A method for controlling a valve arrangement in a vapour compression system
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Solution Overview
Problem
Vapour compression systems face inefficiencies in switching from 'winter mode' to 'summer mode' operation as ambient temperature increases, leading to suboptimal energy consumption, as the automatic switch is not guaranteed during operation.
Innovation Solution
A method for controlling a valve arrangement in a vapour compression system that actively forces a switch to 'summer mode' by determining the refrigerant distribution and temperature differences, using a three-way valve to bypass refrigerant from the receiver to the compressor, ensuring energy-efficient operation across varying temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the system operates in winter mode (supplying refrigerant from evaporator to compressor), then the system can operate at low ambient temperatures, but the system fails to switch to summer mode automatically when ambient temperature increases, leading to suboptimal energy consumption
Solution Approach 1:
The control system continuously monitors the ambient temperature and automatically switches between winter and summer modes based on temperature thresholds. When the ambient temperature exceeds a predetermined threshold, the system transitions from winter mode to summer mode, ensuring optimal energy efficiency without manual intervention
Solution Approach 2:
The system changes its operational parameters based on ambient temperature conditions. In winter mode, the valve arrangement directs refrigerant from the evaporator to the compressor, while in summer mode, it redirects refrigerant from the condenser to the compressor, adapting the system's behavior to match environmental conditions
2Loss of energy
If the valve arrangement actively forces a switch to summer mode, then energy efficiency is improved, but the control system complexity increases
Solution Approach 1:
The system performs self-assessment by monitoring ambient temperature and automatically makes the necessary mode transitions without requiring external control or complex decision-making algorithms. The simplicity of the temperature-based control logic minimizes the added complexity while ensuring energy-efficient operation
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
Ensures the vapour compression system operates in an energy-efficient 'summer mode' by actively switching from 'winter mode' when conditions are met, preventing continuous suboptimal operation and reducing energy consumption.
Implementation Method 1
An ejector is a type of pump which uses the Venturi effect to increase the pressure energy of a fluid at a suction inlet (or secondary inlet) of the ejector by means of a motive fluid supplied to a motive inlet (or primary inlet) of the ejector.
Data Source
Figure 1
AI summary
A method for controlling a valve arrangement (12), e.g. in the form of a three way valve, in a vapour compression system (1) is disclosed, the vapour compression system (1) comprising an ejector (6). The valve arrangement (12) is arranged to supply refrigerant to a compressor unit (2) from the gaseous outlet (11) of a receiver (7) and/or from the outlet of an evaporator (9). The vapour compression system (1) may be operated in a first mode of operation (summer mode) or in a second mode of operation (winter mode). When operated in the second mode of operation, it is determined whether or not conditions for operating the vapour compression system (1) in the first mode of operation are prevailing. If this is the case, the valve arrangement (12) is actively switched to the first mode of operation by closing a first inlet (13) towards the evaporator (7) and fully opening a second inlet (14) towards the receiver (7).