1. 1 Microclimate Simulation for Preservation Presented By: Afaf Aly Badran By: Sabatino Albero Web Address: http://www.architectureweek.com/2003/0924/tools_1-2http://www.architectureweek.com/2003/0924/tools_1-2.html http://www.architectureweek.com/2003/0924/tools_1-2.html http://www.architectureweek.com/2003/0924/tools_1-2 Topic Number: 112 Date: 24 September 2003 Date: 24 September 2003

2. 2 Microclimate Simulation for Preservation In the recent past, preservationists might have used potentially damaging physical probes to study the decay process in old buildings and determine solutions. Today, noninvasive computational fluid dynamics (CFD) analysis software is coming to the rescue.

3. 3 Microclimate Simulation for Preservation Case Study: In an Domus In an ancient Roman structure, The Domus Aurea, Aurea, valuable frescoes are being threatened by variations in temperature and humidity.

4. 4 Microclimate Simulation for Preservation The Domus Aurea ("Golden House") was built in Rome Domus AureaDomus Aurea by Emperor Nero in 64 A.D. by Emperor Nero in 64 A.D. It was richly decorated with frescoes and precious It was richly decorated with frescoes and precious stuccoes and covered in stuccoes and covered in pure gold, representing pure gold, representing imperial Roman architecture imperial Roman architecture at its most opulent. Following Nero's fall in 68, the Domus Aurea was completely buried under Emperor Trajan's baths. at its most opulent. Following Nero's fall in 68, the Domus Aurea was completely buried under Emperor Trajan's baths. The Domus Aurea in Rome. Photo: CISTeC

5. 5 Ever since, the Domus Aurea has survived as one of the world's most architecturally complex underground structures. However, after nearly 2000 years, the elements have taken their toll on this national treasure. Adversely affected by interior microclimatic conditions, the rich frescoes have started to decay. Microclimate Simulation for Preservation Mural paintings inside the Domus Aurea, showing deterioration. Photo: CISTeC

6. 6 Microclimate Simulation for Preservation In 1999, the Domus Aurea has been partially opened to visitors and is scheduled to be fully reopened soon. It was vital to find a solution to the problem of decay before the deterioration became more serious. To study the problem, Italy's Interdepartmental Centre of Science and Technology for Historical and Architectural Conservation (CISTeC) decided to use the CFD software, STAR-CD from the CD adapco Group. Interdepartmental Centre of Science and Technology for Historical and Architectural ConservationCD adapco GroupInterdepartmental Centre of Science and Technology for Historical and Architectural ConservationCD adapco Group

7. 7 The most dangerous factors are: solubilization and crystallization of salts solubilization and crystallization of salts microbiological attack microbiological attack Microclimate Simulation for Preservation Microclimatic variations in temperature, humidity, and airflow contribute to the decaying process. humidity, and airflow contribute to the decaying process. Understanding the Deterioration The decay is part of a complex phenomenon in which:

8. 8 CISTeC decided to use CFD to simulate these conditions to help pinpoint the exact cause of the problem and, hopefully, to suggest a solution. The software is used to simulate and predict how changes in wind velocity, airflow, air temperature, surface temperature of the walls, and humidity could help to prevent further decay of the paintings. Microclimate Simulation for Preservation Using previous studies of other historical underground sites, CISTeC was able to define optimal conditions for the conservation of paintings. These served as a benchmark against which to measure the internal conditions of the Domus Aurea. Approach:

9. 9 The "Room of the Golden Vault" was chosen as the focus for the study, with the expectation of widening the experiment to the entire Domus Aurea if the initial results were positive. Microclimate Simulation for Preservation Geometrical model of the vault Images: CISTeC Model of the vault showing openings studied for their effect on airflow.

10. 10 With STAR-CD, CISTeC analyzed microclimate data in the Room of the Golden Vault for the months of January and August, the coldest and hottest periods of the year in Rome. The data were supported by experimental monitoring of environmental parameters environmental parameters such as relative humidity such as relative humidity and wind velocity. and wind velocity. CFD simulation, showing average velocity due to openings in the vault. Image: CISTeC Microclimate Simulation for Preservation

11. 11 Simulation Results The CFD results showed that openings in the masonry were producing turbulent airflow. It is believed this was causing the frescoes to decay, but for different reasons in different seasons.  In the winter, the optimum temperature for preservation was not being reached.  In the summer, the temperature was high enough, but the humidity was too high. Microclimate Simulation for Preservation

12. 12 Humidity distribution in the simulation with existing openings. Images: CISTeC Isothermal distribution of Inflow of air at 66°F (18.9°C). Microclimate Simulation for Preservation CFD simulation, showing Inlet section of thermal distribution.

13. 13 To find a possible solution to the problem, CISTeC ran another simulation in which the model was modified to close the openings in the masonry. The results indicated that such closures would reduce the effects of the airflow within the Golden Room. the Golden Room. We surmised this would help to preserve the frescoes and to preserve the frescoes and reduce further deterioration. reduce further deterioration. Microclimate Simulation for Preservation Humidity distribution with proposed closed openings. Image: CISTeC

14. 14 The obtained results were in agreement with available experimental data, confirming to CISTeC the accuracy of the CFD analysis. CISTeC now plans to apply the technique to newly discovered and more complex rooms within the Domus Aurea. Microclimate Simulation for Preservation

15. 15 STAR-CD's results have offered an invaluable tool that, together with our knowledge of the complex environment that exists underground, will help us prevent the Domus Aurea from further decay. In addition, the noninvasive technique may be helpful in preserving many other sites of architectural and archeological interest. Microclimate Simulation for Preservation Conclusion

16. 16 End of Show