No technology in process heating carries more simultaneous hype and prejudice than the industrial heat pump — pitched as the future of everything by one visitor and dismissed as a canteen gadget by the next. Both are wrong in ways arithmetic can settle. This lesson is the honest view: what COP really is, why it falls with temperature lift, and the ₹-per-1000-kcal crossover that says exactly where heat pumps win in India today — and where your husk boiler remains unbeatable.
COP: heat moved, not heat made
A heat pump does not convert electricity to heat — it uses electricity to move heat from a cooler place to a warmer one, refrigeration running backwards. Its COP (coefficient of performance) is kcal delivered per kcal of electricity: a COP of 3.5 delivers 3,010 kcal for every kWh (860 kcal). The physics tax is the lift — the temperature gap between source and delivery. A warm source close below a modest delivery temperature gives COPs of 4–6; a cold source far below a hot delivery drives COP toward 2 and the machine toward being an expensive resistance heater. Hence the honest engineer's first two questions to any heat-pump proposal: what is the source, and what is the lift?
The crossover arithmetic
Lesson B2 priced fuels; the heat pump joins the same table through one line:
₹ per 1000 kcal delivered = power tariff (₹/kWh) ÷ (COP × 0.86)
At ₹8/kWh and COP 3.5: 8 ÷ 3.01 ≈ ₹2.7 per 1000 kcal. Set that against B2's ladder: husk at ₹1.0 — the heat pump loses, today, against cheap biomass, and no amount of enthusiasm changes it. But against furnace oil at ₹5.5, PNG at ₹7.6, LPG at ₹9.4 — the heat pump wins by two to three times, before counting its side gifts. That is the honest Indian picture in one sentence: heat pumps compete with the fuel you burn, and India's cheapest process fuel is very cheap. The crossover moves with three sliders: the tariff (open access and solar keep pushing effective ₹/kWh down), the COP (source quality), and the displaced fuel. A dairy running LPG water heating with 30 °C effluent as a source is already deep inside the win zone; a husk-fired practice plant is not — yet.
Where they genuinely win — and the side gifts
The Indian sweet spot today: ≤90 °C hot water displacing oil, gas or electricity, with a warm waste source nearby — dairy and food plants (chilled-side condenser heat begging for a use), effluent streams, compressor cooling, humid dryer exhausts. There the machine often does double duty, and the accounting improves again: a heat pump recovering condenser heat is simultaneously your refrigeration plant, and its "waste" cold side may replace cooling-tower load. The technology frontier — high-temperature machines delivering 120–160 °C and small steam-generating heat pumps — is real and moving, but in 2026 India it is pilot territory: evaluate with F8's measurement discipline, not with brochures. The honest screen for any proposal: source temperature and availability · lift · tariff actually payable (with demand charges) · displaced fuel's B2 number · and the machine's COP at your conditions, not at the rating point.
- List your warm waste streams (anything 25–60 °C flowing to drain or tower) beside your ≤90 °C heat duties. Where the lists touch, run the crossover line.
- Do the ₹/1000 kcal sum with your real tariff and the vendor's COP at your source and delivery temperatures — demand the performance map, not the headline figure.
- Displacing biomass? Park the proposal politely and re-run it at every tariff revision — the sliders move yearly.
- Any pilot gets a meter on both sides (kWh in, kcal out) from day one — measured COP is the only COP (F8).
- A heat pump moves heat; COP = kcal delivered per kcal of electricity, and it falls as the lift grows.
- ₹/1000 kcal = tariff ÷ (COP × 0.86). At ₹8/kWh and COP 3.5 ≈ ₹2.7.
- Today's Indian verdict: beats oil, gas and LPG below ~90 °C with a warm source; loses to husk everywhere.
- Best cases do double duty — heating and cooling from one machine.
- Trust performance maps and site measurement, never the headline COP.
The heat pump's paternity is pure steam-age: Lord Kelvin proposed heat multiplication by reversed heat engines in 1852, and the first large working heat pump — Swiss engineer Heinrich Zoelly's patents and later the celebrated 1938 Zurich town-hall plant, drawing warmth from river water — ran while steam locomotives still ruled outside. The machine then waited eighty years for energy prices and carbon arithmetic to make it fashionable. Like the thermocompressor in lesson F5, it is a reminder that in energy engineering, the physics is usually ready long before the prices are.
FAQ
Are industrial heat pumps worth it in India?
Against oil, gas or LPG below about 90 °C, with a warm waste source nearby — yes, often by two to three times on running cost. Against cheap biomass — not yet: at ₹8/kWh and COP 3.5 a heat pump delivers heat at about ₹2.7 per 1000 kcal, while husk sits near ₹1.0. The machine competes with the fuel you burn, and India's cheapest process fuel is very cheap.
What COP should I expect from a heat pump?
It depends almost entirely on the lift — the temperature gap between your source and your delivery. A warm source close below a modest delivery gives 4–6; a cold source far below a hot delivery drives COP toward 2, where the machine approaches an expensive resistance heater. Demand the vendor's performance map at your temperatures, never the headline rating-point figure.
Can a heat pump replace my steam boiler?
What makes a heat-pump project unusually attractive?
Double duty. A machine recovering refrigeration condenser heat is simultaneously your chiller — its "waste" cold side can replace cooling-tower load, so one machine earns twice. Dairy and food plants, effluent streams, compressor cooling and humid dryer exhausts are the classic Indian sources where the lists of warm waste and ≤90 °C duties touch.
How do I compare a heat pump against my current fuel?
One line: ₹ per 1000 kcal delivered = tariff (₹/kWh) ÷ (COP × 0.86). Put that number on the same fuel ladder as B2's ₹/1000 kcal figures and read off the verdict. Re-run it at every tariff revision — the sliders (tariff, COP, displaced fuel) move yearly, so a losing case can quietly become a winning one.
Check yourself
Five quick questions on this lesson. No marks, no records — the score is for you.