Optimisation of the Physical Climate Comfort in Hospital Bedrooms

Hospital patients need to be protected against the harmful medical side-effects of thermal discomfort during very warm periods. Not only the elderly but also infants and people suffering Parkinson desease, demention or heart and vascular desease are sensitive to heath strokes.

A well-designed façade and an adapted heating, ventilation and lighting system, adapted to the specific needs of the patients and supplying passive cooling at overheating, has been researched for. A condition is to achieve simple and cheap interventions via passive climate techniques. There has been started from the existing installation complemented with automatically/non-automatically controlled solar shading (in particular inner Venetian blinds) and eventually coupled with automatically controlled lighting. To optimise the system, the effective utilisation of the solar shading and the lighting is examined. The capabilities of the ventilation systems with natural air intake are analysed. Finally, the energy consumption of the complete system is calculated and evaluated.

There are existing models describing the effective utilisation of the solar shading and the lighting systems in the case of offices. In the case of hospitals there is a lack of information. The behaviour in hospital bedrooms is definitely different (patients are recovering day and night and are not at work, personnel and patients do have divergent comfort needs). In which way these models can be applied anyway will be investigated.

Not only human factors but also the solar irradiation and the position of the sun are playing a role. It is common to use Venetian blinds to shield direct sunlight on the task surface above 50 Wm-2. Above this limit value, the degree of closing is proportional to the penetration depth in the room. Direct sunlight below 50 Wm-2 entails the opening of the Venetian blinds. The design of the building has equal importance. The geometry, the applied internal and external materials, the implanting in function of the other buildings, the position of the windows, the ratio of window to floor area and the orientation of the façades are determining.

To analyse this complex matter and to be able to test numerical simulations, a number of practical case studies are elaborated.
A number of parameters have been measured.
Indoor parameters are f.i. direct and diffuse illuminance; luminance distribution; colour; temperature; status of the artificial lighting (on/off - dimmed); global solar radiation on a horizontal surface; status of door openings.
Outdoor parameters are f.i. status of the sun shadings; status of the window openings; solar radiation intensity; direct and diffuse illuminance on the façade; temperature.

An enquiry on the visual and thermal comfort with the medical staff and patients will be carried out. All data will be statistically processed, resulting in a comfort model. On this basis, solutions can be put forward to ameliorate the visual and thermal comfort of patients in the rooms. Moreover, the model serves to predict the behaviour of patients and of the real energy consumption and heath gains and losses of the hospital bedrooms.