10:30am - 10:45am
Historic Indoor Microclimate, the role of HVAC in heritage buildings’ restoration: the case of the Palace of Venaria Reale.
University of Bologna Alma Mater Studiorum, Italy
The paper is aimed to illustrate how the study of the indoor microclimate, supported by the virtual simulation and by the knowledge of the historical evolutions of the building (managerial, usage and architectonical changes over the years), represents a preventive practice which allows to evaluate and predict the interactions between the object and the environment.
To do that the authors present a case-study: room 33 in the Palace of Venaria Reale, in Turin, Italy, on which we applied a specific methodology: the study of the indoor microclimate of room 33, combined with the data analysis and virtual simulation, allows to assess the state of conservation of the artifacts hosted inside the building, and the comfort conditions of workers and visitors in that space.
We have reproduced a virtual model -Virtual Building 1- which presents the same indoor and outdoor microclimatic conditions of the original building. Moreover, we evaluated an alternative scenario: Virtual Building 2, that simulates the indoor microclimate of room 33 considering the HVAC systems continuously off, with the aim to present how the virtual simulation can verify preventively the consequences resulting from managerial changes (activation/shutdown of the HVAC system).
The comparison between the two virtual buildings allowed to estimate the impact of the HVAC system on the preventive conservation of the historical building, of the artefacts and of the occupants’ thermal comfort. Those simulations claridied which indoor microclimatic conditions could be guaranteed by the building itself, after the restoration project started in 2001.
The results show that, without the HVAC systems the building couldn’t guarantee proper indoor microclimatic conditions for the occupants’ comfort and not even for the preventive conservation of the artifacts and the building: in this case the HVAC systems allows to dissociate the formal and material characteristics of the building from its microclimatic performances.
10:45am - 11:00am
Hygrothermal assessment of internally insulated historic solid masonry walls with focus on the thermal bridge due to internal partition walls
1Technical University of Denmark, Department of Civil Engineering, Brovej, Building 118, 2800 Kgs. Lyngby; 2Aalborg University, Department of the Built Environement, 2450 Copenhagen, Denmark
Internal insulation of solid masonry walls incurs a risk of high humidity in the masonry/insulation interface. However, it is often the only possibility in the case of historic buildings. Partition walls will act as thermal bridges, where there might be an increased risk of mould growth. The study investigated the hygrothermal performance of five thermal insulation systems for internal retrofitting purposes. Focus was on the hygrothermal performance near partition brick walls compared to the middle of the wall. The setup consisted of two 40-feet (12.2 m) insulated reefer containers with controlled indoor climate, reconfigured with several holes (1x2 m each) containing solid masonry walls with embedded wooden elements on the interior side, an internal brick partition wall and different internal insulation systems, with and without exterior hydrophobisation. Relative humidity and temperature were measured over five years in the masonry/insulation interface and near the interior surface, in the centre of the test field and near the internal partition wall. In addition, calibrated numerical simulations were performed for further investigation of the thermal bridge effect.
Findings for the masonry/insulation interface show higher temperature and lower relative humidity near the internal partition wall in comparison with the central part of the test wall. Near the interior surface, the measurements show lower temperature and higher relative humidity near the partition wall in comparison with the central part, potential with risk of fungal growth. The effect was enhanced if the driving rain was limited either by orientation or hydrophobic treatment.
11:00am - 11:15am
Active Environmental Conditioning Strategies for Brick Historical Buildings, Combining Heritage Conservation and Thermal Comfort
1School of Architecture,Southeast University, Nanjing, PR China; 2Key Laboratory of Urban and Architectural Heritage Conservation of Ministry of Education (Southeast University), Nanjing, PR China
The application of HVAC system in historical buildings can elevate the indoor comfort level for users, but at the same time undesirable effect may also be brought to the heritage preservation environment. It is a challenge to utilize HVAC system to improve the thermal comfort within a reasonable range without increasing the risk of building deterioration. This research selected a traditional temple building located in Hubei Province, China, aiming to clarify the impact of different operation modes of heating system on the heat and moisture behaviour and deterioration risk of the building walls, and to further propose reasonable active environmental conditioning strategies. A two-dimensional hygrothermal model of the temple building was first established, and the model was calibrated using the temperature and humidity field monitoring data. Secondly, for the underfloor heating system in the building, the simulation model was used to evaluate the influence of different heating parameters, operation schedules and ventilation strategies in heritage conservation and thermal comfort. The main conclusions are as follows: with low heating level, the evaporation of floor heating area is higher, but when the temperature setpoint raised to a certain level, the evaporation will decrease and the indoor environment will become dry. In the case of intermittent heating, maintaining low level heating at night can better reduce the evaporation level of indoor envelope surface than directly shutting down the system, which is more conducive to the protection of heritage; In addition, even the most conservative heating scheme (14 ℃) can significantly reduce the user's cold feeling and improve the comfort. If applied properly, the active control including the equipment application can become a reasonable and appropriate measure to protect the cultural heritage.
