THE KHADIJAH HVAC KNOWLEDGE CENTRE
Understand the system.
See the difference.
Equipment photographs, visual explainers and practical guides for making more informed decisions about your building’s cooling.
REFRIGERANTCONNECTED, EXPLAINED.
FEATURED / START WITH THE BASICS
Chilled water or DX?
Let’s make it clear.
Learn what reaches the cooling coil, where the heat goes and why “water-cooled” describes a different part of the system.
Explore the visual guideVISUAL GUIDE LIBRARY
Choose a topic.
Build your understanding one system at a time.
ROOM COOLING
How a split air conditioner works
Follow the heat from the room to the outdoors, and learn what each part of the system does.
Read visual guide +
MULTI-ZONE SYSTEMS
VRV & VRF: cooling by zone
Understand the shared outdoor system, individual indoor units and the connections between them.
Read visual guide +CENTRAL COOLING
Inside a chilled-water system
See how a chiller, pumps, cooling coils and heat rejection work together.
Read visual guide +
AIR-SIDE EQUIPMENT
AHUs & FCUs: follow the airflow
Understand filtration, cooling coils, fans, drainage and how they influence comfort.
Read visual guide +
VENTILATION
Fresh air, extract air & room comfort
Learn why cooling and ventilation are related but different tasks.
Read visual guide +
MECHANICAL SYSTEMS
Pumps, valves & insulated pipework
Understand how water circulates, how flow is controlled and why cold pipes need protection.
Read visual guide +
DESIGN & COORDINATION
AutoCAD, Revit & clearer HVAC drawings
Choose the drawing deliverables that help your team plan, coordinate and install.
Read visual guide +HVAC FUNDAMENTALS
Chilled water or DX? Start here.
Separate the cooling medium from the way heat is rejected outdoors.
Read visual guide +
CARE & TROUBLESHOOTING
Know when your AC needs attention
Recognise changes, record useful symptoms and understand the purpose of routine maintenance.
Read visual guide +PROJECT PLANNING
Prepare a better HVAC project brief
The information that helps turn an enquiry into a clear scope and quotation.
Read visual guide +QUICK REFERENCE
The words you’ll often hear.
| Term | In plain English |
|---|---|
| HVAC | Heating, ventilation and air conditioning. |
| DX | Direct expansion: refrigerant cools air at the coil. |
| CHW | Chilled water: water used to carry cooling through a building. |
| AHU | Air-handling unit: equipment that moves and conditions air. |
| FCU | Fan-coil unit: a local fan and coil assembly. |
| VRF / VRV | Variable refrigerant flow; VRV is Daikin’s trademark. |
| VSD / VFD | A drive that controls motor speed; selection and settings depend on the application. |
| Condensate | Water that forms as humid air meets a cold surface. |
| BIM | Building information modelling: a model-based approach to building information and coordination. |