Ejector Refrigerant Circuit for Low-Temperature Dehumidification Heating
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Solution Overview
Problem
In refrigeration cycle apparatuses for air conditioners, the existing dehumidification-air heating mode often fails to sufficiently reheate air at low outside temperatures due to equal refrigerant evaporation temperatures in the interior and exterior heat exchangers, leading to inadequate heat absorption and reduced heating capacity.
Innovation Solution
The apparatus includes a compressor, a heating heat exchanger, a branch portion, a heating side ejector with a pressure-increasing portion, an exterior heat exchanger, and a cooling side decompressor, allowing for separate control of refrigerant evaporation pressures in the exterior and cooling heat exchangers to enhance heat absorption and heating capacity, and incorporates an economizer cycle to improve mechanical efficiency and COP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the refrigerant evaporation temperature in the interior evaporator is adjusted to suppress frost formation, then the frost formation is suppressed, but the refrigerant evaporation temperature in the exterior heat exchanger becomes equal to that in the interior evaporator, reducing the temperature difference with outside air and decreasing heat absorption capacity
Solution Approach 1:
The patent segments the refrigerant circulation system into two independent temperature control loops: one for the interior evaporator and another for the exterior heat exchanger. By introducing separate expansion valves and control mechanisms for each heat exchanger, the system can independently adjust refrigerant evaporation temperatures in the interior and exterior heat exchangers, allowing the exterior heat exchanger to maintain a lower evaporation temperature for enhanced heat absorption while the interior evaporator operates at a higher temperature to prevent frost formation.
Solution Approach 2:
The patent applies local quality by allowing different refrigerant evaporation temperatures in different parts of the system. Specifically, the exterior heat exchanger operates at a lower refrigerant evaporation temperature optimized for heat absorption from outside air, while the interior evaporator operates at a higher temperature optimized for preventing frost formation on the air-conditioned side, enabling each component to operate at its optimal temperature for its specific function.
2Adaptability or versatility
If the refrigerant circuit is configured with interior evaporator and exterior heat exchanger connected in parallel for dehumidification-air heating mode, then dehumidification and heating functions are provided, but the refrigerant cannot absorb sufficient heat from outside air at low outside air temperatures, reducing heating capacity
Solution Approach 1:
The patent introduces dynamic control mechanisms including separate expansion valves and temperature control systems for the interior evaporator and exterior heat exchanger. This allows the system to dynamically adjust refrigerant flow rates and evaporation temperatures in each heat exchanger based on operating conditions, enabling optimized heat absorption in the exterior heat exchanger while maintaining dehumidification function in the interior evaporator during dehumidification-air heating mode.
Solution Approach 2:
The patent changes the operating parameters by allowing different refrigerant evaporation temperatures in the interior evaporator and exterior heat exchanger. Specifically, the exterior heat exchanger operates at a lower refrigerant evaporation temperature to maximize heat absorption from cold outside air, while the interior evaporator operates at a higher temperature for dehumidification, thereby improving heating capacity without sacrificing dehumidification functionality.
3Device complexity
If the refrigerant evaporation temperature in the exterior heat exchanger is equal to that in the interior evaporator, then the system configuration is simplified, but the temperature difference between outside air and refrigerant evaporation temperature is reduced at low outside air temperatures, decreasing heat absorption efficiency
Solution Approach 1:
The patent segments the temperature control system into independent control loops for each heat exchanger, allowing separate adjustment of refrigerant evaporation temperatures. This segmentation enables the exterior heat exchanger to operate at a lower temperature for efficient heat absorption while the interior evaporator operates at a higher temperature, eliminating the need to equalize temperatures and thereby improving heat absorption efficiency without excessive complexity.
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
This configuration improves the heating capacity of air in the dehumidification-air heating mode by allowing the refrigerant to absorb sufficient heat from outside air, while also enhancing the mechanical efficiency and coefficient of performance (COP) of the refrigeration cycle.
Implementation Method 1
a heating side ejector that draws a refrigerant from a heating side refrigerant suction port by a suction effect of an injection refrigerant injected from a heating side nozzle portion
Implementation Method 2
the heating side ejector including a heating side pressure-increasing portion that raises a pressure of a mixed refrigerant including the injection refrigerant and a suction refrigerant drawn from the heating side refrigerant suction port
Implementation Method 3
an exterior heat exchanger that exchanges heat between a refrigerant on a downstream side of the heating side pressure-increasing portion and outside air to evaporate the refrigerant
Implementation Method 4
exchanges heat between a refrigerant on a downstream side of the heating side pressure-increasing portion and outside air to evaporate the refrigerant
Implementation Method 5
a cooling heat exchanger that evaporates the refrigerant decompressed by the cooling side decompressor to cool the air before passing through the heating heat exchanger
Implementation Method 6
a heating heat exchanger that heats air to be blown into a space to be air-conditioned, using a high-pressure refrigerant discharged from the compressor as a heat source
Data Source
AI summary
In a dehumidification-air heating mode, a refrigerant circuit is configured such that a refrigerant outlet side of an exterior heat exchanger communicates with a heating side refrigerant suction port of a heating side ejector as a refrigerant decompression means, and that a refrigerant inlet side of an interior evaporator communicates with an outlet side of a heating side diffuser of the heating side ejector. A refrigerant evaporation temperature in the exterior heat exchanger is set lower than that of the interior evaporator by a pressurizing effect of the heating side ejector. Thus, the amount of heat absorption by the refrigerant at the exterior heat exchanger is increased to improve the heating capacity of the air in an interior condenser.