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Clinic saves resources with cogeneration system

According to SPIE’s calculations, the CHP system uses about 26% less primary energy than would be needed for the separate generation of electricity and heat. (Copyright: SPIE Deutschland & Zentraleuropa GmbH)

A system that provides the Klinikum am Bruderwald clinic in Bamberg with heating and cooling, steam, and electricity was crowned system of the year 2018 by the Bundesverband Kraft-Wärme-Kopplung, Germany’s federal association for combined heat and power (CHP) systems – also known as cogeneration systems. The prize-winning combined cooling, heat and power system (CCHP) replaced an older CHP. SPIE Energy Solutions was responsible for the planning and construction of both systems. Bamberg’s municipal utilities are financing the system as the contractor, while the customer and operator is the social foundation running the clinic.

The new CHP supplied by Jenbacher offers an electrical capacity of 1,067 kW and a thermal capacity of 1,200 kW. Of this thermal capacity, 400 kW are contributed by a heat recovery steam generator, which can generate high-pressure steam with 8 bar, for instance for sterilization. To enable better use of its full capacity year-round, the CHP system was enhanced with an absorption chiller with a cooling capacity of 500 kW, transforming it into a (C)CHP system. Thus, a large portion of the heat can be used by the chiller in the summer months. Since the system’s availability is high and the CHP is used an average of 93% of the time over the year, the clinic was able to cover around 50% of its electricity demand and 54% of its heating demand last year.

Use of exhaust heat provides a further 100 kW of heat capacity

The radiant heat from the motor and the heat which has to be removed from the boiler room are also used. This achieves around 100 kW of heat capacity via recirculation cooling devices and a heat pump. The system generates around 8 million kWh of electrical power and nearly 9 million kWh of heat a year in total, as well as approximately 2.8 million kWh of steam and about 270,000 kWh of cooling power.

The social foundation which operates the system saves around €1.7 million each year (plus VAT) and relieves the environment of 7,000 metric tons of CO2 equivalents. As part of an Energy Savings Performance Contract, SPIE had been refurbishing the clinic’s energy supply systems since 2007 and has continued optimizing them ever since. This also includes the lighting system, ambient air and water treatment and a building automation system, among other things.

More information: SPIE