Make tenant infills pay their own way with energy savings

Most office buildings have a base building system that provides ventilation air to the space and perimeter heating to warm the cold exterior walls in the winter. Often the perimeter heating is simply finned piping in covers with hot water running through it. The base building pumps hot water through the fin-tube when it is cold outside and shuts off the flow when it gets warm. Unfortunately there is nothing stopping the base building from heating while the tenant is cooling. The tenant can have any number of supplemental AC units installed at their own expense and under their own control. These are used in conference, meeting and boardrooms and telephone/data closets. If the base building heating is activated by mistake while the tenant is cooling the boardroom for a meeting, this extra cooling costs the tenant a dollar for every dollar they are paying for the unneeded heating - a double whammy, courtesy of the HVAC system. One solution is to request access to the central building management system (BMS) from the tenant's local control panel and set a visual alarm at the BMS workstation to indicate when tenant cooling and building heating are happening simultaneously. Alternatively, signals indicating tenant cooling can be sent to the base building BMS and an alarm generated there. Many leases include monitoring tenant energy use for subsequent payment by the tenant. But this "monitoring" may be for the entire floor, or several floors, and does little to help the tenant control energy costs. For example, if a time clock controlling light fixtures malfunctions and lights a portion of a floor all night for a month, this may not be immediately noticed in a bill. The solution is to sub-meter each floor, or each panel, through the tenant's BMS and notify the tenant if energy use suddenly increases. This fixes the problem after a few days of wasted energy instead of a few months. The same thing applies to tenant-installed supplementary cooling units (AC units). If all of these units are powered from a single panel it is easy to monitor their load and see the energy spike that occurs if they run during a three-day weekend when they are supposed to be off. A telltale spike in winter plug loads means plug-in electric heaters under desks. While portable heaters are not the end of the world, they can be safety hazards as well as energy wasters. Increasing the central temperature can help the less efficient heaters go away. Automatic lighting controls save power in perimeter lights by turning them down when the sun shines. The energy-smart tenant uses motion sensors to control lights in restrooms, storerooms, pantries and service areas, as well as open plan work areas. If manual switches are used, a master switch at the exit of the office allows the last person to shut off all lights with a single action (except safety exit lights). Cleaning staff should not leave lights on; after the room is cleaned the light goes off. Some base building systems provide potable hot water and some provide cold water and require the tenants to heat their own. If the tenant can get a lower cost lease in return for using cold water and heating it at the point of use they are better off financially (especially if their hot water cools over long piping runs). Designs that wrap piping in electric "heat trace" are energy hogs that cost money 7x24 for no good reason. The best approach is to keep the water cold until it needs to be hot. These ideas should be included in the design services RFP and discussed with the design team at the start of the project. They will clarify these ideas and, getting the message that the tenant is committed to an energy-smart design, will develop more ideas of their own. Finally, don't forget to hire a commissioning authority to test and verify the correct operation of these energy savers, the training of the Operations & Maintenance staff and the completeness of the O&M documentation. Ron Wilkinson, PE, LEED AP, is LEED commissioning project manager for AKF Group LLC, New York, N.Y.