Energy efficiency in hospitals: comparative analysis of different HVAC configurations

ABSTRACTThe characteristics of health facilities e.g. the need to operate 24 h a day, strict cleaning procedures and indoor environmental parameters made these building-type energy-intensive. The huge potential that can be exploited in terms of energy savings is evident, mainly regarding the HVAC system refurbishment. From literature emerges that there are poor systematic analyses concerning all the possible HVAC retrofit scenarios, considering solutions currently on the market or renewable sources. To fill the research gap pointed out, the present paper proposes a rigorous analysis of the possible generation subsystems available on the market that can be implemented in an HVAC retrofit for a hospital. A real case study of 88,000 m3, represented by a hospital in southern Italy, has been used. Different technologies, such as the photovoltaic system, electric heat pump, absorption heat pump driven by solar energy, cogeneration are analysed from the energy and environmental point of view, with the introduction of the Imported Energy Level Index (IELI). The best retrofit measures is the installation of an absorption heat pump driven by solar thermal collectors and cogeneration, with a primary energy saving of 20%. Considering the installation of a heat recovery unit, the saving is up to 43%.KEYWORDS: Energy savingHVAC hospital building refurbishmentcarbon dioxide emission reduction‌renewable sourcesImported Energy Level Index NomenclatureCO2=Carbon dioxide emission [kgCO2/y]E=Energy [GWh/y]IELI=Imported Energy Level Index [%]PES=Primary Energy Saving [%] Greek symbolsα=Emission factor for electricity generation [gCO2/kWhel]β=Emission factors for natural gas [kgCO2/kWhEp]η=Efficiency [-], [%]Δ=Percent variation with respect to base case [%] SuperscriptAHP=Absorption Heat PumpAHU=Air Handling UnitB=BoilerBMS=Building Management SystemBS=Base CaseCHP=Combined Heat and PowerDHW=Domestic Hot WaterEHP=Electric Heat PumpE-L=Electric LoadsFC=Fan-coilfg=fed into the gridHWST=Hot Water Storage TankISPRA=Istituto Superiore per la Protezione e la Ricerca AmbientalePAC=Proposed Alternative CasePP=Power PlantPV=Photovoltaic systemR=RadiatorsSTC=Solar Thermal Collectorsuos=Used on-site Subscriptco=Coolingel=Electricp=Primary energyth=Thermal AcronymsAHP=Absorption Heat PumpAHU=Air Handling UnitB=BoilerBS=Base CaseCHP=Combined Heat and PowerDHW=Domestic Hot WaterEHP=Electric Heat PumpFC=Fan-coilHWST=Hot Water Storage TankPP=Power PlantPV=Photovoltaic systemR=RadiatorsSTC=Solar Thermal CollectorsVFD=Variable Frequency DriveVP=Variable PitchDisclosure statementNo potential conflict of interest was reported by the author(s).