Heat Pump Refrigerant Leak Detection for Indoor Discharge Prevention
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Solution Overview
Problem
In heat pump systems, when a refrigerant leaks into the water circuit, it can be discharged from both the outdoor and indoor pressure relief valves, posing a risk of refrigerant entering the indoor space.
Innovation Solution
A heat pump apparatus with a refrigerant flow switching device that switches between condenser and evaporator operations, an expansion device set to a closed state, and a compressor operation to retrieve refrigerant into the heat-source-side heat exchanger, along with a refrigerant leakage detecting device and overpressure protection, to prevent refrigerant leakage into the indoor space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure relief valve is installed in the indoor unit, then overpressure protection is provided, but refrigerant may leak into the indoor space through the water circuit
Solution Approach 1:
A refrigerant leakage detecting device is introduced as an intermediary between the water circuit and the indoor space. This device detects refrigerant in the water circuit before it can reach the indoor pressure relief valve, triggering early warning and prevention actions that stop refrigerant from leaking into the indoor environment
Solution Approach 2:
The system performs preliminary detection of refrigerant leakage in the water circuit using the refrigerant leakage detecting device before refrigerant can accumulate enough to discharge through the indoor pressure relief valve. This early detection enables preventive actions to be taken before harmful refrigerant release occurs
2Reliability
If refrigerant leaks into the water circuit, then it can be discharged from pressure relief valves, but this creates safety risks in indoor spaces
Solution Approach 1:
The refrigerant leakage detecting device provides continuous feedback about refrigerant presence in the water circuit to the control system. This feedback mechanism enables real-time monitoring and automatic control actions that prevent refrigerant from reaching discharge points in the indoor space
Solution Approach 2:
The detection device acts as an intermediary monitoring system that intercepts refrigerant leakage information in the water circuit, enabling the control system to take preventive actions before refrigerant can discharge through pressure relief valves into the indoor environment
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
Effectively retrieves and confines refrigerant in the refrigerant circuit, preventing its leakage into the indoor space by switching operations and using detection and protection mechanisms.
Implementation Method 1
The refrigerant circuit is allowed to perform a first operation in which the load-side heat exchanger is used as a condenser, when the state of the refrigerant flow switching device is switched to the first state. The refrigerant circuit is allowed to perform a second operation in which the load-side heat exchanger is used as an evaporator
Implementation Method 2
the refrigerant in the refrigerant circuit is retrieved. In the refrigerant circuit, the retrieved refrigerant is confined in the partial section that extends via the heat-source-side heat exchanger
Data Source
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AI summary
An apparatus using a heat pump includes a refrigerant circuit and a heat medium circuit. The refrigerant circuit is allowed to perform a first operation, in which a load-side heat exchanger is used as a condenser, and a second operation, in which the load-side heat exchanger is used as an evaporator. A container is provided to a suction pipe provided between a refrigerant flow switching device and a compressor. To the heat medium circuit, an overpressure protection device and a refrigerant leakage detecting device are connected. When leakage of refrigerant into the heat medium circuit is detected, the refrigerant flow switching device is switched to a second state, an expansion device is set to a closed state, and the compressor is made in operation. When a requirement for ending the operation of the compressor is satisfied after the leakage of the refrigerant into the heat medium circuit is detected, the compressor is set to a stopped state, and the refrigerant flow switching device is switched to a first state.