Can an 18–150 kW natural gas CHP package supply process hot water?

Yes—an 18-150kW natural gas CHP package can supply process hot water by recovering engine jacket-water and exhaust heat. The qualification is important: electrical capacity alone does not establish how much usable heat the package can deliver, at what temperature, or for how long. A system that performs well for continuous wash-water preheating may be a poor match for short, high-temperature production batches.

For technical evaluators, the decision starts with three process requirements: supply temperature, water flow, and operating schedule. Those requirements must be matched against verified heat-recovery performance, not simply the generator’s nameplate rating. The aim is to obtain dependable process heat without compromising engine cooling, electrical operation, or production continuity.

Start with the hot-water duty, not the generator size

The 18–150 kW range normally refers to electrical output; confirm whether a supplier quotes gross generator output or net output after package auxiliaries. Thermal output is a separate specification. Engines with similar electrical ratings can have different recoverable heat quantities, cooling arrangements, and permitted operating temperatures.

For a water-heating duty, the basic calculation is:

Required thermal power (kW) = water mass flow (kg/s) × 4.18 × temperature rise (°C)

For example, heating 2 m³/h of water from 20°C to 70°C requires approximately 116 kW of thermal power, assuming a water density near 1,000 kg/m³. This is the water-side duty only; pipework losses, storage losses, and design margins must be assessed separately. It does not mean that a 116 kW electrical generator will provide exactly that amount of recoverable heat.

Distinguish fresh-water heating from recirculation. A process loop returning at 60°C and supplied at 70°C has a different duty from the same flow of incoming water heated from 20°C. Confusing circulation flow with fresh-water consumption can substantially distort the equipment selection.

Which recovered heat can reach your required temperature?

A gas-engine CHP system generally offers two principal heat sources. Their temperatures and operating constraints differ, so they should not be treated as interchangeable thermal capacity.

Some engine CHP designs operate jacket-water circuits around 80–90°C, but this is an indicative engineering range, not a specification for any particular package. Process water heated through an exchanger must remain below the hot-side temperature by a practical approach margin. A requested 85°C process supply therefore cannot automatically be guaranteed from an 85°C coolant circuit.

Exhaust recovery may provide the additional temperature lift. However, hotter exhaust does not mean unlimited hot-water production. The supplier must demonstrate the duty at the required process inlet and outlet temperatures while respecting engine and exchanger limits.

Return temperature matters just as much as supply temperature. A high process return temperature reduces the available temperature difference for recovery. Ask for thermal performance at your actual return condition rather than accepting a heat-output figure measured with much colder inlet water.

Evaluate an 18-150kW natural gas CHP package across the working day

A full-load thermal rating answers only one operating question. Plants rarely maintain perfectly constant electrical and heat demand, and those demands may not rise and fall together.

If the generator follows site electrical load, heat production will vary with engine load. If it follows thermal demand, the site must be able to consume or export the resulting electricity within applicable interconnection rules. Neither strategy should be assumed without checking the electrical connection and process schedule.

Request electrical and recoverable thermal performance at several operating points within the permitted load range. Include fuel consumption, auxiliary power, hot-water temperatures, and ambient conditions. Do not assume thermal output decreases in direct proportion to electrical output; heat distribution and efficiency change with load.

A useful screening exercise is to plot the following on the same time axis:

• Site electrical demand and any export restrictions.
• Process heating demand, including startup and cleaning cycles.
• Required supply temperature and expected return temperature.
• Production shutdowns and planned engine maintenance.

The strongest applications have a substantial overlap between electrical demand and useful heat demand. Oversizing to meet a brief heating peak can leave the package rejecting heat or operating inefficiently for much of the day.

Build a hot-water system, not just a heat-recovery connection

In many process applications, the engine coolant circuit and process-water circuit should be hydraulically separated by an appropriately selected heat exchanger. This protects coolant chemistry, simplifies pressure management, and reduces contamination risks. Hygiene-sensitive applications may require additional separation measures under the relevant standards.

The integration design should address pumps, expansion vessels, air removal, water treatment, insulation, instrumentation, and pressure protection. Control valves must maintain acceptable engine temperatures while regulating process heat delivery. CHP heat recovery must never remove the engine’s ability to cool safely.

A buffer tank can smooth short-term differences between heat production and consumption. It cannot compensate indefinitely for an undersized package. Size storage from the energy deficit and allowable temperature swing, rather than choosing tank volume by habit.

Consider a process needing an extra 50 kW for 30 minutes: the deficit is 25 kWh. An ideal 1 m³ water store with a usable 20°C temperature swing holds approximately 23 kWh. Actual usable storage will be lower or otherwise constrained by losses, mixing, stratification, and the minimum acceptable supply temperature.

For production-critical hot water, retain a suitably sized backup or trim heater. It can cover engine downtime, cold starts, demand peaks, and temperatures beyond the recovery circuit’s capability. Where electrical generation must continue without a heat demand, provide an adequately rated heat-rejection path.

Check the whole exhaust path

The exhaust recovery exchanger must be evaluated together with silencers, piping, and any emissions-control equipment. AMICO’s exhaust treatment offering is relevant to this gas-treatment interface, but its suitability and configuration require application-specific confirmation.

Request the combined exhaust pressure-loss calculation and the required temperature conditions for any emissions-control components. Equipment placement can affect both heat recovery and emissions performance. Condensate management and materials selection also deserve attention wherever low exhaust temperatures are contemplated.

What to request before approving a supplier proposal

AMICO Gas Power Co., Ltd. combines gas-power equipment manufacturing with distributed-energy and control-technology development. For an evaluator, that background is a reason to request a coordinated engine, recovery, and controls proposal—not to assume a particular hot-water capability without supporting data.

A decision-ready submission should include:

• Rated and part-load performance: net electrical output, fuel input with a stated heating-value basis, and recoverable thermal output by source.
• Defined thermal conditions: guaranteed flow, supply and return temperatures, coolant limits, and heat-exchanger approach temperatures.
• Site derating: effects of altitude, ambient temperature, and specified natural-gas composition and pressure.
• Integration documents: hydraulic schematic, exhaust pressure-loss calculation, control sequence, and interface responsibilities.
• Operating provisions: startup behavior, minimum permitted load, maintenance needs, backup heating, and heat rejection.
• Acceptance criteria: a test method confirming simultaneous electrical and usable thermal performance at agreed conditions.

Be cautious with a headline “total efficiency” value. It is meaningful only when the fuel basis, auxiliary consumption, and recoverable-heat conditions are clear. Heat that the process cannot absorb at the required temperature should not be counted as useful energy in the project economics.

The practical selection verdict

An 18–150 kW natural gas CHP package is a credible option for process hot water when verified thermal output matches a sustained demand at compatible temperatures. Continuous preheating and steady hot-water loops are generally easier to match than intermittent, high-temperature duties.

The most reliable selection is often not the package that covers every heating peak. It is the package that serves a well-defined base duty, integrates safely with the plant, and works alongside storage or backup heating where necessary. Approve the system on guaranteed water-side performance and operating compatibility—not on electrical rating alone.