TBLN Series Condensing Gas Boiler

How a Condensing Gas Boiler Works

A condensing hot water boiler is equipped with a flue gas heat exchange system that lowers exhaust gas temperature and recovers latent heat from condensed water vapor in the flue gas. The higher the water vapor content in the flue gas, the more latent heat is recycled — natural gas is rich in hydrogen, generating substantial water vapor after combustion.

Main component of natural gas: Methane (CH₄)
Combustion reaction: CH₄ + 2O₂ → CO₂ + 2H₂O(g) + 8600 kcal

When 1m³ of natural gas fully combusts, it produces 2m³ of gaseous water vapor and releases 8600 kcal of heat. Total heat released reaches approximately 880 kcal if all water vapor in the flue gas is condensed. The condensate liquid produced during this process is safely discharged via the integrated drainage system, requiring only standard plumbing connections.

Thermal Efficiency: Why It Can Exceed 100%

Condensing boilers recover heat that conventional boilers waste. Two mechanisms drive the efficiency gain:

• Reduced flue gas exhaust temperature cuts sensible heat loss, boosting efficiency by 3%~5%. By lowering the exhaust temperature to as low as 40–50°C, the boiler minimizes sensible heat loss and ensures stable performance even under variable load conditions.
• Latent heat recovery from condensed flue-gas steam adds another 5%~10%.

Total comprehensive efficiency improvement: 8%~15%, greatly reducing energy consumption.

The key: conventional boilers calculate efficiency against Net Calorific Value (NCV = 8600 kcal/Nm³), which excludes latent heat. Condensing boilers recover that extra latent heat (880 kcal/m³), so efficiency is measured against Gross Calorific Value (GCV = 9480 kcal/Nm³).

Maximum efficiency: η = Recovered Total Heat / NCV × 100% = up to 110%
This is not "free energy" — it is simply counting heat that was always there but previously vented to the atmosphere.

Calorific Value Reference: Sensible heat per 1m³ natural gas: 31669 kJ/m³ | Latent heat: 3427 kJ/m³

Operating Conditions & System Design

Condensing boilers achieve maximum efficiency when the return water temperature is below 50°C, allowing flue gas to condense within the heat exchanger. In typical space heating applications, system design should account for this to ensure the boiler operates in condensing mode for the majority of its runtime.

Applications include domestic hot water preparation and space heating. Unlike a heat only boiler which requires a separate hot water cylinder, our combo boiler configuration integrates both functions in a single unit, saving space and installation cost. Both heat only and combo configurations are available depending on project requirements.

Belitto Condensing Boiler Series

TBLN Series (60–2800kW): Compact footprint, suitable for residential and light commercial applications. Equipped with high-efficiency Al-Mg-Si heat exchanger. All units deliver high efficiency condensing boiler performance with SEDBUK seasonal efficiency ratings among the highest in class.

TBYG Series (3500–7000kW): Designed for large-scale commercial and district heating applications. Compatible with cascade control systems for modular capacity scaling. Ultra-low NOx emission burners comply with stringent environmental standards.

Parameter	TBLN-60	TBLN-90	TBLN-120	TBLN-200	TBLN-240	TBLN-280	TBLN-350	TBLN-420	TBLN-550	TBLN-700	TBLN-1050	TBLN-1400	TBLN-2100	TBLN-2800
Rated Heat Input (kW)	60	90	120	200	240	280	350	420	550	700	1050	1400	2100	2800
Heating Area (m²)	600~900	900~1500	1500~2000	2800–4000	3400–4800	4000–5600	5000–7000	7000-8400	7800-11000	10000-15000	15000-21000	20000-28000	30000-42000	40000-56000
Max Thermal Efficiency at 30% Load (%)	108.9	108.9	108.9	108.9	108.9	108.9	108.9	108	108	108	108	108	108	108
NOx Emission (mg/m³)	<30	<30	<30	<30	<30	<30	<30	<30	<30	<30	<30	<30	<30	<30
Max Gas Consumption (m³/h)	5.9	9.1	12.4	20	24	28	35	42	55	70	10.5	137.2	205.8	274.4
Dimensions L×W×H (mm)	510×640×1050	510×640×1050	550×720×1120	1180×680×1260	1180×680×1260	1560×680×1260	1560×725×1570	1300×725×1570	1350×880×1700	1550×880×1710	1900×980×1710	2610×1000×1850	2650×1350×1900	3350×1400×2000
Net Weight (kg)	70	81	90	200	220	280	315	380	415	530	710	850	1100	1400

Wide Application Scenarios: Houses, commercial buildings, industrial plants, hotels, agricultural greenhouses, and more.

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