Could HVAC help protect antiquities?

As the world becomes more aware of how critical HVAC&R systems can be in certain industries – such as preserving our food and medicine – there is another area in which HVAC&R may play a crucial role: preserving ancient artefacts.

Researchers from the Aristotle University of Thessaloniki in Greece conducted a study into how climate change may be affecting the environmental conditions within museum microenvironments. Titled Climate Change Impacts on Indoor Cultural Heritage and Collections in Greece, the research tracked the temperatures in two modern museums and one ancient church.

The two museums (the Archaeological Museum of Thessaloniki and the Delphi Archaeological Site and Museum) both have HVAC systems to maintain temperatures. The fifth-century Byzantine Church of Panagia Acheiropoietos has only its walls and indoor heaters.

Efstathia Tringa, a PhD candidate and researcher in meteorology and climatology at the Aristotle University of Thessaloniki, authored the study. She told Kathimerini that “monuments are built to withstand a range of different temperatures”.

“Thanks to our data, we were able to calculate the impact of the climate crisis on artefacts at museums and archaeological sites,” she said.

The findings show temperatures at the church rose in line with outdoor temperatures and stayed only about 5 per cent less humid than outside.

According to the study, “the absence of climate control systems within the church’s interior undeniably plays a significant role in influencing this relationship”.

The two museums maintained a temperature below 30°C, even in extreme heat. They also remained about 20 per cent less humid than the ambient conditions outdoors.

The study highlights how modern HVAC systems can have an important role to play in preserving historical artefacts.

The nuts and bolts

Of course, maintaining these microenvironments within museums consumes a lot of energy. The National Gallery of Victoria (NGV) estimates that more than 60 per cent of energy use in art museums goes towards operating HVAC systems to maintain these controlled environments.

The environment within the NGV is controlled by an HVAC system programmed into the building automation system. According to the NGV website, the system can track temperature fluctuations and relative humidity across the galleries. The NGV also uses specific control measures, or active systems, to monitor the air conditions around sensitive collections that might be affected by environmental conditions. These are displayed in special storage cabinets that maintain a microclimate.

According to the study, factors such as architectural design, location and local climate, natural ventilation, and the use of the building are among the other elements that influence the thermal properties in a building.

Hey fresco

In 2010, international teams from United Technologies and Carrier began work on creating an “invisible” air management solution in the Vatican City’s Sistine Chapel to save Michelangelo’s famous frescos. The sheer volume of visitors was slowly degrading the famous paintings, with approximately six million people a year bringing in heat, humidity, dust, and CO₂. The alternative would have been to close the chapel to the public.

The team came up with a video counting application that can detect the number of people in the chapel and adjust the air flow accordingly. Most of the system is invisible to visitors, and it also operates at “church-quiet” levels. The chapel can now hold up to 2,000 visitors at one time; the previous HVAC system accommodated only 700.