District Energy & Thermal Network Equipment worked example

Thermal Storage Size with usable storage discharge capacity of 6 kW: a worked example

Here is what the math looks like when conditions slip. We hold every other input steady and drop usable storage discharge capacity to 6 kW, then walk the calculation through step by step. Estimate usable thermal storage energy for chilled-water, hot-water, or stratified tank systems and the value of discharged storage during a peak period.

The inputs for this scenario

  • Usable storage discharge capacity: 6 kW (the input this scenario stresses; the baseline uses 12)
  • Storage discharge duration: 8 hr (held at the documented default)
  • Stored energy value: 0.12 $ / kWh (held at the documented default)
  • Storage volume or number of tanks: 1,000 m³, gal, or tanks (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Usable thermal storage energy = usable storage discharge capacity × storage discharge duration.
  • Usable thermal storage energy works out to 48 kWh at these inputs, and this is the headline figure for the scenario.
  • Value of usable stored energy works out to 5.76 $ at these inputs.
  • Stored energy value per volume or tank works out to 0.01 $ / piece at these inputs.
  • Hourly storage discharge value works out to 0.72 $ / hr at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where usable storage discharge capacity sits at 12 kW and the headline result is 96 kWh, this scenario comes in 50% below the baseline at 48 kWh.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to usable storage discharge capacity, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. It assumes constant discharge over the full duration and ignores standing losses, stratification decay and charge/discharge efficiency, so real delivered energy is somewhat lower.

Results at a glance

  • Usable thermal storage energy: 48 kWh (headline result)
  • Value of usable stored energy: 5.76 $
  • Stored energy value per volume or tank: 0.01 $ / piece
  • Hourly storage discharge value: 0.72 $ / hr

Run it with your numbers

  • To rerun this with your own numbers, open the live Thermal Storage Size calculator, set usable storage discharge capacity to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.