Turbo refrigerator, refrigerator control device, turbo refrigerator control method, and program
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Solution Overview
Problem
Centrifugal chillers face starting failures due to mismatched vane opening degrees set for varying refrigerant gas states, leading to increased starting current and time, particularly when the load is high.
Innovation Solution
A centrifugal chiller system that includes a vane adjustable for refrigerant flow rate, a condenser, expansion valve, and evaporator, equipped with a chiller control device to acquire refrigerant gas state amounts, determine optimal vane opening degrees, and control them accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vane opening degree is reduced to limit suction flow rate at starting, then the starting current and starting time are reduced, but the opening degree may not match the refrigerant gas state leading to starting failure
Solution Approach 1:
The vane opening degree is changed from a fixed predetermined value to a dynamically adjustable parameter based on real-time refrigerant gas density measurements. The control device acquires density information and automatically adjusts the opening degree to match actual operating conditions, resolving the mismatch problem that causes starting failures.
Solution Approach 2:
A feedback mechanism is introduced where the refrigerant gas density is measured by a density detection device and fed back to the control device. The control device uses this feedback information to determine the appropriate vane opening degree, ensuring accurate matching between the set opening degree and the actual refrigerant gas state at starting.
2Device complexity
If the vane opening degree is set to a fixed target value, then the control system is simple, but it cannot adapt to fluctuations in refrigerant gas density leading to starting failures
Solution Approach 1:
The control system performs self-adjustment by automatically acquiring refrigerant gas density information and determining the appropriate vane opening degree without external intervention. The system serves itself by using its own sensors and control algorithms to adapt to changing conditions, maintaining simplicity while gaining adaptability.
Solution Approach 2:
The vane opening degree parameter is changed from a fixed predetermined value to a variable parameter that is determined based on refrigerant gas density. This parameter change allows the system to adapt to different operating conditions while maintaining a relatively simple control structure through automated calculation.
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
Improves startability by setting vane opening degrees based on real-time refrigerant gas states, reducing starting failures and current demands.
Implementation Method 1
a condenser that condenses the refrigerant gas compressed by the turbo compressor by causing the refrigerant gas to release heat through heat exchange
Implementation Method 2
an evaporator that evaporates the liquid refrigerant expanded by the expansion valve by causing the liquid refrigerant to absorb heat through heat exchange
Data Source
AI summary
This turbo refrigerator comprises: a turbo compressor that compresses a refrigerant gas; a vane that is capable of adjusting the flow rate of the refrigerant gas sucked in by the turbo compressor; a condenser that causes, by means of heat exchange, the refrigerant gas compressed by the turbo compressor to release heat and therefore become condensed; an expansion valve that expands a liquid refrigerant guided from the condenser; an evaporator that causes, by means of heat exchange, the liquid refrigerant expanded by the expansion valve to absorb heat and therefore evaporate; and a refrigerator control device. The refrigerator control device comprises: an acquisition unit that acquires at least a state quantity of the refrigerant gas during startup of the turbo refrigerator; an opening degree determination unit that determines the opening degree of the vane on the basis of the acquired state quantity; and an opening degree control unit that controls the opening degree of the vane on the basis of the determined opening degree.