Variable refrigerant flow (VRF) systems vary the flow of refrigerant to indoor units based on demand.
Required Objects
The variable refrigerant flow (VRF) fan coil must have the following properties.
- It must be attached to a conditioned zone.
- It must be connected to a variable refrigerant flow loop.
Design Assumptions
- If the Draw Ventilation property is selected, the following will occur.
- The unit will provide the design outdoor air flow.
- The fan will run constantly during occupied hours.
- If the Draw Ventilation property is not selected, the following will occur.
- The unit will not provide any ventilation.
- The fan will cycle on and off to meet conditioning needs.
| Property | Value | Notes |
|---|---|---|
| System air flow | Constant | |
| Cooling supply air temperature | 12.78°C | |
| Heating supply air temperature | 40°C |
Cooling Coil
The cooling coil has the following assumptions:
- The sensible-to-latent heat ratio is auto-sized to meet the system needs during sizing.
| Property | Value | Notes |
|---|---|---|
| Coil leaving air temperature | 12.78°C |
Heating Coil
The heating coil has the following assumptions.
- The coil is a DX single speed heating coil.
| Property | Value | Notes |
|---|---|---|
| Coil leaving air temperature | 40°C |
Supplemental Heating Coil
This is an electric resistance coil with an efficiency of 1.0.
Supply Fan
The supply fan has the following properties.
| Property | Value | Notes |
|---|---|---|
| Pressure rise | 250 Pa | |
| Total efficiency | 70% | |
| Motor efficiency | 90% |