Gas Internal Combustion Engine CHP System - High Efficiency, Waste Heat Recovery, and Eco-Friendly Power Generation

I. Core Technology: Internal Combustion Engine Operating Cycle and Waste Heat Recovery Pathways

The core technology of the gas internal combustion engine combined heat and power (CHP) system lies in its adherence to either the Otto cycle or the Diesel cycle (depending on the ignition method), and the precise design that recovers waste heat from multiple sources during the engine’s operation.

1. High Power Generation Efficiency:
   The gas internal combustion engine generates electricity by using the reciprocating motion of the piston to drive the crankshaft, which in turn drives the generator. The power generation efficiency is typically in the range of 40% to 45% (or even higher), making it one of the leading technologies among various gas-powered prime movers. This is its core economic advantage.

2. Multiple Sources of Waste Heat Recovery:
   Unlike the single-source exhaust heat recovery in gas turbines, the waste heat from internal combustion engines comes from a variety of sources, forming the foundation of its high-efficiency integrated energy utilization:

• High-temperature exhaust gas (~400-500°C): This comes from the engine’s exhaust and is the highest-grade waste heat, which can be recovered via a heat exchanger or waste heat boiler to produce steam or high-temperature hot water.

• Cylinder cooling water heat (~90-110°C): Generated by cooling the engine's cylinders, this stable, medium- to low-temperature heat is an ideal source for space heating and domestic hot water production.

• Intercooler heat (~50-70°C) and lubrication oil cooling heat: Although lower in temperature, this waste heat can still be utilized in system optimization designs to preheat makeup water or as a low-temperature heat source for underfloor heating systems.

II. Core Performance: Excellent Energy Comprehensive Utilization Efficiency

By simultaneously recovering the various waste heat flows mentioned above, the gas internal combustion engine CHP system achieves extremely high energy utilization efficiency.
The overall system efficiency (η_total) can consistently reach 85% - 92%. This is calculated as the sum of power generation efficiency (η_power) and thermal recovery efficiency (η_thermal).
This means that approximately 40% of the chemical energy input to the system is converted into high-value electricity, while about 40% to 50% is converted into useful thermal energy, with overall energy losses minimized to very low levels.

III. Technical Advantages for Winter Operation and System Integration

In winter heating conditions, the gas internal combustion engine CHP system demonstrates the following key technical features:

1. Stable Power Output and Excellent Frequency Regulation Performance:

• The internal combustion engine responds quickly to load changes, making it highly adaptable to grid fluctuations, providing reliable support to the regional grid. Its high power generation efficiency means that more electricity is produced to meet the same thermal load, offering better economic performance.

2. Flexibility and Quality of Heat Supply:

• The system can produce heat at different temperature levels (such as 85/60°C heating water or approximately 45°C domestic hot water), perfectly matching the heating and hot water needs of buildings during winter. The stable output of cylinder cooling heat provides basic heat load support for the system.

3. Suitable for Distributed Energy Scenarios:

• Gas internal combustion engine CHP units are modular, with a power range from tens of kilowatts to several megawatts, making them particularly suitable as distributed energy centers in locations such as hospitals, data centers, commercial complexes, and regional energy stations. These systems enable local energy production and consumption, reducing transmission and distribution losses.

IV. Environmental Benefits and Lifecycle Value

From an environmental perspective, modern gas internal combustion engines typically use technologies such as lean combustion to effectively control nitrogen oxide (NOx) emissions.
Due to their exceptionally high overall efficiency, when completing the same electricity and heat supply tasks, the primary energy consumption and carbon emissions of these systems are much lower than the traditional "purchased electricity + gas boiler" approach.

Conclusion

Gas internal combustion engine CHP systems are not simply a replacement for gas turbines but represent a technological path with unique advantages in the distributed energy sector.
Its core competitiveness lies in the highest power generation efficiency and the finely-tuned recovery of multi-source waste heat. In the context of ensuring energy supply during the winter, deploying a gas internal combustion engine-based CHP system is a reliable and efficient solution for achieving local energy self-sufficiency, enhancing energy infrastructure resilience, and meeting energy conservation and carbon reduction goals.