A virtual sensor system (compatible with the VOLTTRON platform) has been designed and an initial
prototype has been tested. The overall architecture of the virtual sensor system has been described
including the data acquisition components and virtual sensor models. Initial prototype hardware has
been designed that measures all required sensor inputs and is capable of running all software
implementations. The software implementation has been described as well as future testing and
evaluation plans to characterize the performance for different systems. Preliminary test results
characterizing the virtual refrigerant charge sensor accuracy have also been described.