How big a heat pump for your process?

How this is worked out

• Every application here is one of three duty shapes — a batch to heat inside a time, a stream to raise continuously, or a temperature to hold against losses. That is why one calculator can cover a plating line and a dyehouse without pretending they are the same thing: the words change, the physics does not.
• Sensible heat = litres × density × specific heat × temperature rise ÷ 3600. A batch duty is a rate: the same volume in half the time needs twice the kilowatts.
• A jacketed vessel is not sized on energy over time. The driving difference shrinks as the batch warms, so the correct result is UA = (M·cp ÷ t) × ln((Tj−T1)/(Tj−T2)). Two things follow that a kilowatt figure hides completely: as the jacket water approaches the target the logarithm runs away and no area is enough; and raising the jacket water buys far more than enlarging the jacket, because temperature acts inside the logarithm and area does not.
• Open tanks lose most of their heat as evaporation, not through the shell. The model is the one validated in our swimming pool calculator: evaporation from the coefficient 25 + 19v kg/m²h against the humidity difference, convection at (3.1 + 4.1v) W/m²K, radiation at emissivity 0.95. It is why floating balls or a lid change a plating line's bill so much.
• Recovery is worth more than it looks. It cuts the rise at the cold end, where the machine is most efficient, so it shrinks the duty and improves the COP at the same time.
• The SE-HT range is published at 20 °C ambient, with the outlet temperature varying — 60, 70 and 80 °C. So this calculator interpolates on process temperature, and the figures assume a 20 °C plant room. Cold outside air will reduce output; that correction is not in the published data, so it is not guessed at here. Ask us for the ambient correction on a specific site.
• Process temperature is the biggest lever on the bill. Across the SE-HT range COP falls from about 4.1 at 60 °C to about 2.7 at 80 °C — a third of the running cost. If the process will accept less, that is the cheapest change available.
• Above 80 °C the SE-HT range stops, and you get two answers instead of one. The first re-sizes the SE-HT as a pre-heater feeding a tank, with your existing boiler taking the last stretch — usually most of the energy moved off fuel, for the easiest retrofit there is. The second sizes a machine that takes the whole lift and removes the boiler altogether, against the same duty, so the two can be compared on one screen.
• The high-temperature ranges are selected on the SOURCE, not on the water. SE-HT publishes capacity against outlet temperature at a fixed 20 °C plant room. None of the three ranges above it does: SE-SHT and the SE-UHT cascade both publish against ambient air at a fixed outlet, so the section asks for a site design temperature; the single-cycle SE-WWUHT publishes one rated point, at 60 / 55 °C into the evaporator, so it is selected on duty at that condition and nowhere else. There is no source-temperature curve for it, and this page does not invent one.
• The single cycle has a hard floor, not a derating. Its R245fa compressor window starts at 22 °C evaporating. Feed the evaporator below roughly 27 °C and the machine is outside its permitted envelope entirely — so the page withdraws the selection rather than quoting a reduced one, and sends you to the cascade, which needs nothing warm from the site.
• Defaults are indicative starting figures for each application, not Sunniva product data. They are all sliders, and the saved sheet records exactly what was used.
• Payback is simple payback — the price you type in, divided by the annual saving. No finance, no maintenance, no discounting, and no price of ours is assumed or disclosed. Carbon is the displaced fuel’s emissions minus the electricity the heat pump draws, at the Indian grid average of 0.71 kg CO₂ per unit. Every factor is a slider, and the saved sheet records what was used.
• Indicative only. Process detail, schedule, pipe runs and water quality all affect the final design — confirm with Sunniva Encon LLP before ordering.