Buffer Device With Phase-Change Material for Heat Pump Retrofit
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Solution Overview
Problem
Traditional heating systems based on fossil fuels are inefficient and require complete replacement when transitioning to heat pumps, which can be costly and impractical for existing infrastructure, especially in older houses, and alternative solutions often require additional space and features.
Innovation Solution
A heating system utilizing a buffer device with phase-changing material and a CO2 air/fluid heat pump, which efficiently stores and provides heat through three fluid flows, allowing for integration with existing systems without full infrastructure replacement, using a buffer device with phase-changing spheres or shells filled with salt hydrates to optimize heat storage and transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a heat pump is used to replace fossil fuel boilers, then environmental impact is reduced and energy efficiency is improved, but the complete heating system infrastructure needs to be replaced
Solution Approach 1:
The buffer device is divided into two distinct sections: a first section for heating fluid storage and a second section for domestic hot water storage. This segmentation allows the heat pump to integrate with existing heating infrastructure while providing dedicated spaces for different thermal requirements, avoiding complete system replacement.
Solution Approach 2:
The buffer device serves multiple functions: it stores heating fluid for the existing heating system, provides domestic hot water, and acts as a thermal buffer for the heat pump. This multi-functionality allows the heat pump to replace fossil fuel boilers without requiring complete infrastructure replacement.
2Use of energy by moving object
If traditional heat pumps are used, then energy efficiency is improved, but additional space and features are required
Solution Approach 1:
The patent utilizes phase change material (paraffin wax) that transitions from solid to liquid at specific temperatures. This phase transition enables high-density energy storage in a compact volume, allowing the buffer device to store significant thermal energy without requiring excessive space.
Solution Approach 2:
The buffer device leverages the phase change temperature of paraffin wax (approximately 50-60°C) to optimize thermal storage. By designing the system around this specific temperature parameter, the device achieves efficient heat storage and release cycles with minimal volume requirements.
3Productivity
If the third flow of fluid warms up the return to the heat pump in the buffer device, then heating efficiency is improved, but the heat pump operates with reduced temperature difference
Solution Approach 1:
The buffer device is segmented into a first section that receives warmed fluid from the heating system and a second section that provides cooler fluid to the heat pump. This spatial separation prevents the warmed return fluid from directly reducing the temperature difference at the heat pump inlet, maintaining operational efficiency.
Solution Approach 2:
The buffer device acts as an intermediary thermal storage unit between the heating system and the heat pump. It absorbs excess heat from the third flow and releases it gradually, preventing direct thermal interference with the heat pump's temperature differential requirements.
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
Enables efficient and compact heat storage and distribution, allowing the system to replace conventional heating systems without full infrastructure replacement, while reducing environmental impact through the use of CO2 heat pumps and solar energy integration.
Implementation Method 1
The buffer device, and preferably the first section thereof, comprises phase changing material, which is used to store heat upon a phase change. The use of such material allows heat to be stores in efficiently in a relatively small volume, decreasing the size of the buffer device needed to store or provide a set amount of energy. The phase changing material also provides heat upon changing is phase
Implementation Method 2
The phase changing material has a phase changing temperature between 30 and 90 degrees Celsius, more in particular between 40 and 80, more in particular between 60 and 75 degrees Celsius. Phase Changing Materials are known in the art and use heat needed or provided by changing phase, such that the materials may be considered as some form of thermal battery or storage for the present heating system
Implementation Method 3
The heat pump increases the temperature of the fluid running through, this increasing the temperature of the buffer device as a whole
Implementation Method 4
The first flow of fluid is partly in heat exchanging contact with the third flow. The third flow of fluid is heated by the first flow and the heat exchange from the phase changing spheres between its travel from inlet to outlet
Implementation Method 5
Such configuration is especially useful when using CO2 heat pumps, which operate particularly efficient with relative high temperature differences or deltaT between the return inlet and supply outlet, opposed to more traditional heat pumps
Data Source
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AI summary
The present invention relates to a heating system, comprising a buffer device, comprising an first inlet for receiving a first fluid and a first exit for delivering the first fluid; a heat pump, a first circuit extending from the first exit of the buffer device, via the heat pump, to the first inlet of the buffer device; wherein the buffer device comprises a second inlet for receiving a second fluid, and a second exit for delivering the second fluid, a second fluid circuit extending between the second inlet and the second exit of the buffer device; wherein the second fluid circuit is at least partially in heat exchanging contact with the first fluid of the buffer device; wherein the buffer device comprises a third inlet for receiving the first fluid and a third exit for delivering the first fluid; a third fluid circuit extending between the third inlet and the third exit of the buffer device; wherein the third fluid circuit comprises a heating element, in heat exchanging contact with the first fluid in the third fluid circuit; wherein the buffer device comprises at least two sections, wherein a first section comprises the first inlet, the second outlet, the third inlet and the third exit; and wherein a second section comprises the first exit and the second inlet; wherein the buffer device comprises a phase changing material, arranged to be in heat exchanging contact with the first fluid of the buffer device; wherein the phase changing material is preferably arranged in at least one of the two sections.