PSI - Issue 29

Alessandro Miglioli et al. / Procedia Structural Integrity 29 (2020) 118–125 Mignoli et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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simula ting the sa turation of the armoury hall during crowded events, while no people occupancy in winter, as this parameter affect the internal ga in. Average annual hea ting and cooling demand (Simula tion B) were ca lculated considering 50 visitors per hours, as foreseen by the Pa lazzo Ducale administrations, while hea ting and cooling setpoint were set to reasonable values.

Table 1: Assumptions made in the dynamic energy analysis. Simulation parameter

Simulation A

Simulation B All the year

Winter

Summer

Building’s usage profile:

Opening hours from 8 to 19 every day. From 15 October to 15 April (180 days)

Heating period

Heating set-point air temperature Cooling set-point air temperature

22 °C

-

20 °C 26 °C

-

24 °C

Occupancy

0 people 0 W/m 2 0.15 vol/h

100 people

50 people

Internal electric loads Air Change Rate (ACH)

4 W/m 2 0.3 vol/h

4 W/m 2

0.15 vol/h

According to the results of simulation A, the maximum thermal power in the design day conditions resulted equal to approximately 70 kW, indeed eachHVAC configurations is sized on tha t peak thermal power. Simulation B was instead carried out to foresee the thermal energydemandof thebuildingduringa typical year. Energy demand of 107 MWh/year and 66.4 MWh/year resulted respectively for heating and cooling, corresponding to approximately 108 kWh/m 2 per year and 65 kWh/m 2 per year. Through these results, in the following sections, the energy performance of three different heating/cooling stra tegies will be eva luated, discussing their integra tion in the armouryhall and the globa l cost of each solution. 4. Technical description of the heating/cooling strategies and calculation of the investment cost In the present section, the different heating/cooling stra tegies that were considered feasible for the specific application, are described under the technical point of view. For each scenario, the electrical consumption and the tota l primary energy demand was calculated considering specific technical systems features, daytime operation and assumptions, as described in each section. All the solutions involve the use of wa ter-condensed heat pump (HP) genera tion systems usinggroundwater or geothermalwells. At present, the water-sourceheat pumpcanbe considered the best available technology on the market for heating and cooling in buildings, as its performance is marginally affected by clima tic conditions (e.g. the ambient air temperature). The three proposed systems described in the following sub-sections. 4.1. All-air system The a ll-a ir system for heatingandcoolingconsists of a water-source HP, theair handlingunit (AHU) anda Variable Air Volume (VAV) distributionandemission subsystem. In detail, the HP provide hot and cold water to the AHUand hea t distribution/emission subsystems which are regula ted in order to optimally control the a ir-conditioned area occupied by visitors. In this way, a ir conditioning consumption are reduced, and alterations of microclimatic conditions can be minimized, preserving the state of conservationof the existingwooden structures. The wa ter supply is guaranteed by withdrawal/rejection groundwater wells (GW), o r a lternatively a system of vertica l geothermal heat exchangers (GHX). The heat distribution/emission and air treatment system indeed consist of the followingmain elements: • AHU with ra ted airflow equal to 9000 m 3 /h of which 6000 m 3 /h maximum for recirculation for heating/cooling, humidification/dehumidification and filtration of the supply a ir in the room. • All-a ir distribution andemission systemof the VAVtype in a ll areas of the armouryhall.