HUMIDIFICATION & DEHUMIDIFICATION Humidification decarbonisation
Dave Marshall-George, sales director at Condair, looks at how a commercial building using humidifiers can reduce its carbon footprint for humidity control and cooling
M
any commercial building operators are actively pursuing strategies to reduce carbon emissions to achieve the required Energy
Performance Certificate (EPC) in time for the forthcoming regulatory changes. Current government targets are for all leased commercial buildings to have an EPC B-rating by 01/04/2030, although it’s expected this date may be shifted to as late as 2035.
So, what does this mean for humidification systems and what preparations, if any, are required to maintain the optimum indoor humidity whilst meeting the Minimum Energy Efficiency Standards (MEES)? Any building operating gas-fired systems will find it increasingly difficult to achieve an EPC B-rating, given their reliance on fossil fuels. Gas-fired steam humidifiers have been popular across the UK, particularly in buildings needing
high-capacity humidification. They offer big outputs with lower energy costs than electric steam humidifiers, as gas is obviously cheaper per kW than electricity. We’ve recently seen many clients replacing gas-fired humidifiers with electric steam humidifiers, as they can be operated on renewable energy, thus reducing overall carbon emissions. The retrofit is a relatively simple swap, as the same space is required in the AHU. In fact, it’s likely the legacy steam distribution systems can be left in the AHU, reducing installation costs and complexity. However, as gas-fired humidifiers offer large outputs from a single unit, it’s likely the overall footprint of an electric system is going to be larger than the gas unit it is replacing. This needs to be considered during project planning. Replacing a 320kg/h gas humidifier may require three or four electric humidifiers to offer the same output. Luckily humidification systems of this size are often on roofs, which may alleviate this concern.
But if plantroom space is limited, or if the amount of available electricity is not sufficient to meet the needs of an electric steam system, adiabatic humidifiers might offer a practical alternative. Cold water humidifiers mounted inside the AHU can offer high outputs but do need pre-heating prior to the humidifier section. The air-on condition needs to be dry enough to absorb moisture from the humidifier. This pre-heating typically comes from a heater coil attached to a gas boiler. Unfortunately, this
If decarbonisation
initiatives involve replacing gas boilers with heat pump chillers, and the heating prior to the adiabatic humidifier can be achieved with a heat pump, the overall electrical load will be less than using self-generating electric steam humidifiers due to the heat pump’s COP. As the adiabatic humidifier uses a very small amount of energy to simply circulate water, employing it in combination with a head pump chiller, could result in the energy consumption being three times lower than self-generating electric steam humidifiers.
16 BUILDING SERVICES & ENVIRONMENTAL ENGINEER JUNE 2026 Read the latest at:
www.bsee.co.uk
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