A method for controlling a vapour compression system based on estimated flow
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Solution Overview
Problem
Vapour compression systems face excessive wear and inefficient operation of the receiver compressor due to insufficient gaseous refrigerant supply, particularly at low outdoor temperatures, leading to repeated switching on and off.
Innovation Solution
A method that estimates the vapour flow entering the receiver and compares it to threshold values to control pressure within the receiver, ensuring the receiver compressor operates only when sufficient gaseous refrigerant is available, thereby minimizing wear and optimizing energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the receiver compressor is operated to improve energy efficiency, then energy efficiency is improved, but excessive wear occurs due to operation under insufficient vapour supply
Solution Approach 1:
The controller uses feedback from estimated vapour flow to determine when receiver compressor operation is energy-efficient. When sufficient vapour is available, the compressor operates to efficiently manage pressure and refrigerant distribution. When vapour is insufficient, the compressor is protected from wear-inducing operation, balancing energy efficiency with equipment protection.
Solution Approach 2:
The operational state of the receiver compressor is changed based on the vapour flow parameter. The system operates the compressor in high-vapour conditions to maximize energy efficiency and switches it off in low-vapour conditions to prevent wear, creating an adaptive control strategy that optimizes both energy use and equipment longevity.
Data Source
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AI summary
A method for controlling a vapour compression system (1) comprising a compressor unit (2) comprising at least two compressors (3, 12), a heat rejecting heat exchanger (4), a receiver (6), an expansion device (7) and an evaporator (8) arranged in a refrigerant path is disclosed. At least one of the compressors is a main compressor (3) being fluidly connected to an outlet of the evaporator (8) and at least one of the compressors is a receiver compressor (12) being fluidly connected to a gaseous outlet (10) of the receiver (6). A flow of vapour entering the receiver (6), such as a mass flow of vapour entering the receiver (6) is estimated and compared to a first threshold value. In the case that the estimated flow is above the first threshold value, a pressure prevailing inside the receiver (6) is controlled by operating the receiver compressor (12).