Decarbonisation of humidification in commerical buildings

Article summary

EPC-B rating needed

Buildings with gas-fired humidifiers will find it difficult to meet the Minimum Energy Efficiency Standards.

Electric humidifiers popular

Using electric steam humidifiers rather than gas-fired reduces a building's reliance on fossil fuels.

Evaporative cooling benefits

Exhaust air evaporative cooling AHU strategy can reduce a building's cooling energy use by over 50%.

Decarbonisation of humidification in commerical buildings

Across the Nordic region, building owners and facility managers are under increasing pressure to improve energy efficiency, reduce carbon emissions and transition away from fossil fuels. As sustainability targets become more ambitious and energy costs remain a key operational concern, HVAC systems are playing an increasingly important role in achieving these goals.

Humidification systems are no exception. Maintaining the optimum indoor humidity while minimising energy consumption requires careful consideration of both the humidification technology and the building's overall energy strategy.

Gas-fired steam humidifiers have traditionally been a popular choice for applications requiring high-capacity humidification, thanks to their high steam output and historically lower operating costs compared to electric systems. However, as buildings move towards electrification and renewable energy sources, many organisations are reassessing their humidification technology to support long-term sustainability objectives and reduce their dependence on fossil fuels.

Many organisations are now replacing gas-fired steam humidifiers with electric steam humidifiers as part of their sustainability strategy. When powered by renewable electricity, electric humidification can help reduce carbon emissions while supporting the transition away from fossil fuels. In many retrofit projects, the replacement is relatively straightforward, as existing steam distribution systems and available installation space can often be reused, helping to minimise installation costs and disruption.

When planning a replacement, however, it is important to consider system capacity and available infrastructure. Gas-fired humidifiers can deliver very high steam outputs from a single unit, whereas achieving the same capacity with electric steam humidifiers may require multiple units. In addition, the available electrical supply and plant room space should be evaluated early in the project.

Where electrical capacity is limited or space constraints make electric steam humidifiers less practical, adiabatic humidification may offer an energy-efficient alternative. Adiabatic systems provide high-capacity humidification with significantly lower electrical energy consumption than steam-based technologies. The most suitable solution depends on the building design, air handling system and humidity requirements, making a thorough technical assessment essential before selecting the replacement technology.

As more buildings transition to low-carbon heating technologies such as heat pumps, the potential benefits of adiabatic humidification become even greater. When combined with heat pump-based HVAC systems, adiabatic humidifiers can deliver the required humidity levels with significantly lower energy consumption than steam humidification. Because the humidifier itself only requires a small amount of electricity to circulate water, the overall energy demand can be substantially reduced.

Adiabatic humidifiers such as the Condair ME also provide the added benefit of evaporative cooling. As water evaporates, it naturally absorbs heat from the air, reducing the cooling load on mechanical refrigeration systems. For every kilogram of water evaporated, approximately 0.68 kW of cooling is produced, making adiabatic humidification a highly energy-efficient solution for both humidity control and cooling.

While direct evaporative cooling is only suitable in certain climates and applications, indirect evaporative cooling integrated into modern air handling units can provide reliable and energy-efficient cooling without increasing the humidity of the supply air. This makes it an attractive solution for commercial buildings, industrial facilities and data centres seeking to reduce energy consumption and carbon emissions while maintaining a stable indoor climate.

Instead of cooling the incoming supply air directly, an Exhaust Air Evaporative Cooling (EAEC) system applies evaporative cooling to the extract air leaving the building. Because the extract air typically has stable temperature and humidity conditions, it can be humidified close to saturation to maximise the cooling effect.

The cooled extract air then passes through a high-efficiency heat exchanger, where its thermal energy is transferred to the incoming fresh air before the extract air is discharged outdoors. This indirect process can reduce the supply air temperature by up to 10°C, significantly lowering the demand for mechanical cooling.

As the evaporation process takes place only in the extract air, the humidity of the supply air remains unchanged. This makes EAEC an effective solution for applications where cooling is required without increasing indoor humidity.

By reducing the cooling load on mechanical refrigeration systems, EAEC can significantly lower energy consumption and carbon emissions. When integrated into modern air handling units, it offers a reliable and sustainable cooling strategy for commercial buildings, industrial facilities and data centres.

As building owners continue to improve energy performance and reduce operational carbon emissions, upgrading HVAC and humidity control systems has become an important part of long-term sustainability strategies. Selecting the right humidification and evaporative cooling technology can improve energy efficiency, reduce operating costs and support future-ready building performance.

Condair provides expert guidance to help building owners, consultants and facility managers identify the most suitable humidification and evaporative cooling solution for their application.