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Figure 11. Flow diagrams to illustrate the methodology to investigate (a) the greenhouse effect; (b) the combined effect between the evaporation from the archaeological remains and the air exchanges between the showcase and the exterior; (c) the glass misting and dewing. Figure 11. Flow diagrams to illustrate the methodology to investigate (a) the greenhouse effect; (b) the

Figure 11 Flow diagrams to illustrate the methodology to investigate (a) the greenhouse effect; (b) the combined effect between the evaporation from the archaeological remains and the air exchanges between the showcase and the exterior; (c) the glass misting and dewing. Figure 11. Flow diagrams to illustrate the methodology to investigate (a) the greenhouse effect; (b) the

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Figure 1. The pergola and the two showcases. (a) Side view of the pergola as it was during the monitoring period, with the family quarters in the background. Small vegetation and a tree are planted in proximity of the pergola. (b) Detail of the glass top of the walkway showcase in the middle of the pergola and the tanoor showcase on the right side. (c) The pergola as it is now, with the operable louvres in vertical position to separate the walkway from the courtyard. (d) The operable louvres in horizontal position, protruding from the ceiling, to connect the eastern and western courtyards. Note that in both the vertical and horizontal positions the shade is partial, part of the solar radiation passing through the gaps between slats. Figure 1. The pergola and the two showcases. (a) Side view of the pergola as it was during the
Figure 1. The pergola and the two showcases. (a) Side view of the pergola as it was during the monitoring period, with the family quarters in the background. Small vegetation and a tree are planted in proximity of the pergola. (b) Detail of the glass top of the walkway showcase in the middle of the pergola and the tanoor showcase on the right side. (c) The pergola as it is now, with the operable louvres in vertical position to separate the walkway from the courtyard. (d) The operable louvres in horizontal position, protruding from the ceiling, to connect the eastern and western courtyards. Note that in both the vertical and horizontal positions the shade is partial, part of the solar radiation passing through the gaps between slats. Figure 1. The pergola and the two showcases. (a) Side view of the pergola as it was during the
Figure 2. Scheme of the two showcases, i.e., walkway (W) in the pergola, and tanoor (T) on the eastern side of the pergola, and the location of the monitoring system. T/RH: temperature (T) and relative humidity (RH) sensors; ext: external sensors; Tg: temperature of the glass pane; SMC: soil moisture content. Figure 2. Scheme of the two showcases, i.e., walkway (W) in the pergola, and tanoor (T) on the
Figure 2. Scheme of the two showcases, i.e., walkway (W) in the pergola, and tanoor (T) on the eastern side of the pergola, and the location of the monitoring system. T/RH: temperature (T) and relative humidity (RH) sensors; ext: external sensors; Tg: temperature of the glass pane; SMC: soil moisture content. Figure 2. Scheme of the two showcases, i.e., walkway (W) in the pergola, and tanoor (T) on the
Figure 3. Dewing at the walkway showcase.
Figure 3. Dewing at the walkway showcase.
Figure 4. (a) Temperature and precipitation in Al Ain. Gray band: daily minimum and maximum temperatures (average 1995-2022) recorded by WMO AI Ain station at the International Airport; red line: average daily temperatures measured at BMBK, this study; blue lines: daily mean precipitation over 1995-2022 period (right y-axis) recorded by the WMO station; the black arrows highlight rainy days during this monitoring. (b) External temperature, recorded in this study close to the showcases from April 2022 to May 2023; red line: best fit. (c) External mixing ratio, calculated using the data of this study; red line: best fit.
Figure 4. (a) Temperature and precipitation in Al Ain. Gray band: daily minimum and maximum temperatures (average 1995-2022) recorded by WMO AI Ain station at the International Airport; red line: average daily temperatures measured at BMBK, this study; blue lines: daily mean precipitation over 1995-2022 period (right y-axis) recorded by the WMO station; the black arrows highlight rainy days during this monitoring. (b) External temperature, recorded in this study close to the showcases from April 2022 to May 2023; red line: best fit. (c) External mixing ratio, calculated using the data of this study; red line: best fit.
