Cutting Heating Costs Energy-Saving Tips for Steam Customers

 As winter looms, property owners can cut costs and save on their heating bills  with preventive maintenance and upgrades to their steam systems. Here are some  suggestions for savings from Con Edison.  

 Optimize Steam Piping System

 One simple solution is installing insulation on distribution piping, valves, and  fittings. In most buildings piping is generally well insulated. However, some sites have  pipe runs, mechanical fittings, and valve bodies that are bare because of  access to fittings, valves, traps and unions, need for movement (such as at  valve bonnets) or because insulation was not restored after maintenance.  

 On valves and fittings removable insulation jackets provide a practical  solution. They are ordered to specific sizes and patterns, strap into place and  are easily removed and replaced. For stationary pipes, or areas that don’t need to be accessed, more permanent insulation may be installed. Overall  un-insulated components result in energy waste as it heats unoccupied basement  spaces.  

 Another way to save steam energy is repairing leaks, potentially the source of  significant waste. Leaks are most often found at pipe junctions, fittings, or in valves. The leaks  may be due to a leaking gasket or loose connection, or maybe, even a pinhole.  

 Efficiently Heat the Building

 For buildings with independent core and perimeter HVAC systems, lowering the  operating temperature of core units may also help lower bills. Engineers may  reduce core equipment temperature set points by a couple of degrees (say from  72-73°F to 70-71°F) from 6 a.m. to 11 a.m. These variations probably won’t be noticed by residents, and offer a reduction in peak and total energy usage.  

 Recycling heat in facilities with high temperature data centers may make use of  this rejected heat by allowing these continuous heat sources to discharge  heated air to the return plenums. Install programmable clock thermostats in  small, subleased spaces. These spaces include restaurants, professional offices  and other storefronts that operate independently from the main distribution  system(s).  

 Coordinating startup times and early morning settings of thermostats with the  operation of the main building zones can help to reduce peak demand on your  system. In some cases, another option may be to preheat these spaces before the  6 a.m. start of the peak steam period. Controlling and optimizing radiator use in buildings can also help eliminate  residents using the window as a thermostat and literally heating the city’s skyline.  

 One optimization tool is a Thermostatic Radiator Valve (TRV). TRV’s provide individual zoning control at the radiator level and as such even  within an apartment; the occupant can select and set different temperature set  points to meet individual comfort levels within each room. In buildings with  large southern exposure, installation of TRV’s just in the rooms with southern exposure will help minimize overheating and  help balance the building’s heating. For older radiators with poor or fragile valves, a recent alternative to TRV’s is a temperature-controlled radiator cover with built-in fan. The radiator  cover insulates the radiator, keeping in heat. A built-in fan cycles hot air  from the radiator when the room temperature falls below a set minimum  temperature. The heat that is unused by the room is then available for the rest  of the building.  

 Use Hot Water as Needed  

 Adding or adjusting domestic hot water (DHW) recirculation controls can also  lower bills. Rather than having DHW recirculation pumps run continuously to  circulate hot water through the pipes around buildings at 130-140° F, installing and setting a reverse-acting aquastat on the return line will  reduce the amount of energy used to provide hot water to offices or apartments.  Additionally, there will be some electrical savings by running the pumps less  frequently. For optimal results, the aquastat should be installed a few feet  upstream of the pump and set at 110° F, with the dead band set at +/-5° F, and wired into the domestic hot water circulation pump in the building,  according to a NYSERDA report on recirculation system controls.  

 Customers may also install high temperature DHW water storage tanks. High  temperature water storage tanks utilize steam during the overnight to heat  water to 180°F. During the peak period, the stored high temperature water is used as a feed for  domestic hot water production. The capacity of the high temperature water tanks should be sized to provide  coverage of your peak demand period.  

 Improve Heating Technology  

 In addition, a more sophisticated way to improve energy efficiency is by adding  a computerized building management system (a BMS—sometimes also referred to as EMS, or energy management system) for heating  system control and monitoring. With a BMS/EMS, it is possible to monitor and  trend operational data more easily. Savings from the installation of a  well-designed and maintained BMS/EMS will come from a number of areas including  the following:  

 • Personnel cost optimization—reduced time requirements for “rounds,” enabling personnel to respond to complaints and conduct other activities such  as maintenance  

 • Essential support to implementation of other demand response or energy  efficiency measures  

 • Greater control and ability to respond to occupant comfort complaints  

 • Reduction/elimination of overheating of spaces—reduction of system “lag” time  

 • Documentation of conditions for occupant complaint response/resolution  

 Adjusting air handler unit (AHU) schedules in an existing BMS/EMS may also help  to lower peak demand. In many facilities the AHU schedules in the BMS is set to  change operating mode to Startup or Occupied mode at or close to 6 a.m., the  beginning of the peak demand period. A recommended procedure is to start up only those air handling units early that  serve the spaces that get the coldest overnight. Starting up earlier all the air handlers, including those that serve spaces that  remain warm through the night, may not be justified due to a more significant  increase in electric charges.  

 Alternatively, if the air-handling units are already running, set point  temperatures should be raised to preheat the building prior to peak hours. At 6 a.m. and through 11 a.m. the set point can be reduced to normal, and demand  should be reduced, trimming costs. This would be a very low cost energy  efficiency measure to implement and it could be adjusted and refined quickly  through a BMS or other automated/time based control.  

 Charles J. Viemeister is section manager of steam business development for  Consolidated Edison Company of New York, Inc.  

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