Efficiency Controls for Commercial HVAC Cut the Costs of Electricity More than 50 Percent

With the controls, advanced energy-efficiency, the commercial building can easily cut by an average of fifty-seven percent their HVAC (heating, ventilating and air conditioning) electricity use and the result found by a trial (year-long) of advanced controls at different commercial buildings, grocery stores and malls across the country. The PNNL (Pacific Northwest National Laboratory) of the Department of Energy conducted the study and demonstrated that the Commercial HVAC saved higher energy than a prediction.

The HVAC boxes called as packaged units (HVAC) placed on the roofs of some commercial buildings. These packaged units (HVAC) consume pretty equal amount of energy of 2,600 trillion (British) units (thermal) or 8 million residents (U.S.).

Srinivas Katipamula, the lead researcher of the study and his PNNL colleagues found that air handling units (HVAC) have better controls in case of using packaged units (rooftop HVAC). Based on the conditions outside and inside of a building, they tried to adjust the operations with packaged units automatically. Using variable-speed motors and sensors, the controls determine how fast and when should ventilation fans run and make sure the units can use cold air naturally in lieu of indoor mechanically cooling air.

Actually, everybody knows that heating & cooling consume a huge amount of energy as most of the buildings don’t have sophisticated control systems. However, if the advanced controls are properly installed at working, real commercial building, then the energy efficiency of the air conditioning systems clearly demonstrates its true performance and energy-efficiency.

The PNNL team was working with various controls and some companies started developing and processing advanced controls in the meantime. The PNNL team installed some energy-efficient and commercially available HVAC units (rooftop) at some commercial buildings. They were amazed to see the results as it cuts almost 57 percent of energy on an average in comparison with standard operations. In fact, the range was 20 to 90 percent (energy savings). However, the bigger buildings (or malls) saved more energy compared to smaller buildings. Moreover, the stores (that ran ventilation) save more energy as these are usually open relatively long hours.

In fact, the researchers found that the HVAC units or advanced controls would help to save a lot of money every year for the building owners. This is for sure that the owners of the buildings would be inspired by the figures and install the advanced controls for greater savings.

A Brief Guide to Understanding AC Drive System

The function of an AC Drive is to change the speed and torque of an electric motor (AC Motor) used in electro-mechanical drive systems by changing the frequency and voltage of the power supplied to the motor. An AC Drive system, which is also known as a variable-frequency drive (VFD), inverter drive, variable speed drive, and adjustable-frequency drive, mainly performs the speed adjustment of a motor.

AC Drive System

AC Drives Applications

The AC Drive system has a variety of applications in different electrical systems. Let’s take a look at some common uses:

Control Performance

AC Drives control the performance of various systems in commercial and industrial applications. They work for bringing the quality improvements of different systems’ speed, acceleration, tension, torque, flow, and pressure.

The advantage of using the drives is that they ramp up the motor to the operating speed gradually, reducing the electrical and mechanical stress on the motor and the driven equipment. On the other hand, fixed-speed load keeps torque and current surge at a high point at the beginning, creating damage risk for the motor and other equipment.

Energy Savings

The AC Drives provide the flexibility of tuning the configuration of a system to the most energy-efficient level. They help saving more energy than drives that offer the optimization of individual functions of a system.

HVAC Applications

AC Drives are most commonly used in compressors, pumps, and fans of HVAC systems. Using them other than any other tool in controlling the output of a fan, pump, or compressor system saves a substantial amount of energy.

AC Drives Working Principle

An AC Drive system converts the frequency of a power network, and thus controls the motor speed in a proportional rate to the frequency. Understating some simple basics of AC Drives will help you figure out their working principle. The procedure consists of:

Rectifier unit. The electrical network connects to the AC drive via a uni- or bi-directional rectifier unit. The AC Drive takes energy from the system and uses it to accelerate and run the motor if the rectifier is unidirectional. In the case of a bidirectional rectifier, the drive supplies energy to the network by taking mechanical rotation energy from the motor.

DC circuit. The DC circuit mainly assists the inverter by storing energy for it from the rectifier.

Inverter unit. It works as a bridge for the transmission of energy from the DC circuit to the motor. It creates the three-phase AC voltage output for the motor, which influences the motors speed aka output of the process. A higher frequency of the output voltage results in a higher speed of the motor.

Benefits of AC Drive System

AC Drives offer various benefits regarding system stress, process control, and energy savings of the motors they control. Some of the advantages are:

  • Gradually ramp up the torque and current surge, and thus reducing stress on the tools and machines
  • Reduce thermal and mechanical stresses
  • Cut the level of noise and vibrations in low load situations
  • Secure smooth flow of energy by synchronizing between different parts of the main process
  • Control the output of the process as required
  • Save energy more than the traditional methods of process control