Method for controlling and regulating heat pumps and cooling systems
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Solution Overview
Problem
Existing heat pump and cooling systems face inefficiencies in controlling the evaporation process, particularly in maintaining optimal overheating temperature setpoints, leading to unstable operation and reduced efficiency.
Innovation Solution
A method that determines a virtual energy flow balance to set optimal overheating temperature setpoints, using a virtual MSS characteristic curve that is proportional to the real energy flow balance, incorporating superheat temperature, specific heat capacity, enthalpy, and expansion valve lift, with a correction factor, to ensure stable operation and adapt to changing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the superheat temperature setpoint is fixed or adjusted based on simple rate of change, then the control is simple to implement, but the system efficiency and stability deteriorate under varying operating conditions
Solution Approach 1:
The invention changes the parameter basis for control from simple superheat temperature rate of change to a comprehensive energy flow balance calculation involving multiple parameters (refrigerant mass flow, heat output, specific enthalpy, specific heat capacity). This allows the control system to adapt to varying operating conditions while maintaining efficiency, resolving the contradiction between simple control implementation and system efficiency.
Solution Approach 2:
The invention introduces an intermediary virtual energy flow balance calculation that mediates between direct superheat control and complex real energy flow measurement. This virtual balance serves as a simplified representation that captures essential energy relationships without requiring direct measurement of all energy flows, enabling efficient control while maintaining simplicity.
2Loss of energy
If the superheat temperature setpoint is lowered to improve efficiency, then energy use improves, but system stability deteriorates due to increased variability
Solution Approach 1:
The invention implements feedback control by continuously monitoring the virtual energy flow balance and adjusting the expansion valve position accordingly. The control system uses the calculated energy balance to determine optimal superheat temperature setpoints dynamically, allowing the system to maintain stability while optimizing energy efficiency through adaptive feedback rather than fixed or purely reactive control.
Solution Approach 2:
The invention makes the superheat temperature setpoint dynamic rather than fixed, allowing it to vary based on current operating conditions captured in the virtual energy flow balance. This dynamic adjustment enables the system to maintain optimal efficiency across different operating points while preserving stability through condition-dependent adaptation.
3Productivity
If complex energy flow measurements are used to determine optimal setpoints, then system efficiency improves, but device complexity and measurement requirements increase
Solution Approach 1:
The invention introduces an intermediary virtual energy flow balance calculation that mediates between direct superheat control and complex real energy flow measurement. This virtual balance serves as a simplified representation that captures essential energy relationships without requiring direct measurement of all energy flows, enabling efficient control while maintaining simplicity.
Solution Approach 2:
The invention creates a virtual copy or model of the energy flow balance that mirrors the essential relationships of the real system without requiring direct measurement of all physical energy flows. This virtual model uses readily available sensor data (temperatures, pressures, valve position) to reconstruct energy relationships, reducing measurement complexity while maintaining control accuracy.
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 enhances the efficiency and stability of the evaporation process by maintaining the system close to the MSS characteristic curve, reducing fluctuations, and ensuring optimal energy use, thereby improving the overall performance of the heat pump or cooling system.
Implementation Method 1
one or more evaporators, one or more compressors, one or more condensers or liquid condensers and one or more expansion valves controllable by a control device are arranged in a closed circuit one after the other
Implementation Method 2
one or more evaporators, one or more compressors, one or more condensers or liquid condensers and one or more expansion valves controllable by a control device are arranged in a closed circuit one after the other
Implementation Method 3
one or more evaporators, one or more compressors, one or more condensers or liquid condensers and one or more expansion valves controllable by a control device are arranged in a closed circuit one after the other
Data Source
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AI summary
The invention relates to a method for controlling and regulating the superheating temperature of a coolant in an evaporation device in the circuit of a plant system of a heat pump or cooling system, characterized in that an energy flow balance is formed for determining the target value for the controlled variable, wherein the virtual energy flow balance is formed such that the virtual energy flow balance is approximately proportional to the actual energy flow balance at all operating points of the heat pump or cooling system, in that a virtual heat output of the evaporation device is determined that is functionally dependent on the known parameters of superheating temperature, specific heat capacity of the coolant, and specific enthalpy in the saturated vapor condition, the stroke of the expansion valve, and a correction factor formed for each operating point of the expansion valve.