Together with the designers and contractors, TROX has developed a special concept for this project
The ward block at St. Josef Hospital in Moers is a five-storey building
A special concept was required for the gradual core refurbishment of the ward block while hospital operations were ongoing. The floors will be refurbished one by one in an unknown sequence, starting from the fifth floor. For this reason, a combination of conventional wiring and RadioDuct, the radio-controlled control system from TROX, is being used in the building. The concept was developed in close cooperation with Hein Klimatechnik from Duisburg and the architects Schlapeit PBG and implemented accordingly.
The centralised ventilation unit
The TROX X-CUBE centralised ventilation unit supplies the building from the roof with up to 25,000 m³/h of air. Thanks to the proven and extremely easy-to install design of the X-CUBE, the requirements of VDI 6022 and DIN 1946-4 for hospital hygiene have been exceeded. The integrated measuring and control technology uses the latest bus technology to transmit information. During commissioning of each floor, the parameters of the system are adjusted accordingly; this was taken into account right from the design stage through the additional functions in the control programmes.
The floors are each divided into three areas: patient rooms, corridors and treatment rooms. The temperature and air quality are controlled to meet demand via the X-AIRCONTROL room control system. Since the cable guides are not fixed until each floor is renovated, RadioDuct is being used to avoid increased wiring and long cable routes.
A combined system is installed to control the central air treatment and the temperature; this system also fully automates the ventilation control. For this purpose, it is necessary to install temperature sensors in the supply air, in the exhaust air and in the various room zones.
The ventilation system is operated 24 hours a day, 365 days a year and only provides as much air as is actually needed inside the building and in the room zones.
It supplies the different parts of the building with the ventilation required for hygiene purposes. If necessary, the demand control is adjusted via the in-house technician’s remote control level; the downstream room control zones do not have their own time programme. The fresh air that is introduced undergoes flexible temperature control based on the outdoor temperature; in summer or when cooling is needed, the minimum supply air temperature is 18°C for room zones that are attached to the system, while in winter or when heating is needed, the maximum supply air temperature is 21°C.
To enable the on-site functions, the existing measurement, control and regulation technology (MCR) of the X-CUBE unit was extended to include project-related additional functions in the programming.
In order to visualise the system for the ward block and a further ventilation system including X-AIRCONTROL for the urology department, the system controllers are integrated into the building’s network. Using a web browser, this makes it possible to monitor and operate the systems from a central point.
Intelligent supply air distribution
Supply air and exhaust air fans generate a specific overpressure in the supply air system and a negative pressure in the exhaust air system in order to supply all downstream room volume flow control loops so that the system is supplied with conditioned air as required.
The volume flow control loops are infinitely variable with 50 to 100% of the rated air flow. When the set zone exhaust air temperature of 22°C is maintained or if there is an exhaust air CO₂ content of < 700 ppm, the rated air flow of the zones is reduced to 50%. By increasing the zone exhaust air temperature to 24°C or lowering the CO₂ quality to 1,000 ppm, this is raised to 100%. The zone air flow is continuously reduced with a delay of up to half an hour until the basic air flow is reached in order to ensure that air of a similar quality is achieved in all room air zones.
The air temperature and air quality-dependent zone control ensures that the necessary fresh air is supplied for the people in the building and that the humidity is removed from the bathrooms so that it is not necessary to open windows, as this is disadvantageous from an energy perspective.
The three ventilation control loops per floor have a ventilation function in continuous operation that automatically ensures energy-efficient overall operation of the system. The ventilation control loops are controlled automatically via the ventilation system’s central measuring and control technology; manual intervention is only required for checks and, if necessary, adjustments. For this purpose, the system is connected to the on-site network technology and enabled for access by trained personnel who monitor the system via a web browser.
Energy-saving supply air conditioning
The X-CUBE unit is equipped with energy-saving adiabatic exhaust air humidification. In summer, this system enables the supply air temperature to be reduced by 8 to 10 K without any additional mechanical cooling. The exhaust air is conveyed via the roof and out of the centralised ventilation unit using a directly driven exhaust air twin fan with speed-regulated controller.
Fire technology with a high safety factor
Fire dampers with thermal release and spring return actuators are installed in the fire compartments of the ceilings on each floor and partition walls, as well as in the corresponding shafts. They are triggered at channel temperatures > 72°C via a temperature control. If there is a message from the corresponding limit switch, the ventilation system is switched off and all fire dampers with spring return actuators are closed.
Duct smoke detectors are installed in the supply air and vent ducts. If smoke is detected, the systems are switched off and the motor-operated fire dampers are closed so that any transfer of cold smoke or ventilation flow between the floors is prevented.
The TROXNETCOM-AS-i fire damper system has been integrated to enable a flexible response to future fire safety engineering requirements. By positioning the necessary TROXNETCOM-AS-i controllers both in the field and directly in the switch cabinet of the X-CUBE, gradual inclusion of up to 124 AS-i participants is possible.
