The idea
Most of the electrical energy used by a compressor ends up as heat. In some plants, part of that heat can be captured, for example to heat water or space, instead of being rejected.
When it makes sense
Good conditions:
- A steady need for warm air or hot water close to the compressor
- Long compressor running hours
- A way to use the heat when compressor load changes
- Enough space and a practical connection route
What to assess
Check:
- How much heat is available at what temperature
- How much the plant actually needs, and when
- The installation cost and effect on compressor cooling
- Maintenance and safety implications
- Whether the recovered heat replaces a real cost
Do the economics honestly
A project should be judged on the actual heat used and the cost of the fuel or energy it replaces, not on the theoretical heat available.
Starting data
To start, it helps to have:
- Compressor make, model, rated power and controls
- Operating pressure settings and the lowest pressure the processes need
- Operating hours and shift pattern
- Any existing power, flow or pressure records
Frequently asked questions
Does heat recovery affect the compressor?
It changes the cooling arrangement, so it must be designed with the machine's requirements in mind.
Is it worth it for a small compressor?
The benefit depends on the heat available and a real use for it. For small machines the economics may not justify it.
What if there is no steady use for the heat?
Then the project may not pay back. Assess the use first.
Field guide
Heat recovery: using the energy you already pay for
Almost all the electrical energy that goes into an air compressor ends up as heat. On oil-injected screw compressors much of it can be captured, through the oil circuit or the cooling air, and used elsewhere in the plant.
Typical uses
- Hot water for washing, process or boiler feed pre-heating.
- Space heating or drying, using ducted warm cooling air.
- Pre-heating process fluids.
When it pays
- The compressor runs long hours with steady load.
- There is a heat user close by that needs heat at the same time the compressor runs.
- The heat replaces fuel or electricity that would otherwise be bought.
Points to check
The compressor must still be cooled properly when the heat user does not need heat, so a bypass or backup cooler is essential. Hot-water recovery needs the right heat exchanger for the machine and a temperature that suits the user. Estimate the saving from the compressor's loaded hours and power, the share of heat recoverable, and the cost of the fuel replaced.
What to send for a quotation
- Compressor make, model and rated power of each machine.
- Electricity tariff and annual running hours.
- Typical pressure at the compressor and at the furthest user.
- Any measurements you already have (power, flow, loaded hours).
Send it through find my part or the spare parts enquiry, or call +91 99590 60718 or +91 92468 88812.