GIFSQ Tools · Module 17 — Food Processing, Thermal Engineering & Utilities · Tool 334 of 500
Work out how much steam a heating duty needs, from the duty, the latent heat of the steam and the operating hours.
Try sample values — fills the form with the worked example below.
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Steam rate (kg/h)
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Steam total (kg)
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Steam per kWh (kg/kWh)
Equation: Steam rate (kg/h) = duty (kW) × 3600 ÷ latent heat (kJ/kg); total = rate × hours; steam per kWh = 3600 ÷ latent heat.
Method: Steam balance from the latent heat of vaporisation, standard boiler and process engineering practice; latent heat at 100 °C is 2257 kJ/kg from the steam tables.
Assumptions: saturated steam condensing fully with no sub-cooling; condensate leaves at saturation temperature; no steam losses or flash losses.
Limitations: latent heat falls as steam pressure rises (2202 kJ/kg at 150 °C, 2086 at 200 °C) — enter the value for your steam pressure from the steam tables.
Rounding: steam rate and total to 1 decimal place, steam per kWh to 3; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Method: Steam balance from the latent heat of vaporisation, standard boiler and process engineering practice; latent heat at 100 °C is 2257 kJ/kg from the steam tables.
Assumptions: saturated steam condensing fully with no sub-cooling; condensate leaves at saturation temperature; no steam losses or flash losses.
Limitations: latent heat falls as steam pressure rises (2202 kJ/kg at 150 °C, 2086 at 200 °C) — enter the value for your steam pressure from the steam tables.
Rounding: steam rate and total to 1 decimal place, steam per kWh to 3; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Worked example: A 500 kW duty with steam at 2257 kJ/kg for 8 h: steam rate = 797.5 kg/h, total = 6380.2 kg.
Enter values above to see results.
Latent heat: 2257 kJ/kg at 100 °C (atmospheric), 2202 at 150 °C, 2133 at 175 °C, 2086 at 200 °C. Tool 334 of 500 — GIFSQ
