Thermal storage system containers external features and modularity
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Solution Overview
Problem
Conventional thermal energy storage systems, such as 'ice-on-coil' and 'encapsulated ice' systems, face inefficiencies due to slow or inconsistent ice nucleation, limited contact between storage fluid and heat transfer fluid, and degradation over time, leading to reduced performance and discharge rates, making them unsuitable for commercial buildings.
Innovation Solution
A modular thermal storage system comprising elongate containers with phase-change material, where multiple containers are stacked and coupled to enhance heat exchange efficiency, with a fluid distribution system that allows for controlled activation of subsets of ice bricks to manage thermal energy storage and discharge effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional ice-on-coil storage systems are used to store thermal energy, then thermal energy can be stored by utilizing phase change of water into ice, but ice builds up around the coil forming a massive block that increases insulation layer thickness and makes it increasingly difficult to freeze the whole volume of the storage tank
Solution Approach 1:
The storage tank is divided into multiple compartments with separate coils in each compartment. This segmentation prevents ice from forming a single massive insulating block, as ice builds up independently in each compartment around its respective coil, maintaining freezing efficiency while increasing overall storage capacity.
2Quantity of substance
If very low temperatures are used for cooling the coil to overcome ice build-up, then the whole volume of the storage tank can be frozen, but the chiller's COP (coefficient of performance) is hurt
Solution Approach 1:
Multiple compartments with separate coils allow the storage system to achieve full volume freezing without requiring excessively low temperatures. Each compartment operates independently, preventing the formation of a single thick insulating ice block that would necessitate extreme cooling temperatures, thus maintaining chiller COP.
Solution Approach 2:
Each compartment is designed with optimized coil placement and configuration tailored to its specific geometry and thermal requirements. This local optimization ensures efficient heat transfer in each compartment without requiring the entire system to operate at extremely low temperatures, improving overall chiller efficiency.
3Quantity of substance
If encapsulated ice storage systems are used, then thermal energy can be stored with containers containing water as PCM, but there is slow or inconsistent ice nucleation resulting in inefficient thermal energy storage and discharge
Solution Approach 1:
Ice nucleation promoters or seeds are introduced into the water before freezing begins in each compartment. This preliminary action ensures rapid and consistent ice nucleation when cooling starts, eliminating the delay and inconsistency associated with spontaneous nucleation in encapsulated systems.
Solution Approach 2:
The coil acts as an intermediary heat transfer surface that facilitates controlled and uniform heat extraction from the water in each compartment. This intermediary mechanism ensures consistent cooling rates and promotes uniform ice nucleation throughout the water volume, improving both storage efficiency and discharge reliability.
4Quantity of substance
If conventional thermal storage systems are designed, then thermal energy can be stored, but there is limited contact between the storage fluid and the heat transfer fluid due to growing water barrier, low packing factor, or poor container design
Solution Approach 1:
The storage system is divided into multiple compartments, each with its own coil and fluid circulation path. This segmentation ensures that the heat transfer fluid maintains direct and consistent contact with the storage water in each compartment, preventing the formation of a growing insulating water barrier that would limit heat exchange in single-compartment systems.
Solution Approach 2:
The coil is configured in a three-dimensional arrangement within each compartment, maximizing the surface area of contact between the heat transfer fluid and the storage water. This dimensional optimization ensures comprehensive heat exchange throughout the entire volume of each compartment, eliminating limitations imposed by poor container design or low packing factors.
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
The modular system improves heat transfer rates, maintains stable discharge performance, and extends the lifespan of thermal energy storage, making it suitable for commercial applications by addressing inefficiencies in existing systems.
Implementation Method 1
exchanging heat by fluid flow adjacent phase-changing material in thermal-storage containers
Implementation Method 2
utilizing the phase change of liquid water into ice
Implementation Method 3
exchanging heat by fluid flow adjacent phase-changing material
Data Source
AI summary
A thermal-storage container used in a thermal-storage system to exchange heat by fluid flow though phase-changing material disposed inside the thermal-storage container, including a thermal-storage container housing, a fluid inlet and a fluid outlet, and one or more capsules containing the phase-change material, wherein the housing is shaped as an elongate container, a ratio of length to width of the housing is between 2 and 20. Related apparatus and methods are also described.