Saving Energy in On-Air Studios
February 01, 2006
Appeared in Broadcast Engineering
Every building manager, especially in the broadcast industry — and particularly in post-production — is continuously on the lookout for new ways to cut energy costs. With energy prices being what they are right now, assessing the energy efficiency of a facility makes good business sense. Given the fact that utility bills for on-air studios and support facilities can easily reach thousands of dollars per month, saving even a few hours of HVAC and lighting per day translates into substantial annualized savings. These savings can help avoid budget cuts in other more painful areas.
The process of analyzing potential energy savings can be disarmingly simple, even if the means to realize those savings are not usually as straightforward. Monthly energy costs can be determined by the following formula: (consumption kWh/day) × (hours of operation per day) × (365 days/year) × (1year/12months) × (cost $/kWh).
Next, determine the energy savings that could be achievable by reducing the use of HVAC and lighting. Based on the above equation, the energy savings can be obtained by replacing the hours of operation by the number of hours that can be saved by turning the HVAC and electrical systems down.
Cutting down HVAC costs
The biggest culprit for high-energy costs in a studio setting will always be the HVAC system. This holds particularly true for older facilities that do not have energy saving features or means, such as a variable air volume (VAV) system, direct digital control (DDC), heat recovery units, etc. Thus, these older facilities have to rely on a constant volume system and manually regulate studio temperature during the various production stages.
Given the fact that the average one-hour live-audience show requires up to four hours of preparation time, it's easy to see how converting a constant volume HVAC system to a VAV system could significantly cut down on energy use, depending on the size of the facility and the capacity of the HVAC system.
Implementing automation, such as DDC, can also play a major role in maximizing energy savings. Such an automated system allows the user to properly plan and control the space temperature in addition to the lighting.
That could be easily achieved via a control integration system. Control integration may include HVAC, lighting, security and other building systems. Overall, studio managers could save between 15 percent and 20 percent on utility costs, depending on usage.
There are three main ways to make a studio more energy efficient. The least expensive way is taking an already existing HVAC system and turning it into a VAV system.
The next best option for energy savings involves the installation of heat-recovery units that allow a facility to recover some of the energy that is being released back into the atmosphere in order to comply with code requirements. The air that is being exchanged for outside air is usually low temperature and large quantity air. Putting this air through an air-to-air heat exchanger, heat pipe or enthalpy wheel presents a cost-conscious alternative to using compressors and chillers to bring the hot outside air temperature down to the desired room temperature.
The costs of such a retrofit are low to moderate, depending on the type of facility, age of equipment and space availability. From a logistical point of view, such an undertaking entails converting existing systems and installing variable frequency drives, controls and a heat recovery wheel.
The third, but admittedly most capital-intensive method of saving energy, involves the installation of a cogeneration plant. Cogeneration by definition is the simultaneous generation of electricity and use of waste heat to drive a chiller and/or boiler that provides cooling and heating to a building.
Historically, it has been employed to generate energy for large-scale applications, such as industrial complexes, college campuses and hospitals, where there is considerable electricity usage. Today's changing economy and technology advances now make it a viable alternative solution for many other uses. An example of a small-scale cogeneration application is generating electricity on-site in a building to supplement utility-supplied power while also providing chilled water, heating hot water or domestic hot water for the building's domestic use.
An added benefit is the fact that several states, including New York and California, and many utility companies nationwide offer some financial incentives to install cogeneration facilities. However, for broadcast facilities, this tends to be the least-favored energy saving approach. The reason may be that studios mostly operate within leased spaces and thus tend to refrain from high-end, long-term investments.
Reducing lighting costs
Studios will typically use up to 75W/sq ft for lighting. Compare that to 1.5W/sq ft for the average office building, and it is clear that cutting down on even two operating hours of full lighting time can have a substantial impact on energy cost.
Automating lighting systems, changing light controls and adding different lighting options are all extremely effective means to significantly cut energy costs. For instance, installing adequate maintenance fluorescent lighting for use during preparation for a show will result in energy reduction by keeping the high-wattage studio lights off until the commencement of the actual show or taping.
In many studio designs, installing house light fluorescent fixtures with energy-efficient lamps help cut energy costs. The fluorescent lighting can be used during tasks that don't require spotlight level, such as pre- and post-work.
In other cases, complex dimmer systems are a viable option, with up to 60 circuits that would allow a studio operator to switch to many different lighting configurations.
Education is key
Proper use of automated control systems will allow lighting and HVAC use to be carefully scheduled, ensuring the entire studio isn't turned on during pre-production or the space is cooled for full-house use when only a handful of employees are working and that the spotlights are off.
But as is always the case with technological innovations, reaping the full benefits requires that these systems be used properly. All too often, facilities fail to realize the level of savings they expected due to lack of proper training. Staff must be educated on the systems in place and possess the discipline necessary to ensure the system functions at its optimal potential. Not only is initial training required, but also follow-up training sessions are necessary to refresh facility personnel.
Charbel Farah, P.E., is associate partner in the Los Angeles office of Syska Hennessy Group, a consulting, engineering, technology and construction firm that provides technical solutions in such areas as building system design, facilities management, energy management, technology consulting/engineering and turnkey design/build services.