Mijnwater B.V.

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Mijnwater BV is the operating company of the Municipality of Heerlen to develop, exploit and innovate the low-exergy DHC-grid supported by shallow geothermal energy. The project originated from a Interreg IIIb pilot and is developed to servicing heat and cold to 200.000 m2 building area. Mijnwater substantially contributes to the regions carbon neutral goal. By deploying intelligent control and operating on ultra low temperatures a reduction of 50% is realized in used energy sources (exchanging heat and cold and utilizing waste heat). The remaining demand is effectively generated by de-central heat pumps which reach very high CoP’s (up to 8 and more). Mijnwater has the experience of developing a DHC grid in a green field environment and is now expanding its working area towards 20.000 dwellings. LT waste heat is available on large scale in urban environment and Mijnwater aims to gain a large share of its demand from these resources. Mijnwater is able to deliver energetic, financial and technical KPI’s and may act as living lab. Waste heat from data centers and supermarkets is already implemented. A large contribution from industrial waste heat is desirable in order to raise the net energy input and to gain experience in this field. The flooded mines are used to gain geothermal heat and as a large storage provision. The Heerlen grid is divided in 4 clusters of building connections, linked by a 7,800 meters 3-pipe backbone. Operating temperatures are 28 °C for heating and 16 °C for cooling. Modular demand controlled de-central building plants bring the water to the right temperature for the customer, depending on building characteristics. Heat pumps are configured in a cascade setup to provide up to 60 °C for old buildings and DHW. The return flow from heating (which is cold) is re-injected into the grid. If delivering cooling the return heat is regained.

Herman Eijdems