Commercial buildings and their HVAC systems are designed by a professional team of architects and engineers. The design engineers need accurate design tools which require accurate algorithms to model and predict the HVAC system energy use and electrical demand. The designer must have confidence in the tools and algorithms, particularly when it comes to higher capital cost, energy-efficient systems. Once confident of the predicted performance of such energy-efficient systems, the designer is more likely to specify these HVAC systems in client projects.

At the outset of project RP-620, published validation results for computer programs and algorithms to simulate water-loop heat pump and heat recovery/double-bundle chiller performance were not available. Without validation, the accuracy of the predicted energy use and demand of these systems could not be assured and the results would contain substantial uncertainties.