Heat pump device
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Solution Overview
Problem
Existing heat pump devices using non-azeotropic refrigerants face challenges in accurately estimating the circulation composition ratio without reducing capacity, due to the need for a bypass circuit that decreases pressure and the difficulty in obtaining accurate composition ratios from mixed refrigerants.
Innovation Solution
A heat pump device with a refrigerant circuit incorporating a container, temperature and pressure measurement units, and a control unit to estimate the physical properties and composition ratio of non-azeotropic refrigerants based on temperature and pressure measurements, allowing for accurate estimation without reducing capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a bypass circuit is used to accumulate two-phase refrigerant in the accumulator, then the composition ratio of circulating refrigerant can be detected, but the capacity of the heat pump device is reduced due to the bypass of high-pressure refrigerant
Solution Approach 1:
The invention extracts the composition ratio detection function from the accumulator system and implements it directly in the refrigerant circuit using a temperature measurement unit and pressure measurement unit. This eliminates the need for a separate bypass circuit to the accumulator, as the composition ratio is determined by measuring temperature and pressure at a specific location in the refrigerant circuit and comparing it with pre-stored reference data.
Solution Approach 2:
The invention introduces a composition ratio determination unit that uses temperature and pressure measurements as intermediaries to determine the composition ratio of the non-azeotropic mixture refrigerant. Instead of directly measuring composition or using a bypass circuit, the system uses temperature and pressure as intermediary parameters that can be easily measured and correlated to composition ratio through pre-stored reference data.
2Ease of operation
If a small amount of liquid refrigerant flows out with gas refrigerant from the accumulator, then refrigerating machine oil can be returned to the compressor, but accurate composition ratio cannot be obtained
Solution Approach 1:
The invention dynamically adjusts the expansion valve opening degree based on the determined composition ratio to optimize both oil return and measurement accuracy. The control unit continuously monitors temperature and pressure, determines composition ratio, and adjusts the expansion valve to maintain optimal operating conditions that facilitate oil return while ensuring accurate composition ratio measurement.
Solution Approach 2:
The invention implements a feedback control system where the composition ratio determination unit continuously monitors the refrigerant composition, and the control unit adjusts the expansion valve opening degree based on this information. This closed-loop feedback ensures that the system maintains optimal conditions for both oil return and accurate composition ratio measurement.
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 precise estimation of refrigerant composition, flammability, toxicity, and likelihood of disproportionation reactions, while maintaining device capacity by adjusting the gas-liquid phase ratios through control of expansion mechanisms.
Implementation Method 1
a temperature measurement unit configured to measure a temperature of the non-azeotropic mixture refrigerant in the container
Implementation Method 2
a pressure measurement unit configured to measure a pressure of the non-azeotropic mixture refrigerant in the container
Implementation Method 3
the non-azeotropic mixture refrigerant accumulates in the container in a state where the gas phase and the liquid phase are separated
Data Source
Figure 1
Figure 2~3A
Figure 3B~4A
AI summary
A problem to be solved by the present disclosure is to provide a heat pump device capable of accurately estimating a circulation composition ratio of a refrigerant without reducing a capacity. In an air conditioner (100), during an operation, a gas-liquid two-phase non-azeotropic mixture refrigerant enters a receiver (25) and accumulates in the receiver (25) in a state where a gas phase and a liquid phase are separated. For example, when the non-azeotropic mixture refrigerant includes two components, i.e., a high-boiling refrigerant and a low-boiling refrigerant, the control unit (40) may estimate the ratio (composition ratio) between the low-boiling refrigerant and the high-boiling refrigerant in each of the gas phase and the liquid phase based on the temperature and the pressure of the non-azeotropic mixture refrigerant in the receiver (25). Thus, the control unit (40) may estimate the composition ratio of the liquid-phase non-azeotropic mixture refrigerant flowing out of the receiver (25) as the composition ratio of the non-azeotropic mixture refrigerant circulating in the refrigerant circuit (10).