LOW CARBON HEATING/HVAC
Mechanical Vapour Recompression
(MVR) is one of the
cheapest methods of evaporating water
THE ELECTRIFICATION OF INDUSTRIAL
HEATING PROCESSES With industrial heat demand amounting to over 20% of
global energy consumption, the electrification of industrial heating processes is essential. Matt Hale, global key account director, HRS Heat Exchangers, comments
D
ecarbonisation of industrial heat is essential to meet net-zero targets. The electrification of processes and equipment – from space heating to furnaces – is one of the most obvious ways to achieve this, while also resulting in greater energy efficiency and lower energy costs. There are, however, barriers which make the move to electricity challenging, such as economics, technical ability, a lack of knowledge and infrastructure issues. 37% of total global energy consumption comes
from industry. While two thirds of this is used for heat generation, approximately 80% of this thermal demand is generated by fossil fuels. According to McKinsey & Company: ‘Overall,
manufacturing, food and beverage, and agriculture and forestry, are the industries most reliant on processes with low-temperature heat (less than 200˚C). In particular, manufacturing and food and beverage could see significant potential from electrification in the short to medium term, with electrification rates of 62 and 44% of total energy demand, respectively, by 2030’.
THE RIGHT TECHNOLOGY There are a number of factors which determine the optimal technology to provide electrical heat for different industrial processes, including the required temperature, holding time and process capacity. Mature and well-established technologies, such as
mechanical vapour recompression (MVR) and heat pumps, are suitable for temperatures from 50 to >200˚C, while e-boilers and turbo heaters are becoming more mainstream and can produce temperatures of up to 500˚C or 1,000˚C respectively. Rapid advances in induction heating are also making this method increasingly suitable for a wide range of uses, including high temperature scenarios. Speed of heat pick up is another important consideration, and one where e-boilers would be favoured over heat pumps, for example. McKinsey & Company stress that the market has
not yet picked technological ‘winners’, with market maturity not expected until 2030 at the earliest. However, some technologies such as MVR and ohmic heating are already well established and utilised by HRS Heat Exchangers where appropriate.
OHMIC HEATING When pasteurising fruit juice, for example, ohmic heating (which uses electricity to heat the product rapidly and uniformly) has been scientifically shown to be highly effective at inactivating bacteria, yeast and moulds while maintaining the flavours and quality of fruit juice. The HRS Ohmic System passes electricity between
two electrodes in the product in a 1m ceramic tube. The juice is heated to 105˚C within one second and then held at this temperature for four seconds before being cooled. The HRS system uses the latest
electronics to ensure that the temperature curve is very smooth, which helps to preserve product quality and improve process efficiency. Depending on electricity prices, ohmic heating can
be more expensive than traditional methods of pasteurisation and it represents a larger capital investment. However, more and more clients around the world are turning to the technique because of proven benefits in terms of product quality, allowing them to access premium ‘as fresh’ juice markets.
MECHANICAL VAPOUR RECOMPRESSION (MVR) HRS Heat Exchangers has also seen increased interest in using MVR for evaporation. The electrical energy employed in MVR is normally considerably cheaper than the thermal energy needed for traditional evaporation. Traditional evaporation techniques use a high
temperature service fluid (such as pressurised steam) to raise the temperature of the product above its boiling point so that water (and other volatile compounds) is driven off, leaving a more concentrated solution. The principal source of energy for this process is therefore the fuel used to heat the water (steam) in the boiler, such as gas or oil. In MVR, the steam which comes off the product
in the evaporator is channelled into a compressor which increases the pressure (and therefore the temperature). This steam, which is now above the boiling point of the product, is then used as the service fluid for the evaporator. As the compressor uses an electric motor, the process is driven by electricity rather than thermal energy. Because the compressor reuses/recycles evaporated steam, a lot of latent heat is recovered. This makes MVR one of the cheapest methods of evaporating water in terms of operational costs, although it is not always the most suitable or cost-effective solution, depending on the nature of the product or waste stream being evaporated. HRS tests any material that the client will be
The heating elements of the HRS Ohmic System raises the temperature of the orange juice to 105˚C within one second
14 ENERGY & SUSTAINABILITY SOLUTIONS - Winter 2025
working with in order to determine not only the best heat exchanger solution for the evaporation process, but also what pre-treatment may be necessary. This results in the best MVR or traditional thermal-based evaporation solution for each individual project.
HRS Heat Exchangers
www.hrs-heatexchangers.com
www.essmag.co.uk
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