Digi RTU Optimizer Case Study: New Technology to Maximum Energy Efficiency

摘要

The Digi RTU optimizer is a proven new technology for roof top unit (RTU) air conditioners. The Digi RTU Optimizer utilizes one variable frequency drive (VFD), to control both fan and compressor speed on the RTU to which it is installed. As an after factory addition it is a perfect fit for the multitude of existing inefficient RTU’s that are currently in the market. The fact that it only takes one drive to control two components keeps the cost relatively low and minimizes the concern of having multiple drives on one RTU. The Omaha Public Power District (OPPD) reviewed the product and concurred that it performed as the manufacturer said it would and that it was unique to the industry. The utility then proceeded to initiate their pilot to test performance and public acceptance. Customers were recruited to represent a variety of operations including offices and manufactures. Loggers were set to measure performance data before and after the installation. Outdoor air temperature, indoor air temperature, kWh of usage and kW of demand were all measured and compared. The Digi-RTU optimizers reduced electricity consumption by up to 60%, kW of peak demand by up to 60%, compressor hunting (on/off short cycle) by up to 70% and held room temperature. Humidity was also better controlled. Based on these results OPPD is working to incorporate prescriptive incentives for this technology into their program in 2012. If this technology is widely adopted it truly has the potential to transform the market for RTU efficiency.