You may not have heard of an economizer before, but it’s an instrument that can save tons of money for commercial building owners by saving on the energy that is used to cool and ventilate those buildings.
An economizer uses a sensor that is capable of measuring the outdoor air temperature and humidity. When the temperature is cool enough, it causes the building’s cooling system to shut off and uses the outside air to cool the building down.
Compared to a traditional air conditioner, an economizer uses far less energy, and over time that can amount to significant cost savings. For the most part, exterior air is cooler than interior air during the nighttime, so that’s when an economizer would typically be operating.
By mixing just enough exterior air with the warmer interior air, the economizer can reach the temperature that has been set on the thermostat, without ever making use of the compressor in an HVAC unit.
Not only does this accomplish the necessary cooling, but the building is also ventilated via the same process, so there would be no need to use other means for air circulation.
In effect, the building would have free cooling and free ventilation, although the minimal cost of running the economizer would still be there.
An economizer is not a standalone mechanism but is generally an add-on feature for any HVAC system responsible for cooling a commercial building. It would most often be mounted on the roof alongside the cooling system and work in tandem with it.
The economizer needs to have ready access to the cooling system, so it can switch off the compressor when it is operating and drawing in the cool outside air.
Since it is situated outside itself, it has no trouble obtaining the temperature and humidity measurements needed for efficient operation.
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Benefits of economizers
It’s very important for the owner or manager of a large commercial building to achieve whatever savings are possible on energy, given the fact that energy costs can be substantial, and the heating/cooling of a large building can be extremely expensive.
Whenever the compressor of an air conditioning unit is not running, it can save you money on energy costs. By having an economizer installed in your building, you will spend less on energy because the economizer will be running at night while your compressor is shut down.
Many older buildings were not originally designed with good ventilation as an important feature in their overall structure. By bringing in fresh air from the outside and exhausting used interior air to the outdoors, an economizer can help improve indoor air quality.
With higher indoor air quality, occupants of your building will be more comfortable, and those with respiratory issues will experience some relief.
Studies have shown that the improved air quality produced by economizers has resulted in significant savings to business owners because fewer sick days were used by employees working in affected buildings.
An efficiently operating economizer can save a great deal of wear and tear on your HVAC system, primarily because the compressor can be idle for hundreds of hours every year, if not thousands of hours.
This will cause your air conditioning system to last far longer than it normally would have, and you won’t have to replace the cooling unit nearly as soon as you would have otherwise.
Commercial air conditioning units are not cheap, and it is definitely to your advantage to keep one operating for the longest possible time before replacing it.
One last benefit of using economizers is that they’re extremely easy to install. Some modern cooling systems actually come equipped with economizers already, but if yours did not, it doesn’t take much expertise to have one fitted onto your HVAC unit.
They also don’t take up much space, so if your rooftop is already crowded, you won’t have to worry about trying to free up a large amount of space in order to have your economizer installed.
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Types of economizers
There are several different types of economizers available, the simplest of which is a ‘dry bulb’ economizer. This device has a special sensor that determines when the exterior air temperature dips below 55 degrees Fahrenheit (or some other pre-selected temperature).
When that point is reached, an actuator is triggered and this allows exterior air to mix with exhausted interior air. While it is very good at detecting favorable air temperatures for interior cooling, a dry bulb economizer is not usually capable of sensing the humidity in the exterior air.
A single enthalpy economizer is specifically geared to sensing humidity levels before triggering its cooling operation. Enthalpy refers to the total heat content of any given system, and it is roughly equivalent to a system’s internal energy plus the product of volume and pressure.
Sometimes called a ‘wet bulb’ economizer, this is the most popular type in use today, and as long as it is periodically calibrated for accuracy, it can be very effective.
The last type of economizer in use today is called a differential enthalpy economizer. This is the most sophisticated type of economizer, as it uses two or more sensors for measuring both the return air (interior exhausted air) and the outside air.
This extra level of sophistication permits advanced damper modulation, which calculates the lowest level of enthalpy that can be used for cooling, and it also determines the most advantageous level that can be used.
This type of economizer is often integrated with the interior thermostat so there is constant communication between the two devices.
This economizer is commonly used in commercial buildings where one major cooling system is responsible for sending conditioned air to as many as twenty different building zones using a number of different air handlers.
In such complex scenarios, the savings achieved by a differential enthalpy economizer can be even more significant, because so many different areas are being cooled by a single energy-efficient device.
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You can trust Design Mechanical with any of your commercial building-related needs!
Design Mechanical is one of the most trusted and reliable mechanical service providers in the Kansas City area. For years, we have been helping commercial building owners optimize their energy efficiency and improve their overall cost savings.
We offer a number of HVAC-related services, as well as refrigeration services, building automation system (BAS) installation, and indoor air purification. If you have any questions or require one of our services, please don’t hesitate to email us at email@example.com or call us at (913) 281-7200!