Integrating waste heat and ground-source heat pumps into district heating

Waste heat, ground-source heat pumps, and district heating are each recognized as important elements of the heating transition, but they are still often studied and implemented separately. In a recent paper, published in the Journal Renewable & Sustainable Energy Reviews, researchers examine their synergistic integration and show how combining them within one system can support more flexible and low-carbon urban heating.

The paper addresses a central challenge in this field: although industrial and urban waste heat sources are often abundant and steady, they are typically low-grade and seasonally misaligned with heating demand. By coupling these sources with ground-source heat pumps and district heating networks, it becomes possible to upgrade waste heat to useful temperature levels, store part of it in the ground, and distribute it more effectively across the urban energy system. In this way, waste heat can evolve from a rejected by-product into a dispatchable energy resource, while the subsurface can be used as a managed seasonal storage asset.

Researchers focused on a structured review of the international literature on this topic. They analyzed publications from 2010 to 2025, complemented by selected technical reports and demonstration projects, and synthesized 242 relevant sources.

The review also examined key technical and operational aspects such as energy flow pathways, thermal energy storage, advanced control strategies, seasonal mismatches between waste heat availability and demand, long-term ground thermal balance, and temperature matching between heat sources and loads. In addition, the paper discusses the economic, institutional, and market conditions that influence implementation.

"The added value of this paper lies in the fact that it brings together three research areas that have largely been treated independently: waste heat recovery, hybrid ground-source heat pump systems, and district heating. While previous studies have covered parts of this nexus, this review provides a unified framework that captures their interactions at system level. It shows that the combined use of these technologies is not merely additive but creates new complementarities such as storage-enabled temporal shifting, improved utilization of low-grade waste heat, better long-term ground balance, and reduced reliance on fossil peak supply. At the same time, the paper expands the discussion beyond technical feasibility by identifying market design, tariff structures, and stakeholder coordination as critical conditions for wider deployment. In this sense, the study contributes not only to a synthesis of the state of the art, but also a clearer roadmap for future research, planning, and implementation of integrated low-carbon heating systems" explains A.M. Jodeiri, first author of the work.

Here the link to the original review