Figure 5. Daytime length calculated from sunrise to sunset, and monthly insolation (average number of sunshine hours) at Al Ain. Personal elaboration of insolation data (average 1991-2021) from [33]. Daytime is the time elapsed between sunrise and sunset, when Ho = 0 in the mornin and in the afternoon. At the equator, the Sun rises in the east, and sets in the west, verticall and the daytime period always lasts about 12 h, in all seasons. At the latitude of A Ain, daytime has a modest variability with the seasons, and lies from around 10.5 h at th winter solstice to 13.5 h at the summer solstice (Figure 5). Daytime at the winter solstic is 23% shorter than at the summer solstice. At higher latitudes, the variability of daytim increases. For instance, at 45° latitude, daytime at the winter solstice is 55% that of th summer solstice. If one excludes the time with cloud cover or precipitation, the averag number of sunshine hours per month (average 1991-2021) is about 1 h less [33]. The declination angle 65 between the Earth—Sun line and the equatorial plane varies seasonally between +23.45°. The coordinates of Al Ain are 24.22082° north latitude and 55.7471° east longitude. As a consequence of this particular latitude (that is in close proximity to the Tropic of Cancer, i.e., 23.43621° north latitude), at the summer solstice (21st June), the culmination of the Sun is close to the zenith. When this happens, the Sun is overhead, almost perpendicularly above Al Ain, and shadows almost disappear underfoot.
Figure 5. Daytime length calculated from sunrise to sunset, and monthly insolation (average number of sunshine hours) at Al Ain. Personal elaboration of insolation data (average 1991-2021) from [33]. Daytime is the time elapsed between sunrise and sunset, when Ho = 0 in the mornin and in the afternoon. At the equator, the Sun rises in the east, and sets in the west, verticall and the daytime period always lasts about 12 h, in all seasons. At the latitude of A Ain, daytime has a modest variability with the seasons, and lies from around 10.5 h at th winter solstice to 13.5 h at the summer solstice (Figure 5). Daytime at the winter solstic is 23% shorter than at the summer solstice. At higher latitudes, the variability of daytim increases. For instance, at 45° latitude, daytime at the winter solstice is 55% that of th summer solstice. If one excludes the time with cloud cover or precipitation, the averag number of sunshine hours per month (average 1991-2021) is about 1 h less [33]. The declination angle 65 between the Earth—Sun line and the equatorial plane varies seasonally between +23.45°. The coordinates of Al Ain are 24.22082° north latitude and 55.7471° east longitude. As a consequence of this particular latitude (that is in close proximity to the Tropic of Cancer, i.e., 23.43621° north latitude), at the summer solstice (21st June), the culmination of the Sun is close to the zenith. When this happens, the Sun is overhead, almost perpendicularly above Al Ain, and shadows almost disappear underfoot.
The key features of the apparent solar motion around Al Ain are shown in Figure 6. The Sun is represented in terms of the altitude and the azimuth during the summer and the winter solstices, as well as the equinoxes (note that the astronomical situation at the spring and autumn equinoxes is the same). Figure 6. The coordinates i.e., altitude (red) and azimuth (blue) of the Sun during its apparent motion around the local sky of Al Ain at the two solstices and the equinoxes. Daytime (from sunrise to sunset) is white, night-time grey.
The key features of the apparent solar motion around Al Ain are shown in Figure 6. The Sun is represented in terms of the altitude and the azimuth during the summer and the winter solstices, as well as the equinoxes (note that the astronomical situation at the spring and autumn equinoxes is the same). Figure 6. The coordinates i.e., altitude (red) and azimuth (blue) of the Sun during its apparent motion around the local sky of Al Ain at the two solstices and the equinoxes. Daytime (from sunrise to sunset) is white, night-time grey.
Figure 7. Solar energy impinging per second and square meter on the tanoor (dashed line) and the walkway (continuous line) showcases at the winter solstice (blue), the equinoxes (green), and the summer solstice (red). The comparison between the solar energy impinging on the glass pane of the tanoor and the walkway at the winter solstice, the equinoxes, and the summer solstice (Figure 7) gives interesting results. At the winter solstice, when the Sun is low over the local horizon, he inclined glass pane of the tanoor collects more energy than the horizontal pane of he walkway. This difference is strongly reduced at the equinoxes. Finally, the situation reverses slightly at the summer solstice, when the Sun approaches the zenith, because the horizontal glass pane of the walkway is almost perpendicular to the solar beams, while the inclined tanoor is not, and collects less energy. The incoming energy increases from the winter solstice to the summer one, passing through the equinox as an intermediate phase. However, the energy at the equinoxes is not centrally located between the values at the two solstices, but is shifted towards the summer solstice. More precisely, at the equinoxes, at noon, the peak of energy is 5% less than that of the summer solstice for the walkway and 11% for the tanoor; at the winter solstice is 30% less for the walkway and 40% for the anoor.
