Indoor Climate in Jesuit Church of Holy Name of Jesus in Telc

. The Jesuit church of Holy Name of Jesus from year 1667 is integral part of main square of Telc with Baroque houses from 17 th century listed in UNESCO World Heritage Site since 1992. The natural indoor climate of Jesuit church is heated only in occupied pews during liturgical ceremony in winter season. The hygrothermal analysis of natural indoor climate in Jesuit church is performed by preventive conservation method of Target range and Historical climate in period from April 2017 to October 2018. The obtained result shows appropriate indoor climate for preventive conservation of historical furniture (main altar, lateral chapels, pulpit, confessional, organ, paintings), holy remains and valuable artefacts for liturgical ceremony. This hygrothermal analysis of natural indoor climate in Jesuit church supports current state of local heating in occupied pews during liturgical ceremony in winter season.


Introduction
The historical church is usually monumental building with altar, chapel, pulpit, confessional, organ, paintings and other furniture. The sacral aspect of historical church is supported by holy remain and valuable artefacts for liturgical ceremony. The conservation of historical furniture, holy remain and valuable artefacts is important as spiritual and cultural heritage.
The conservation is possible to base on appropriate indoor climate with for delay of degradation process. This conservation method known as Target range is defined by hygrothermal range of appropriate indoor climate, see [1][2][3][4][5][6][7][8]. This method of Target range is useful in building with controlled indoor climate, for example museum, library, gallery, exhibition, see [6][7][8]. This conservation method of Target range is difficult to applied in case of natural indoor climate formed by outdoor weather.
The other preventive conservation approach is based on natural hygrothermal response of historical building. This conservation approach known as Historical climate method is based on long-term hygrothermal moving average and short-term fluctuation of indoor climate in past-present-future, see [9]. This conservation method of Historical climate is useful in historical building with natural indoor climate, see [10][11][12].

Research Aim
This conference contribution is aimed at hygrothermal analysis of experimental measurement of indoor climate in Jesuit church of Holy Name of Jesus in Telc, Czech Republic. This hygrothermal analysis of indoor climate is performed by preventive conservation method of Target range and Historical climate with respect to historical furniture (altar, chapels, pulpit, confessional, organ, paintings), holy remains and valuable artefacts for liturgical ceremony in Jesuit church from year 1667.

Jesuit church of Holy Name of Jesus
This Jesuit church of Holy Name Jesus is integral part of main square in town Telc with mainly Baroque houses from 17 th century listed in UNESCO World Heritage Site since 1992, see Fig. 1.

Historical context
The

Construction of Jesuit Church
The Jesuit church in Telc from year 1667 is located uncommonly with two towers in row of Baroque houses and therefore main entrance is located uncommonly also at left side of church, see  This Jesuit church in Telc type of wandpfeilerkirche includes central nave with lateral chapels between wall pillars on both sides. The main altar in presbytery is flanked by two church towers. The left church tower on Evangelist side is used for spiral staircase to gallery above lateral chapels. The right church tower on Epistle side includes corridor to sacristy. This sacristy is located in neighbour Jesuit college. The under-roof space of Jesuit church is accessible also from Jesuit college. The historical timber roof is type of lying chair in early Baroque style. Under the Jesuit church is located large crypt accessible from courtyard of Jesuit college in Telc. This crypt is connected with two closed tunnels below square in Telc, see Fig. 3.

Internal disposition of Jesuit Church
The internal disposition of Jesuit church is designed with accordance to Concilium Tridentinum (1545 -1563) launched by Pope Paulus III. The simple interior of Jesuit church is painted by white colour and decorated by historical furniture. This interior includes six lateral chapels between wall pillars on both sides and main altar in presbytery, see Fig. 4. The choir loft with organ is located in central nave opposite to presbytery, see Fig. 5. The indoor climate in Jesuit church in Telc is possible to heat by radiant panels located in 12 rows of wooden pews. The heat power of one radiant heat panels is 125 W and count of installed radiant heat panel is 48 pieces. The maximal installed heat power is 6 kW. The local radiant heating in wooden pews for visitors is used only during liturgical ceremony in occupied pews (usually lower than 3 rows) in winter season, see Fig. 6.

