A packaged terminal air conditioner (PTAC) is a type of self-contained heating and air-conditioning system. Some PTACs are cooling-only type.
Required Objects
The packaged terminal air conditioner (PTAC) must have the following property.
- It must be attached to a conditioned zone.
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.
- It has a single speed DX coil.
- The sensible-to-latent heat ratio is auto-sized to meet system needs during sizing.
| Property | Value | Notes |
|---|---|---|
| Coil leaving air temperature | 12.78°C | |
| Chilled water design inlet temperature | 3.0 |
Heating Coil
The heating coil has the following assumptions.
-
- The electric resistence heating coil is 100% efficient.
- The furnace heating coil is 80% efficient.
- The hot water coil has the following properties.
| Property | Value | Notes |
|---|---|---|
| Coil leaving air temperature | 40°C | |
| Hot water design inlet temperature | N/A | Set by the hot water loop. |
| Hot water design outlet temperature | N/A | Set by the hot water loop. |
Supply Fan
The supply fan has the following properties.
| Property | Value | Notes |
|---|---|---|
| Pressure rise | 250 Pa | |
| Total efficiency | 70% | |
| Motor efficiency | 94% |