber provides uniform air distribution across the floor surface, while strategically positioned openings and side air outlets create localized airflow patterns that ensure adequate reach to rear and upper cargo regions.
2Power
If refrigeration unit is positioned at front wall, then cooling capacity is provided, but air flow does not reach rear regions adequately causing undercooling
Solution Approach 1:
The air distribution system transitions from primarily longitudinal airflow (front to rear) to three-dimensional distribution by introducing vertical plenum chambers and side air outlets. This multi-directional airflow pattern ensures cooling reaches all cargo regions including upper corners and rear areas that conventional single-direction systems cannot adequately serve.
3Productivity
If T-bar floor with longitudinal passageways is used, then air can be circulated, but overcooling occurs at front end and undercooling at rear end
Solution Approach 1:
The plenum chamber acts as an intermediary between the refrigeration unit and the cargo space. It receives conditioned air, distributes it uniformly across the floor surface through multiple openings, and directs flow through side air outlets. This intermediary structure eliminates the direct longitudinal flow path that causes temperature gradients, achieving uniform temperature distribution while maintaining efficient air circulation.
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 configuration ensures that conditioned air is more evenly distributed, preventing overcooling at the front and undercooling at the rear, maintaining optimal temperature conditions across the entire cargo space, including the upper corners near the rear wall.
Implementation Method 1
The refrigeration unit includes a compressor, a compressor motor, and a condenser unit isolated from the cargo space, and an evaporator unit operatively associated with the cargo space defined within the container. The condenser unit includes a refrigerant heat rejection heat exchanger and a condenser fan that draws ambient outdoor air through the condenser heat exchanger and discharges that air back into the outdoor environment. The evaporator unit includes a refrigerant heat absorption heat exchanger and one or more, typically two, evaporator fans which draw return air from the cargo space defined within the container through the evaporator heat exchanger for temperature conditioning and delivers that conditioned supply air back into the cargo space defined within the container.
Implementation Method 2
The evaporator unit includes a refrigerant heat absorption heat exchanger and one or more, typically two, evaporator fans which draw return air from the cargo space defined within the container through the evaporator heat exchanger for temperature conditioning and delivers that conditioned supply air back into the cargo space defined within the container.
Implementation Method 3
The condenser unit includes a refrigerant heat rejection heat exchanger and a condenser fan that draws ambient outdoor air through the condenser heat exchanger and discharges that air back into the outdoor environment.
Implementation Method 4
In standard practice in the industry, the floor of the container is formed of a plurality of parallel, longitudinally extending T-bars supported. The T-bars are spaced apart laterally to form a series of longitudinally extending air passageways that are open to the cargo space above the floor. A portion of the temperature-controlled air discharging from the evaporator passes downwardly along the front wall of the container and into these passageways. As the air flows along the passageways towards the rear wall of the container, air passes from the longitudinally directed airflow upwardly into the cargo space.
Data Source
AI summary
The distribution of condition air into the cargo space of a temperature controlled container is improved. Conditioned air may be selectively distributed into the cargo space from a plenum beneath the cargo support floor through a plurality of longitudinally and laterally spaced apart openings through the cargo support floor. Side air ducts may be provided extending rearwardly along the side walls of the container for distributing conditioned air received from a pair of side air outlets in a refrigerant unit associated with the container. The side air ducts may have a plurality of air discharge openings and may discharge conditioned air into vertically extending recesses in the side walls. The side air outlets have a selectively variable flow area. The number, location and size of the openings through the cargo support floor, as well as the air discharge openings in the side air ducts, may be selectively varied so as to selectively distribute the conditioned air flow throughout the cargo space.