Heat pump system having CO2 as the first heat pump medium and water as the second heat pump medium
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Solution Overview
Problem
Conventional CO2 heat pump systems face inefficiencies and high operational costs due to the need for high pressures and complex configurations, especially during subcritical operation, and the use of refrigerants with high global warming potentials.
Innovation Solution
A heat pump system comprising a first CO2 heat pump arrangement coupled with a second water heat pump arrangement, where the water heat pump has a turbocompressor with a radial impeller and a controller to adjust rotational speed based on temperature, allowing for efficient thermodynamic coupling and reduced energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CO2 heat pump systems operate at high pressures to maintain subcritical operation, then the system can achieve efficient heat transfer and maintain operation throughout the year, but the technical expenditure and complexity of high-pressure components increases
Solution Approach 1:
The system is divided into two separate heat pump arrangements: a first CO2 heat pump arrangement operating in subcritical mode and a second water heat pump arrangement operating in subcritical mode. This segmentation allows each arrangement to operate at lower pressures suitable for its respective refrigerant, eliminating the need for complex high-pressure components while maintaining year-round operation capability.
Solution Approach 2:
A thermal coupling unit acts as an intermediary between the first CO2 heat pump arrangement and the second water heat pump arrangement. This thermal coupling enables heat transfer between the two arrangements, allowing the CO2 system to benefit from the water system's lower pressure operation while maintaining subcritical CO2 operation for year-round reliability.
2Device complexity
If CO2 heat pump systems use conventional compressors, then the system structure is simpler, but the energy consumption and operational costs increase
Solution Approach 1:
The conventional mechanical compressor in the water heat pump arrangement is replaced with a turbocompressor, which uses a radial impeller to compress the refrigerant. This substitution reduces mechanical complexity while significantly improving energy efficiency through more efficient compression thermodynamics, directly addressing the contradiction between simple structure and low energy consumption.
3Ease of manufacture
If conventional refrigerants are used in heat pump systems, then the system design is straightforward, but the environmental impact due to high global warming potential increases
Solution Approach 1:
The system changes the refrigerant parameter from conventional high-GWP refrigerants to CO2 (R744) with its distinctive thermodynamic properties. This parameter change requires designing the first heat pump arrangement specifically for subcritical CO2 operation, but it eliminates the environmental harm associated with high global warming potential refrigerants while maintaining straightforward system design through proper thermal coupling.
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 enables efficient operation at high ambient temperatures with reduced technical expenditure, maintaining subcritical operation throughout the year and minimizing environmental impact by using water as a working medium, which requires lower pressures and reduces the need for high-pressure components.
Implementation Method 1
The fluid flow machine is configured to compress the working vapor to a vapor pressure at least larger than 25 hPa
Implementation Method 2
The fluid flow machine is coupled to a condenser (liquefier) 18 configured to condense the compressed working vapor
Implementation Method 3
a water evaporator 10 for evaporating water as a refrigerant, or refrigerating medium, so as to generate vapor within a working vapor line 12
Data Source
AI summary
A heat pump system includes a first heat pump arrangement configured to operate with a first heat pump medium including CO2; a second heat pump arrangement configured to operate with a second heat pump medium including water; and a coupler for thermally coupling the first heat pump arrangement to the second heat pump arrangement.