Figure 7. Solar energy impinging per second and square meter on the tanoor (dashed line) and the walkway (continuous line) showcases at the winter solstice (blue), the equinoxes (green), and the summer solstice (red). The comparison between the solar energy impinging on the glass pane of the tanoor and the walkway at the winter solstice, the equinoxes, and the summer solstice (Figure 7) gives interesting results. At the winter solstice, when the Sun is low over the local horizon, he inclined glass pane of the tanoor collects more energy than the horizontal pane of he walkway. This difference is strongly reduced at the equinoxes. Finally, the situation reverses slightly at the summer solstice, when the Sun approaches the zenith, because the horizontal glass pane of the walkway is almost perpendicular to the solar beams, while the inclined tanoor is not, and collects less energy. The incoming energy increases from the winter solstice to the summer one, passing through the equinox as an intermediate phase. However, the energy at the equinoxes is not centrally located between the values at the two solstices, but is shifted towards the summer solstice. More precisely, at the equinoxes, at noon, the peak of energy is 5% less than that of the summer solstice for the walkway and 11% for the tanoor; at the winter solstice is 30% less for the walkway and 40% for the anoor.
Figure 8. Solar energy impinging per second and square meter on the surface of a vertical cylinder at Al Ain, at the winter solstice, the equinoxes, and the summer solstice. The figure is representative of the energy falling on any vertical surface (e.g., wall, window) facing a selected compass direction. Figure 8. Solar energy impinging per second and square meter on the surface of a vertical cylinder at — ea On the horizontal plane, the situation is different from vertical surfaces. The general case of a vertical cylinder in Al Ain is represented in Figure 8. At the winter solstice, he maximum irradiation is from south around noon, while almost the whole northern sector, from west to east, is unreached because the Sun is below the horizon. At the summer solstice, the maximum intensity is reached around the east in the morning, and then around he west in the afternoon; the northern sector has gained solar energy, while the south is not reached because the Sun is overhead, and the beams are parallel to vertical surfaces. A comparison between the vertical and the horizontal plane (e.g., walkway) shows tha he latter, going from winter to summer, gradually increases the amount of the collected energy. On the other hand, the vertical surfaces have a different, more complex behaviour. For instance, a vertical surface facing south, and a horizontal surface, have similar trends at he winter solstice, but opposite trends at the summer solstice. This situation may confuse he ideas of those who rely on daily personal sensations, but do not verify them with calculations or measurements.
Figure 8. Solar energy impinging per second and square meter on the surface of a vertical cylinder at Al Ain, at the winter solstice, the equinoxes, and the summer solstice. The figure is representative of the energy falling on any vertical surface (e.g., wall, window) facing a selected compass direction. Figure 8. Solar energy impinging per second and square meter on the surface of a vertical cylinder at — ea On the horizontal plane, the situation is different from vertical surfaces. The general case of a vertical cylinder in Al Ain is represented in Figure 8. At the winter solstice, he maximum irradiation is from south around noon, while almost the whole northern sector, from west to east, is unreached because the Sun is below the horizon. At the summer solstice, the maximum intensity is reached around the east in the morning, and then around he west in the afternoon; the northern sector has gained solar energy, while the south is not reached because the Sun is overhead, and the beams are parallel to vertical surfaces. A comparison between the vertical and the horizontal plane (e.g., walkway) shows tha he latter, going from winter to summer, gradually increases the amount of the collected energy. On the other hand, the vertical surfaces have a different, more complex behaviour. For instance, a vertical surface facing south, and a horizontal surface, have similar trends at he winter solstice, but opposite trends at the summer solstice. This situation may confuse he ideas of those who rely on daily personal sensations, but do not verify them with calculations or measurements.
Figure 9. Solar energy impinging per second and square meter on the four vertical walls of the tanoor, at the winter solstice, the equinoxes, and the summer solstice. Wall names are attributed with the criterion of the closest compass direction, but calculations are based on actual directions. standards, and WMO N. 8 [38]. The types, measuring principles, range, accuracy, and standard reference of all sensors are reported in Table 1. The sensors comply with the European Standards EN 15758 [36] for temperature, EN 16242 [37] for relative humidity, and EN 16682 [39] for moisture content.
