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Summary

Heat exchangers transfer heat between two or more fluids and are essential components in a variety of applications including industrial processing and heating, ventilation, air-conditioning and refrigeration (HVAC&R) equipment. Reliable, efficient design is critical to reduce overall cost and energy consumption. However, refrigerant maldistribution is a common problem in heat exchangers that use microchannel technology. Heat exchangers have up to 20 to 30 percent loss capacity due to maldistribution. This innovation consists of a piezoelectric driven magnetic actuator (PEDMA) that controls the flow to avoid refrigerant maldistribution in heat exchangers, significantly improving energy and cost efficiency.

Description

This device is a piezoelectric driven magnetic actuator (PEDMA) for control of refrigerant flow in microchannel heat exchangers to adjust the flow distribution and correct maldistribution. PEDMAs use a lot less energy, and have a lot more force, than solenoids found in traditional heat exchangers. Magnetically driven, they do not require penetration into the heat exchanger itself. The device can slow down an area that has too much refrigerant flow and temporarily stop the flow and then reallow it if needed. The magnets work to actively redistribute the flow inside the exchanger once inserted into the equipment. This results in control of refrigerant flow in adverse conditions. Piezomagnetic actuators are a well-established technology. Their simple design eliminates the need for many moving parts found in motorized or pneumatic valve assemblies. This reduces the system cost and complexity and enables the technology to be retrofitted into existing microchannel heat exchangers. Testing has shown a 37-percent reduction in temperature maldistribution. Also, real-time control enables greater flexibility for the heat exchanger to respond not only to refrigerant-side flow non-uniformity, but to compensate for air-side flow maldistribution as well. Magnets require no additional power, contrasted with solenoids that require constant power to maintain the electromagnetic field. Solenoids consume 8 times more power than the PEDMA device, which can actuate with 40 times the force at the same stroke length.

Applications and Industries

• Heating, ventilation, air conditioning and refrigeration (HVAC-R) industry
• HVAC equipment manufacturers
• Automobiles, aircraft, drone manufacturers
• Wherever heat pumps and cooling components are used

Benefits

• Regains lost capacity of the heat exchanger
• Significantly reduces refrigerant maldistribution
• Eliminates need for many moving parts
• Permanent magnets superior to other mechanical drivers
• Increases efficiency, reduces operating cost

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