A new dimension of heating with residual heat delivered by truck

Let’s dwell on the following data: In Europe, electricity generation solely produces enough residual heat to meet the continent's entire heating needs. In addition, many other facilities, from iron foundries to cement factories and plastics processing plants, also produce such residual heat. Some of this heat can be used locally (for example to heat the plant), but most of it cannot. Pipelines for transport are expensive and complicated to build, and many heat emitters require many pipes.

The logical conclusion is that the heat should then be transported in mobile storage. The development of such a prototype has recently been completed as part of a project funded by the Ministry of Energy, and the pilot is already bringing heat from the Thermofoam Ltd. packaging products plant in Felsőpakony to the local kindergarten. One of the members of the development consortium is BME, and its professional leader is Attila Imre, head of the Department of Energy Engineering, while the three companies involved in the project - Thermofoam, HeatVentors, IMSYS - all have ties to BME.

The heat storage works with a so-called phase change material, which absorbs heat during melting and releases it during solidification.

Typically, it is some kind of wax or similar material, like candle wax (which is also a phase changer, but it changes around 40 degrees Celsius, which is not a high enough temperature for this process). Hot water is circulated in a coil of tubing in the structure, which melts the material, then the circulating system is closed, taken to the point of use, connected to the system there and finally it heats the water circulating in it - that is the principle of operation in a nutshell. For an apartment or small building in average winter weather, one carriage worth of heat can be sufficient for a half or even a full day.

Insulation is important

"The idea of a heat storage unit has been around for a long time, and has been tried in many countries, but rarely has a marketable product been developed. In London, for example, there are two barges that use this technology. A location must be found where heat is emitted at a sufficiently high temperature and needs to be transported over short distances so that high fuel costs do not compromise efficiency. This is not an easy task," explained Attila Imre.
The storage tanks developed range from 1 to 9 cubic metres, with the smallest being capable of storing 50 kWh of energy. They are not expensive by comparison, costing 1.5 million HUF, but you have to take transportation into account, which a van can manage, given the weight of around 1 tonne. "There are already orders, for example one town located in the Great Hungarian Plain could use 7-8 larger containers. However, the production capacity still needs to be built up and tested before serial production can start, so it will take at least 2-3 years before this all can become a market product" - Attila Imre told bme.hu.

The "unloading" of a container filled with heat at the Mesevár kindergarten. Attila Imre, fifth from right, among the project participants

The question may arise as to how much money an emitter will be able to charge to make its residual heat available for use, but the head of the department says that it may not necessarily have to be paid directly. As it is an energy efficiency investment, which also reduces the environmental heat load, it is a given that it has the potential to reduce carbon dioxide emission quotas, which means that a public incentive scheme can be used to make companies interested in cooperating.

Filling the cooled container with heat at the Thermofoam site

The only regret is that the original, genius working title of the development - Sándor-József-Benedek-Project - has been changed in the meantime, so it became Hőhajó (Heatship).

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photos: Ministry of Energy