11:15am - 11:30am
Diurnal winter thermal profiles and thermal comfort in historical housing – mixed methods field study.
Wroclaw University of Science and Technology, Poland
In winter thermally inefficient building envelopes of pre-retrofit historical housing allow for ca. sevenfold higher heat loss from heated apartments than the new built housing in Poland. As a result space heating in pre-retrofit tenements is regarded to be highly energy demanding and costly if the internal temperatures were to be kept on average at standard 20oC assumed in building regulations. In this field study, carried out in January-March 2020, we investigated diurnal thermal profiles and the associated thermal comfort in historical tenements both pre- and post-retrofit. The 16 apartments participating in our research were equipped with heating systems prevalent in Polish urban historical buildings, i.e. solid fuel stoves, electric heating, district-supplied central heating, or individual gas boilers. The former systems provided intermittent local heating while the latter central heating with thermostats. Our research comprised spot check multi-parameter measurements and continuous monitoring of the thermal environment, together with a longitudinal thermal comfort questionnaire survey (N=.2539), energy consumption analysis and semi-structured interviews with the residents. The differences detected in average (12.6oC) and range (up to 4.2oC) of diurnal temperatures did not explain the thermal comfort survey results on individual thermal sensations and preferences. What proved more important for the residents was the time of day when the maximum or minimum temperatures occurred and their perceived control over temperature and the cost associated with heating. Accordingly, we identified a need for further studies investigating the link between domestic thermal comfort and satisfaction with the usability of heating system and control over the cost of heating.
11:30am - 11:45am
Assessment of Deterioration Risk of Maijishan Grotto under the Radiation Difference Based on Heat and Moisture Transfer Model
1School of Architecture, Southeast University, Nanjing, 210096, China; 2School of Architecture Internationalization Demonstration, Southeast University, Nanjing, 210096, China; 3Art Institute of Maijishan Grotto, Gansu, Tianshui, 620503, China
The ambient environment of architectural heritage is an important factor affecting its conservation. Two adjacent rows of Buddha statues in Grottoes No. 3 (semi-open) of Maijishan Grottoes in Gansu, China, show apparent differences in the degree of deterioration. This study made a monitoring scheme of grottoes microenvironments such as air temperature, relative humidity, radiation, and surface temperature to explore the cause of the difference. A two-dimensional heat and moisture transfer model was established and verified to simulate the temperature and humidity fields on the surface and inside of the Buddha statues. Then, temperature and humidity fluctuation and the risks of freeze-thaw destruction on the surface of the Buddha statues were evaluated. The results show that the radiation difference at different heights is the main reason for the different deterioration. The eaves shaded the upper of Buddha statues not only much longer but also more often than the lower ones. This study evaluates the degradation of Grottoes No. 3 in Maijishan Grottoes in the semi-open environment, which has guiding significance for its preservation methods and the design of protective eaves.
11:45am - 12:00pm
Hygrothermal Evaluation of Waterline Rising of a Masonry Tower based on Measurements and Simulations
1School of Architecture, Southeast University, 210096，Nanjing, China; 2School of Architecture Internationalization Demonstration, Southeast University,210096 Nanjing, China
Wet walls in ancient masonry buildings are common due to rainfall, groundwater and other environmental factors, and usually accompanied by the degradation phenomena such as powdering, shedding, salting out, which threatens the value and safety of ancient buildings. It is found that the bottom of Dayan Pagoda, the earliest and largest existing brick pagoda of the Tang Dynasty in China, which was built more than 1400 years ago, has been damp and gloomy for a long time. In recent 40 years, the waterline at the bottom has risen by about 0.5 ~1m, and the wet area on the north wall is even as high as 5m, as shown in Figure1.
In this research, a field survey and numerical simulation were adopted to clarify the cause of the rising waterline and the source of water of Dayan Pagoda. The moisture distribution and waterline height changes of the east, south, west and north walls of Dayan Pagoda from 2018 to 2020 were observed and recorded. The correlation between degradation of Dayan pagoda and environmental factors such as temperature, humidity, rainfall and solar radiation was established. Then a coupled heat and moisture transfer model is developed to obtain the heat and moisture distribution in the brick wall and evaluate the impact of rainfall and groundwater. Finally, the trend of waterline rises and deterioration in the future is predicted by simulation.
The measured results show that during 2018-2020, the waterline of the west wall of Dayan Pagoda has the largest rise (about 20cm), while the south wall has the smallest rise (about 10cm). The simulation results show that the water source of rising waterline is mainly rainfall rather than groundwater rising. The result contributes to propose environmental control measures to alleviate the degradation of masonry buildings caused by water.