Heating at Floriade 2022 with the Weerwater

The Weerwater recreational lake in Almere can provide five times the expected demand for energy if energy from the surface water is used. Deltares and NUON Warmte studied this option for the Municipality of Almere. In addition to the potential for obtaining heat from the lake, this study looked at the effects on water temperature and flow. The effect on both is minimal.

Sustainability ambitions of the Municipality of Almere

The international horticultural exhibition expo 2022 Floriade will take place at the Weerwater recreational lake at Almere in 2022. The Municipality of Almere wants not only to showcase the latest techniques in horticulture at the event but also to demonstrate how the municipality is contributing to the energy transition by using natural resources from the environment for heating purposes. Initially for the event and later for the 600 homes that will be built on the site.

Thermal potential of the Weerwater

The study shows that the Weerwater is large enough to supply more than five times the expected heat requirement (25,000 GJ annually). The temperature difference in the water due to heat extraction is largest in autumn by comparison with the average water temperature because there is less warm air and solar radiation to compensate for the release of cold water. Furthermore, the releases cause almost no flows in the water.

Effect on water temperature and flow

To determine how much energy the Weerwater can supply, all the relevant heat flows in and from the water to the soil and atmosphere were modelled. In addition, local meteorological records from the Lelystad weather station were used to obtain data about wind, sunlight, air temperature, air humidity and cloud cover.

Minimal spatial impact

The spatial impact for the wells was limited to an access hatch for the well pumps and filter pipes (Figure 1). More space – approximately 100 m² – was required for the surface water thermal energy system. But because this system has to be installed in a cellar to ensure that the pumps work properly, the spatial impact is only minor.