Temperature-Based Compressor Switching in Heat Pump Water Heating
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Solution Overview
Problem
Conventional heat pump hot water feeding apparatuses operate suboptimally due to unnecessary activation of the second compressor when external air temperatures are high or target water temperatures are low, leading to decreased performance.
Innovation Solution
A heat pump interoperating hot water feeding apparatus that dynamically controls the operation of first and second compressors based on external air temperature and target water temperature, determining whether to activate only the first coolant circulation circuit or both circuits, utilizing a cascade heat exchanger for efficient heat exchange between the first and second coolants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the second compressor is activated in conventional heat pump systems, then the system can provide heating capability in cold conditions, but the system performance decreases when external air temperatures are high or target water temperatures are low due to unnecessary activation
Solution Approach 1:
The system dynamically adjusts the operation mode between single-compressor and dual-compressor configurations based on real-time temperature conditions. The controller activates the second compressor only when both external air temperature and target water temperature indicate cold conditions are present, otherwise operating with only the first compressor to optimize performance.
Solution Approach 2:
The system changes operational parameters by switching between different compressor activation states based on temperature thresholds. When external air temperature is high or target water temperature is low, the system changes from dual-compressor mode to single-compressor mode, adjusting the operational parameters to match environmental conditions.
2Power
If both first and second coolant circulation circuits are activated, then the system can achieve higher heating output, but energy efficiency decreases due to unnecessary operation of the second compressor
Solution Approach 1:
The system applies partial action by activating only the necessary portion of the compressor system based on demand. Instead of always running both compressors at full capacity, the system activates only the first compressor when heating demand is low to moderate, and adds the second compressor only when high heating output is required, avoiding excessive energy consumption.
Solution Approach 2:
The first compressor is designed to handle multiple operating conditions independently. It can provide sufficient heating output across a wide range of conditions, making the second compressor unnecessary in many scenarios. The universal design of the first compressor allows it to serve as the primary heating source for most operational scenarios.
3Ease of operation
If the system operates with fixed compressor activation logic, then control is simplified, but adaptability to varying temperature conditions deteriorates
Solution Approach 1:
The system incorporates feedback mechanisms by continuously monitoring external air temperature and target water temperature. Based on this feedback, the controller automatically adjusts compressor activation status, switching between single and dual compressor modes to adapt to varying temperature conditions while maintaining straightforward control logic.
Solution Approach 2:
The system performs self-adjustment by automatically determining the appropriate operational mode based on sensed temperature conditions. The controller autonomously decides whether to activate the second compressor without requiring manual intervention, enabling the system to adapt to changing conditions while maintaining simple operation for the user.
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 approach optimizes performance by ensuring that only the necessary coolant circulation circuits are active, enhancing the overall efficiency of the heat pump system by up to 20% compared to existing systems.
Implementation Method 1
a cascade heat exchanger, wherein the first and second coolant circulation circuits partially cross each other so that the first coolant is primarily condensed by the used water circulation circuit in a first heat exchanger and then heat exchanged with the second coolant to be secondarily condensed in the cascade heat exchanger, and the second coolant is heat exchanged with the first coolant to be evaporated in the cascade heat exchanger
Implementation Method 2
a first heat exchanger arranged over the first coolant circulation circuit, wherein the first heat exchanger primarily condenses the first coolant by allowing the first coolant to be heat exchanged with the used water flowing through the used water circulation circuit
Implementation Method 3
a second heat exchanger arranged over the second coolant circulation circuit, wherein the second heat exchanger primarily condenses the second coolant by allowing the second coolant to be heat exchanged with the used water flowing through the used water circulation circuit
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A heat pump interoperating hot water feeding apparatus is provided that may determine whether to activate only the first coolant circulation circuit along which the first coolant is circulated or the first coolant circulation circuit as well as the second coolant circulation circuit along which the second coolant is circulated depending on an external air temperature or target water temperature, thus providing the optimal performance.