Cool Cash: Beating the Heat of Soaring HVAC Costs
By Deidre Macklen

Whether it's soaring cooling and heating costs or, more recently, skyrocketing prices at the gasoline pump, most Americans have felt the effects of rising energy costs. And it doesn't look like there will be any relief soon with both energy costs and demands continuing to increase. Consequently, with declining operating budgets, one area that facility managers should consider for energy savings are HVAC systems, which continue to be a source of high energy costs. HVAC systems account for approximately 45 percent of energy bills.

Several key areas can be explored for energy savings:

• Installing an Energy Management Control System
• Having the right size HVAC equipment
• Keeping up with new technology
• Performing proper maintenance on HVAC systems

First, let's take a look at installing an Energy Management Control System, which centralizes the HVAC system. Energy Management Control Systems can save 30-50 percent in HVAC energy costs and can control and monitor other energy as well, such as indoor and outdoor lighting. In manufacturing, processes are centrally planned and constantly adjusted; however, HVAC equipment is rarely centrally controlled. Each piece of equipment has its own thermostat and on/off switch. This can be a nightmare to control internally because no one can get to all the switches and adjust them efficiently. With an energy management control system, networking and computer control sensors are installed and link the existing HVAC equipment. An engineer can monitor and control plant-wide HVAC operation on a computer screen whether on-site or off-site. With plant engineering staffs being cut, this is definitely an advantage.

Secondly, the "right sizing" of equipment is another area to explore for energy savings. A review of HVAC energy efficiency may show that systems are substantially oversized. In fact, according to the Consortium of Energy Efficiency, at least 25 percent of all rooftop HVAC units are oversized. The result is increased energy costs and equipment deterioration. While undersized HVAC equipment won't be able to provide sufficient cooling, oversized HVAC equipment costs more up front and also leads to higher costs associated with ductwork and other supporting components. Oversized units also are poor at controlling humidity because the units cycle on and off too frequently.

It is worthwhile from an energy savings standpoint to determine the age of your HVAC system. There have been many technological advances and federally mandated energy efficiency increases for HVAC equipment. Even if your equipment was once state-of-the-art, it might now be technologically disadvantaged the way systems are changing so rapidly. An older HVAC system might provide heating and cooling, control humidity reasonably well, and circulate the air, but energy costs may be higher than they should be.

Let's take a look at an area in HVAC where new technology can save energy costs. Chillers consume nearly 20 percent of all electricity in North America, making optimization critical to cost savings. Most chillers operate below their design capacity for the majority of their lives. A tremendous amount of resources are still being invested in designing compressors that operate at high efficiencies during partial loading. Some manufacturers are offering high-speed centrifugal compressors with magnetic bearings and built in variable speed control, making them ideally suited for part loads.

Motormaster+, software developed by the U.S. Department of Energy (DOE), helps users select efficient, cost-effective motors. Motors that drive chillers and air handlers can make up the largest electrical loads; therefore, motors are the key to high-efficiency chiller operation. Motormaster+ contains a large database of integral-horsepower motors sold in the USA, including motors that fall under the Energy Policy Act of 1992 and many older models that do not. Using a built-in spreadsheet, users can compare a motor's costs based on operating conditions, utility rates, demand charges and other factors. The software then compares the cost, in kWh and dollars, of buying a new, more efficient motor versus rebuilding an existing one. The program even calculates the payback period for the new motor's cost premium, if any.

ChillerCheck is a sophisticated data-logging and analytical program. Larry Siegel, founder and president of Chillergy Systems LLC, an Atlanta-based application service provider, created the software. Seigel explains how the system works for Emory University:

ChillerCheck collects data from dozens of sensors on Emory's chillers. The data are then entered into a PDA by the technician who then hot-syncs the data to the Web site. We monitor water inlet and outlet temperatures and flow rates, refrigerant temperature and pressure, bearing performance and other factors, along with power consumption (volts and amperes for each phase on drive motors). The software calculates real-time efficiency for each chiller and compares it with guaranteed nameplate values. It then reports each unit's efficiency loss, if any, to the system operator at a central control station. When efficiency loss drops more than five percent from the nameplate rating--that's the action limit we recommendÑthe operator can switch chillers and dispatch a maintenance crew to the under performing unit.

Finally, and most important of all, a regularly scheduled maintenance program is essential to lowering energy consumption and cost. The DOE says that by effectively operating and maintaining existing systems, facilities can save 10 percent or more on energy.

Correct filter specification and servicing are important aspects of HVAC maintenance. In addition to providing clean air and protecting HVAC equipment, filters play a major role in minimizing energy consumption. The energy used is directly related to the resistance of the air passing through the filter. The lower the resistance, the lower the energy consumption.

Also, the cleanliness of evaporation and condenser coils can affect HVAC capacity, thus having a direct impact on energy efficiency and operating costs. A study completed by Pacific Gas & Electric indicates that the compressor efficiency of a 10-ton package unit can be improved 16 percent by cleaning. Regular checkups of refrigerant levels, belt drives, etc. assure the lowest operating costs.

Deidre D. Macklen is a marketing representative for Total Comfort Service Center. Contact Total Comfort at 803-772-4495 or www.totalcomfort.ac.