Figure 9. Solar energy impinging per second and square meter on the four vertical walls of the tanoor, at the winter solstice, the equinoxes, and the summer solstice. Wall names are attributed with the criterion of the closest compass direction, but calculations are based on actual directions. standards, and WMO N. 8 [38]. The types, measuring principles, range, accuracy, and standard reference of all sensors are reported in Table 1. The sensors comply with the European Standards EN 15758 [36] for temperature, EN 16242 [37] for relative humidity, and EN 16682 [39] for moisture content.
Figure 10. (a) Data logger measuring microclimate parameters for the walkway showcase. (b) Temperature and relative humidity sensor, with solar shield, located near the tanoor showcase. criterion of the closest compass direction, but calculations are based on actual directions.
Figure 10. (a) Data logger measuring microclimate parameters for the walkway showcase. (b) Temperature and relative humidity sensor, with solar shield, located near the tanoor showcase. criterion of the closest compass direction, but calculations are based on actual directions.
Table 1. Technical characteristics of the used sensors.
Table 1. Technical characteristics of the used sensors.
Figure 12. Soil moisture content measured at the walkway. Blue arrows: plant watering. Yellow arrow: perturbation for maintenance works. The record of the soil moisture content (SMC) (Figure 12) shows some peaks (cyan arrows) in 2022. The peaks indicate that some irrigation water has reached the remains. At the beginning of the year 2023, a sharp and long decrease (i.e., evaporation during some maintenance works of the walkway) is visible (yellow arrow). After these works, the SMC returned to a new equilibrium, lower than in 2022 (i.e., from around 17% to 10%).
Figure 12. Soil moisture content measured at the walkway. Blue arrows: plant watering. Yellow arrow: perturbation for maintenance works. The record of the soil moisture content (SMC) (Figure 12) shows some peaks (cyan arrows) in 2022. The peaks indicate that some irrigation water has reached the remains. At the beginning of the year 2023, a sharp and long decrease (i.e., evaporation during some maintenance works of the walkway) is visible (yellow arrow). After these works, the SMC returned to a new equilibrium, lower than in 2022 (i.e., from around 17% to 10%).
Figure 13. Temperatures and mixing ratios at the two solstices. (a) Walkway, winter solstice; (b) tanoor, winter solstice; (c) walkway, summer solstice; (d) tanoor, summer solstice. Daytime (from sunrise to sunset) is white, nighttime grey.
Figure 13. Temperatures and mixing ratios at the two solstices. (a) Walkway, winter solstice; (b) tanoor, winter solstice; (c) walkway, summer solstice; (d) tanoor, summer solstice. Daytime (from sunrise to sunset) is white, nighttime grey.
Figure 14. Relative humidity in the two showcases and external values at the two solstices. (a) Winter solstice; (b) summer solstice. Daytime (from sunrise to sunset) is white, nighttime grey. At the winter solstice (Figure 14a), in the open air, the relative humidity RHey has a linear, increasing trend during the nighttime, then a rapid decrease after sunset for the solar warming of the ground, and finally reaches a plateau around RHex+ = 27% in the afternoon. After the sunset, RH-x; shows a sharp rise by ARHex; = 17%, followed by a slow linear increase. The tanoor follows a similar trend. We have seen (Figure 13b) that the temperature inside the tanoor was initially higher than the external air, but had a similar mixing ratio, and this combination gives a slightly lower relative humidity inside the showcase (ie., RHr < RHext), and the two trends, i.e., RHey+ and RH, differ between them by around ARH = 10%. However, at noon, when the tanoor enters the shade of the pergola and cools, RHr has a sharp increase, i.e., ARH; = 10%, followed by a gradual increase that will continue till the next sunrise. The walkway is at saturation, or very close to saturation (i.e., RHw = 95%), throughout the whole day, except for the short period in the morning in which the solar radiation impinges on it, causing a sharp decrease in RHy up to 64%. However, when the glass is reached by the shadow of the pergola, the RHy immediately rises to 90%, and later to (near) saturation, around 95%. It must be specified that at these extreme values of temperature and humidity, the uncertainty band of RH sensors increases, so that it is impossible to distinguish between values close to saturation (e.g., 95%) and saturation (i.e., RH = 100%).