Results
The hygrothermal measurement of indoor climate in Jesuit church in Telc is performed on right side of presbytery in height 3.20 m above floor. The outdoor climate in Telc is measured at north-east façade of Jesuit church in height 11.20 m above ground. The outdoor and indoor hygrothermal sensor is data logger Comet S3120 with temperature range from -30 °C to 70 °C, sensitivity ± 0.10 K and accuracy ± 0.40 K. The range of data logger Comet S3120 for air relative humidity is from 5 % to 95 % with sensitivity ± 0.10 % RH and accuracy ± 2.5 % RH. These hygrothermal sensors of outdoor and indoor climate are measured in period from 27 th April 2017 (12:20 am) to 23 rd October 2018 (11:00 am) with interval of record 20 minutes. This hygrothermal measurement includes record of outdoor/indoor air temperature, outdoor/indoor air relative humidity and outdoor/indoor dew-point temperature.

Analysis of Indoor and Outdoor Climate
The continual hygrothermal measurement over 543 days is plotted by red line for indoor air temperature, blue line for indoor air relative humidity, purple line for indoor dew-point temperature and grey line for outdoor climate, see Fig. 7. This graph includes also coloured area named as Frost risk (T < 0 °C), Microbiology risk (RH > 80 %) and Dryness effect (RH < 40 %) according to [22]. The median of indoor air relative humidity is 54.4 % with minimal indoor air relative humidity 32.9 % (1 st March 2018 at 12:40 pm). This minimal indoor air relative humidity is coupled with end of unusually frozen days. The indoor air relative humidity over frozen days is measured in risked area Dryness effect (RH < 40 %) for 127 hours with insignificant frequency 9.6 ‰ from 543 measured days. The Dryness effect in summer season is caused by direct solar radiation over window in presbytery on wall with indoor sensor. The maximal indoor air relative humidity is 73.5 % (7 th January 2018 at 11:00 am) and this maximal indoor air relative humidity is measured at Sunday with liturgical ceremony of Three Kings.

Hygrothermal difference of Indoor climate
The natural indoor climate in Jesuit church is measured over 543 days in interval 20 minutes. This evolution of natural indoor climate in time is discretized in 39 164 hygrothermal time steps. The hygrothermal difference of indoor climate is possible to plot in point graph as temperature difference on vertical axis and difference of indoor air relative humidity on horizontal axis. The point in graph is coloured according to month in the year. The winter season is coloured by blue shades and summer season is coloured by red shades, see Fig. 8. The hygrothermal difference of indoor climate in Jesuit church in summer season (red points) is higher than hygrothermal difference in winter season (blue points), see Fig. 8. The optical orthogonal raster of points in graph is caused by hygrothermal sensitivity of sensor for air temperature ± 0.10 K (optical rows) and relative humidity ± 0.10 % (optical columns).

Target range method
The hygrothermal measurement of indoor climate in Jesuit church is possible to display in point graph with indoor air temperature on horizontal axis and indoor air relative humidity on vertical axis in interval 20 minutes. The point in graph is coloured according to month in the year. The winter season is coloured by blue shades and summer season is coloured by red shades, see Fig. 9.  remains and valuable artefacts for liturgical ceremony in Jesuit church in Telc are sorted to seven categories according to material.

A) Bone relics in religion connects spiritual and secular world. The bone relic is insert in relic stone and located in altar.
B) Wood parts is wooden structure of main altar, wooden part of lateral chapels, wooden pulpit, wooden construction of organ, wooden doors and frame of painting.  Table 1. The frequency of indoor climate in Target range in upper part of Table 1 is over 30 % measured days (see category A -E). The end part of Table 1 shows frequency of indoor climate in Target range below 22 % measured days (see category F and G). This low frequency of natural indoor climate in Target range is caused by temperature range more often than range of indoor air relative humidity, see Table 1. For example, category A -E shows appropriate indoor air relative humidity in frequency over 82 % measured days, according to Italian Standard M.BB.CC., 2001 [3] and UNI 1999 [4], see frequency in brackets in Table 1.
The recommended minimal air temperature in Target range is often over 10 °C, but natural indoor climate in Jesuit church formed by hygrothermal response of church is measured below 10 °C in frequency 27 % days.
This result shows on heating demand in Jesuit church, but heating of indoor climate is coupled with possible hygrothermal stress in historical furniture and valuable artefacts, see [23][24][25] The repetitive switch on/off of heating system causes cyclic drop of indoor air relative humidity as well as accelerate dust particles and deposit them on painting canvas etc., see [26][27][28][29][30].
The heating system is appropriate in case of indoor air temperature below 0 °C, but frequency of Frost risk in Jesuit church in Telc is not detected.

