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All courses20-part course

Cooling Fundamentals

A free 20-lesson course on how buildings are cooled: the refrigeration cycle, humidity, fresh air, chillers, pumps, cooling towers and efficiency, with a route for buildings on split units.

Start the course

How cooling works

  1. 1

    How Does an Air Conditioner Work? It Moves Heat, It Doesn't Make Cold

    An air conditioner does not create cold. It scoops heat out of your room and dumps it outside. This one reframe unlocks how all cooling actually works.

  2. 2

    The Refrigeration Cycle Explained Simply: The Loop That Carries Heat Outside

    The refrigeration cycle explained in plain language: one fluid boils indoors to soak up heat and condenses outdoors to dump it, round and round forever.

  3. 3

    Why Is My Office Cool but Still Humid? Sensible Heat, Latent Heat and Dew Point

    Why is my room cool but humid? Learn how sensible and latent heat, relative humidity and dew point explain sticky air in tropical Malaysian buildings.

  4. 4

    Indoor Air Quality in Offices: Fresh Air, Filters and What CO2 Really Tells You

    How offices keep air healthy with ventilation, filters and CO2 sensing — why 1000 ppm is Malaysia's legal limit and how fresh air costs cooling energy.

How much cooling

  1. 5

    What Is a Ton of Refrigeration? Tons, BTU and kW of Cooling Made Simple

    A ton of refrigeration is 12,000 BTU/h, or 3.517 kW of cooling. Learn what tons, BTU and kW really mean — and why the word kW trips up almost everyone.

  2. 6

    How to Calculate a Building's Cooling Load: Where Heat Sneaks In

    Learn how to calculate cooling load: solar gain, envelope, humid outdoor air and internal gains, why tropical buildings differ, and why right-sizing matters.

The machines

  1. 7

    Window, Split and VRF Air Conditioners: What's the Difference?

    Window vs split vs VRF air conditioners explained simply: how each cools, why VRF's inverter compressor matches demand, and which suits your building.

  2. 8

    How Does a Chilled-Water System Work? The Three Loops Explained

    How does a chilled water system work? A plain-language guide to the two water loops plus one refrigerant loop that cool an entire building from one chiller.

  3. 9

    Pumps, Valves and Flow: How Chilled Water Reaches Every Coil

    How chilled water pumps and valves work: why cooling equals flow times temperature rise, what pump head means, two-way vs three-way valves, the decoupler, and why variable-speed pumps save power.

  4. 10

    AHU vs FCU: The Difference Between an Air Handling Unit and a Fan Coil Unit

    AHU vs FCU difference, explained in plain terms: one big unit ventilates a whole zone with fresh outdoor air, one small unit trims cooling in a single room.

  5. 11

    What Is a VAV System? How Ducts, Dampers and Static Pressure Deliver Cool Air

    What is a VAV system? Learn how ducts, motorised dampers and static pressure deliver just the right amount of cool air to each zone — and save fan energy.

  6. 12

    How Does a Cooling Tower Work? Throwing a Building's Heat at the Sky

    How a cooling tower rejects a building's heat by evaporating water, why range and approach grade it, and how Malaysia's humid wet-bulb sets a cold-water floor.

Cost and efficiency

  1. 13

    COP, EER and kW per Ton: How to Read Chiller and Aircon Efficiency Numbers

    COP, EER, CSPF and kW/ton all grade one thing: cooling delivered per unit of electricity. Learn to read each one and honestly grade your own chiller plant.

  2. 14

    Why Air Conditioning Is the Biggest Line on a Malaysian Building's Electricity Bill

    In a Malaysian building, cooling is often over half the electricity bill. Follow the ringgit to see why the chiller wins over lights, lifts and plug loads.

  3. 15

    Why Chiller Efficiency Is Measured at Part Load: Understanding IPLV

    Why a chiller's full-load nameplate number lies, and how IPLV blends part-load efficiency into one honest figure that reflects how chillers really run.

Measure and act

  1. 16

    BEI Malaysia: Scoring Your Building's Cooling by Measuring It

    What Malaysia's Building Energy Index and MS1525 reveal about the hidden cooling waste in a building that feels perfectly fine — and why you can't fix a plant you don't…

  2. 17

    Low Delta-T Syndrome: The Silent Efficiency-Killer of Chilled-Water Plants

    Low delta-T syndrome forces chilled-water plants to over-pump and over-stage chillers for the same comfort. Learn what it is and why it hides on the bill.

  3. 18

    Oversized Chillers, Short-Cycling and Dirty Coils: The Cheapest Efficiency Wins

    Why bigger chillers waste energy through short-cycling and how dirty coils quietly starve cooling capacity — the cheapest efficiency fixes in any building.

  4. 19

    What Is a BMS? How Building Controls Run the Cooling Plant

    What is a building management system? Learn the sense-compare-act control loop, BACnet vs Modbus, smart cooling strategies, and the honest limit of a BMS.

Finish

  1. 20

    One Complaint, Three Loops: A Worked Cooling Plant Check

    A worked exercise to finish the course. Trace a warm, humid complaint in our example office tower through the air, chilled water and condenser water loops using trend readings: delta-T, kW and RT of cooling, kW/RT and tower approach. Then a short version for a shoplot with split units and cassettes.

Optional side readings

Background and history. Not needed to finish the course.