The challenge of installing a heat pump in existing buildings is a lot greater than in a new-build home. And when the demand comes from a 14th-century castle, the challenge is many times greater even more …

Castle de Merode in Westerlo is a historic castle with a rich history surrounded by a moat, an ideal source for aquathermal energy. EXTRAQT performed the necessary feasibility analyses at the moat before putting the project into practice.

A Digital Twin was drawn up of the moat to model the cooling of the water when the entire heat demand of the castle is extracted from it. This involves dividing the water into different layers and dynamically simulating the thermal effects – both natural and anthropogenic. In a scenario analysis, energy, financial and ecological evaluations were made for different concepts. The scenario analysis showed a 50kW aquathermal plant supported by the existing CHP and gas plant to be the most optimal. In addition to an economic benefit, this also achieves CO2 savings of 50%.

This made aquathermal energy a no-brainer for the castle in Westerlo, after which the installation could be installed. EXTRAQT worked together with Eco-technix to implement the installation. A pond or water lock is ideal for a closed aquathermal installation, in which the heat exchanger is placed directly in the water.

The following installation was realised for the Castle de Merode:

• Eco-forest High Power 15-70 modulating water-to-water heat pump
• 24 MultiQ panels 65 cm high and 3.5 m long with a total heat exchanger area of 70 m2

The aquathermal heat exchangers in the moat form the source for the heat pump. It is a closed circuit, filled with water and glycol. The heat exchangers were placed in the moat and connected to the heat pump in the castle via 100 m of piping.
The heat generated by the heat pump is delivered to a buffer tank. From the buffer tank, the radiator circuits are fed. The output temperature of the heat pump is 53°C, at which the heat pump already achieves a SCOP of 3.2 after a few cold winter months.