Cooling container using phase change material and method for operating
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Solution Overview
Problem
Existing cooling solutions, such as Phase Change Materials (PCM) and thermal electric technologies, face inefficiencies in maintaining consistent and accurate low temperatures due to the need for multiple PCM types and lack of active temperature control, leading to suboptimal cooling capacity and energy conversion.
Innovation Solution
A portable cooling container design separates the PCM from the product, using a two-chamber system where the PCM is isolated from the product, allowing for controlled heat transfer through a circulating cooling fluid, with temperature sensors and controllers to maintain user-determined temperatures, and optional use of radiators or heat exchangers for enhanced cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple PCM types are used to match different desired temperatures, then temperature matching accuracy is improved, but device complexity and material selection complexity increase
Solution Approach 1:
The system divides the cooling function into two independent parts: a single PCM chamber containing the most efficient PCM material, and a product chamber with active temperature control. This segmentation allows the PCM to operate at its optimal temperature range while the active control system handles temperature regulation for the product, eliminating the need to select from multiple PCM types.
Solution Approach 2:
An active temperature control system acts as an intermediary between the PCM and the product. This mediator decouples the direct thermal coupling, allowing the PCM to maintain a fixed temperature while the control system adjusts the heat transfer to achieve the desired product temperature, thus simplifying PCM selection to just one or a few efficient materials.
2Productivity
If PCM is directly contacted with product, then cooling efficiency is improved, but temperature control accuracy deteriorates due to lack of active control
Solution Approach 1:
The direct contact between PCM and product is segmented into indirect heat transfer through a controlled fluid medium. The PCM chamber and product chamber are separated, with a circulating cooling fluid acting as the heat transfer medium. This allows efficient heat extraction while enabling precise temperature control through the active control system that regulates fluid circulation.
Solution Approach 2:
A circulating cooling fluid serves as an intermediary heat transfer medium between the PCM and the product. This fluid can be actively controlled in terms of flow rate and circulation timing, allowing the system to maintain high cooling efficiency while achieving accurate temperature control that direct PCM contact cannot provide.
3Ease of operation
If thermal electric technology is used for active temperature control, then temperature control capability is improved, but energy conversion efficiency deteriorates
Solution Approach 1:
The system utilizes the phase transition properties of PCM (such as dry ice sublimation or water ice melting) as the primary cooling mechanism. These phase transitions occur at fixed temperatures and provide large latent heat absorption, creating a more efficient cooling source compared to thermal electric devices. The active control system only needs to regulate fluid circulation rather than generate cooling, significantly improving overall energy efficiency.
Solution Approach 2:
The PCM provides self-service cooling through its phase transition process, automatically absorbing heat at its phase change temperature without requiring external power input. The active control system only needs to manage the circulation of cooling fluid to distribute this self-generated cooling effect, rather than using energy-intensive thermal electric conversion to create cooling from scratch.
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 design enables efficient temperature control independent of PCM phase change temperatures, reducing the need for multiple PCM types and improving cooling capacity by using the most efficient materials, while minimizing power consumption through sophisticated temperature regulation.
Implementation Method 1
A cooling container uses a phase change material (PCM) such as dry ice
Implementation Method 2
PCM will typically consist of dry ice, water ice or commercial PCM
Implementation Method 3
Cooling fluid (gas or liquid) from the PCM circulate between the PCM chamber and the product chamber
Implementation Method 4
In another embodiment a heat exchanger is provided on a divider wall between the PCM chamber and the product chamber
Implementation Method 5
Heat flow between the two chambers is controlled by measuring the temperature in the product chamber and adjusting the movement of fluid
Data Source
AI summary
A cooling container having a coolant chamber and a product chamber. Cooling gases from the coolant chamber circulate between the coolant chamber and the product chamber to retain the latter at a desired low temperature. In one embodiment the cooling gases flow through a radiator disposed in the product chamber. In another embodiment a heat exchanger is provided on a divider wall between the coolant chamber and the product chamber. When a temperature sensor detects that the temperature in the product chamber exceeds a temperature set point, a controller opens valves that allow cool gases in the coolant chamber to circulate through the radiator or across the heat exchanger to lower the temperature in the product chamber.