The larger the building, the more costly it is to maintain a constant temperature. This is particularly true in areas of the country where extreme heat, humidity, or combinations of these factors put a heavy strain on the rooftop types of HVAC systems.
The purpose of HVAC economizers in any rooftop system is to supplement the HVAC system to help to reduce the draw on energy for operation. In other words, these devices are used to make the HVAC system more efficient and economical to run, without using additional power or resources.
Different Options
The operation of all HVAC economizers is based on the external air temperature and humidity. When this temperature and humidity is below a pre-selected level, the unit can use the outdoor air for the purpose of indoor cooling without the need for the air to be cooled through the compressor.
The different options in HVAC economizers use a variety of types of sensors to detect the condition of the ambient air for this “free cooling” option. In areas where humidity is not a problem, a dry bulb economizer is a cost-effective option to use. This system only measures the air temperature and cannot detect the specific humidity level.
In areas where temperature and humidity are factors, an enthalpy economizer is the best option. This type of economizer senses both the temperature and the humidity in the area to create a total heat content measurement. There are single and differential options, with the integrated differential enthalpy economizer the most advanced.
This type of economizer is able to read internal thermostats and either bring in the outdoor air for cooling or to turn on the compressor system and allow the outside air to be cooled and circulated through the building. These types of economizers are more costly, but they also offer significant energy saving benefits in any system.
