Direct Expansion Air Conditioning System
Direct expansion Air Conditioning System is a common air conditioning system that uses condensed refrigerant liquid (freon) directly to cool indoor air.
The refrigerant is being expanded directly before going through the evaporator. The system is installed inside the building, with some parts installed outside.
Direct Expansion Air Conditioning System Types
DX solution comes in different shapes and sizes and cooling capacities, examples of the system types are:
- Mini-splits
- Window air conditioner
- Packaged units
Best places to use DX system
This system is best used in large areas such as:
- Office buildings
- Malls
- Hospitals
- Library & Museums
How the system operates
The Direct Expansion Air Conditioning System uses a refrigeration cycle to cool the space, which goes through:
Freon expansion:
Where a thermal expansion valve(TXV) or capillary tube is used in a flow control device.
Freon vaporization:
The freon evaporates in the evaporator coil at a constant temperature and pressure.
Compression:
The evaporated freon goes through the compressor to be compressed and increases its temperature and pressure.
Condensation:
The compressed vapor then moves to the condenser. The condenser fan pulls the air to the condenser coil surface, where vaporis transferred to it.
System alternatives
- Concealed ducted split
- Split-System air conditioners
- Chilled water
- Variable refrigerant flow (VRF)
- Variable refrigerant volume (VRV)
Benefits
- Low installation cost
- Doesn’t need much space like centralized cooling systems
- Flexible installation for most designs
- Easy adjustment of the system, it can be adjusted to suit the building needs
- Easy to control and highly efficient
- Doesn’t need high maintenance or repair cost
- Packed systems don't need a high ventilation level, and usually take smaller spaces compared to the split system.
- Because the compressor in the mini split system is away from the cooling area, the noise levels for this system is low.
- Mini split system comes with low maintenance cost
Maintenance
Direct expansion system is a low maintenance system, however, following the manufacturer instructions could help maintain the system in a good condition for a longer period of time.
- Keep the inlet and approaches to DX system and compressor unit clean
- Check the fasteners tightness after each maintenance check
- Check the DX coil regularly, to avoid dust accumulation.
- Clean the drain and the DX coil twice a year
- Check the coil yearly for damage