Heat-pump using apparatus
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Solution Overview
Problem
In heat-pump systems, refrigerant leaks into the water circuit can lead to discharge through both outdoor and indoor pressure relief valves, risking refrigerant entry into indoor spaces, especially when outdoor and indoor units from different manufacturers are combined.
Innovation Solution
A heat-pump apparatus with a refrigerant circuit and a heat medium circuit, featuring a refrigerant flow switching device, expansion devices, and a refrigerant leakage detecting device, which switches operations to retrieve refrigerant when leakage is detected, preventing indoor contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure relief valve is provided in both outdoor and indoor units, then overpressure protection is improved, but refrigerant leakage into indoor spaces increases
Solution Approach 1:
A refrigerant leakage detecting device is introduced as an intermediary between the refrigerant circuit and the indoor space. This detector monitors the refrigerant concentration in the heat medium circuit and triggers an alarm or shutdown before refrigerant can discharge into the indoor environment through the pressure relief valve, thus maintaining overpressure protection while preventing harmful refrigerant leakage.
Solution Approach 2:
The system implements feedback control by continuously monitoring the refrigerant concentration in the heat medium circuit using the leakage detecting device. When refrigerant leakage is detected, the system provides feedback to the control unit, which then activates the pressure relief valve or shuts down the compressor to prevent further leakage into the indoor space, resolving the contradiction between protection and safety.
2Object-affected harmful factors
If refrigerant leakage detection is added to the heat medium circuit, then refrigerant leakage prevention is improved, but device complexity increases
Solution Approach 1:
The refrigerant leakage detecting device serves multiple functions: it detects refrigerant concentration in the heat medium circuit, triggers alarm signals, and can initiate shutdown procedures. By consolidating these functions into a single device integrated with the existing control system, the patent minimizes the increase in device complexity while maximizing leakage prevention capability.
Solution Approach 2:
The leakage detection system is designed to automatically monitor and respond to refrigerant leakage conditions without requiring external intervention. The control unit automatically processes detection signals and activates protective measures, making the system self-sufficient and reducing the need for additional complex control mechanisms.
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
Early detection and retrieval of refrigerant leaks minimize indoor refrigerant exposure, ensuring safer operation by preventing refrigerant discharge into indoor spaces.
Implementation Method 1
a heat-source-side heat exchanger (1), a first expansion device (6), an intermediate-pressure receiver (5), a second expansion device (7) and a load-side heat exchanger (2)
Implementation Method 2
a first expansion device (6), a second expansion device (7)
Implementation Method 3
a compressor (3)
Data Source
AI summary
A heat-pump using apparatus includes a refrigerant circuit and a heat medium circuit. The refrigerant circuit is capable of executing a heating operation and a cooling operation. A first expansion device is provided downstream of a reservoir, and a second expansion device is provided upstream of the reservoir, in the flow of refrigerant in the heating operation. A main circuit of the heat medium circuit includes a branching part and a joining part. An overpressure protection device is connected to a connection part which is located between a load-side heat exchanger and one of the branching part and the joining part or at the load-side heat exchanger. A refrigerant leakage detecting device is connected to the other of the branching part and the joining part, or between the other of the branching part and the joining part and the connection part, or to the connection part.