Compressor failures are one of the most costly repairs to an air conditioning system. It is rare for the compressor to fail simply due to the compressor itself. Usually a compressor failure is symptomatic of another problem with the AC system (more on this in a later Service Matters).
A variable frequency drive (VFD) is a type of motor controller that drives an electric motor by varying the frequency and voltage supplied to the motor. VFDs have been in use since the 1980s, and today, the combination of energy awareness, energy regulations, and new VFD technologies are driving an increasing demand for these energy-saving products.
The concept of a VFD is fairly straightforward. Frequency (hertz) is directly related to a motor’s speed (RPMs). The faster the frequency is, the faster the RPMs go. If an application does not require an electric motor to run at full speed, a VFD can be used to ramp down the frequency and voltage to meet the requirements of the electric motor’s load. As the application’s motor speed requirements change, the VFD can turn the motor speed up or down to meet the speed requirement.
So, if a facility has an application that does not need to be run at full speed (an HVAC component, process system, etc.), then energy costs can be reduced by using a VFD to match the speed of the motor-driven equipment to the load requirement. With electric motors responsible for a high percentage of electric consumption in many facilities, utilization of VFDs can be a major energy reduction strategy. Utilization of energy tax rebates and /or utility rebates can mean quick paybacks for VFD installations.
Demand for VFD installations is increasing. Some experts estimate that this demand increase will be close to 40% between now and 2021, the increase fueled primarily by new regulations and new technology. For example, California recently expanded its energy standards to require VFD installations on motors in HVAC applications down to 5 horsepower in some applications. Other states are either enacting similar standards or are exploring the possibility.
With electric motors responsible for a high percentage of electric consumption in many facilities, utilization of VFDs can be a major energy
In addition, rapid technological improvements are impacting VFDs just like other products and equipment. VFDs are quickly becoming interconnected and part of smart machines (think the Internet of Things) with extensive built in communication and BACnet capabilities. Other advancements include VFDs for niche markets such as independent HVAC components and specific process equipment, and like many other technology related products, VFDs are becoming smaller with space saving design features.
Some experts estimate that the demand for VFDs will increase nearly 40% between now and 2021, based on new regulations and new technology.
Maybe it’s time to take another look at VFDs to meet your building needs. Speer Mechanical can help. Contact us at 614.261.6331 for more information.
Some things just naturally go together. Consider:
• Peanut butter and jelly
• The 4th of July and fireworks
• Fred & Ginger
• A cold beer at the ballpark
Good indoor air quality (IAQ) and effective mechanical system maintenance are two more. Good indoor air quality is complex, and your mechanical system plays a critical role in its two most important components, adequate ventilation and moisture control. Adequate ventilation includes both the proper utilization of outside air and the assurance of proper airflow into occupied spaces.
Sometimes it seems that many energy conservation measures related to HVAC systems are incompatible with providing good indoor air quality (IAQ).
However, with a little forethought and proper maintenance, significant energy savings from HVAC-system use can be achieved while still providing
good IAQ. Follow these simple guidelines and see how you can improve air quality and maximize energy conservation for your building.
At a base level, take care to provide adequate ventilation and always meet the standards of ASHRAE 62.1-2016.
A good starting point is to understand the basic HVAC energy conservation or retrofit measures that are compatible with IAQ, including:
- Tightening the building shell, as long as adequate ventilation is provided
- Reducing internal loads with lighting or office equipment upgrades (if these measures reduce air flow requirements, be sure to consider the
increased outdoor air necessary to maintain ventilation requirements)
- Upgrading fans, motors and drives
- Upgrading chillers and boilers
- Installing energy recovery ventilation systems (ERV)
- Equipment downsizing
There are also operational improvements and other measures compatible with IAQ that can positively impact air quality while at the same time improving
energy efficiency. These include:
- Proper preventive maintenance to remove potential contaminants while ensuring efficient operation of HVAC components
- Use of economizers (air or water)
- Night pre-cooling (remember to consider humidity control)
- Reducing demand charges (use caution with load shedding that reduces outdoor air during building occupancy)
- Supplying air temperature resets (practice appropriate control strategies and consider humidity concerns)
- CO2 controlled ventilation (use proper control strategies and consistent calibration)
Be sure to use caution with energy strategies like these:
- Reducing outdoor ventilation below ASHRAE standards –remember, those standards are in place to provide for dilution of potential pollutants
in the occupied spaces
- Reduction in HVAC operating hours – to maintain proper ventilation, be sure to provide appropriate lead-in time prior to occupancy, and do
not shut down HVAC equipment prior to people leaving the building
- Relaxation of temperature or humidity set points below industry standards – recognize this can make it difficult to properly diagnose any potential
Discover how the LEED accredited professionals at Speer Mechanical can help with all your energy needs and concerns to make your building healthier
for occupants and more energy efficient for you. Contact us at 614.261.6331 for more information.
A boiler is a complex piece of equipment. While some diagnostics can be done by observation, a detailed understanding of a boiler’s operation can be diagnosed through a combustion analysis, similar to your family doctor ordering “a complete blood-workup” with your annual physical.