HVAC Cooling and Heating Efficiency Degradation
Friday, January 20th, 2012 at
10:15 PM
Filed under HVAC System Efficiency.
Question:
I am trying to come up with a reasonable annual efficiency degradation factor for air source air conditioners and heat pumps. Is there a study or any data based on Lincus’ M&V of HVAC equipment?
Answer:
Based on Lincus’ energy audit experience and measurement and verification (M&V) at audit sites (which required ASHRAE Level III analysis), we believe that a typical HVAC (packaged/split ACs/Heat Pumps) unit degrades from in efficiency by about 1.1% each year. Please note that this degradation efficiency percentage is only an average, conservative and reasonable estimate based on Lincus’ M&V on selected HVAC systems that operate in typical conditions (10-12 hours of operation on weekdays and a few hours during the weekends, typical maintenance (for instance, filter cleaning every 3 month at a minimum, etc). The HVAC degradation in reality, is dependent on a lot of factors ranging from how its operated to where its operated and could be exactly determined only with an M&V on that specific HVAC unit. Some examples of why a unit’s efficiency may degrade faster than Lincus’ experience are higher than average operating hours or poor maintenance. However, we believe that this estimate of 1.1% should be consistent and a safe estimate that one can use in lieu of monitored data.