No-nonsense techniques for quality, uninterrupted care at CH Les Viviers

For heating and cooling, we explored various geothermal options:

1. The ‘classic’ closed-loop geothermal system based on Borehole Energy Storage (BES).
2. The possibility of using water from the abandoned mine tunnels beneath the site as an energy source.
3. Utilizing a deep (>2 km) aquifer with a constant temperature of 70°C as a source for heating and absorption cooling.

A test drilling revealed that due to unknown mine tunnels beneath the site, a BES field would be too risky and therefore not a viable option. Similarly, the unpredictability of the underground tunnels made the use of mine water impractical. A deep aquifer, in terms of temperature stability and sustainability, remains an excellent option. However, its high investment cost and excessive available capacity for just the hospital require a broader approach. This solution would need to be considered on a larger scale, potentially involving government or private partners. In such a scenario, the aquifer could serve as the foundation for a district heating network, with the hospital as one of its users—an opportunity for a broader societal discussion.

During the design phase in 2014-2015, we chose a scenario that accounted for the energy transition as much as possible at a time when “full electric” was not feasible. The system includes low-temperature heating and high-temperature cooling. Heating is provided by two gas-fired boilers, while two additional gas-fired boilers are dedicated to steam production and serve as backup for heating via a steam-to-water heat exchanger. Cooling is managed by three water-cooled chillers in combination with cooling towers.

Heat pumps facilitate direct exchange between cooling and heating during winter and transitional seasons, optimizing energy consumption. When outdoor temperatures are sufficiently low, a dry cooler enables free cooling. Additionally, two cogeneration units simultaneously generate heat and electricity.

We also optimized insulation and airtightness within the constraints of a large-scale project.

The hospital is directly powered by the Elia transformer station in Gilly, with two separate parallel feeders ensuring high reliability at the grid level.

Three emergency generators, each with a capacity of 1,500 kVA, provide internal electrical redundancy. They can supply emergency power to the entire hospital except for part of the cooling system. Each building section is reinforced with its own medium-voltage substation, redundant transformers, main low-voltage switchboards, and an uninterruptible power supply (UPS) system. A high-performance and redundant control system monitors and manages all electrical installations.

The hospital also features high-performance low-voltage systems such as a nurse call system, extensive access control, CCTV surveillance, and ICT infrastructure. For the central server room (MER room), the hospital opted for prefabricated containers on the logistics platform, ensuring autonomy and flexibility for future ICT developments.

Water is just as crucial as electricity in a healing environment. The hospital has two storage tanks of 100 m³ each, ensuring approximately eight hours of autonomy at peak consumption in case of a public water supply failure. Domestic hot water production is decentralized per building. Toilets are flushed using rainwater, which is treated and filtered before use via flush mechanisms.