Refrigeration cycle apparatus
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Solution Overview
Problem
Existing refrigeration cycle apparatuses fail to achieve sufficient cooling capacity for controllers due to insufficient temperature difference between the controller and refrigerant in the refrigerant cooler, leading to reduced performance and increased refrigerant diversion, which compromises the overall capacity of the refrigeration cycle.
Innovation Solution
A refrigeration cycle apparatus with a bypass pipe configuration that includes a precooling heat exchanger and a second expansion device upstream of the refrigerant cooler, reducing the pressure and temperature of the refrigerant further before it enters the cooler, enhancing the temperature difference and cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the refrigerant is cooled in the refrigerant cooler at high pressure, then the refrigerant temperature is reduced, but the temperature difference between the controller and refrigerant becomes insufficient, reducing cooling capacity
Solution Approach 1:
The patent divides the refrigerant cooling process into two separate stages: a precooling heat exchanger for initial cooling at high pressure, and a refrigerant cooler for final cooling after pressure reduction. This segmentation allows each component to operate optimally - the precooling heat exchanger handles the bulk temperature reduction, while the refrigerant cooler achieves the final temperature difference needed for effective controller cooling, resolving the contradiction between refrigerant temperature reduction and cooling capacity.
2Quantity of substance
If a large amount of refrigerant is diverted to the bypass pipe to achieve required cooling capacity, then the controller cooling requirement is met, but the capacity of the refrigeration cycle apparatus is reduced
Solution Approach 1:
The precooling heat exchanger performs preliminary cooling of the refrigerant before it enters the refrigerant cooler. This preliminary action reduces the temperature difference required in the refrigerant cooler, allowing a smaller refrigerant flow rate to achieve the same cooling capacity for the controller, thereby maintaining the overall refrigeration cycle capacity while meeting the controller cooling requirement.
3Ease of operation
If the expansion device is located downstream of the refrigerant cooler, then the refrigerant flow rate is adjusted after cooling, but the temperature difference in the refrigerant cooler is insufficient
Solution Approach 1:
The expansion device is repositioned upstream of the refrigerant cooler, performing pressure reduction before the refrigerant enters the cooler. This preliminary pressure reduction lowers the refrigerant's evaporating temperature, creating a sufficient temperature difference in the refrigerant cooler for effective heat exchange with the controller, while the expansion device still maintains its flow rate adjustment function.
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 cooling performance of the controller by achieving a greater temperature difference between the controller and refrigerant, allowing for a smaller refrigerant flow to achieve the necessary cooling capacity while maintaining system performance.
Implementation Method 1
a precooling heat exchanger that is provided in the bypass pipe and that cools the refrigerant diverted to the bypass pipe
Implementation Method 2
a second expansion device that is provided in the bypass pipe and that reduces a pressure of the refrigerant cooled by the precooling heat exchanger
Implementation Method 3
The refrigerant cooled through the precooling heat exchanger is reduced in pressure through the second expansion device such that the temperature of the refrigerant is further reduced
Implementation Method 4
a refrigerant cooler that is provided in the bypass pipe and that cools the controller with the refrigerant reduced in pressure by the second expansion device
Data Source
AI summary
A refrigeration cycle apparatus includes a refrigerant circuit, through which refrigerant is circulated, including a compressor, a heat source side heat exchanger, a first expansion device, and a load side heat exchanger, a controller controlling the refrigerant circuit, and a bypass pipe that branches off from a high-pressure pipe extending from the compressor to the first expansion device and that is connected to a low-pressure pipe on a suction side of the compressor. The apparatus further includes a precooling heat exchanger that is provided in the bypass pipe and that cools the refrigerant diverted to the bypass pipe, a second expansion device that is provided in the bypass pipe and that reduces a pressure of the refrigerant cooled by the precooling heat exchanger, and a refrigerant cooler that is provided in the bypass pipe and that cools the controller with the refrigerant reduced in pressure by the second expansion device.