Validation of a Building Simulation Tool Using Field Data for Three Identical Configuration Full-Serve Restaurants Using Different HVAC Systems

Abstract

A new building application for a pre-existing HVAC software tool which calculates the benefits of desiccant-assisted HVAC equipment versus the performance of a standard vapor-compression system is used to model the monitored results, see Yborra and Spears (2000), for three full-service restaurants. A standard vapor-compression system, an enthalpy assisted vapor-compression system, and a desiccant-assisted vapor-compression system are compared. The vapor-compression portion of each system is comprised of three rooftop units, specifications for each may be found in Yborra and Spears, "Field- Evaluation of Alternative HVAC Strategies to Meet Ventilation, Comfort, and Humidity Control Criteria at Three Full-Serve Restaurants". The software tool uses DOE 2.1E as a calculation engine which runs in the background. Previously, the software tool could model two different hotel configurations, a quickserve restaurant, a supermarket, a retail store, an ice arena, a school, a movie theater, a nursing home and a hospital. With the larger eating area, the full-serve restaurant had the capacity for sensible or enthalpy heat recovery from the exhausted air in the sit-down area. Quick-Serve Restaurants (QSR's) were precluded from these energy saving devices as the exhausted air was heavily laden with grease. Still, even with the kitchen exhausts facing away from the rooftop unit (RTU) intakes, the enthalpy wheels showed noticeable loading from grease. As the field monitoring was performed near Philadelphia, PA, National Renewable Energy Laboratory (NREL) hour-by-hour bin TMY2 meteorological data was used for Philadelphia to model the annual outdoor conditions experienced by each site. Output was provided in the form of humidity bins, monthly energy usage and cost, as well as total annual gas and electric costs. As the fill-serve restaurants were located on the North-Eastem region of the United States, patron comfort was of greater importance to management than annual energy cost savings. Once the model results were determined to properly reflect those of the case studies, the different building equipment types were "moved" around the United States by choosing different bin weather data sets corresponding to Chicago, IL, Atlanta, GA, and Houston, TX. While the default energy rates available in the program are 4 years old, the economic results provide a sound cost comparison.