An 800 kW heat pump at an API plant, tied in outside the classified perimeter

An Indian manufacturer of active pharmaceutical ingredients moved its low-temperature process heat onto an 800 kW Tetra Heat Pump installation, sited outside the classified perimeter so that no qualified utility was modified. The system holds supply temperature to ±0.5°C, the energy saving on the converted load is 70%, and the change avoids 300 tonnes of CO2 a year. Sterilisation in place and autoclaving at 121 to 134°C, and the water for injection still, run on pure steam and were left alone.

Why the tie-in sat outside the classified perimeter

The objection raised in a pharmaceutical plant is about GMP change control rather than about efficiency.

Modify a qualified utility and requalification comes into scope: documentation, a validation exercise and production time the site does not have. So the saving gets left on the table.

The way through is architectural. The heat pump was installed in the utility block, outside the classified area, feeding hot water distribution that was already there. Nothing downstream of the tie-in changed: the same air handling coils, the same clean-in-place skid, the same loop heat exchangers, all still qualified. What changed is the machine heating the water arriving at them, which keeps the work inside engineering change control rather than pulling the classified area into a requalification.

A hot water circuit below 100°C is also outside the Indian Boiler Regulations, so the certified attendant on every shift and the annual inspection shutdown do not come with it.

Which loads the 800 kW covers, and which it does not

Load	Temperature	On the heat pump
HVAC reheat after dehumidification	Continuous, set by the room condition	Yes
Clean-in-place	To 100°C	Yes
Purified water and WFI loop sanitisation	80 to 95°C	Yes
Fluid bed drying	60 to 80°C	Yes
Sterilisation in place and autoclaving	121 to 134°C, pure steam	No
Water for injection multi-effect still	Above the range	No

Reheat after dehumidification is the largest single low-temperature heat load in an Indian pharmaceutical plant, and the one most often left out of a heat recovery scope. Air is cooled below dew point to dry it, then warmed back to the room condition, every occupied hour. It is a continuous, moderate-temperature, water-side load, the profile a heat pump serves best, and it is usually met by a boiler raising steam far hotter than the coil needs.

Tetra Heat Pump units hold supply temperature to ±0.5°C and deliver continuous output up to 120°C, which covers reheat, clean-in-place, loop sanitisation and fluid bed drying, and none of the pure steam duties. The tolerance earns its keep on reheat, where the coil trims a room to a specified condition rather than filling a tank, and drift shows up in the environmental record before it shows up in the energy bill.

What was installed

800 kW, in the utility block, on the water side. Single-unit capacity runs to 1,450 kW, so this duty sits inside one machine rather than a bank of them. Tetra Heat Pump, a product of Promethean Energy Private Limited, builds air source, water source and cascade configurations, on refrigerants including R1234ze and R245fa.

Controls integrate to existing building management, SCADA and PLC networks, including Siemens and Allen-Bradley, over Modbus and BACnet, so supply temperature is a trend QA can pull rather than a local display nobody reads.

One thing to budget early: moving heat from fuel to electricity raises the sanctioned load, and the security deposit is recalculated against the higher average bill at the next revision.

What the 70% covers

The saving is on the converted load, not on the plant’s whole energy bill. The boiler is retained for pure steam, so what falls is its firing hours.

The wider arithmetic is set by the fuel displaced rather than by the industry. Against piped natural gas, LPG, furnace oil, light diesel oil and diesel the breakeven coefficient of performance is 1.0 to 1.2, so almost any working machine is cheaper to run. Against coal or biomass briquette that is not true: the cost case does not hold, and the reasons to change are compliance, air quality, labour and customer audit. A pharmaceutical site running solid fuel should be evaluated on that basis, not on a savings percentage.

The qualification pack

This is what a utility change of this kind generates, and it is also what QA will ask for in the very first meeting.

Document or activity	What it demonstrates	Who reviews it
Engineering change control record	The change is bounded and the classified area is untouched	QA and plant engineering
Marked-up utility drawing and tie-in detail	Where new plant meets existing distribution, and that no qualified equipment is modified	Plant engineering and validation
Installation and operational checks at handover	The unit is installed as designed and operates across its stated range	Validation and utilities
Supply temperature record against setpoint	The duty is held to ±0.5°C in service	Validation and QA
Instrument calibration certificates	The temperature and flow instruments reading the duty are traceable	QA
Revised operating and maintenance procedures, with training records	The utilities team can run the plant to a documented method	QA and utilities

Where a project requires certification of the equipment itself, Promethean Energy obtains it for that project, to the standard the site sets, as it has on previous projects.

What to settle before the order

Agree the change control route with QA before the specification is frozen, because that answer decides where the tie-in goes and the tie-in decides the capacity. And scope the reheat load with the dehumidification duty in front of you: it runs whenever the plant is occupied, so it sets the running hours.

Working out whether your plant is a fit

The screening question is which loads sit below 100°C and what is heating them now. There is more on sector loads on the pharmaceutical industry page, on the equipment at high temperature heat pumps, and on tie-ins and controls at integration. Chemical processing scopes the same way. The calculator turns your tariff and fuel rate into a breakeven; other projects sit on the case studies page.