Air Conditioning Heating Terms Definitions & Acronyms

Posted on February 4, 2008 by Richard Ashworth

This is a comprehensive list of HVAC Acronyms and HVAC Terms. High Performance HVAC is certain there are more terms and acronyms. If you know of something we missed please email us. Thanks!

AC – Air Conditioning or Alternating Current

ACCA – Air Conditioning Contractors Associations

AFUE – Annual Fuel Utilization Efficiency

AHU – Air Handling Unit

AI – Analog Input

AMCA – Air Movement and Control Association

AO – Analog Output

AQS – Air Quality Systems

ASHRAE – American Society of Heating, Refrigerating, and Air Conditioning Engineers

AV – Automatic Air Vent

AWG – American Wire Gage

B – Boiler

BACnet – Computer communication protocol for building automation systems and control networks

BAS – Building Automation System

BI – Binary Input

BMS – Building Management System

BO – Binary Output

BP – Backflow Preventer

BTU – British Thermal Unit

BTUh – Brtish Thermal Units per Hour Continue reading “Air Conditioning Heating Terms Definitions & Acronyms” »

Cooling Tower Evaporation Cools Water

Posted on January 25, 2008 by Richard Ashworth

Cooling Tower Evaporation Cools Water Cooling towers use the process of evaporation to cool or removes heat from the condenser water that was transferred to the water in the chiller condenser barrel. The heat is absorbed at the load in this case in a data center on a data center floor. The servers and electrical equipment produce a massive amount of sensible heat. The heat is absorbed by computer room air conditioners or computer room air handlers. These systems, computer room air handlers and air conditioners, have chilled water coils. The chilled water originates at the chiller into the primary loop. The water circulates through the primary loop and makes its way into the secondary loops of the chilled water loop. Continue reading “Cooling Tower Evaporation Cools Water” »

Data Center Perforated Tiles for Cooling Servers

Posted on January 25, 2008 by Richard Ashworth

There is a lot to consider with perforated tiles in data centers and depending on who you talk to you will get different answers. The server floor in a data center is typically built on a raised floor with cold air being pumped under the floor by large CRAH(Computer Room Air Handlers) or CRAC units (Computer Room Air Conditioners). This cold air is flows through the perf tiles and into the data center to cool the load of the heat the servers and other ancillary data center electrical equipment produce. The data center load is a sensible load as data centers do not have a lot of humidity in them from outside sources so the cooling equipment need only be capable of cooling the sensible load with little worry about any latent loads. Continue reading “Data Center Perforated Tiles for Cooling Servers” »

Computer Room Air Conditioner Units

Posted on January 6, 2008 by Richard Ashworth

Computer Room Air Conditioner Units are essential inside data centers where cooling is necessary for all the computer and electrical equipment most data centers utilize. It is important to keep the equipment cool to prevent overheating for some equipment. Removing the heat is the job of CRAC units in some cases and in other cases large Data centers use large air handlers to remove the heat however CRAC Units are the commonly used HVAC equipment used in most data centers for cooling data center equipment such as computers and electrical equipment. In a typical data center heat loads include servers, ups systems, power distribution units, static and automatic transfer switches, switchgear and other electrical equipment that produces heat during normal operation. Continue reading “Computer Room Air Conditioner Units” »

DX CRAC Unit Condensers

Posted on January 6, 2008 by Richard Ashworth

DX CRAC Unit Condensers Most data centers do not utilize HVAC DX (Direct Expansion) CRAC units or air conditioning but instead use chilled water systems to provide cooling for the data center. In smaller buildings such as remote telecom buildings DX air conditioning systems are used to keep the equipment cool and operating efficiently. A DX CRAC Unit uses vapor compression refrigeration to provide cooling with a chemical refrigerant versus a chilled water system that utilizes chilled water from a chiller. CRAC Units or Computer Room Air Conditioners also serve telecom facilities for telephone services including cellular telephone facilities in remote locations. The CRAC units that serve telecom facilities in remote locations are typically DX CRAC Units that have utility back-up by stand-by generator so that if the utility fails to provide electricity for whatever reason the stand-by generator kicks on and provides power so that the telecom facility can remain on line. Continue reading “DX CRAC Unit Condensers” »

Chilled Water System Basics

Posted on January 6, 2008 by Richard Ashworth

Chilled water systems work much the same way as direct expansion systems work except they used chilled water in the coil rather than refrigerant (Technically speaking, water can be classified as a refrigerant). Chilled Water systems can be rather complex and many chilled water systems are found in commercial and industrial applications. There are some chilled water systems used in residential applications. However, chilled water systems in residential HVAC systems are extremely rare. A typical chiller uses the process of refrigeration to chill water in a chiller barrel. This water is pumped through chilled water piping throughout the building where it will pass through a coil. Air is passed over this coil and the heat exchange process takes place. The heat in the air is absorbed into the coils and then into the water. The water is pumped back to the chiller to have the heat removed and make the trip back through the building and the coils all over again.