When waste heat is not a burden, but a resource.

Utilizing waste heat represents one of the biggest challenges of modern energy production, while also providing great potential for ecologically and economically efficient preparation of useful heat. Waste heat is therefore heat that can be used elsewhere. What is waste heat, why it is produced, and how it can be smartly utilized to create greater savings is revealed below.



Heat is always generated during cooling processes. This heat can be waste heat if it is not used or it can be utilized to heat something else. A clear example from everyday life is a refrigerator, which keeps its interior cool while emitting heat into the surrounding environment. Since a refrigerator is a small device, the emitted heat is negligible and is not felt in the room. However, in industrial and other larger facilities where cooling needs for processing and manufacturing are huge, we can imagine them as huge refrigerators that consequently emit a lot of waste heat into the environment. If the impact of emitted heat into the environment is negligible in the case of a refrigerator, this is not true for “huge refrigerators” – large industrial facilities whose waste heat needs to be removed from the building with fans and cooling devices and discharged into the air, rivers, lakes or seas. Processes that require intensive cooling include cooling wine cellars, laser cooling for cutting, laundries, ventilation of mining shafts, food processing, and more.


Waste heat is low-temperature heat that cannot be directly used. We can see it as untapped energy, a valuable heat source that is already here and does not need to be obtained – we just need to know how to utilize it.


Waste heat that is not waste


We can view this heat as a burden that represents waste, or as a great resource that can be used to our advantage. At Kronoterm, we chose the second option years ago, so we offer systems that utilize waste heat to make it useful for other processes. Typical processes that can use waste heat include heating buildings and heating domestic hot water.


How can we utilize waste heat?


Waste heat can be utilized through air-to-water heat pumps and water-to-water heat pumps. Let’s consider a specific example. Many industrial facilities often release wastewater with a temperature of 30°C directly into the environment, such as into the air or nearby bodies of water (streams, rivers, etc.). Water with such a temperature represents a very favorable source of heating that can be utilized by Kronoterm company with a heat pump. Water at 30°C is not yet usable on its own, but with Kronoterm’s heat pump, it can be heated to 50°C, and with Kronoterm’s heat pump with boosters, it can be heated to over 80°C. This heated water can then be used for heating buildings and domestic hot water, and can also be utilized in district heating systems.


The investment in the heat recovery system from waste water in the tomato greenhouses in Slovenia has paid off in a record time: in less than a year!


Waste heat: a valuable resource we’re throwing away?


The favorable nature of a heat source with an initial temperature of, for example, 30°C or higher, can be illustrated by comparing it with other heat sources utilized by heat pumps. Typically, water-to-water heat pumps effectively utilize a heat source, such as groundwater with a more or less constant temperature between 8 and 12°C throughout the year, while air-to-water heat pumps utilize heat from the air, which in winter may have a temperature as low as -10°C. If both types of heat pumps have to extract heat from heat sources with temperatures as mentioned above, and produce usable heat that can be used for space heating or producing hot water at a temperature of 60°C, this means that they have a more difficult task than heat pumps (especially air-to-water heat pumps) that utilize waste heat at a temperature of 30°C. The difference between the temperature of the heat source and the desired temperature of the usable heat is much greater – raising the temperature from 30°C to 60°C requires less energy input. And if we return to the utilization of waste heat based on what has been said, waste heat with a temperature of 30°C is simply too good of a heat source to just throw away.


Positive environmental impacts


Utilizing waste heat not only significantly reduces the operating costs of a building due to saving primary energy, but also has a major impact on the environment and the reduction of greenhouse gas emissions. With the described technology, the company Kronoterm has successfully helped to reduce environmental pollution and costs also for the company Lušt, where the largest heat pump in Slovenia is installed – the Kronoterm heat pump. You can read more about the successfully realized visionary project here.


If you want to utilize waste heat that is generated during the operational processes of your building with the help of a heat pump system, and significantly reduce the operating costs of your building, contact us and we will design a comprehensive solution.