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%
|
|