HOT|COOL NO. 2/2019 - "Smart Heating System Integration"



By Kristina Lygnerud (PhD), Energy department manager at the Swedish Environment Research Institute (IVL) and researcher focusing on business model innovation in district heating at Halmstad University (HU)

Urban waste heat recovery is a key to smart cities but to get there, many challenges need to be managed. The industry needs to go beyond its tradition of technical orientation and grasp the window of opportunity of the low temperature heat recovery. The opportunity allows the companies stepping over the threshold of technology to capitalize on the value of green and long-term customer relationships. Heating and cooling are important players on the European energy scene. Approximately half of the final energy is consumed by these sectors. Even so, the sector is challenged and needs to be modernized to be part of the future, smart city. One challenge is the increasing energy efficiency of the building stock. Another challenge is the changing customer demand. Customers see an optimized energy consumption as being the responsibility of their energy provider and they want the possibility to generate and sell energy on a heat market. Indeed, the energy citizen who is a prosumer is materializing. Yet another challenge is the competitive pressure from other heating alternatives (notably gas on the European continent and heat pumps in the Nordics). In the light of challenge, it is important to identify new ways to undertake business. INTEGRATION WITH THE URBAN ENERGY SYSTEM One way is to become smarter, becoming an integrated part of the urban energy system. Today, approximately one fifth of the fuels used in district heating are renewable. One efficient pathway to go fossil free is to recover waste heat. In European district heating networks, 9% of the heat comes from waste heat sources. These are predominantly high tempered originating from industry, the potential of industrial waste heat in Europe can be as high as 2.7 EJ/year. There is however, a growing interest for recovering low temperature heat sources into district heating. Those sources are really smart since they are both local (reducing the transport costs and CO2 emissions from fuel transport) and fossil free (being the result of people living and moving around in cities).

In combination with heat pumps, the low tempered sources found in cities, the urban waste heat, can be an important heat resource in the future fuel mix of district heating. Low temperature heat recovery is gaining attention and an ongoing project under the IEA-DHC framework (the TS2 project on 4th generation implementation found at confirms that there is a low temperature district heating trend. To date, the project has identified over 100 low temperature district heating installations across Europe. In another project, the Reuseheat project (H2020 found at specifically targeting urban waste heat recovery the potential of four urban waste heat sources has been quantified. In the project, four urban heat sources are addressed (heat from metro systems, computer centers, service sector buildings and sewage water). The combined, brute potential of these sources has been assessed to be 1,562.5 PJ/year. SHIFTS IN DISTRICT HEATING GENERATIONS That there have been several district heating generations is known, and the shift from 3rd (current technology) to low temperature installations (4th: low temperature and 5th: ultra- low temperatures) is a nascent paradigm shift. There are many advantages from using the low temperature heat sources. Lower distribution losses and integration of renewables such as solar and geothermal heat have been addressed as explicit advantages. In the Reuseheat project, the low temperature heat sources and their potential to decarbonize Europe are explicit. In a survey addressing five stakeholder groups (policy makers, investors, district heating operators, owners of waste heat and end customers) in eight European countries (Sweden, Denmark, Germany, Belgium, Romania, Spain, France and Italy), it is confirmed that there is an interest in low temperature heat installations amongst all five stakeholder groups. Advantages mentioned are, apart from the distribution costs and increased efficiency of solar heating, a lower need for district heating companies to reinvest in central production units. Instead, the decentralized heat installations can be a more cost-efficient alternative.


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