Figure 14. Relative humidity in the two showcases and external values at the two solstices. (a) Winter solstice; (b) summer solstice. Daytime (from sunrise to sunset) is white, nighttime grey. At the winter solstice (Figure 14a), in the open air, the relative humidity RHey has a linear, increasing trend during the nighttime, then a rapid decrease after sunset for the solar warming of the ground, and finally reaches a plateau around RHex+ = 27% in the afternoon. After the sunset, RH-x; shows a sharp rise by ARHex; = 17%, followed by a slow linear increase. The tanoor follows a similar trend. We have seen (Figure 13b) that the temperature inside the tanoor was initially higher than the external air, but had a similar mixing ratio, and this combination gives a slightly lower relative humidity inside the showcase (ie., RHr < RHext), and the two trends, i.e., RHey+ and RH, differ between them by around ARH = 10%. However, at noon, when the tanoor enters the shade of the pergola and cools, RHr has a sharp increase, i.e., ARH; = 10%, followed by a gradual increase that will continue till the next sunrise. The walkway is at saturation, or very close to saturation (i.e., RHw = 95%), throughout the whole day, except for the short period in the morning in which the solar radiation impinges on it, causing a sharp decrease in RHy up to 64%. However, when the glass is reached by the shadow of the pergola, the RHy immediately rises to 90%, and later to (near) saturation, around 95%. It must be specified that at these extreme values of temperature and humidity, the uncertainty band of RH sensors increases, so that it is impossible to distinguish between values close to saturation (e.g., 95%) and saturation (i.e., RH = 100%).
Figure 15. (a) Walkway showcase temperature during the recording period. Vertical blue segments are the (compresses) daily Ty cycles. The red interpolation line shows the annual cycle of the daily Tw averages. (b) Frequency distribution of the showcase temperature during the monitoring period. Figure 15. (a) Walkway showcase temperature during the recording period. Vertical blue segments
Figure 15. (a) Walkway showcase temperature during the recording period. Vertical blue segments are the (compresses) daily Ty cycles. The red interpolation line shows the annual cycle of the daily Tw averages. (b) Frequency distribution of the showcase temperature during the monitoring period. Figure 15. (a) Walkway showcase temperature during the recording period. Vertical blue segments
Figure 16. (a) Difference between the walkway showcase temperature and the external temperature (ATw —ext) during the recording period. Blue line: recorded data; red line: median, i.e., 50th percentile on weekly basis; light gray areas: band from 8th to 92th percentile; dark gray area: bands of the most extreme events, i.e., Oth to 7th percentile and 93rd to 100th percentile. (b) Difference between the showcase temperature and the glass temperature (ATw_.). The distribution of the difference ATw_, x; between the showcase temperature and he external temperature (ATw—ext = Tw — Text) is represented in Figure 16a. In this plot, he central interpolation line represents the 50th percentile (i.e., the median) of ATw_ext; he band around it (contoured by two black lines at the 7th and 93rd percentiles) includes he events from the 8th to 92nd percentile. The vertical lines crossing the grey area are the nost extreme values. The choice of the above percentiles has been made according to the Suropean Standard EN 15757 ([12,42]). The largest differences (ATw_ex = Tw — Text) are eached from April to October, and the smallest from November to March, when the Sun is ow over the horizon, and the greenhouse effect is modest. Only exceptionally, in winter, he difference vanishes or changes sign. on weekly basis; light gray areas: band from 8th to 92th percentile; dark gray area: bands of the most
Figure 16. (a) Difference between the walkway showcase temperature and the external temperature (ATw —ext) during the recording period. Blue line: recorded data; red line: median, i.e., 50th percentile on weekly basis; light gray areas: band from 8th to 92th percentile; dark gray area: bands of the most extreme events, i.e., Oth to 7th percentile and 93rd to 100th percentile. (b) Difference between the showcase temperature and the glass temperature (ATw_.). The distribution of the difference ATw_, x; between the showcase temperature and he external temperature (ATw—ext = Tw — Text) is represented in Figure 16a. In this plot, he central interpolation line represents the 50th percentile (i.e., the median) of ATw_ext; he band around it (contoured by two black lines at the 7th and 93rd percentiles) includes he events from the 8th to 92nd percentile. The vertical lines crossing the grey area are the nost extreme values. The choice of the above percentiles has been made according to the Suropean Standard EN 15757 ([12,42]). The largest differences (ATw_ex = Tw — Text) are eached from April to October, and the smallest from November to March, when the Sun is ow over the horizon, and the greenhouse effect is modest. Only exceptionally, in winter, he difference vanishes or changes sign. on weekly basis; light gray areas: band from 8th to 92th percentile; dark gray area: bands of the most
Figure 17. (a) Relative humidity inside the walkway showcase during the recording period. Vertical blue segments are the (compresses) daily RH cycles. (b) Frequency distribution of the RH values inside the showcase during the monitoring period. Figure 17. (a) Relative humidity inside the walkway showcase during the recording period. Vertical though with some general features. Winter is characterized by high RH levels, with satura- tion or near saturation in the night, and minimum values around 70% near noon. In summer, and the mid-seasons, RHyw is highly variable during the day, lying from extreme dryness i.e., RHy around 20%) to high humidity levels (e.g., RHyw = 70-80%). The extreme dryness reached around midday is responsible for the enhanced evaporation, which in turn tends 0 raise the humidity levels. The histogram of the frequency distribution (Figure 17b) highlights this extreme variability.
