Skip to main content

Posts

AHU Selection & Design – Basic Engineering Approach

  AHU Selection & Design – Basic Engineering Approach Air Handling Unit (AHU) is the heart of any central HVAC system. Proper selection ensures efficient cooling, air quality, and energy performance.  1️⃣ Airflow Requirement First step in AHU design is determining airflow. • Based on cooling load (TR) • Typical rule: 400–450 CFM per TR for comfort air conditioning Airflow directly affects coil size, fan capacity, and duct design. 🔹 2️⃣ Cooling Coil Selection Key parameters: • Entering air temperature • Leaving air temperature • Chilled water temperature (7°C / 12°C typical) • Air velocity across coil Proper coil design ensures good heat transfer and low pressure drop. 🔹 3️⃣ Fan Selection Fan is selected based on: • Required airflow (CFM) • Total Static Pressure (TSP) • System losses (filters, coil, duct) Common fan types: • Backward curved centrifugal fan • Plug fan (EC fan) – energy efficient modern design 🔹 4️⃣ Filtration System Filters maintain indoor air quality. Ty...
Recent posts

HVAC Actuator – Site Installation Update

  HVAC Actuator – Site Installation Update HVAC actuators are essential components in modern building systems, responsible for precise control of dampers and valves to regulate airflow and maintain optimal indoor environmental conditions. Proper installation and calibration of actuators ensure efficient system performance, improved energy management, and reliable operation within the HVAC network. As part of the ongoing HVAC works on site, the actuator installation and functional checks were carried out to ensure accurate damper control and seamless integration with the control panels Committed to delivering quality HVAC installations and ensuring efficient building services performance. hashtag Activate to view larger image, Activate to vi

FCU Coil and Duct Humidity (Moisture) & Water Condensation Problem

  FCU Coil and Duct Humidity (Moisture) & Water Condensation Problem 1. What is Condensation? When a cold surface (like a coil, duct, or diffuser) temperature drops below the room’s dew point temperature, the moisture present in the air turns into water droplets. This is called condensation or sweating. Example: If room dew point = 16°C And duct surface temperature = 14°C Then water droplets will definitely form. 2. How Does Condensation Occur in an FCU Coil? ✓. Normal Condition Chilled water temperature in FCU coil = 7–12°C Warm air passes over the coil Moisture turns into water Water collects in drain tray Water goes out through drain pipe This is normal operation. What is FCU Coil Block Problem? When the Fan Coil Unit (FCU) cooling coil gets blocked due to dust, dirt, sludge, or scale, airflow or water flow becomes disturbed. Two Main Reasons for Blockage: 1. Air Side Blockage Dust accumulates on coil fins Filter becomes dirty Airflow reduces When Does the Problem Occur? 1. ...

Air Handling Unit (AHU) Working Principle

  Air Handling Unit (AHU) Working Principle The Air Handling Unit (AHU) is the central device in large buildings that cleans, heats/cools, humidifies/dehumidifies, and distributes air. Let’s explain the typical AHU sections and airflow shown in the diagram. Outdoor fresh air (outside air) enters the system and first passes through filters. These filters capture dust, pollen, and airborne particles. In some models, UV lamps (antibacterial) destroy bacteria and viruses. The air then enters the mixing chamber (mixing box), where it is blended with return/relief air coming back from the building. This mixing is important for energy savings. Next, the air passes through the heat recovery wheel (heat wheel). The heat or cooling energy from the exhaust air is transferred to the incoming fresh air, significantly reducing the load on the chiller or boiler. After that, the air goes through cooling coils (cooling coil) where it is cooled using chilled water. When needed, a steam humidifier ad...