Integrate or Upgrade?
Tips to help you know when and how to make that decision.
Upgrading or integrating an existing building automation system is no small undertaking. It requires a major commitment on the part of the entire organization in terms of time, resources and understanding. There are plenty of reasons to upgrade an older system. Increase operating efficiency, improved maintenance operations, enhanced occupant comfort and reduced overall operating costs.
There are equally important benefits to integrate older building automation systems. Today’s systems provide more capabilities at lower costs, more efficiency and remote access via the WEB. Most systems can tie together facility operations that older systems only address independently. Integrating your older existing system provides a migration path to adhere to the new industry standard open protocols. As a result, facility executives are faced with important decisions as the existing components are either obsolete or too expensive to replace. Given that each system is unique, a systems analysis should be completed. Control Solutions Inc, staff has extensive experience in systems upgrades and integrations, and is available to partner with you to develop a customized solution for your organization.
DDC vs. conventional pneumatic controls
Sold-state sensors and controllers used in DDC systems have considerable energy-efficiency advantages over conventional pneumatic systems. Substantial advantages are realized in calibration and maintenance, but the critical value lies in the accuracy and reliability of the DDC systems. These features can yield operational energy savings of 15% and greater when compared to the conventional pneumatic system. The inherently precise positioning of valves and dampers with EMCS control loops and blocks are responsible for these energy savings. For instance, to realize the energy-savings opportunity offered by VAV fume hoods, an 8:1 turndown ratio of the exhaust air flow is required. Pneumatic airflow systems typically lose accuracy at 25% of their span, resulting in the capability of only a 4:1 turndown ratio. Solid-state DDC systems provide the degree of precise air-flow measurement and control that enables the operation of these VAV systems.
DDC systems can accurately modulate VAV boxes, control dampers, valves and other mechanical equipment with electronic operators. However, pneumatic operators are still used for certain components in air-handling systems. When a large amount of torque is required to position large air-handling unit dampers and control valves, cost-effective, reliable electronic operators may not be available. Control air systems give the system designer the option of using the combined powerful control capabilities of a DDC system with inexpensive, reliably operating conventional pneumatic valve and damper control systems. [Ruys, 1990]
Reducing Energy Use
Building owners have a number of ways to creatively address rising costs and environmental concerns. One option is to conduct an energy audit to find ways to increase efficiency. In the auditing process, energy meters collect energy usage data for a period of time, typically 30 to 90 days. After this collection period, the data is analyzed and used to identify sources of energy waste. Building owners can use this information to adapt to more efficient usage patterns. Additionally, usage data can be compared to time-of-use costing data from the local utility provider. Utilities charge more for power at peak usage times. Building owners can choose to modify their practices to reduce their electricity usage at these peak times. After a formal energy audit, many building owners choose to have energy meters permanently installed in their facility to routinely monitor and adapt their power usage practices.
“To manage your energy, you have to be diligent and monitor your energy usage. Using the monitored data to make intelligent decisions can save time and money,” states Cheryl Kennedy, member of the Cascadia Regional chapter of the US Green Building Council and product manager at Veris Industries, Portland, OR.
Additionally, a smart BAS control design can address both rising energy costs and increasing awareness of the threats to our natural resources. Studies have shown that a well-operated control system can reduce energy use by 15 to 20%, lowering the energy bill and the carbon footprint for the building.
Environmental sensors are an integral component of a smart BAS control system. Sensors provide valuable real-time information about interior conditions, enabling the best decisions regarding the use of energy with respect to the immediate needs of the building. For example, an occupied building will accumulate CO2, which can lead to drops in productivity. Typical comfortable CO2 levels in commercial spaces are approximately 600 ppm. Running the ventilation system will maintain this level, but continuously running the fans and conditioning the outside air for interior comfort are costly. Incorporating CO2 sensors into the BAS design will trigger the ventilation controls to activate only when levels are high (usually above 1000 ppm), in much the same manner as a thermostat triggers temperature controls only when they are needed. Humidity sensors work similarly to maintain comfortable interior moisture levels. The sensors also use control algorithms that use interior measurements to determine whether to draw in air from outside the building and condition it for interior comfort, or to recirculate interior air.
Temperature, humidity and CO2 level are the three most important criteria for measuring interior comfort. Inefficient operation of a BAS system with regard to comfort levels consumes excess energy, which raises the building’s utility bill and enlarges the carbon footprint. In recent years, BAS designers have been integrating the monitoring systems for all environmental comfort criteria into a single network. All data is sent to a central control system, which then makes decisions about how to balance the building’s comfort needs with energy-efficient practices. Buildings that use this integrated, whole-building approach to monitoring are known as “intelligent buildings.” (Sarah Romero, Veris Industries)
Helping you achieve your energy management goals
Tips & Strategies taken from Xcel Energy Resource Library
Making sure that your HVAC system is regularly cleaned and serviced can help to prevent costly heating and cooling bills.
Check the economizer. Many air-conditioning systems use a dampered vent called an economizer that draws in cool outside air when it is available to reduce the need for mechanically cooled air. If not regularly checked, the linkage on the damper can seize up or break. An economizer stuck in the fully open position can add as much as 50 percent to a building's annual energy bill by allowing hot air in during the air-conditioning season and cold air in during the heating season.
Have a licensed technician check, clean, and lubricate your economizer about once a year, and repair it if necessary. If the economizer is still operating, have the technician clean and lubricate the linkage and calibrate the controls. Check air-conditioning temperatures. With a thermometer, check the temperature of the return air going to your air conditioner and then check the temperature of the air coming out of the register that is nearest the air-conditioning unit. If the temperature difference is less than 14° Fahrenheit (F) or more than 22°F, have a licensed technician inspect your air-conditioning unit.
Change the filters. Filters should be changed on a monthly basis, or more often if you are located next to a highway, construction site, or other place where the air is dirtier than usual.
Check the cabinet panels. On a quarterly basis, make sure the panels to your rooftop air-conditioning unit are fully attached, with all screws in place and all gaskets intact so that no air leaks out of the cabinet. Chilled air leaking out can cost $100 per rooftop unit per year in wasted energy.
Clean the condenser coils. Check the condenser coils quarterly for either man-made or natural debris that can collect in them. At the beginning and end of the cooling season, thoroughly wash the coils.