Vehicle Refrigeration Cycle Layout for Dehumidification Heating
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Solution Overview
Problem
Conventional refrigeration cycle devices for vehicle air conditioners face challenges in effectively heating ventilation air during dehumidification heating mode, especially at low outside temperatures, due to increased refrigerant evaporation temperature and pressure loss, which reduces the heating capacity and coefficient of performance (COP).
Innovation Solution
The refrigeration cycle device incorporates a compressor, refrigerant radiator, decompression devices, an exterior heat exchanger, evaporator, internal heat exchanger, and a gas-liquid separator to manage refrigerant flow and phase separation, ensuring efficient heat exchange and reducing pressure loss, thereby improving the heating capacity and COP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the refrigerant evaporation temperature is increased to prevent frost formation at the interior evaporator, then the reliability is improved, but the heating capacity decreases
Solution Approach 1:
The patent divides the refrigerant circulation system into two separate loops: an interior loop with the interior evaporator and interior condenser, and an exterior loop with the exterior heat exchanger. This segmentation allows independent temperature control in each loop, enabling the interior evaporator to maintain higher temperatures for frost prevention while the exterior heat exchanger operates at lower temperatures for efficient heat absorption, thereby resolving the contradiction between reliability and heating capacity
Solution Approach 2:
The patent introduces a heat exchanger as an intermediary device between the interior and exterior refrigerant loops. This intermediary enables thermal coupling between the two loops, allowing heat transferred from the exterior heat exchanger to supplement the heating function of the interior condenser, thus maintaining heating capacity even when the interior evaporator operates at higher temperatures to prevent frost
2Productivity
If the refrigerant flow path is extended to include both interior and exterior heat exchange, then the heating capacity is improved, but the pressure loss increases
Solution Approach 1:
The patent segments the refrigerant flow into two distinct circulation paths: an interior path and an exterior path. Each path has its own evaporator and condenser/heat exchanger. This segmentation allows the system to optimize each path independently, minimizing the total flow path length and reducing pressure losses while still achieving combined heating capacity from both paths
Solution Approach 2:
The patent merges the heating outputs of the interior condenser and exterior heat exchanger to provide supplemental heating. By combining the thermal outputs of both heat exchange devices, the system achieves enhanced heating capacity without requiring a proportionally longer refrigerant flow path, thus improving productivity while controlling pressure loss
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 enhances the heating capacity for ventilation air and improves the coefficient of performance (COP) by preventing an increase in refrigerant evaporation temperature and pressure loss, ensuring effective dehumidification and heating even at low outside temperatures.
Implementation Method 1
an internal heat exchanger that exchanges heat between the refrigerant flowing out of the exterior heat exchanger and the refrigerant flowing out of the interior evaporator
Implementation Method 2
a refrigerant radiator that exchanges heat between a high-pressure refrigerant discharged from the compressor and ventilation air to be blown into a space to be air-conditioned, to heat the ventilation air
Implementation Method 3
an evaporator that exchanges heat between a low-pressure refrigerant and the ventilation air before being heated by the refrigerant radiator, to cool the ventilation air
Implementation Method 4
a gas-liquid separator that separates the refrigerant flowing out of the first decompression device into gas and liquid phases
Data Source
AI summary
A refrigeration cycle device includes an interior condenser that exchanges heat between a high-pressure refrigerant and ventilation air to heat the ventilation air, an exterior heat exchanger that exchanges heat between outside air and the refrigerant downstream of the interior condenser, an interior evaporator that exchanges heat between a low-pressure refrigerant downstream of the exterior heat exchanger and the ventilation air before passing through the interior condenser, and an internal heat exchanger that exchanges heat between the refrigerant flowing out of the exterior heat exchanger and the refrigerant flowing out of the interior evaporator. The refrigeration cycle device further includes a gas-liquid separator that separates the refrigerant at a downstream side of the interior condenser into gas and liquid phase refrigerants. In a dehumidification heating mode of evaporating the refrigerant at the exterior heat exchanger, the liquid-phase refrigerant separated by the gas-liquid separator flows into the exterior heat exchanger.