Lead Performer: Pacific Northwest National Laboratory (PNNL)
Partner: Parker and Hannifin – Washington, MO
DOE Total Funding: $187,500
Cost Share: $187,500
Project Term: October 1, 2019 – September 30, 2021
Funding Type: Technology Commercialization Fund

Project Objective

Pacific Northwest National Laboratory (PNNL) in collaboration with Parker and Hannifin will develop, demonstrate, and fabricate a compact, inexpensive, and highly sensitive and selective surface acoustic wave sensor coated with fluorophilic sorbents that include high surface area porous metal organic frameworks or porous organic cages for detecting leaks of fluorocarbon refrigerants from HVAC systems. Having a highly effective sorbent sensitive to fluorocarbon refrigerant vapors provides a means to develop a sensing device for leak detection. Surface acoustic wave (SAW) sensors with a gas sensing film deposited between the delay lines or on the interdigital transducer have been used to detect gas molecules, such as NO2 and NH3, under harsh environments with high sensitivity. They can be manufactured at low cost ($1-$2) because of their simple fabrication methods and small sizes. The SAW sensor’s principle of operation involves monitoring the frequency shift of the surface acoustic waves on a piezoelectric substrate due to the increased mass or stress loading after gas molecules attach to a MOF sensor film bonded to the substrate. PNNL will assemble a prototype sensor for field testing of leak detection at Parker-Hannifin. Parker-Hannifin will conduct evaluations of sensor performance on an HVAC system with a variety of induced leaks to evaluate sensor performance.

The objective of this project is to develop and demonstrate a cost-effective surface acoustic wave (SAW) sensor that can detect refrigerant leaks with high selectivity towards fluorocarbon refrigerants and specifically R32 (difluoromethane) and R1234yf (2,3,3,3-tetrafluoropropene) with sensitivity to 36,000 ppmv. Refrigerants R32 and R1234yf are class A2L refrigerants and were chosen because they are of principal interest for Parker-Hannifin’s customers. A simple change of the selective sorbent used is all that is required to repurpose the sensor for detection of other gases including Class A3 refrigerants and Class A1 fluorocarbon refrigerants. Hence the sensor technology could be applied to virtually any refrigerant in use today for HVAC&R systems.

Project Impact

The project technology will serve to advance SAW sensors based on fluorophilic sorbents that can be used in detections of refrigerant leaks from HVAC&R. Detection of leaks can have huge energy savings for residential and commercial building. When a refrigerant leak occurs from a HVAC system, there are several consequences. One direct consequence is reduction in cooling efficiency, which results in increased power consumption and costs for the additional kWh consumed until the leak is detected and repaired. Costs are also incurred to replace the lost refrigerant during the repair. Indirect consequences include higher CO₂ emissions from the additional energy consumed (depending on energy source mix) and additional greenhouse gas emissions to the atmosphere, the impacts of which depend on the global warming potential of the refrigerant. When considering flammable A2L or A3 refrigerants, refrigerant leaks take on an additional overriding consideration regarding safety of the occupants in the building where this kind of HVAC equipment is operating. Reliable detection of refrigerant leaks is thus a critical technology necessary to enable more widespread use of class A2L and A3 refrigerants in HVAC systems.

Contacts

DOE Technology Manager: Antonio Bouza
Lead Performer: Praveen K. Thallapally, Pacific Northwest National Laboratory