Grid interactive water heater
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Solution Overview
Problem
Conventional grid interactive water heaters face limitations in storing heat energy within a narrow temperature range, leading to inefficiencies in energy storage and utilization, especially when renewable energy sources like solar power are used, as they require large tank sizes and suffer from temperature losses over time, resulting in wasted energy.
Innovation Solution
The integration of phase change materials (PCMs) in thermal energy storage systems within water heaters, allowing for efficient storage and release of heat energy at consistent temperatures, combined with heat pumps and control systems to optimize energy usage and reduce tank size, enables the storage of excess electrical energy for later use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the acceptable temperature range is narrow to meet user requirements, then user satisfaction is improved, but the amount of heat energy stored is reduced
Solution Approach 1:
The patent utilizes phase change materials (PCMs) that undergo phase transitions (solid-liquid) at specific temperatures within the acceptable range. During phase change, PCMs absorb or release large amounts of latent heat while maintaining nearly constant temperature, enabling significant heat energy storage within narrow temperature differentials that satisfy user requirements.
Solution Approach 2:
The system changes the thermal properties parameters by incorporating PCMs with specific phase change temperatures and latent heat values. This allows the water heater to store much more heat energy within the same narrow temperature range compared to conventional sensible heat storage in water alone.
2Quantity of substance
If the tank size is increased to store more heat energy, then heat energy storage capacity is improved, but device complexity and space requirements increase
Solution Approach 1:
By using PCMs that undergo phase transitions, the system achieves high heat energy density in a compact form. The latent heat stored during phase change allows significant energy storage in much smaller volumes compared to conventional water-only storage systems.
Solution Approach 2:
The system employs composite structures combining PCMs with water and heat transfer materials. This composite approach maximizes heat energy storage capacity while minimizing tank volume, achieving both high energy density and compact size.
3Productivity
If thermal energy is stored for extended periods to match renewable energy availability, then energy utilization is improved, but temperature losses increase
Solution Approach 1:
PCMs maintain their phase change temperature relatively stable during storage, and the phase change process itself can absorb or release heat to counteract temperature drift. This reduces temperature losses during extended storage periods compared to conventional sensible heat storage.
Solution Approach 2:
The system continuously maintains the PCM in or near its phase change state, ensuring that heat energy remains available for use. The phase change mechanism provides a continuous heat buffer that minimizes temperature losses over time.
4Object-generated harmful factors
If electric power is used to heat water instead of fossil fuels, then greenhouse gas emissions are reduced, but energy storage efficiency is limited by temperature range
Solution Approach 1:
The patent employs phase change materials that undergo solid-liquid phase transitions at temperatures within the acceptable hot water range. During phase change, PCMs absorb or release large amounts of latent heat while maintaining nearly constant temperature, enabling significant heat energy storage within narrow temperature differentials that satisfy user requirements.
Solution Approach 2:
The system changes the thermal properties parameters by incorporating PCMs with specific phase change temperatures and latent heat values. This allows the water heater to store much more heat energy within the same narrow temperature range compared to conventional sensible heat storage in water alone.
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 enhances the storage capacity of heat energy, reduces energy waste, and improves the efficiency of heat transfer, allowing for longer hot water supply and better alignment with renewable energy availability, while also reducing greenhouse gas emissions by using electric power instead of fossil fuels.
Implementation Method 1
Some thermal energy storage systems use phase change materials (PCM). Commonly used PCMs include hydrated salts, eutectic salts, and paraffins.
Implementation Method 2
The integration of phase change materials (PCMs) in thermal energy storage systems within water heaters, allowing for efficient storage and release of heat energy at consistent temperatures
Implementation Method 3
The integration of phase change materials (PCMs) in thermal energy storage systems within water heaters, allowing for efficient storage and release of heat energy at consistent temperatures, combined with heat pumps and control systems to optimize energy usage
Implementation Method 4
These water heaters can use electricity from an electrical grid to store hot water. The electrical energy is stored as heat for later use as heat energy.
Data Source
AI summary
The present disclosure generally relates to hot water heaters 1 that are for the use of using electricity to store heat energy for current or later use. In some embodiments, the heat energy is stored in Thermal Energy Storage 7 (TES) to store excess electrical energy for the later use of heating water. The present disclosure also relating to several species of the invention which relate to the water tank 1 being a Grid Interactive Water Heater (GIWH). Some of the embodiments disclose methods of storing heat energy at a lower temperature than the hot water in the tank, which avoids being limited to phase change materials that phase change withing the narrow range of the hot water temperature. Another embodiment makes hydrogen for the use of heating water. Another uses the exhaust heat from a heat engine to improve the overall efficiency over common CHP water heaters.