The Elements Of An Successful HVAC Program



Today's systems are designed to meet stricter environmental, indoor quality of air and consumer requirements. Lots of the gains in HVAC system efficiency have come as the effect of advancements in the operating efficiency of key products. Various other gains are the consequence of the use of solutions that are either new, or new to the HVAC field. Even the use of computer-aided design tools have helped system engineers design HVAC systems that perform more skillfully.

Although there are many individual advances which may have helped to improve HVAC system operating efficiency, most of the overall improvement can be attributed to five key factors:

For years, building owners were satisfied with the performance and efficiencies of chillers that operated in the range of 0. 8 to 0. 9 kW/ton when new. As they grow older, actual operating efficiencies land to more than one particular. 0 kW/ton at full load.

Today, new chillers are being installed with full load-rated efficiencies of 0. 50 kW/ton, a near 50 % increase. Evenly impressive will be the part-load efficiencies of the new hvac near me of chillers. Although the operating efficiency of practically all older chillers quickly falls off with reduced load, the operating efficiency of new chillers will not drop off practically as quickly.

Chiller design changes

Several design and procedure changes have helped improve chiller performance. To increase the heat transfer characteristics of the chillers, manufacturers have increased the dimensions of the units' heat exchangers. Electromechanical control systems have been changed by microprocessor-based electronic settings that provide greater accuracy, reliability and flexibility. Adjustable frequency drives control the speed of the converter, resulting in a climb in part-load performance.

Elevated energy efficiency is not the sole benefit for the new generation of building chillers; these chillers offer better refrigerant containment. Though older chillers routinely may have lost 10 percent to fifteen percent of the refrigerant charge every year, new chillers can limit losses to less than 0. 5 percent. Lower leak rates and better purge systems reduce the amount of non-condensable emissions found in the refrigerant system -- the factor in maintaining chiller performance over time.

Another significant development is in furnace operation: the replacement of pneumatic and manual handles with microprocessor-based systems. Since a rule of thumb, the systems can be expected to achieve energy savings of 5 percent to 7 percent over conventional pneumatic-based systems.

Microprocessor-based control systems achieve their savings mostly as the result of their potential to modulate the boiler's procedure more accurately than pneumatic-based systems. By modulating the boiler's procedure effectively, the systems help to keep up with the proper fuel-to-air percentage and track the fill put on the furnace by the HVAC system.

Microprocessor-based systems offer several additional advantages, including distant monitoring and operating functions, automated control sequences, monitoring of steam flow, and reduced maintenance costs. A single way the systems can help reduce maintenance costs is through their capacity to maintain proper fuel-to-air ratio. By maintaining the proper ratio, the systems reduce the rate from which soot collects on furnace tubes, thus decreasing the frequency of required eliminate and cleaning. Keeping the boiler tubes clean of soot also helps to increase the thermal efficiency of the boiler.

Direct digital controls

A significant change in the HVAC field is the widespread implementation of direct digital controls (DDC). Introduced more than 12-15 years ago, DDC systems have end up being the industry standard for control systems design today. Having the ability to provide accurate and precise control of temp and air and drinking water flows, the systems have widely replaced pneumatic and electric control systems.

DDC systems help building owners save energy in a number of ways. Their accuracy and finely-detailed practically eliminate the control problems of offset, overshoot, and hunting commonly present in pneumatic systems, resulting in better regulation of the system. Their ability to respond to a pretty much unlimited range of receptors ends in better coordinated control activities. This also allows the systems to perform more complex control strategies than could be performed with pneumatic controls. Finally, their simple or programmed calibration ensures that the control systems will perform as designed over time, with little or no loss of accuracy.

DDC systems also offer several other advantages. Because the control strategies are software-based, the systems can be easily modified to match within occupant requirements without costly hardware changes. DDC systems also are well suited for applications that benefit from remote monitoring and procedure.