Heat loss from flue gas: The boiler reduces heat loss by 75% compared to traditional single-unit boilers. In conventional single-unit steel tube boilers, the flue gas temperature is typically maintained above 150°C to minimize low-temperature corrosion and condensation on the tail heating surfaces. In contrast, modular boilers utilize corrosion-resistant cast iron materials for their heating surfaces, providing exceptional resistance to corrosion. Through optimized heat transfer design, the flue gas temperature is reduced to below 100°C (typically between 60°C and 80°C). As a result, modular boilers achieve a 75% reduction in heat loss from flue gas compared to traditional single-unit boilers. Additionally, each modular boiler is equipped with a ventilation regulator. When a module is operational, its ventilation regulator opens, and when the module is idle, the regulator closes, preventing heat loss from residual heat in the standby module. Furthermore, the furnace walls of each modular boiler are insulated with thermal barriers to minimize heat loss from the combustion chamber. Actual measurements show that modular boilers reduce fuel costs by 1% compared to single-unit boilers. Shaanxi Deli Energy developed the cast iron gas-fired modular atmospheric hot water boiler, which holds national patent numbers 201320778345.0, 201310632249.X, 201320784596.X, 201320778344.6, and 201320784600.2. This product represents an innovative invention with internationally advanced independent intellectual property rights. Its core components feature a uniquely designed, high-quality cast iron mechanism developed in-house, ensuring a service life of over 50 years and meeting diverse user needs. Multiple units can be combined in parallel, leveraging the advantages of modular design to enable fully automated startup, alternating operation, and unattended operation based on heating demands. The boiler is highly adaptable to various gas sources, including natural gas, liquefied petroleum gas, coalbed methane, and biogas, effectively addressing gas supply shortages in different regions. It can also be integrated with central air conditioning, solar energy, and underground heat sources for complementary heating, making it widely applicable for residential communities, shopping malls, villas, hotels, spas, schools, and hospitals for heating and domestic hot water supply. It is a multifunctional device characterized by energy efficiency, high performance, low noise, environmental friendliness, and zero pollution. The primary reason for the boiler's long service life is the use of cast iron furnace panels. Most single-unit large boilers currently use steel furnace panels. As is well known, cast iron offers significantly better resistance to acid, alkali, and oxygen corrosion compared to steel. National standards stipulate a service life of 14 years for steel furnace panels, whereas cast iron furnace panels can last up to 50 years. Of course, the actual lifespan of a boiler also depends on factors such as reasonable operational management, correct operation, and proper daily maintenance. The boiler is equipped with a comprehensive, scientifically sound operational management and control system, and the company provides technical training for operators to ensure safe and correct operation.