Inverter Heat Pump Water Temperature Control Under Variable Terminal Load
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Solution Overview
Problem
The primary pump system in heat pump heating projects experiences large fluctuations in outlet water temperature due to changes in terminal load, as it uses a fixed-frequency heat pump that cannot adapt to load changes.
Innovation Solution
A water temperature control method for heat pump systems that includes an inverter compressor heat pump, where the compressor frequency is dynamically adjusted based on real-time outlet water temperature differences, using a preset energy level range table to maintain constant water temperature by determining the current compressor energy level range and corresponding frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed-frequency heat pump is used in a primary pump system, then the system structure is simplified and operation costs are reduced, but the outlet water temperature fluctuates greatly when terminal load changes
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a fixed-frequency heat pump to a variable-frequency heat pump system. The compressor frequency is dynamically adjusted based on terminal load changes and outlet water temperature feedback, allowing the system to adapt to varying conditions while maintaining stable temperature output. This resolves the contradiction by making the previously static system dynamic and responsive.
Solution Approach 2:
The patent implements a feedback control mechanism where the outlet water temperature is continuously monitored and used to adjust the compressor frequency. When terminal load changes cause temperature deviations, the system detects these changes and automatically adjusts the heat pump operation to restore the desired temperature, thereby maintaining stability while using a simplified primary pump structure.
2Ease of manufacture
If a fixed-frequency heat pump is used, then equipment cost is reduced, but the system cannot adapt to terminal load changes
Solution Approach 1:
The system transitions from static fixed-frequency operation to dynamic variable-frequency operation, enabling the heat pump to adapt to changing terminal loads. The compressor speed is continuously adjusted based on load conditions, providing the necessary adaptability while maintaining cost-effectiveness through the primary pump system architecture.
Solution Approach 2:
The patent changes the operating parameter of the heat pump from fixed frequency to variable frequency. By adjusting the compressor frequency parameter in response to terminal load changes, the system achieves adaptability without requiring complex additional equipment, thus balancing manufacturing cost with operational flexibility.
3Stability of the object's composition
If compressor frequency is dynamically adjusted based on outlet water temperature difference, then outlet water temperature stability is improved, but control system complexity increases
Solution Approach 1:
The patent employs a feedback control system that monitors outlet water temperature and uses the temperature difference from the setpoint to adjust compressor frequency. This closed-loop control maintains temperature stability by continuously comparing actual temperature with desired temperature and making corrective adjustments, accepting moderate control complexity as necessary for achieving the stability goal.
Solution Approach 2:
The control system operates autonomously by automatically detecting temperature deviations and adjusting compressor frequency without manual intervention. The system serves itself by using its own output (outlet water temperature) as the input signal for control adjustments, simplifying the overall control architecture while maintaining stability.
Data Source
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AI summary
This application discloses a water temperature control method for a heat pump system, and a heat pump system. The method includes: detecting a current outlet water temperature of an equipment end in real time, and obtaining a current outlet water temperature difference between the current outlet water temperature and a specified outlet water temperature; and determining a current compressor energy level range based on the current outlet water temperature difference, and obtaining a current compressor frequency corresponding to the current compressor energy level range from a preset energy level range table, so as to control a compressor of an inverter compressor heat pump by using the current compressor frequency. According to this application, equipment can adapt to a change in terminal load. After a terminal changes, an output water temperature is dynamically adjusted to keep the water temperature constant, improving performance of a primary heat pump system.