Figure 3-134: VRF System >Design parameters dialog with Reference condition – indoor unit tab selected for an air-source VRF system.
Entering coil wet-bulb temperature (Tewbref) is the cooling-mode reference condition for air entering the indoor unit coils in a VRF system. This is used, along with the performance curves, for deriving the cooling performance at design and off-design conditions.
Entering coil dry-bulb temperature (Tedbref) is the heating-mode reference condition for air entering the indoor unit coils in a VRF system. This is used, along with the performance curves, for deriving the heating performance at design and off-design conditions.
Outdoor air dry-bulb temperature (Todbref) defines the reference condition for the outdoor unit at which the reference indoor unit cooling performance is determined. By default, this value is the same as the outdoor air dry-bulb temperature for the outdoor unit at the reference condition, defined on the Reference condition – outdoor unit tab. To independently edit the outdoor air dry-bulb temperature as a reference outdoor unit condition for the reference indoor unit performance, uncheck the box labeled “Use same outdoor dry-bulb temperature as for outdoor unit”.
Outdoor air wet-bulb temperature (Towbref) defines the reference condition for the outdoor unit at which the reference indoor unit heating performance is determined. By default, this value is the same as the outdoor air wet-bulb temperature for the outdoor unit at the reference condition, defined on the Reference condition – outdoor unit tab. To independently edit the outdoor air dry-bulb temperature as a reference outdoor unit condition for the reference indoor unit performance, uncheck the box labeled “Use same outdoor wet-bulb temperature as for outdoor unit”.
