With the combination of the surface water temperature, polder pumping stations and heat and cold storage in the soil, a substantial part of the heat and cold demand of homes and buildings can be met, according to calculations by the Union of Water Boards and Rijkswaterstaat.
Rijkswaterstaat and the Union of Water Boards came up with their plan to use all energy and infrastructure of Dutch waters. The point of the plan is that the surface water contains a lot of heat energy. In the summer that water is around 20 ° C and in the winter around 5 ° C. This means that a great deal of heat can be gained in the summer and coolness in the winter, even if the temperature difference in energy is only extracted from the water by 6 ° C.
Which Power Source Is Most Efficient?
The plan is to use the hot/cold water in the summer/winter to ‘charge’ a heat / cold source in the soil. The heat source is then used in the winter to heat buildings, and the cold source to cool those buildings in the summer.
‘Naturally, there is already heat and cold storage in the soil, but in many buildings, it appears to be difficult to keep the temperature of that soiled storage in balance. With surface water replenishment, that is possible, “says Barry Scholten of the energy technology consultancy IF Technology and creator of the entire concept. “In fact, via the surface water, we can ensure a very stable supply of the storage, which makes it function much better.”
Favorable Environmental Effect
Because the temperature difference caused remains below 6 ° C, the surface water used can be returned to the channels and ditches without any problem. Especially in the summer, the cooling of the surface water used also contributes to the ecological quality of the surface water. Blue-green algae are less likely to grow explosively with colder summer water.
The ground is already there
To use the surface water for storage, pumps are needed, and Scholten saw a nice combination with the equipment that is already on a large scale in the surface water, namely the pumping stations that ensure that the polders remain dry. “Those pumps only run at full capacity at extreme water levels, and therefore have the capacity to also take care of the circulation of surface water to the soil storage.” By using ground, fewer separate installations are needed.
Other Cooling Sources
In urban areas along rivers, the energy potential of the water can often be used immediately, without the combination with soil storage. “The water flowing past contains so much energy that it can be cooled immediately.” An example is the Maas tower on the Kop van Zuid in Rotterdam, which uses the heat energy from the river water.
Coolness can also be obtained from deep puddles, where the water at the bottom has a more or less constant temperature of around 5 ° C. For example, Nuon has been supplying cooling water for more than ten years that it draws from the Nieuwe Meer at a depth of 30 m. That cooling water is used for offices and homes along the Zuidas. The heated return water is returned to the lake via a number of steps at a depth of 15 m, where it releases its heat and sinks further to the bottom.
12% Of The Heat Demand
An inventory of the existing watercourses and ponds, pumping stations, possibilities for heat and cold storage in the soil and proximity to the demand for energy from homes and buildings shows that using this surface water in this way has enormous energy potential. This means that around 12% of the total heat demand of buildings (total of 350 PJ (petajoules)) can be provided and more than half of the demand for cooling (total of 7 PJ). By far the largest share is supplied by the combination of surface water and pumping stations. Scholten: “With such a pumping station it’s no problem at all to provide buildings with heat and cold at a distance of a kilometer.”
Chilled Fish Readily Available
The feasibility depends strongly on local circumstances and is always tailor-made, says Scholten. A favorable side effect is that many pumping stations are due for renovation. “The combination with soil storage can contribute to its financing.”
Furthermore, IF Technology is discussing pilot projects with various water boards. Scholten calls a project in Urk very promising. “We want to use the Vissering pumping station there for delivery to the dozens of fishing companies in the village, which mainly need cooling.”
Surface water apart from providing great energy is also picture-perfect. The way energy sources had been designed and built is way too scenic that you would want to take a quick photo using your best lense and various camera accessories there is. You can take advantage of the energy it brings and the scenic view it offers.