Hospitals do normally occupy large buildings and are designed for long-term use. The actual lifetime is often longer than 50 years. During their lifetime they will be renovated and retrofitted several times, due to the shorter lifetime of technical equipment, the ageing of the building and the development of new technologies. Hospitals in Denmark are large consumers of energy. They use around 2/3 of the county energy consumption. The energy is mainly used for ventilation, space heating, lighting and for production of domestic hot water. A Danish survey has shown that a systematic approach towards energy savings could reduce the total energy consumption from Danish hospitals with 10-15%. A large part of the Danish hospitals face considerable renovation tasks. This project will serve as a demonstration of renovation of facades and installations in a hospital taking energy efficiency into account. The project aim is to introduce innovative energy efficient design solutions into an existing hospital. The proposers are aiming at reducing the energy demand of the hospital to a level equivalent to or lower than that of new hospitals. For space heating this means a heating demand close to the demand of a building constructed in accordance with the Danish building code of 1995. This will result in a significant reduction of CO2 emissions in the local area.

• To obtain substantial energy savings through utilisation of energy efficient technologies and a systematic approach to energy efficient design
• To significantly improve the indoor climate in the hospital, especially the thermal comfort conditions
• To implement innovative passive and active solar energy components
• To demonstrate and document energy efficient renewals in hospitals
• To inform decision-makers in other hospitals about the possibilities of reducing the energy consumption of hospital buildings

Six different innovative energy efficient design solutions are to be implemented into the renovation of the hospital. Covering courtyards with high performance glazing Three courtyards will be glazed creating a pleasant and attractive patient recreation area. This area will be heated by direct solar gain and comfortable daylight conditions will be provided. The glazing will be high performance double glazing with a low U-value (1,1 W/m²K) and attractive solar and daylight properties. The daylight conditions in the adjacent permanently used offices will also receive special attention as daylight levels here are increased. Furthermore, it is assured that the indoor climatic conditions in terms of indoor temperatures in the closed courtyards are close to optimal. For the new built part of Aabenraa Sygehus (Phase II), the design of the heating supply will be based on the most attractive state-of-the-art techniques identified by the respective consultants. Double skin facade for exploitation of passive solar heating Double skin facades / glazed facades will be implemented in order to optimise the solar and daylight access especially to the bed wards. The double facade has several advantages. By making the outer layer of glass, substantial contributions to the heating demand can be achieved from solar radiation. By letting the cavity between the inner and outer layer act as chimney, it can increase the natural ventilation of the wards on hot days. The resulting heat loss through the facade will be very limited, as it will act as a passive solar collector on sunny days and as a buffer zone on cold days. The proposed design of the facade will reduce energy consumption and at the same time make it possible to increase the window area letting in more daylight, thus increasing the daylight conditions in the building. The hybrid ventilation system is used to ventilate the common areas in the glazed courtyards including therapy areas and patient recreation areas. Besides, parts of the bed wards in the new built part of the hospital shall be equipped with hybrid ventilation. For the glazed courtyards, the fresh air passes through the basement in large closed channels (temperature constant at about 16°C) including filters and convectors for comfort heating. The ventilation system will operate as displacement ventilation. Exhausts are based on roof integrated wind cowls, as the wind load will create a sufficient under pressure in the system ensuring an air change in the courtyard at 1,0 - 1,5 ach-1. The roof integrated wind cowls are equipped with a small back-up ventilator to provide a sufficient ventilation level in periods where the wind load is not sufficient. The roof mounted/integrated solar collectors for domestic hot water are constructed as three separate systems providing hot water for each their section of the hospital. If possible and technical attractive the solar collectors are integrated in the roof lights of the glazed courtyards acting as solar shading during summer. International investigations have shown that hot water cylinders and distribution pipes are a breeding ground for bacteria. Special focus is kept on Legionella (Legionella pneumophila), which can be lethal. For this reason, hospitals facility managers often want to avoid storage tanks and to reduce the length of distribution pipes. Therefore, the three systems are made with separate storage tanks enabling quick ”boosting” of the water temperature which will kill the bacteria. An active hot water solar heating system will heat the domestic hot water and thus in average increase the temperature of the water from approximately 10°C to between 15°C and 25°C. This will reduce the consumption of fossil fuel for hot water production by 10-20%. The complete existing control system is replaced by an advanced Building Management System. The mechanical systems for ventilation, heating and domestic hot water will be equipped with sensors and automatic controls connected to the BMS. The BMS will contribute to a reduced energy consumption, as all temperatures etc. can be controlled far more accurate. Furthermore, this will increase thermal comfort in the bed wards, therapy areas and common rooms. The immediate alarms, generated by the system, contribute to a fast reaction by the maintenance department, when mechanical defects occur. The excess energy consumption arising from defect pumps, valves, dampers etc. will thus be eliminated. The advanced BMS system will also enable an in-expensive and detailed and accurate monitoring of the use of resources in the hospital. The total energy demand for space heating and ventilation is expected to be reduced by 2 700 MWh/year and the electricity demand is expec- ted to be reduced by 200 MWh/year compared to the existing conditions. The reduction in the energy consumption for heating derives from the closing of the courtyards thus reducing the area of facade facing the outside, use of state of the art heating system, use of active solar heating and introduction of the new double skin facade. On top of this, the Building Management System will ensure an accurate control of all energy consuming installations. The savings in the electricity consumption are expected to become effective trough the introduction of natural ventilation reducing electricity consumption, but also the accurate control carried out by the Building Management System will contribute significantly to the savings. In addition, the improved daylight conditions will reduce the electricity demand for artificial lighting. 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