Method for controlling a heat pump system and heat pump system
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Solution Overview
Problem
Existing heat pump systems face challenges in accurately controlling room temperature when thermostatic radiator valves (TRVs) are closed without the controller's knowledge, leading to unpredictable changes in heating system response, especially in rooms without temperature sensors.
Innovation Solution
A method for controlling a heat pump system that measures the flow rate of the heat transport medium into a first heat exchanger and adjusts control parameters of the compressor operation frequency using PI or PID control, even in the absence of temperature sensors, by detecting changes in flow rate and temperature differences, allowing for stable response control across multiple rooms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the controller uses predefined data to control supplied heat based on water flow temperature, then the control is simple and responsive, but the control accuracy deteriorates when TRVs are closed without detection
Solution Approach 1:
The patent implements feedback by measuring the actual water flow rate through the heat exchanger and using this measured value to dynamically adjust control parameters. The controller continuously monitors the flow rate and compares it against expected values to detect TRV closures, then adapts the control strategy accordingly. This closed-loop feedback mechanism maintains control accuracy even when TRVs are closed by compensating for the changed system characteristics.
Solution Approach 2:
The patent changes control parameters dynamically based on detected flow rate conditions. When a TRV closure is detected through flow rate measurement, the controller modifies parameters such as the relationship between water flow temperature and supplied heat calculation, or adjusts compressor operation frequency. This parameter adaptation allows the system to maintain optimal control performance under varying TRV configurations without requiring complete reconfiguration.
2Measurement precision
If temperature sensors are installed in all rooms to detect TRV operations, then the control accuracy improves, but the device complexity and cost increase
Solution Approach 1:
The patent uses water flow rate measurement as an intermediary indicator to infer TRV operation status indirectly. Instead of directly monitoring TRV positions or installing temperature sensors in each room, the system measures the flow rate of heat transport medium through the heat exchanger as a proxy. This intermediary measurement provides information about overall system conditions and TRV closures without requiring direct sensing in each controlled space, thereby reducing complexity.
Solution Approach 2:
The system uses its existing flow measurement infrastructure (already present for control purposes) to additionally detect TRV operations. The flow rate measurement, originally intended for basic control functions, serves dual purposes by also indicating when TRVs are closed. This self-service approach extracts additional information from existing measurements without adding dedicated detection sensors or increasing system complexity.
3Adaptability or versatility
If the controller adapts control parameters dynamically based on flow rate changes, then the adaptability improves, but the control algorithm complexity increases
Solution Approach 1:
The patent implements dynamic adaptation by continuously monitoring flow rate and adjusting control parameters in real-time based on detected changes. The system transitions from static predefined control relationships to dynamic parameter adjustment, where control characteristics automatically adapt to current TRV configurations. This dynamic approach maintains high adaptability while using relatively simple adjustment logic based on flow rate threshold comparisons and basic parameter scaling.
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 enables precise control of the heat pump system to maintain target temperatures across rooms with varying TRV configurations, ensuring accurate heating and reducing the impact of unrecognized TRV operations, even in rooms without temperature sensors.
Implementation Method 1
a first heat exchanger (4) for exchanging heat between the refrigerant cycle (1) and the heat transport medium cycle (2)
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present invention relates to a method for controlling a heat pump wherein a flow rate of a heat transport medium flowing into a first heat exchanger is measured, and if the measured flow rate changes below a predetermined smaller flow-threshold or above a predetermined upper flow-threshold, at least one control parameter in the formula of a control method to control a compressor operation frequency is changed.