Chilling unit, control method, and program
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Solution Overview
Problem
Chilling units face significant downtime and costly repairs when a water heat exchanger is damaged, leading to pressure equalization between refrigerant and water circuits, causing water to enter the refrigerant circuit and potentially damaging connected devices.
Innovation Solution
A control method and program that quickly detect anomalies in the water heat exchanger by monitoring pressure and temperature sensors, issuing alarms, and performing processing to suppress water entry into the refrigerant circuit, maintaining pressure differences and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the chilling unit continues to operate in a state where the water heat exchanger is damaged, then the refrigerant can leak from the refrigerant circuit to the water circuit, but pressure in the refrigerant circuit and pressure in the water circuit become equalized causing water to enter the refrigerant circuit and damaging connected devices
Solution Approach 1:
The control device detects anomalies in the water heat exchanger before pressure equalization occurs between the refrigerant and water circuits. By monitoring for signs of refrigerant leakage and detecting anomalies early, the system takes preliminary action to identify problems before water can enter the refrigerant circuit and cause damage to connected devices such as the compressor, accumulator, receiver, and valves.
2Loss of time
If refrigerant leakage is detected late, then repair costs increase and restoration time extends to days, but early detection requires monitoring systems that may increase device complexity
Solution Approach 1:
The control device continuously monitors the refrigerant circuit for signs of leakage from the water heat exchanger and provides feedback about the system's condition. This feedback mechanism enables early detection of anomalies, allowing the system to identify problems before they lead to extensive damage and long restoration times, while the monitoring integrates with existing control systems to minimize added complexity.
3Ease of repair
If pressure equalization occurs between refrigerant and water circuits, then water enters the refrigerant circuit requiring replacement of multiple devices, but maintaining pressure difference requires active control
Solution Approach 1:
The control device detects anomalies in the water heat exchanger before pressure equalization occurs between the refrigerant and water circuits. By monitoring for signs of refrigerant leakage and detecting anomalies early, the system takes preliminary action to identify problems before water can enter the refrigerant circuit and cause damage to connected devices such as the compressor, accumulator, receiver, and valves.
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
Enables rapid detection and mitigation of refrigerant leakage, reducing the likelihood of damage spread and minimizing repair time by maintaining pressure differences between circuits.
Implementation Method 1
a water heat exchanger (23) that performs or that is configured to perform heat exchange between the refrigerant and water
Implementation Method 2
an air heat exchanger (26) that performs or that is configured to perform heat exchange between the refrigerant and outside air
Implementation Method 3
a compressor (21) that compresses or that is configured to compress a refrigerant
Data Source
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AI summary
Object To provide a chilling unit that can quickly detect an anomaly in a water heat exchanger. Solving Means A chilling unit includes: a refrigerant circuit including a compressor that compresses a refrigerant, an air heat exchanger that performs heat exchange between the refrigerant and outside air, a water heat exchanger that performs heat exchange between the refrigerant and water, an expansion valve provided between the air heat exchanger and the water heat exchanger, and a four-way valve that switches a flow path of the refrigerant to a cooling operation flow path or a heating operation flow path; a water circuit including a water pipe inserted through the water heat exchanger, a water pump that sends the water to the water pipe, and a water valve provided closer to a downstream side of the water pipe than the water heat exchanger; and a control device configured to control the refrigerant circuit and the water circuit. The control device includes a detecting unit configured to detect an anomaly in the water heat exchanger when a saturation temperature of the refrigerant circuit on a low-pressure side or a high-pressure side is less than a predetermined saturation temperature lower limit value.