Detection of R290 leaks in RACHP equipment using ultrasonic sensors.

• Used off-the-shelf components to build an ultrasonic leak detector. • Conducted experiments to identify response of detector to simulated leaks in wall AC unit. • Depending upon sensor and leak location, detector responds to maximum safe leak rate. • Environmental ultrasonic noise is unlikely to interfere with detector. There is a growing need for cost-effective leak detection in smaller RACHP equipment that uses R290 and other flammable hydrocarbon refrigerants. Gas detection technology may not be suitable in many cases due to cost and reliability implications whilst detection with system parameters can suffer long response times. Ultrasonic leak detection can be an economical and reliable method. This study presents the development and testing of an ultrasonic leak detector using off-the-shelf components, within a conventional split type wall-mounted air conditioner indoor unit. Depending upon the chosen sensor, a fast and effective response to simulated "small" R290 leaks was achieved. Measurements of potential interference from environmental noise across ultrasonic frequencies suggests false alarms are unlikely. Such a leak detector was found to be potentially effective. [ABSTRACT FROM AUTHOR]