HEATING, VENTILATION & SERVICES


No longer a hard cell


With new funding mechanisms slashing the cost of combined heat and power systems run on hydrogen fuel cells, now is the right time to look closely at this income-generating, low-carbon technology, according to Viessmann’s Christian Engelke


H


ydrogen fuel cell systems that generate both heat and electricity in domestic and commercial


buildings while greatly reducing energy costs and carbon emissions are not new. Despite the numerous advantages these systems offer, it is still not commonly found on the consideration list of UK self-builders.


SUITABILITY Fuel cell micro-CHPs suit a diverse range of properties and circumstances, from high-end new builds and renovations to more regular boiler replacements where homeowners are looking for an environmentally friendly solution, but where heat pumps aren’t feasible. hey wor most eficiently when the


return temperatures of the water in the pipe system after heat has been released around the building are very low – ideally with an underoor heating system However, radiators that have a maximum return temperature of 50o work well.


C can also


Installation requires a gas connection and a three-core power cable electrical connection. The most compact models have a footprint of well under 1 m2


,


including everything you need for heating, hot water and power – avoiding the need for a bulky water cylinder elsewhere in the building.


HOW FUEL CELLS WORK


Fuel cells work by converting natural gas to hydrogen, which is then used to generate both power and heat through an electrochemical reaction known as cold combustion. In an exceptionally clean and eficient process, hydrogen is used as both a fuel source and energy store, while the carbon-producing


combustion that takes place in conventional condensing boilers doesn’t happen, saving around two tonnes of CO2


per year.


As energy and heat are generated on site where they are needed, there are no losses in transmission, and, unlike with conventional power stations, the heat produced is captured and used for heating and hot water, so there is far less waste.


Hybrid models combine a hydrogen uel cell with a highly eficient combination boiler which is used only to cover peak demand periods, such as when it’s very cold outside or a lot of hot water is required at short notice. This keeps energy consumption and carbon emissions to an absolute minimum while ensuring total comfort. There are also energy and income advantages. As well as reducing CO2


emissions by up to 30% and energy costs by up to 40% compared to a conventional boiler and electricity, fuel cell micro-CHPs generate green electricity which can be exported to the grid, bringing in income. A hydrogen fuel cell can generate as much power as 30 m2


of photovoltaic


cells, but, unlike solar panels, it will work day and night and in all weather. That’s enough electricity to cover the base load of most households and an electric car, with any surplus stored for later use or eported or profit Although the potential revenue that can be earned in this way reduced greatly when the government’s Feed-in Tariff (FiT) was replaced by the Smart Export Guarantee (SEG) in 2019, it is now growing again as energy prices increase. Furthermore, the value of independence from the stresses of spiralling electricity


Fuel cells work by converting natural gas to hydrogen, which is then used to generate both power and heat through an electrochemical reaction known as cold combustion


sep/oct 2022 www.sbhonline.co.uk 61


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