About

Facility managers and utility engineers often need to convert the mass of a heating medium into billable energy units. While Gigacalories (Gcal) remain a standard in many district heating networks, modern systems typically interface with Gigajoules (GJ) or Megawatt-hours (MWh). Accuracy here determines the validity of utility bills and efficiency reports.

For water, the energy depends on the specific heat capacity and the temperature drop (Δt). For steam, mass alone is insufficient; pressure determines the specific enthalpy (heat content). This tool approximates saturated steam enthalpy to provide quick load estimations without consulting complex thermodynamic tables.

Formulas

For Hot Water, the formula utilizes the specific heat capacity (c):

Q = m × c × (t_in − t_out) × 10^-3

For Steam, we use enthalpy (h):

Q = m × (h_steam − h_condensate) × 10^-3

Reference Data

Medium	Parameter	Value / Approximation	Energy Factor (Gcal/ton)
Water	ΔT = 1°C	c_p ≈ 1 kcal/kg°C	0.0010
Water	ΔT = 50°C	District Heating Return	0.0500
Steam	Low Pressure (2 bar)	h ≈ 646 kcal/kg	0.6460
Steam	Med Pressure (6 bar)	h ≈ 659 kcal/kg	0.6590
Steam	High Pressure (10 bar)	h ≈ 663 kcal/kg	0.6630
Steam	Process (20 bar)	h ≈ 668 kcal/kg	0.6680
Condensate	Boiling @ 100°C	h_f ≈ 100 kcal/kg	0.1000

Frequently Asked Questions

1 Gcal is approximately equal to 4.1868 GJ (Gigajoules). This factor is derived from the definition of the calorie (4.1868 Joules).

Thermal energy is not contained in the water's mass itself, but in the heat it releases as it cools. The energy delivered is proportional to the temperature drop (Delta T). If water enters at 90°C and leaves at 90°C, zero energy was transferred.

Yes, the Steam mode approximates the specific enthalpy of saturated steam at the selected pressure, assuming full condensation (latent heat release) unless a specific condensate temperature is defined.

Not exactly. It varies slightly with temperature, but for most industrial heating applications (Calculations under 150°C), assuming c = 1.0 kcal/(kg·°C) provides sufficient accuracy for load estimation.