On its four levels, the countless rooms of the main body of the Château de la Bussière house the decorations and collections of the castle, which are exhibited to the public during permanent and temporary exhibitions organized here. This public reception activity, combined with private events (weddings and seminars), is essential for the proper maintenance of the castle, building its reputation, the economy and that of its entire area of influence. This year, new rooms, previously neglected, will welcome beautiful bedrooms that will serve as accommodations for the tenants of the premises. It is a historical revival for this central building, which has not been inhabited for a long time and is finally being reutilized by its current owners, but how can we sustainably heat it ?
Context
The impossibility of insulation
Opening rooms in an old building that cannot be insulated or minimally insulated without altering its character is a significant challenge. The size of the rooms, the cost of energy, and current comfort standards make the task difficult. By considering the closest available resource and the current technological options, the owners were able to find an extremely relevant solution for their monument: hydrothermal heating, also known as aquathermy.
Hydrothermal
Water-to-water heat pump
Heat pumps, which are widely used today, operate relatively simply and economically. By compressing a gas, heat is generated, and during its decompression, cold is generated. The idea is to compress this gas inside the building to heat a hot water circuit, and then decompress it outside to dissipate the generated cold. Therefore, the external environment must be sufficiently warm throughout the year to be able to heat the decompressed gas from the heat pump. This is why they perform poorly in areas with harsh winters.
If the cold gas is not brought back to ambient temperature, it cannot be compressed again to generate heat. Under ideal conditions, this technique can generate up to 4 times more heat inside the building than the electrical energy consumed by the system. This is particularly advantageous for heating energy-intensive buildings such as castles during winter!
The pond
The ideal environment for cold dissipation
The Château de la Bussière has a particular architectural feature: it stands on a 6-hectare artificial pond. Fed by a stream, the temperature at the bottom of the pond remains constant throughout the year, thanks to the significant thermal mass provided by the water. It was only natural, then, that a thermal exchange system was installed here to efficiently capture the ambient temperature, which would effectively warm the decompressed gas of the heat pump throughout the winter. This system would continuously operate, heating dozens of radiators required for the hotel activity, with minimal impact on cooling the bottom of the pond. It's worth noting the system's invisibility, whereas air-dispersed heat pumps require large external ventilation units.
The investment is significant, and the installation was not straightforward. Estimated at around €135,000 (based on our conversations with the owners), the price difference compared to installing a conventional heating system would be recouped in less than 5 years due to the energy efficiency of the system.
コメント