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Le chiese costituiscono un patrimonio inestimabile di oggetti sacri e di culto, reliquie, opere d'arte, organi, costruzioni monumentali, arredi, decorazioni, non inferiore a quello contenuto in musei e palazzi storici. Questo patrimonio che in seguito viene indicato con il termine beni culturali, va preservato da costanti ingiurie ambientali. I beni culturali sono sensibili alla temperatura e all'umidità relativa e negli anni si sono adattati al particolare microclima locale, ai suoi valori medi e alla sua variabilità. Molte chiese, rimaste per secoli al freddo, ci hanno tramandato numerosissime opere in buone condizioni, ma negli ultimi decenni, dopo che ha preso piede l'uso del riscaldamento, il loro stato di conservazione ha subito un pesante contraccolpo. Sono possibili due strategie di riscaldamento delle chiese: 1) riscaldare l'ambiente destinato ad accogliere le persone (riscaldamento generale); 2) lasciare l'ambiente freddo e cercare di riscaldare solo le persone (riscaldamento localizzato). Il riscaldamento generale ha il vantaggio di utilizzare tecniche tradizionali, ben note; comporta però un grande spreco energetico, ma soprattutto un alto rischio di provocare danni alle opere. Nel riscaldamento localizzato, invece l'utilizzo mirato del calore consente una ridotta dispersione e quindi un basso costo energetico, e soprattutto offre ai manufatti condizioni microclimatiche imperturbate, senza rischi per la conservazione. L'oggetto della presente guida è fornire un supporto scientifico per la scelta e l'uso del sistema di riscaldamento e per ridurre al minimo le conseguenze negative ai fini della conservazione. Il problema nella sua complessità è enorme, date la quantità, la qualità, la varietà e la delicatezza dei manufatti presenti nelle chiese. Questa guida non ha l'ambizione di chiarire tutti gli aspetti della questione, ma cerca semplicemente di far capire a quali rischi per i beni culturali possa portare un sistema di riscaldamento, suggerendo che questi rischi vergano sempre affrontati e discussi da esperti nelle varie problematiche coinvolte.

In this research, a study is being performed on a local radiant heating system which purpose is to avoid damage to the monumental building and its interior, while creating a local thermal comfort zone for the people who are seated in large spaces / buildings. This purpose is met by radiating heat to the people directly, thus creating a comfortable climate zone around the people, instead of heating the whole (large) room. This way, the overall indoor climate is not influenced greatly by the heating system. As a result, the building and its interior objects are not exposed to abrupt changes in indoor climate (temperature and relative humidity) which can cause great damage to them. Apart from reducing the risk on damaging the monumental objects and increasing the human thermal comfort, the local radiant heating system should also reduce the energy consumption. This research is performed within the European project "Friendly Heating". A case study within this project is the application of the local radiant heating system in the St. Maria Maddalena church in Rocca Pietore (Italian Dolomites). The indoor climate in the church in the Dolomites is quite cold for European standards. Since a lot of problems (concerning the conservation of historical objects, the thermal comfort of people, and high energy costs) occur due to heating the whole church during winter, this situation is investigated in the European project. To find a solution for all these problems, within the European project a local bench heating system is being designed. The goal of this heating system is to provide the heat only in the benches, where it is needed for creating a comfortable local climate for the people. The system consists of 3 heating elements, based on radiant heating foil and placed under the seat, in the back and under the kneeler pad of the church benches. These elements radiate the heat to the people directly instead of heating the air first.

De meeste kerken in Nederland hebben een luchtverwarmingssysteem. Deze systemen verwarmen het gehele luchtvolume en kennen 3 soorten problemen: I ) thermische stratificatie, 2) abrupte veranderingen in temperatuur (T) en relatieve vochtigheid (RV), en 3) een hoog energieverbruik. Voor voorbeelden van deze problemen, zie de bijdrage van Henk Schellen in dit Bouwfysicablad over klimaatbeheersing in monumentale kerken. In dit onderzoek is een studie uitgevoerd naar een lokaal bankverwarmingssysteem. Dit lokale systeem heeft tot doel, schade aan het monumentale kerkgebouw en het interieur te vermijden, terwijl er wel een thermisch comfortabele zone wordt gecreëerd in de banken waar de mensen zitten. Dit wordt gerealiseerd door stralingselementen toe te passen die de warmte direct naar de mensen stralen, zonder de gehele (grote) ruimte te verwarmen. Op deze manier wordt het algemene binnenklimaat zo min mogelijk beïnvloed: het gebouw en het interieur worden niet blootgesteld aan abrupte veranderingen in het binnenklimaat (temperatuur en relatieve vochtigheid) die schade kunnen aanrichten. Behalve het verminderen van het risico op het beschadigen van het monumentale interieur, en het verhogen van het thermische comfort, verlaagt het lokale bankverwarmingssysteem ook het energieverbruik. Dit onderzoek is uitgevoerd binnen het Europese project "Friendly Heating': Als case study binnen dit EU-project is een lokaal bankverwarmingssysteem toegepast in de St. Maria Maddalena kerk in Rocca Pietore (Italiaanse Dolomieten). Het binnenklimaat in de kerk in de Dolomieten is vrij koud voor Europese begrippen. Aangezien heel wat problemen ontstaan zijn door het verwarmen van de gehele kerk met het oorspronkelijke luchtverwarmingssysteern tijdens de winter, is deze situatie onderzocht in het Europese project.

