Boiler plant retrofit: project background
At one of our customer’s locations, Arvin Air Systems identified an opportunity to retrofit the boiler plant, comprised of four atmospheric boilers, with 83% fuel efficiency and intermittent pumping, to a highly efficient boiler plant – with the objective of reducing energy consumption and carbon footprint.
Three connected system changes
The boiler plant retrofit addressed the piping arrangement, boiler equipment and operating controls together.
To achieve this, several system design changes were required:
- The piping layout was modified to a variable primary / secondary loop, whereupon a low loss header was installed to separate the loops.
- Three high efficiency boilers were installed to replace the four low efficiency boilers. They are 96% fuel efficient, with variable speed pumps on the primary loop to maintain a constant temperature difference, and variable frequency drives on the secondary loop pumps maintain water flow to the minimum required. Controls were added to automate the operation of the entire heating system.
Reported project outcome
The original project account reported a 36% yearly reduction in gas consumption after commissioning. In addition to the yearly energy savings, Arvin Air Systems, representing the customer, applied for a rebate with the local utility company resulting in a historical cash rebate totaling 8% of the project cost. That project-specific rebate does not establish current incentive availability or eligibility.
This is an example of how the highly skilled Arvin Air technicians and engineers identified a cost saving opportunity for the maintenance agreement client. Arvin Air incorporates a continuous improvement plan for all preventative maintenance customers.
The figures above are the results reported for this individual project. They are not a prediction or guarantee for another building. Equipment condition, operating hours, heating demand, control sequences and the basis used to compare energy consumption can all affect the result.
What facility owners can learn from this boiler plant retrofit
A boiler replacement is also an opportunity to review how the heating plant works as a system. New equipment must operate with the building’s piping, pumps, controls and distribution. Replacing the boilers alone does not explain how heat will reach the spaces or processes that need it. This project illustrates why those interfaces belong in the scope from the beginning.
The existing installation used intermittent pumping. The published project account describes changes to the piping arrangement, variable-speed pumping and automated controls alongside the new boilers. For another facility, the appropriate combination of changes would need to follow a site assessment rather than copying this equipment arrangement.
Questions to ask before selecting replacement equipment
- What is the operating problem? Record recurring faults, comfort complaints, maintenance concerns and any changes in building use. Distinguish equipment reliability issues from control or distribution problems.
- How does the existing plant operate? Gather available drawings, equipment schedules and control sequences. Review how boilers and pumps respond as heating demand changes, including during periods of lower demand.
- What will be included in the scope? Clarify piping modifications, controls integration, commissioning, maintenance access and the handover information that operators will receive.
- How will performance be assessed? Agree on the baseline, records and comparison method before using energy savings as a project objective. Changes in weather, operating hours or production may need to be considered.
Related engineering, controls and maintenance services
Arvin Air’s HVAC engineering and design-build approach starts with the existing installation and the facility’s operating needs. Our DDC controls and building automation work addresses the sequences that coordinate mechanical equipment. For ongoing equipment care, review our service and maintenance agreements.
Our HVAC energy management page explains why operating schedules, setpoints and available energy records matter when assessing an existing building. To discuss a particular boiler plant retrofit, contact Arvin Air Systems with the equipment details and issues you would like reviewed.
For broader HVAC design references, consult ASHRAE standards and guidelines. The requirements and design choices for a particular boiler installation depend on its application and location; this project account is not a substitute for a site-specific engineering review.