Historical climate method
The conservation method of Historical climate is based on natural hygrothermal response of historical building, see [9]. The historical furniture (altar, lateral chapels, pulpit, confessional, organ, paintings), holy remains and valuable artefacts for liturgical ceremony are adapted on natural indoor climate in Jesuit church since 1667.
The hygrothermal change of natural indoor climate in Jesuit church is coupled with reversible or irreversible internal tensions in material, see [30]. This internal tension increases risk of cracks, expansion, deformation, relaxation of joints etc. The method of Historical climate is applied as long-term hygrothermal moving average (over 30 days) and short-term fluctuation of indoor climate in range from 7 th to 93 rd percentile of measured values, see Fig. 10. The annual average of indoor air temperature in Jesuit church in Telc is 15.4 °C. The moving average of indoor air temperature is obtained in range from 3.98 °C (28 th February) to 23.2 °C (14 th August) with short-term fluctuation of indoor temperature in range from -2.4 °C to 2.1 °C. The annual average of indoor air relative humidity in Jesuit church is 54.2 %. The moving average of indoor air relative humidity is obtained in range from 47.9 % (21 st February) to 60.7 % (12 th April) with shortterm fluctuation of indoor air relative humidity in range from -8.8 % to 7.4 %. This short-term fluctuation of indoor climate lower than ± 10 % RH is assessment as stable indoor climate with lower risk of failures according to EN 15757, see [9].

Discussion
The outdoor and indoor climate in Jesuit church in Telc is measurement by hygrothermal data loggers located in presbytery and north-east façade in period from April 2017 to October 2018. This measurement over 543 days shows insignificant frequency of Microbiology risk, Frost risk and Dryness effect in Jesuit church, see 3.1.
This hygrothermal measurement is used for calculation of time-lag between outdoor and indoor climate (5 hours for dew-point temperature and 4 days for indoor air temperature). The hygrothermal attenuation in envelope of church (2.4 °C for dew-point temperature and 5.5 °C for indoor air temperature), see 3.2.
The hygrothermal difference of natural indoor climate in interval 20 minutes shows impact of solar radiation (2.8 °C) in summer season and impact of liturgical ceremony on indoor air relative humidity (4.4 % RH) at Advent Sundays, see 3.3.
The conservation method of Target range shows low frequency of natural indoor climate in recommended hygrothermal range, according to [1][2][3][4][5][6][7][8]. The appropriate indoor climate is obtained in range from 3.90 % days (wood parts, bellows organ, light metals and wood inlays with lacquer) to 68.8 % measured days (bone relics). This low frequency of indoor climate in Target range is caused by natural indoor air temperature, see 3.4.
The conservation method of Historical climate shows indoor climate in narrow hygrothermal corridor with short-term fluctuation of air temperature <-2.4 °C; 2.1 °C> and short-term fluctuation of indoor air relative humidity <-8.8 %; 7.4 %>. This short-term fluctuation shows stable indoor climate in Jesuit church, see 3.5.
This hygrothermal analysis shows appropriate indoor climate in Jesuit church for preventive conservation of historical furniture (main altar, lateral chapels, pulpit, confessional, organ, paintings), holy remains and valuable artefacts. This historical furniture and valuable artefacts are without failures, according to conservators. Therefore, idea from year 1993 about central heating system in Jesuit church is not supported. The current state of local radiant heating in occupied pews during liturgical ceremony is appropriate, because impact of local pews heating on historical furniture and valuable artefacts is insignificant. The other research is suitable aimed at organ and extended current monitoring system in Jesuit church in Telc.

Conclusion
The indoor climate in Jesuit church in Telc is formed by natural hygrothermal response of historical church on outdoor climate since 1667. This natural indoor climate with small hygrothermal fluctuation is assessments by Historical climate method as stable indoor climate. The low frequency of natural indoor climate in Target range is caused by low indoor air temperature in Jesuit church. This low indoor air temperature is formed by natural hygrothermal response of historical church on outdoor climate. The change of natural indoor climate is not supported with respect to good condition of historical furniture and valuable artefacts without failures. This good condition of historical furniture and valuable artefacts is caused probably by stable natural indoor climate with insignificant frequency of Frost risk, Microbiology risk and Dryness effect.
Finally, preventive conservation method of Historical climate is preferred in case study of Jesuit church of Holy Name Jesus in Telc.