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Plant Engineering Calculator

Updated Sep 18, 2026

Chiller Condenser Water Reset Savings Calculator — Lift, kW & Annual Energy

Screen chiller compressor savings from lowering entering condenser-water temperature using measured baseline power and a site-validated percent-per-degree response.

Live calculationWorking shownPrivate in browser

Inputs

Results

Power saved 8.00 kW
New chiller power 392.00 kW
Annual energy saved 40000 kWh
Annual value $4000
More actions

Shared links reopen these inputs. Recent and saved calculations stay in this browser unless you clear site data.

Formula

saved kW=Pbase×ΔT×saving factor.

Your calculation, step by step

These steps use the values currently entered above so the result can be checked independently.

  1. 1.Linear saving fraction = 2.000 °C × 1.000%/°C ÷ 100 = 0.02000.
  2. 2.Compressor power saved = 400.00 × 0.02000 = 8.000 kW.
  3. 3.Screened new chiller power = 400.00 − 8.000 = 392.000 kW.
  4. 4.Annual energy saved = 8.000 × 5000 = 40000.0 kWh; value = $4000.00.

How to use this calculator

  1. Enter measured or design values using the units shown beside each field.
  2. Review the live results and the substituted calculation steps before using the estimate.
  3. Check the assumptions below, then continue to a related calculator when the next engineering decision needs another model.

Worked example

A 400 kW chiller with a validated 1%/°C response and 2°C reset screens at 8 kW compressor savings.

Assumptions and limits

  • Tower fan/pump penalties must be evaluated separately; lower condenser-water temperature is not automatically lower total plant kW.
  • Respect OEM minimum condenser-water temperature and lift limits.
  • Treat the percent-per-degree factor as a local/site-validated response, not a universal linear law over large resets.

How to interpret the result

Treat the primary result as an engineering screening value, then use the secondary outputs to understand scale, energy or operating impact. Confirm site measurements, equipment limits and applicable standards before making a design or control change.

Questions engineers ask

Why is the savings factor entered instead of hard-coded?

Chiller response to entering condenser-water temperature depends on machine type, loading and lift. ASHRAE describes meaningful compressor savings from colder condenser water, but the plant should use a site-validated or OEM-derived percent-per-degree response for this screening calculation.

Can lowering condenser-water temperature always save total plant energy?

No. Colder condenser water reduces chiller lift but may require higher cooling-tower fan power or different pump operation. The compressor saving shown here must be compared with tower and pumping penalties to find the plant optimum.

Why reject a reset that mathematically saves more than baseline chiller power?

The linear percent-per-degree model is only a local screening relationship. If ΔT × saving factor reaches or exceeds 100%, the extrapolation is physically meaningless and indicates the entered factor/reset is outside its defensible range.

Continue the calculation

Use the next calculator in the same engineering workflow instead of restarting from search.

chiller liftchiller kw per toncooling tower fan power savings
Methodology. MAXScanner shows the governing formula, entered values and calculation outputs so the estimate is auditable. The calculator is a screening aid; assumptions and equipment-specific limits remain part of the engineering review.