High-Performing Commercial Rooftop Units

GPG, in collaboration with Pacific Northwest National Laboratory researchers, evaluated the first RTU to meet the Department of Energy's High Performance RTU Challenge. Results from measurement and verification at a warehouse in Fort Worth, Texas demonstrated energy savings of 26%. A concurrent PNNL study of high-performance RTUs at two Florida supermarkets found payback of 3.8 years. View full-size infographic. [PDF - 263 KB]

GPG Findings 034, April 2018, Advanced commercial rooftop units. Opportunity: RTUs condition how much floor space nation-wide? >50% OF COMMERCIAL FLOOR SPACE IN THE U.S. IS CONDITIONED BY ROOFTOP UNITS (RTUS). Technology: How do advanced RTUs work? VARIABLE SPEED INVERTER COMPRESSOR MAINTAINS AIR TEMPERATURE SETPOINT. VARIABLE SPEED SUPPLY FAN RESPONDS TO ZONE CONDITIONS Measurement and Verification: Where did M and V occur? PACIFIC NORTHWEST NATIONAL LABORATORY (PNNL) assessed the first RTU to meet the Department of Energy’s High Performance RTU Challenge2. The RTU was provided by Daikin Applied and installed in a GSA warehouse in Fort Worth, Texas. PNNL also conducted a concurrent study of the advanced RTU at two Florida supermarkets. Results: How did the advanced RTU perform in M&V? 26% ENERGY SAVINGS Models predicted 40% savings compared to a standard RTU. COSTS FOR INSTALLATION VARY Heavier unit and different footprint may require infrastructure reinforcement or duct changes. 3.8 YR PAYBACK demonstrated at two Florida supermarkets. Advanced RTU exceeds baseline efficiency, particularly at higher outdoor air temperatures. Deployment:Where does M&V recommend deploying advanced RTUs? END-OF-LIFE REPLACEMENT Modeling indicates that savings will be greatest in hot, humid climates. [PDF - 263 KB]


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