CO2 Water Heater Flow Switching Between Air and Water Heat Sources

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Solution Overview

Problem

Existing CO2 water heaters face challenges in seamlessly switching between water-heat-source and air-heat-source operations due to differences in CO2 usage capacities and states, leading to increased electricity usage when an air-heat-source unit is added.

Innovation Solution

A CO2 water heater design with a CO2 circulation path, compressor, gas cooler, expansion valve, bypass passage, and a CO2 reservoir tank, along with flow regulating valves and heat exchangers for both air and water sources, allows seamless switching between operating modes by adjusting CO2 circulation and storage, maintaining efficient operation without stopping the system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If an air-heat-source CO2 water heater is additionally provided to increase utilization rate, then the utilization rate is improved, but the electricity usage increases

Engineering Contradiction:
Improveutilization rateVSAvoidelectricity usage
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The CO2 water heater is designed to perform multiple functions by switching between water-heat-source operation and air-heat-source operation using a single unit. The system includes a flow path switching mechanism that directs CO2 flow to either the water-heat-source heat exchanger or the air-heat-source heat exchanger, allowing the same equipment to serve dual purposes and eliminate the need for separate units.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the water-heat-source CO2 water heater and air-heat-source CO2 water heater into a single integrated system. The CO2 circulation path is configured with branch passages that can direct flow to either heat source, and a bypass passage with a CO2 reservoir tank that accommodates different CO2 circulation amounts required by each mode, merging two separate systems into one unified device.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If a CO2 water heater is designed to switch between water-heat-source and air-heat-source operations, then the adaptability is improved, but the device complexity increases

Engineering Contradiction:
Improveoperation mode switching capabilityVSAvoidsystem structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The CO2 circulation path is segmented into multiple branch passages, with one branch leading to the water-heat-source heat exchanger and another branch leading to the air-heat-source heat exchanger. This segmentation allows independent control of each heat source path while maintaining a unified overall system structure, making the switching mechanism more manageable and less complex.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A bypass passage with a CO2 reservoir tank serves as an intermediary component that facilitates smooth transitions between different operation modes. The reservoir tank acts as a buffer to accommodate the different CO2 circulation amounts required by water-heat-source and air-heat-source modes, enabling seamless switching without requiring complete system reconfiguration.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If the CO2 circulation amount is adjusted for different heat sources, then the adaptability is improved, but the difficulty of detecting and measuring increases

Engineering Contradiction:
ImproveCO2 circulation adjustmentVSAvoidCO2 state monitoring
Core Design Contradiction:
Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The system adjusts the CO2 circulation amount parameter based on the selected operation mode. A flow regulating valve on the bypass passage controls the CO2 circulation amount to match the requirements of either water-heat-source or air-heat-source mode. The controller automatically adjusts this parameter when switching modes, simplifying the measurement and control process.

Inventive Principle:
Principle #35Parameter changes

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 flexible operation mode switching, reducing electricity usage and increasing utilization rate by allowing the CO2 water heater to adapt to varying heat loads and power conditions, effectively using either water or air as a heat source depending on demand.

Implementation Method 1

when compressed to high pressure by a compressor, CO2 gets into the supercritical state

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

CO2 gets into the supercritical state (a state under a temperature and a pressure above the critical point, where distinct liquid and gas phases do not exist)

Methodology Applied
Scientific EffectSupercritical fluid formation: Supercritical Fluid

Implementation Method 3

CO2 is likely to transfer a high-temperature heat to e.g. water in nature

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 4

transfer a high-temperature heat to e.g. water

Methodology Applied
Scientific EffectThermal energy transfer: Conduction (thermal)

Implementation Method 5

an expansion valve, each of which is provided on the CO2 circulation path

Methodology Applied
Scientific EffectPressure reduction: Depressurisation

Implementation Method 6

an air-heat-source heat exchanger provided on one of the CO2 branch passages; a water-heat-source heat exchanger provided on the other one of the CO2 branch passages

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3098541B1Co2 water heater
Publication Date: 2018.06.06 MAYEKAWA MFG CO LTD
  • EP3098541B1 patent drawingFigure 1
  • EP3098541B1 patent drawingFigure 2
  • EP3098541B1 patent drawingFigure 3

AI summary

A CO2 water heater includes: a CO2 circulation path 14; a compressor 16, a gas cooler 18 and an expansion valve 20 provided on the CO2 circulation path 14; a bypass passage 30 to bypass the expansion valve 20; a supercritical tank 32 and flow regulating valves (34, 35) provided on the bypass passage 30. The CO2 circulation path 14 has two CO2 branch passages (14b, 14c) branched in a parallel manner between the compressor 16 and a downstream portion of the expansion valve 20. An air-heat-source heat exchanger (22a, 22b) is provided on the CO2 branch passage 14b, and a water-heat-source heat exchanger 24 is provided on the CO2 branch passage 14c. Electromagnetic valves (48, 50) to switch a CO2 flow path to the CO2 branch passage 14b or the CO2 branch passage 14c, and a blower 46 to form an air flow to be sent to the air-heat-source heat exchanger (22a, 22b) are provided.