Advanced Onboard Diagnostics for HVAC Systems

70382S02-II The majority of air conditioning systems are not installed or maintained correctly. Recent studies have shown that 60% of the systems are significantly deficient in evaporator airflow, refrigerant charge, or both. When duct efficiency problems are included, over 95% of the systems are running well below their design efficiency. This project will introduce a continuous measuring device for residential and small commercial air conditioners. The device will determine an air conditioner¿s performance and pinpoint corrective actions, direct a responding technician to the cause of the problem, and confirm that it has been fixed. Phase I determined the identification of that critical parameters of proper HVAC operation is possible with appropriate sensor elements. Updated algorithms for detecting air conditioner faults were generated from analyzing air conditioner data, and potential designs and costs were analyzed. Phase II will develop a prototype of the continuous measuring device, and test it in residential and small commercial air conditioners. Issues of final cost, ease of installation, ease of use, and reliability also will be considered. Commercial Applications and Other Benefits as described by awardee: The device should be applicable to all residential and small commercial air conditioners. It can be applied in the factory, or retrofitted to existing equipment. The device also would provide a ready platform for monitoring and reacting to pollutants important to building occupants.