AHU

 An Air Handling Unit (AHU) 

is used to re-condition and circulate air as part of a heating, ventilating and air-conditioning system.

 An air handler, or air handling unit (often abbreviated to AHU), is a device used to regulate and circulate air as part of a heating, ventilating, and air-conditioning (HVAC) system. ... Sometimes AHUs discharge (supply) and admit (return) air directly to and from the space served without ductwork.

A packaged rooftop unit, or RTU, is a type of HVAC system that contains all the components needed to provide conditioned air in one concise unit. Packaged rooftop units are commonly found in light and large commercial applications. They are very popular with retail and industrial properties.

 An AHU capacity of an air conditioning system is expressed in BTU's or Tons. 1 Ton = 12,000 BTU's/hours of cooling capacity. As far as my knowledge, an AHU capacity in a cooling coil system can be identified only by decoding the air conditioner number.

 A chiller plant is a centralized system that cools the air for a building or for a collection of buildings and provides the air-conditioning portion of HVAC systems. According to the federal government's Energy Star website, over 35 percent of buildings larger than 100,000 square feet contain chiller plants.

Unit of airflow employed in air-conditioning. A typical air conditioner, for example, produces about 400 CFM for each ton of its cooling capacity. One CFM equals about 28.31 litters per minute.

 Cubic feet per min- CFM

 The airflow is measured in cubic feet per minute (CFM). 350 to 400 CFM per ton of cooling is required for proper air conditioning system operation. For example, if you are checking a 3-ton system, the air flow required is between 1050 and 1200 CFM. Usually, chillers used to carry R-22 gas in the refrigerant circuit.

 There are three different types of chillers:(1) air, (2) water, and (3) evaporative condensed chiller. There are four subcategories in each of the above categories for industrial chillers: (1) reciprocating, (2) centrifugal, (3) screw driven (4) and absorption chillers.

 How many CFM do I need for 1000 square feet?

Heat and energy recovery ventilators

Total area of home (square feet)             Continuous ventilation rate

1,000 square feet                                                       50 CFM

2,000 square feet                                                       100 CFM

3,000 square feet                                                        150 CFM