Challenge
The Deventer Hospital has about 20,000 in-patients and 300,000 outpatients annually and the highest overall rating of all Dutch hospitals. It is also at the forefront in the field of sustainability. The Deventer Hospital was the first modern hospital in the Netherlands where heat and cold storage (ATES) was an integral part of the building concept.
The original heat pumps are now due for replacement. Based on the CO2 roadmap from 2022, the hospital has entered the replacement process.
The requirements were focused on sustainability and reliability. In addition to a flow temperature of 55 °C, key requirements included future-proof refrigerant, higher energy efficiency, two refrigerant circuits and dual compressors for redundancy, better controllability, ease of maintenance and fast parts delivery.
Solution
It was decided to replace the nine existing heat pumps with nine new Trane RTWD heat pumps operating R1234ze and with High Seasonal Efficiency (HSE) through Adaptive Frequency Drive (AFD) on the compressors. Considering that the heat pumps have had an average running time of 8000 out of a total of 8700 hours, 90% of the time in partial load, the AFD solution made perfect sense.
Trane's solution with inverter compressors was based on technical performance, controllability and efficiency at partial load. The investment decision was substantiated by a TCO analysis, which looked at performance in addition to the purchase costs.
Because operating rooms and nursing wards cannot manage without heating and cooling, the replacement of the old heat pumps with the new heat pumps therefore had to be thoroughly coordinated.
Before the disconnection of the old heat pumps, the hospital's cooling system was connected directly to the thermal energy storage system via a bypass. As a backup for emergencies, the Deventer Hospital already had gas boilers. They temporarily provided heating.
The new Trane heat pumps for the various building parts were installed in basements and on roofs.
Results
The new RTWD heat pumps efficiently produce heat and cold with a future-proof refrigerant and AFD ensures high seasonal efficiency. The RTWD's twin screw compressors offer the Deventer Hospital double security: if one compressor fails, the heat pump will still deliver half of its power.
Energy meters have been installed to collect data and monitor the savings gained from the new heating and cooling plant.
Learn more about Trane's RTWD heat pumps here.
