subject: Hvac: Energy Hogs: Methods For Efficiency [print this page] Chillers Chillers
Of building systems, chillers would be the single largest user of electricity in practically all buildings. So even minor improvements in operating efficiency may result in significant savings. Oversizing is the single largest reason behind energy waste in chiller systems. Building chillers typically are made to carry the most important cooling load that occurs after a typical year from the facility, of course this load might occur for only some hours.
The rest of the time, the chillers system operates in a reduced load, a decrease load. Unfortunately for maintenance and engineering managers, chillers run at their peak efficiency only once they operate at or near full-load conditions. Since the strain on the chiller decreases, does the unit's operating efficiency.
If the facility has more than one central chiller, managers can improve operating efficiency by staging the entire process of the chillers. If the cooling load from the facility is fairly low, merely one chiller should come online. Because load increases, additional units will come online to fulfill the increased need for cooling.
As the typical building chiller is extremely reliable and has an extended service life, it does require ongoing maintenance whether it is to operate efficiently. Deficiency of proper maintenance will create a slow but steady deterioration in their performance that may go undetected unless someone starts to closely monitor the chiller's energy use.
Boilers: The Largest Users of Fuel
While chillers will be the largest users of electricity in many institutional and commercial facilities, the only biggest user of combustible fuels may be the heating boiler. The responsible for energy waste in connection with boilers is improperly adjusted controls, especially in large, boiler system boilers.
Complete combustion of the fuel in almost any boiler necessitates proper combination of air and fuel. An excessive amount of air, along with the operating efficiency in the boiler drops. Not enough air, and also the fuel will never be completely combusted, allowing the generation of soot that clogs heat-transfer surfaces minimizing the boiler's efficiency. To make certain complete combustion, all boilers introduce more air compared to actually require. Even though this excess air does slow up the boiler's efficiency, in addition, it prevents the generation of soot.
Proper adjustment from the boiler's combustion controls will limit how much excess air introduced into the boiler and, therefore, increase its seasonal operating efficiency.
Motors: Influence on Energy Efficiency
Commercial and institutional facilities normally have a lot more motors operating inside their HVAC systems than most managers realize. Since these motors use a great deal energy, they have great opportunities to make a significant impact on facility energy use.
Certainly the best source of energy inefficiency with HVAC system motors is often a mismatch between your motor's rated horsepower as well as the load it really is driving. Most HVAC system motors are induction motors.
While these motors are efficient and reliable, their efficiency, like building chillers, drops off significantly whenever they operate under part-load conditions.
Replacing older motors with properly sized ones offers two benefits. First, matching the motor horsepower to the actual load increases the operating efficiency from the system.
Second, changes in motor design have triggered an era of motors which have operating efficiencies 2-8 percent more than older, standard motors.
