01 / Getting started
Gather the operating facts first.
Bruce is HeatSponge’s online engineering and proposal tool. It uses the information you enter to evaluate an economizer for a specific boiler and water circuit. You can start with a few core values, then improve the selection as project information becomes available.
- Boiler manufacturer, type, capacity, and fuel
- Flue-gas temperature at the proposed economizer inlet, especially at high fire
- Water inlet temperature, flow, and whether the water is deaerated
- Firing profile, annual operating hours, and available exhaust-system pressure
- Space, stack connection, and any emissions equipment in the gas path
Use measured conditions when possible. If a value is uncertain, identify it as an estimate and verify it before a final specification or purchase order.
02 / First selection
Enter the boiler and heat-sink essentials.
Select the boiler make or type and enter capacity in the units shown by the form. Boiler identification helps Bruce evaluate the allowable gas-side resistance; confirm the actual fan and stack limits for the installation.
Enter the temperature of the water that will pass through the economizer—not the boiler’s steam temperature. The available heat sink and water chemistry influence recovery and material selection.
Enter the gas temperature where the economizer will connect at 100% firing. Part-load temperatures can be supplied separately; the form can estimate them when those optional values are left blank.
Choose the requested location and temperature units so the selection and proposal are expressed in the intended convention.
03 / Annual performance
Make the operating profile representative.
The boiler rarely spends every hour at full fire. Enter annual hours at the firing rates that reflect actual plant operation. Where known, supply gas temperatures and excess-air values for each load condition; otherwise the tool uses its own part-load estimates.
Enter fuel price if you want an economic comparison. Identify flue-gas recirculation (FGR) and whether its takeoff is before or after the economizer, because the gas flow through the heat exchanger can change. For feedwater service, enter the applicable blowdown rate. These details affect estimated recovery and annual savings.
Review the total operating hours and the assumed load distribution before relying on a yearly savings figure. A correct high-fire design point alone does not describe annual fuel use.
04 / Application choices
Use optional selections when the project requires them.
For a standard feedwater economizer, the form can evaluate HeatSponge models using its selection logic. If an equipment family, stack diameter, material, fin spacing, or maximum water-side pressure drop is specified, enter those constraints so the proposal reflects the intended installation.
Use this when the water circuit does not follow the boiler’s feedwater flow—for example, make-up or process-water preheat. Enter the actual flow and verify that the water will be available while the boiler fires.
When a second water stream is available, enable the two-stage option and enter its inlet temperature and flow. Bruce can assess arrangements including split, stacked, or side-by-side designs. The cold-water duty and condensate path determine whether condensing recovery is appropriate.
Enter a required outlet temperature only when the project has a defined performance target. The tool can work within a selected model or consider a larger arrangement; feasibility depends on the available water heat sink and system limits.
Stainless tube overrides, fin selections, water-side pressure limits, fuel characteristics, and space constraints should match the actual service. Review any automatic material choice against water chemistry and the intended operating regime.
05 / Expert controls
Leave manual overrides to qualified reviewers.
The form also offers advanced controls for manual unit selection, gas-side backpressure, and flue-gas-flow overrides. These can be useful when working from verified test data or a defined boiler specification. They can also force a result outside the boiler’s fan capability or change the basis of the calculation.
If you bypass Bruce’s automatic selection, verify the boiler and burner data, flue-gas flow units, exhaust pressure available at every relevant load, and water-side hydraulics. A generated calculation or proposal is not, by itself, approval of a manually overridden installation.
06 / Before specifying
Read the output as a design proposal.
Check the selected model, design and part-load heat recovery, gas and water outlet temperatures, pressure drops, materials, and installation assumptions. Compare annual savings against the hours and fuel price you entered. Confirm that cold-water demand, minimum flow, condensate drainage, and service access are consistent with the proposed arrangement.
For unusual fuels, high particulate loading, tight fan margins, custom process-water circuits, or nonstandard code requirements, ask Boilerroom Equipment to review the application before finalizing the specification.