This information will also be useful for developing and/or supporting test standards for VRF HP systems. Detailed laboratory testing of this advanced HVAC system provided invaluable performance information which does not currently exist in the form required for proper analysis and modeling. The project goal was to investigate the complex interactions of VRF HP systems from an HVAC system perspective, more » and explore the operational characteristics of this HVAC system type within a laboratory and real world building environment. Detailed laboratory testing and field demonstrations were performed to measure equipment performance and compare this performance to both the manufacturer's data and that predicted by the use of this new model through computer simulation. DOE) EnergyPlus? building energy simulation tool. The University of Central Florida/Florida Solar Energy Center, in cooperation with the Electric Power Research Institute and several variable-refrigerant-flow heat pump (VRF HP) manufacturers, provided a detailed computer model for a VRF HP system in the United States Department of Energy's (U.S. The computer generated VRF performance closely resembled the field measurements. Differences between the computer model results and actual field measurements are discussed.
Infiltration model inputs were adjusted in the beginning to tune the computer model and then subsequent field measurements were compared to the simulation results. Other inputs to the model included building construction, VRF system model based on more » lab measured performance, occupancy of the building, lighting/plug loads, and thermostat set-points etc. For increased accuracy in the comparison, a customized weather file was created by using measured outdoor temperature and relative humidity at the test facility. This paper presents the comparison of energy consumption as measured in the national lab and as predicted by the program. Due to increasing demand by the energy modeling community, an empirical model to simulate VRF systems was implemented in the building simulation program EnergyPlus. An effort was made in this direction to monitor VRF system performance over an extended period of time in a US national lab test facility. Since VRF systems are increasingly gaining market share in the US, it is highly desirable to have more actual field performance data of these systems. However, there is limited data available to show their actual performance in the field. One of the key advantages of VRF systems is minimal duct losses which provide significant reduction in energy use and duct space. Variable Refrigerant Flow (VRF) heat pumps are often regarded as energy efficient air-conditioning systems which offer electricity savings as well as reduction in peak electric demand while providing improved individual zone setpoint control.
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