Brushless DC Fan Motor With Segmented Loops for Flammable Refrigerants
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Solution Overview
Problem
Refrigeration systems using flammable heat transfer fluids face challenges with the high cost and weight of commercially available explosion-proof motors, which are required to meet safety standards, limiting efficiency and practicality.
Innovation Solution
A heat exchanger system with separate heat transfer fluid circulation loops uses a brushless DC motor for the fan to prevent explosions and incorporates remote placement of ancillary components to meet explosion-proof criteria, along with the use of non-flammable fluids in one loop and flammable but safer fluids in another, allowing for efficient heat transfer and reduced motor costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If explosion-proof motors are used to meet safety standards with flammable refrigerants, then safety is improved, but motor weight and cost increase significantly
Solution Approach 1:
The system divides the motor into two separate circulation loops: Loop 1 uses a flammable refrigerant (propane) with a brushless DC motor that is not explosion-proof, while Loop 2 uses a non-flammable refrigerant (CO2) with an explosion-proof motor. This segmentation allows each loop to have motor protection appropriate to its refrigerant type, reducing overall system weight and cost while maintaining safety.
Solution Approach 2:
The invention extracts the explosion-proof requirement from the entire system and applies it only to the loop containing flammable refrigerant. By taking out the flammable refrigerant (propane) from the indoor loop and placing it in the outdoor loop, the explosion-proof motor is eliminated from the indoor unit where it would add significant weight, while safety is maintained in the outdoor location.
2Reliability
If explosion-proof motors are used to meet safety standards with flammable refrigerants, then safety is improved, but motor cost increases significantly
Solution Approach 1:
The system divides the motor into two separate circulation loops: Loop 1 uses a flammable refrigerant (propane) with a brushless DC motor that is not explosion-proof, while Loop 2 uses a non-flammable refrigerant (CO2) with an explosion-proof motor. This segmentation allows each loop to have motor protection appropriate to its refrigerant type, reducing overall system weight and cost while maintaining safety.
Solution Approach 2:
The invention replaces the expensive explosion-proof motor in the indoor unit with a cheaper brushless DC motor by relocating the flammable refrigerant to the outdoor loop. This substitution significantly reduces motor cost while maintaining safety through the outdoor placement and alternative refrigerant selection in the indoor loop.
3Productivity
If flammable refrigerants like propane are used, then system efficiency is improved, but safety risks increase requiring expensive explosion-proof equipment
Solution Approach 1:
The system divides the refrigerant circulation into two separate loops with different refrigerant types: Loop 1 uses flammable but efficient propane for outdoor heat rejection, while Loop 2 uses non-flammable CO2 for indoor heat absorption. This segmentation allows the system to maintain high efficiency through propane while eliminating flammability risks from indoor spaces.
Solution Approach 2:
The invention extracts the flammable refrigerant (propane) from the indoor circulation loop and confines it to the outdoor loop where it can be used for its superior heat transfer efficiency. The indoor loop uses non-flammable CO2, thereby taking out the harmful flammability factor from occupied spaces while preserving the efficiency benefits of propane in the outdoor environment.
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
The system effectively manages flammability risks while reducing motor weight and cost, enabling efficient and safe operation of refrigeration systems by using a brushless DC motor and remote ancillary components, and optimizing fluid circulation loops for different heat transfer requirements.
Implementation Method 1
a fan driven by a brushless direct current (BLDC) motor
Implementation Method 2
heat rejection heat exchanger, commonly referred to as a condenser
Implementation Method 3
an expansion device where it is expanded to a lower pressure and temperature
Implementation Method 4
an evaporator, where heat transfer fluid cools a secondary heat transfer fluid
Data Source
Figure 1~2
AI summary
A heat exchanger system includes a heat exchanger coil circulating a first heat transfer fluid therethrough, and a fan at least partially surrounded by the heat exchanger coil to urge a flow of air through the heat exchanger coil to dissipate thermal energy from the first heat transfer fluid. A brushless direct current fan motor is located the fan to urge rotation of the fan and an ancillary electrical component operably connected to the heat exchanger system and electrically isolated from the first heat transfer fluid.