Figure 17. (a) Relative humidity inside the walkway showcase during the recording period. Vertical blue segments are the (compresses) daily RH cycles. (b) Frequency distribution of the RH values inside the showcase during the monitoring period. Figure 17. (a) Relative humidity inside the walkway showcase during the recording period. Vertical though with some general features. Winter is characterized by high RH levels, with satura- tion or near saturation in the night, and minimum values around 70% near noon. In summer, and the mid-seasons, RHyw is highly variable during the day, lying from extreme dryness i.e., RHy around 20%) to high humidity levels (e.g., RHyw = 70-80%). The extreme dryness reached around midday is responsible for the enhanced evaporation, which in turn tends 0 raise the humidity levels. The histogram of the frequency distribution (Figure 17b) highlights this extreme variability.
Figure 18. (a) Mixing ratio inside the walkway showcase during the recording period. Vertical blue segments are the (compresses) daily MR cycles. The red line is the best fit interpolation. (b) Frequency distribution of the MR inside the showcase, and in the external air, during the monitoring period. The mixing ratio inside the showcase MRy (Figure 18a) is characterized by a sinu- soidal annual cycle, with maximum values, and largest daily cycles, in summer. The mini- mum values, and the most reduced daily cycles, are in the cold season. This is explained because the glass is less heated, the greenhouse effect is modest (being limited to a few °C) and the maximum amount of MRy is limited by the saturation.
Figure 18. (a) Mixing ratio inside the walkway showcase during the recording period. Vertical blue segments are the (compresses) daily MR cycles. The red line is the best fit interpolation. (b) Frequency distribution of the MR inside the showcase, and in the external air, during the monitoring period. The mixing ratio inside the showcase MRy (Figure 18a) is characterized by a sinu- soidal annual cycle, with maximum values, and largest daily cycles, in summer. The mini- mum values, and the most reduced daily cycles, are in the cold season. This is explained because the glass is less heated, the greenhouse effect is modest (being limited to a few °C) and the maximum amount of MRy is limited by the saturation.
Figure 19. (a) Difference between the relative humidity inside the walkway showcase and the external values. Colour code as in Figure 16. (b) Difference between the mixing ratio inside the walkway showcase and the external values. The plot of the difference AR Hwy _, + between the relative humidity inside the showcase RHy and the external values RH-x+ (Figure 19a) shows that on average, the humidity level! in the showcase is higher than in the external air. This situation does not have a well-defined seasonal trend, except that the maxima of ARHw-_.,; are reached in winter. Sometimes and especially in spring, some negative values may occur. This variable (i.e., RH) is affected by marked daily cycles (i.e., the thickness of the band), with differences between the internal and external level reaching 50%. The difference between the showcase and the external ait is explained as follows. During the day, for the high temperature levels reached inside the showcase, the inside RHy drops and extracts moisture from the ground and the earthen remains by evaporation. During the nocturnal cooling, this excess of moisture reaches saturation and condenses, generating large RHy cycles.
Figure 19. (a) Difference between the relative humidity inside the walkway showcase and the external values. Colour code as in Figure 16. (b) Difference between the mixing ratio inside the walkway showcase and the external values. The plot of the difference AR Hwy _, + between the relative humidity inside the showcase RHy and the external values RH-x+ (Figure 19a) shows that on average, the humidity level! in the showcase is higher than in the external air. This situation does not have a well-defined seasonal trend, except that the maxima of ARHw-_.,; are reached in winter. Sometimes and especially in spring, some negative values may occur. This variable (i.e., RH) is affected by marked daily cycles (i.e., the thickness of the band), with differences between the internal and external level reaching 50%. The difference between the showcase and the external ait is explained as follows. During the day, for the high temperature levels reached inside the showcase, the inside RHy drops and extracts moisture from the ground and the earthen remains by evaporation. During the nocturnal cooling, this excess of moisture reaches saturation and condenses, generating large RHy cycles.
