Hangzhou is a pleasant city with a population of around 9 million (2015), located in the Chinese Province of Zhejiang, approximately 1 hour by train south of Shanghai.
It is located near the end of the Grand Canal, the oldest and longest man-made waterway in the world, built to connect Beijing with Ningbo, on the eastern coast, and support commerce to and from the capital; some 1100 miles (1800 km) long, construction began in the 4th century BC, and it has been used ever since.
By Groverlynn - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=51142376
Hangzhou’s West Lake, a UNESCO World Heritage Site, immediately west of the city, is one of its best-known attractions, with numerous temples, pagodas, gardens and lotuses.
Thanks to its fortunate position, Hangzhou has flourished over the centuries, accumulating wealth and triggering new ventures, such as e-commerce giant Alibaba, whose headquarters are in the city; it is for the same reason that Hangzhou will host the 2022 Asian Games.
Wealth often accompanies works of art, as wealthy people, especially in the past, used to host and mentor artists and scholars, who were thus able to advance their studies in various fields and create the masterpieces that we can nowadays admire in museums. This happened not only in Hangzhou, but also in thousands of other locations across China: for instance, to mention just two, Beijing with its Forbidden City, and Xi’an with its terracotta warriors.
There are many works of art still stored in warehouses across China, which, if exhibited, could boost tourism and further support the growth of the Chinese economy. The Chinese Government has expressed the need to exhibit more works, and consequently an estimated 3000 new museums (approximately 10 million m²) will be built by 2020 (the existing museums are in fact not sufficient to display all the stored artefacts).
Artefacts and works of art require stable air conditions to be properly preserved and protected from both contact with the public and the environment inside the display cases in museums, which is always very different from that of the spaces where they were previously stored, be it underground or in warehouses “hidden” from the influence of people.
A conference dedicated to this topic was held in Hangzhou on 23-24 August 2018, entitled: the “2nd Cultural Heritage Preservation Environmental Monitoring and Control Technology conference” (the 1st was held in 2016).
The speakers (all scholars, actually) and audience met to exchange ideas and learn from each other regarding the available and state-of-the-art solutions for closely controlling the air conditions so as to best preserve artefacts. The most important parameters examined were: pollution, which must be low as it is aggressive to materials; and humidity and temperature, which must be stable within ranges that depend on the materials (with humidity being a bit more important than temperature).
It is important to point out that, before exhibiting artefacts, these often need to be recovered (dug out, in many cases), cleaned and prepared for display in museums. When a piece is rediscovered, it is clearly not in the same conditions as when it was originally made: time and the place where it was stored for a long time always affect the object, or better, cause it to deteriorate. Such deterioration, indeed all changes to the original, become part of the artefact’s history: they testify its age, what has happened to it over time, the events it has experienced, so that, even if it now looks different from the original, the artefact has an intangible and fundamental value that is intrinsic in its current aspect, thanks to all of the historic changes it bears. As such, artefacts must be not restored to their original state, but rather must be cleaned and conserved so that they show all of the tiny details engraved in them and caused by the course of events. Their current aspect expresses the “sum” of the history they have witnessed: if we tried to restore artefacts to their original conditions, we would destroy the evidence of history.
This is one great example: the Pazyryk Carpet
“One of the oldest knotted carpets was discovered in 1949 by Professor S.J. Rudenko’s team at a rich archaeological site in the Altai mountains in southern Siberia. During excavation of the site, in the tomb of a Scythian prince, a carpet with a very sophisticated motif was discovered. It had remained frozen in the ice and was therefore preserved in its original state. The Pazyryk Carpet, named after the valley where it was found, dates back to the 4th-5th century BC and is on display at the Hermitage Museum in St. Petersburg” . Just think if the carpet were to be restored to its original conditions using the textiles available nowadays: it would be pure folly. The carpet is beautiful and valuable for how it is now, with all the history it bears.
This concept was presented by Professor Gabriella Guarisco, Senior Associate Professor in Restoration at the Politecnico of Milano, during her opening speech, one that was much appreciated by the audience and the organisers, CAR, the Chinese Association of Refrigeration.
CAREL INDUSTRIES S.p.A. had been invited by CAR to contribute to the conference for two main reasons: firstly, because CAREL Industries SpA is an Italian company and Italians have extensive knowledge on the conservation of works of art; secondly, because CAREL Industries SpA has the knowledge and solutions for properly controlling air conditions. The honour of being invited, apart from the evident business opportunities, was greatly emphasised by the fact that we were the first non-Chinese speakers at the conference.
Finally, it is worth mentioning that evaporative cooling was more than once reported as an efficient way to combine energy saving with humidification.
What can we learn from the conference?
First of all, each country’s history must never be neglected: rather, it must be “displayed” in an open and honest way, without patching up and restoring artefacts and possibly destroying their historic value.
Secondly, history, properly shown and displayed through museums, supports tourism. And teaches people.
Thirdly, only companies that develop more detailed knowledge on an extensive range of applications can participate in such challenges. Which is what we continue to do at CAREL.
Artworks sensitivity to relative humidity
The materials used in artworks and their reactions to fluctuations in relative humidity