Thermoeconomic analysis of energy saving measures for hospital facilities equipped with trigeneration plants

Hospital and health care facilities consume a huge amount of primary energy. The use of a trigeneration plant based on an internal combustion engine is a very common and reliable energy measure, widely adopted and studied, for reducing primary energy consumption and operating costs of this type of user. With the aim of further decreasing the primary energy consumption of hospital/health care facilities, additional retrofit energy measures are usually implemented. The aim of this work is to point out that if the retrofit of the hospital is carried out after the trigeneration plant installation, the possible energy and economic savings are dramatically limited by the trigeneration system. Unfortunately, this is a common mistake performed by system designers and facility managers. Conversely, energy saving measures must be performed before the installation of the trigeneration unit since they dramatically affect the selection of its capacity and operating strategy. Thus, the correct approach should consider the trigeneration unit installation only after a deep and carful energy retrofit of the hospital, allowing one to correctly select the capacity of the trigeneration unit. In order to prove this conclusion, a case study is performed for a real hospital in Italy. Here, a trigeneration unit has been installed and then additional energy saving measures are going to be implemented. This analysis is carried out by means of a dynamic simulation carried out using the TRNSYS software. In addition, each considered energy measure is validated against the measured data. The system was simulated in the present scenario where energy saving measures are implemented in the facility equipped with the trigeneration unit. In addition, the correct scenario was also simulated, calculating energy and economic performance parameters in the case in which such measures were implemented before the installation of the trigeneration unit. The comparison of the results proved that it is crucial to implement such energy saving measures before designing and installing the trigeneration unit.