Figure 20. (a) Difference between the glass temperature and the dew point inside the walkway showcase (blue lines). When the values enter the yellow band, the glass starts misting; when they enter the red band, the glass starts dewing. The red line is the best fit interpolation. (b) Percent of time in which the glass pane is transparent (i.e., no condensation), or is misting or dewing.
Figure 20. (a) Difference between the glass temperature and the dew point inside the walkway showcase (blue lines). When the values enter the yellow band, the glass starts misting; when they enter the red band, the glass starts dewing. The red line is the best fit interpolation. (b) Percent of time in which the glass pane is transparent (i.e., no condensation), or is misting or dewing.
Figure 21. Overview of the three temperatures (walkway, tanoor, and external air) and the solar irradiation impinging on the walkway and the tanoor at the summer solstice. time in which the glass pane is transparent (i.e., no condensation), or is misting or dewing.
Figure 21. Overview of the three temperatures (walkway, tanoor, and external air) and the solar irradiation impinging on the walkway and the tanoor at the summer solstice. time in which the glass pane is transparent (i.e., no condensation), or is misting or dewing.
Figure 22. (a) Temperature inside the tanoor showcase. Red interpolation line: annual cycle of the daily Tr averages. (b) Difference between the showcase temperature and the glass temperature. Colour code as in Figure 16.
Figure 22. (a) Temperature inside the tanoor showcase. Red interpolation line: annual cycle of the daily Tr averages. (b) Difference between the showcase temperature and the glass temperature. Colour code as in Figure 16.
Figure 23. Overview of the mixing ratios in the walkway, tanoor, and open air, at the summer solstice
Figure 23. Overview of the mixing ratios in the walkway, tanoor, and open air, at the summer solstice
Figure 24. (a) Mixing ratio inside the tanoor showcase. (b) Difference between the values of the MR inside the showcase and the MR of the external air. Colour code as in Figure 16. Over the year, the mixing ratio changes seasonally, with maximum in summer and minimum in winter (Figure 24a), and the same can be said for the difference between the internal and external values (Figure 24b).
Figure 24. (a) Mixing ratio inside the tanoor showcase. (b) Difference between the values of the MR inside the showcase and the MR of the external air. Colour code as in Figure 16. Over the year, the mixing ratio changes seasonally, with maximum in summer and minimum in winter (Figure 24a), and the same can be said for the difference between the internal and external values (Figure 24b).
In the tanoor, the MR values are always much lower than those observed in the walkway, confirming that even a modest natural ventilation avoids the accumulation of large amounts of water vapour inside the showcase. However, this does not mean that the evaporation from the archaeological remains is reduced, because a slightly lower temperature, associated with a much lower MR, implies a lower RH, as shown in the next figure (Figure 25a). In the walkway, the RH is always higher than in the open air, while in the tanoor, it is lower for most of the time. (Figure 25b). For the tanoor, the risk that the glass temperature falls below the dew point, with the consequence of glass misting or dewing, is rare (Figure 26a) and for short (nocturnal) periods, being 5% of the total time for misting and 1% for dewing (Figure 26b). This natural ventilation may be a satisfactory remedy against misting, but is not sufficient to counteract the glass overheating, the related greenhouse and the forced evaporation.
In the tanoor, the MR values are always much lower than those observed in the walkway, confirming that even a modest natural ventilation avoids the accumulation of large amounts of water vapour inside the showcase. However, this does not mean that the evaporation from the archaeological remains is reduced, because a slightly lower temperature, associated with a much lower MR, implies a lower RH, as shown in the next figure (Figure 25a). In the walkway, the RH is always higher than in the open air, while in the tanoor, it is lower for most of the time. (Figure 25b). For the tanoor, the risk that the glass temperature falls below the dew point, with the consequence of glass misting or dewing, is rare (Figure 26a) and for short (nocturnal) periods, being 5% of the total time for misting and 1% for dewing (Figure 26b). This natural ventilation may be a satisfactory remedy against misting, but is not sufficient to counteract the glass overheating, the related greenhouse and the forced evaporation.
Figure 26. (a) Difference between the glass temperature and the dew point in the Tanoor showcase. When the values enter the yellow band, the glass starts misting; when they enter the red band, the glass starts dewing. (b) Percent of time in which the glass pane is transparent (i.e., no condensation), or is misting or dewing.