Electron probe X-ray microanalysis (EPMA) of single particles and energy dispersive X-ray fluorescence analysis (EDXRF) were applied to determine the chemical composition, size and probable origin of the suspended particulate matter. The aim of the performed research was to determine the chemical composition, size and abundance of aerosol particles responsible for blackening and soiling of the works of art displayed within the Cathedral of Weert in the Netherlands and to verify the possible sources responsible for these processes.

In het kader van een Europees onderzoek wordt een lokaal verwarmingssysteem voor in kerkbanken ontwikkeld. Het doel is een verwarming te ontwerpen die voorziet in een thermisch comfortabele situatie voor de kerkgangers en die het behoud van interieur en kunstwerken waarborgt. In dit onderzoek zijn metingen gedaan aan het lokale thermische klimaat. Deze metingen zullen worden gebruikt voor de verificatie van simulaties. Tevens is aan de hand van metingen aan het thermisch klimaat en onderzoek met proefpersonen het thermisch comfort van de kerkgangers geëvalueerd. Hieruit blijkt dat met het in deze studie gebruikte proto-type verwarmingssysteem geen comfortabele situatie wordt gerealiseerd.

Within the European project "Friendly Heating" [8] a local bench heating system is being designed. This local heating system is designed to only heat the area where the churchgoers are sitting, instead of heating the whole church. In this way, damaging the building and it’s interior is prevented. The first software tool evaluated in this paper is "WaVo" [7]. This tool allows one to perform computer simulations of the whole building. The second tool presented here, is the CFD program "Fluent" [2], which allows one to perform simulations on the local climate (including air velocities) in the benches.

Within a European research project on the heating of churches a local heating system, mounted into the pews, is being developed. The goal of the project is to design a heating system that provides a comfortable climate for people and that is compatible with the preservation of historical churches and their interior. The evaluation of different variants of the pew heating system by using Computational Fluid Dynamics (CFD) plays an important role in the design study. These CFD calculations should be verified with measurements in order to obtain reliable results. First a simplified environment with known boundary conditions was used to determine the characteristics of the heating systems, both in CFD modeling and measurements. In this paper the measurement set-up and methods as well as the qualitative and quantitative outcomes are presented. The measurements of air temperatures, surface temperatures, air velocities and the visualization of the airflows in the set-up are used for verification. The first simulation results show good correspondence with the measurements. In this way it is possible to determine in a simplified environment how the heating systems should be modeled. Afterwards these models can be implemented in a more complex geometry with real boundary conditions.

In a PhD study on the heating of monumental churches one of the problems, which was encountered, was the damage to wooden interior parts due to the changing of the indoor climate. Particularly warm air heating frequently leads to sudden changes in relative humidity, which turned out to be dramatically hard for monumental organs during wintertime. The warm air inlet conditions and their result on the airflow and air conditions were examined experimentally and by CFD-simulation. These results provided boundary temperature and humidity conditions, to which the monumental organ was exposed. In an experimental study the response of wooden parts to changing indoor conditions was tested. In a Nuclear Magnetic Resonance (NMR) test setup the moisture content of samples was measured as a function of time and place. These moisture content changes were related to the free mechanical deformation of samples. Together with the measurement of typical material properties of wood, a two-dimensional model was developed in FlexPDE: a finite element program to solve partial differential equations simultaneously.

The paper presents the characteristics of the Walloon Church in Delft (Netherlands) and a description of constraints for the indoor climate, giving criteria for the indoor air temperature and relative humidity with the focus on the preservation of the monumental organ. The setpoint operation of the HVAC system is evaluated by simulation using MatLab, FemLab and Simulink models. The next main model components are presented and combined in a single integrated SimuLink model: 1) a WaVo Simulink building model for simulating the indoor temperature and relative humidity, 2) a FemLab PDE model for simulating detailed dynamic moisture transport in the monumental wood (organ) and 3) a Simulink controller model. The building model is validated with measurements. The main advantage of the integrated model is that it directly simulates the impact of HVAC control setpoint strategies on the indoor climate and the organ. Two types of control strategies are discussed. The first type is a limited indoor air temperature changing rate. The second type is a limited indoor air relative humidity changing rate. Recommendations from international literature suggest that 1) a changing rate of 2 K/h will preserve the interior of churches and 2) a limited drying rate is important for the conservation of monumental wood. This preliminary study shows that a limitation of indoor air temperature changing rate of 2 K/h can reduce the peak drying rates by a factor 20 and a limitation of the relative humidity changing rate of 2 %/h can reduce the peak drying rates by a factor 50. The second strategy has the disadvantage that the heating time is not constant

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