06/23/2023
Source: Energy & Management Powernews
The Institute for Energy and Environmental Research Heidelberg (Ifeu) investigated low-temperature heating systems as a way to implement renewable local heating in municipalities affordably.
In most EU countries, the heat transition away from fossil fuels such as coal, oil or natural gas is on the agenda. This would serve both the secure supply and climate protection. The Institute for Energy and Environmental Research Heidelberg (Ifeu) investigated how low-temperature heating systems in municipalities can implement renewable local heating in an affordable way. As an example, the researchers examined Steinheim an der Murr near Stuttgart.
The city initially supports homeowners with energy advice. If the energy standard of the buildings improves as a result of renovations, a low-temperature local heating network is to be established. "The expansion of low-temperature heat, as in Steinheim, is the right first step to implement the heat turnaround in municipalities," explained Martin Pehnt, study director and managing director of Ifeu.
Low temperature against energy waste
The combination of lowering the temperature in individual buildings and the subsequent expansion of the district heating supply, which is also fed by large heat pumps, is a new way in cities and municipalities to leave the world of oil- and gas-based heating, he said. Older heating systems in Europe often operate at flow temperatures of 70 degrees or more. These high temperatures are not necessary with more modern heating systems.
"Low-temperature systems," on the other hand, operate at less than 55 degrees even on the coldest days of the year. Often it is enough to exchange too small radiators purposefully. Hydraulic balancing of the heating circuit, insulation of parts of the building envelope or replacement of old windows and doors also help to reduce the required flow temperature. "The low temperature level makes the use of heat pumps, solar collectors and district heating more attractive and cost-effective," Pehnt explained.
The neighborhood under study in Steinheim is not actually predestined for the expansion of district heating because of the oil and gas boilers that predominate there and its relatively thin development, Pehnt said. The consulting energy agency, Energieagentur Kreis Ludwigsburg, was nevertheless successful with the idea of offering a cost-effective supply of district heating based largely on renewables. The experience with the enormous energy price increases for gas as a result of the Ukraine war had made the advantages of renewable energies clear to many people,
Refurbish first, then expand district heating
The low-temperature district heating network relieves citizens of the cost and effort of converting their buildings individually. To ensure that all connected buildings are "low-temperature-capable," energy consultations and renovation roadmaps are first prepared. For this purpose, a room-by-room heating load calculation is also prepared.
Because not all buildings are ready for cooler heating from the start, local heating is initially operated at 64 degrees and only reduced to 58 degrees around 2030. The success: on average, heat losses and thus energy costs in the network drop by 30 percent compared to 90-degree systems. As the operator of the district heating network, the municipal company does not aim to maximize profits.
"The experience gained in Steinheim, for example, can be a role model for municipalities throughout Germany and Europe," explains Pehnt. The study "Towards low flow temperatures: Making buildings ready for heat pumps and modern district heat" was prepared by Ifeu together with the NGO "The Regulatory Assistance Project" (RAP). It was funded by the European Climate Foundation and in the process also investigated the transferability of the concept of low-temperature capability to other European member states and the inclusion of supply temperature in support programs, information activities and legal instruments.
At the same time, the authors identify policy frameworks for the heat transition:
- defining a long-term vision of a climate-neutral building stock, prioritizing low-temperature readiness,
- generating and using renewable energy,
- raising awareness of existing heating systems among building owners and industry,
- Integrating low-temperature testing or readiness into inspections, consulting, audits, and assessments,
- Creating a low-temperature readiness indicator and measures to achieve it through energy performance certificates and building retrofit passports,
- Funding programs for retrofit and heating replacement
- Normalizing low-temperature heating through product standards and
- prescribing low-temperature readiness through building codes.
The Study on Low-Temperature Local Heating is available in English on the Internet.
Author: Susanne Harmsen
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