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Modular Boiler Technical Bulletin: A Case Study

Geoffrey Bell, P.E., Lawrence Berkeley National Laboratory

Energy savings can be realized in the production of heating hot water by modularizing the boiler system. Equipment in modular or multiple boiler systems (MBS) are designed to operate singly or together to meet heating hot water loads. Overall benefits include:

  • Right-sizing boiler capacity to match variable load.
  • Providing redundancy to improve boiler maintenance and replacement.
  • Increasing flexibility for upgrading or expanding boiler capacity.
  • Eliminating standby energy waste.

In 1992 Lawrence Berkeley National Laboratory (LBNL) completed a simple energy-use study was completed of an older boiler system installation in its Energy, Environment, and Nuclear Science Laboratory (B70). This study indicated that a significant amount of B70's original boiler system's energy was being wasted through a variety of standby losses including air convection up boiler stacks, radiant through jacket insulation, and water convection through boiler hot water tanks. Consequently, a more thorough, detailed analysis was performed to more carefully estimate potential energy savings. Completed in 1993, this analysis provided justification for implementing a retrofit project to install LBNL's first modular boiler system. Right-sizing the MBS became an immediate design issue.

For LBNL's first MBS in B70, the standby losses of over 49,000 Therms per year were eliminated and the boiler conversion efficiency improvement reduced natural gas use by an additional 17,000 Therms per year for a total of more than 66,000 Therms per year.

MBSs have proven their ability to save energy and increase operational reliability in a wide spectrum of building types for many years. Use in laboratory facilities is especially appropriate due to highly variable loads, heating-capacity redundancy requirements, future flexibility needs, and energy use reductions.


Geoffrey Bell, P.E., is an energy engineer in the Environmental Energy Technology Division at Lawrence Berkeley National Laboratory (LBNL). He is credited with a number of publications, including serving as a principal author of the Design Guide for Energy Efficient Laboratories. This publication is intended to assist facility owners, architects, engineers, designers, facility managers, and utility energy-management specialists in identifying and applying advanced energy efficiency features in laboratory-type environments. Mr. Bell is a certified state energy auditor in New Mexico and a registered professional engineer in both New Mexico and California. He has served as an investigator for the U.S. Department of Energy, a teacher at the University of New Mexico, and an energy engineer contractor to Sandia Corporation in addition to various other mechanical engineering consulting positions. Mr. Bell received his Bachelor of Science in mechanical engineering from Newark College of Engineering and a Masters of Architecture in environmental design from the University of New Mexico.

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