Field Analysis of Commercial Variable Refrigerant Flow Heat Pumps

The objective of this project was to monitor the in-situ performance of a VRF-HR (heat recovery) system and provide performance characterization based on the data recorded.  The site is a 4-floor PG&E office building in Auburn, California which is in California Climate Zone 11.  The VRF system is a 24 ton Mitsubishi City Multi 2-pipe system with heat recovery capabilities (simultaneous heating and cooling operation is possible), to which are connected 13 indoor units. Data representing thermal and electrical characteristics of the system was collected from the site for a period of 1 year – from June 2013 to May 2014. The electrical characteristics were used to determine the energy used, load profile, and demand imposed by the system on the grid. As a part of this project, the building and the VRF system were modeled by PECI, Inc. The results from the modeling exercise are presented in this report. The energy model was developed using AecoSim Energy Simulator (AES), which is a front end for EnergyPlus.