Efficient heat use can help cut agricultural emissions

The last detailed study of heat use in the agricultural industry was carried out almost 10 years ago*, but it showed that UK farmers used almost 2,200 GWh of heat each year, and that heating accounted for 37 % of the total energy used in agriculture. When horticulture (greenhouses and nurseries) are added, these figures rise further.

While direct electrical heating is important in some sectors, 86% of the total heat demand was provided by the on-site combustion of conventional fossil fuels including petrol, gas and coal, showing the potential to further decarbonise in this area.

Since the study was carried out, the UK agricultural and horticultural industries have made great strides to reduce their share of the nation’s greenhouse gas (GHG) emissions. According to the latest government statistics available, in 2015 the sector accounted for 10% of total UK emissions, a fall of 17% since 1990. Heat has been at the forefront of decreasing agricultural GHGs in recent years, largely through the adoption of biomass boilers, improved system efficiencies, and the rise of anaerobic digestion (AD) on farms.

There are many uses for heat on farms; from livestock production (poultry and pigs) and drying arable crops, to heating greenhouses and polytunnels. Where farms have diversified to create offices, business centres or leisure facilities, there is often the scope to install district heating systems. However, getting this heat from one part of the process to another easily and quickly is essential if the benefits of this renewable heat are to be maximised and agricultural emissions curtailed. This is where heat exchangers come in.

Whatever the source of heat – biomass boiler, AD plant or other technology – efficiently transferring and using the generated heat is a vital part of making sure the overall system works as intended and keeping running costs to a minimum. Whether you are transferring boiler heat to a storage tank in a greenhouse, or taking the heat from a biomass boiler to the drying fans in a grain store, it is important that the right kind of heat exchanger has been specified and that it is suitably maintained. For example, Plate Heat Exchangers can easily become clogged with dust and dirt if not regularly cleaned, severely reducing their effectiveness and requiring more fuel and time to dry the same quantity of grain.

With experience in many agricultural sectors, such as anaerobic digestion and dairy processing, HRS Heat Exchangers are happy to offer advice on the design or maintenance of new or replacement systems. The difference between an effective and efficient heat exchanger and an old or poorly maintained one can be striking, both in terms of running costs, but also energy use and the associated GHG emissions.

 

*Study conducted by Warwick HRI and FEC Services Ltd