Figure 26. (a) Difference between the glass temperature and the dew point in the Tanoor showcase. When the values enter the yellow band, the glass starts misting; when they enter the red band, the glass starts dewing. (b) Percent of time in which the glass pane is transparent (i.e., no condensation), or is misting or dewing.
Figure 28. Efficiency of a vertical or a horizontal shield at the winter solstice (a,b) and the summer solstice (c,d), on a north-south cross section, at noon. (a) Winter solstice and horizontal shield; the solar beams (red arrow) are inclined (i.e., Ha = 42.44°) and the showcase is reached by them. (b) Winter solstice and vertical shield, the showcase is shaded. (c) Summer solstice and horizontal shield; the Sun is overhead (i.e., Ho = 89.14°) and the showcase is shaded. (d) Summer solstice and vertical shield; the Sun is overhead and the showcase is reached by the solar radiation. (e) A combination of a vertical and horizontal shield. (f) Wider horizontal shield, extended towards the southern side. (g) An inclined shield may constitute a good solution, equivalent to the combination of a vertical and horizontal shield, as in (e). (h) Shade obtained in the pergola using slats angled 45°, i.e., normal to the winter beams, and at the same time able to stop the vertical beams in summer.
Figure 28. Efficiency of a vertical or a horizontal shield at the winter solstice (a,b) and the summer solstice (c,d), on a north-south cross section, at noon. (a) Winter solstice and horizontal shield; the solar beams (red arrow) are inclined (i.e., Ha = 42.44°) and the showcase is reached by them. (b) Winter solstice and vertical shield, the showcase is shaded. (c) Summer solstice and horizontal shield; the Sun is overhead (i.e., Ho = 89.14°) and the showcase is shaded. (d) Summer solstice and vertical shield; the Sun is overhead and the showcase is reached by the solar radiation. (e) A combination of a vertical and horizontal shield. (f) Wider horizontal shield, extended towards the southern side. (g) An inclined shield may constitute a good solution, equivalent to the combination of a vertical and horizontal shield, as in (e). (h) Shade obtained in the pergola using slats angled 45°, i.e., normal to the winter beams, and at the same time able to stop the vertical beams in summer.
Figure 29. (a) Solar radiation passing at noon through the louvred panels, crossing the gaps between the slates (left scale) and stopped by the slates (right scale). Circles indicate the first day of the month, e.g., J: Ist January; F: 1st February, and so on. (b) An example of the walkway near noon in mid-May or mid-July, when 80% of the radiation passes through the ceiling and 20% is stopped. (c) Overview of the solar radiation passing through the louvred ceiling and the projected shade on the walkway floor on selected dates of the calendar year.
Figure 29. (a) Solar radiation passing at noon through the louvred panels, crossing the gaps between the slates (left scale) and stopped by the slates (right scale). Circles indicate the first day of the month, e.g., J: Ist January; F: 1st February, and so on. (b) An example of the walkway near noon in mid-May or mid-July, when 80% of the radiation passes through the ceiling and 20% is stopped. (c) Overview of the solar radiation passing through the louvred ceiling and the projected shade on the walkway floor on selected dates of the calendar year.
Figure 30. Solar spectral irradiance outside the atmosphere (upper line) and the quantity that reaches he Earth surface at sea level, after absorption and scattering. UV: ultraviolet from 300 to 380 nm; VL: visible light from 380 to 780 nm); NIR: near-infrared from 780 nm to 2300 nm (adapted from [48].). i.e., reflectance (i.e., the fraction of solar radiation reflected by the glass and film system), absorptance and transmi (i.e., the fraction of solar radiation absorbed by the glass and film system), tance (i.e., the fraction of solar radiation passing through the glass and film system), properties for the UV, visible, and thermal ranges. The standard EN 15752-1 refers to the SCF made of adhesive backed polymeric films based on biaxially oriented polyester film, while t he glass products that have an adhesive-backed polymeric film applied are regulated by EN 15775-1 [49]. Their performance depends on the combined effect of the glass substrate and the applied SCF. A critical issue is to reach conditions of overheating and potentia thermal shock breakage, that is increased by the solar absorptance of the SCF. Therefore, their application should be carefully evaluated [50].
Figure 30. Solar spectral irradiance outside the atmosphere (upper line) and the quantity that reaches he Earth surface at sea level, after absorption and scattering. UV: ultraviolet from 300 to 380 nm; VL: visible light from 380 to 780 nm); NIR: near-infrared from 780 nm to 2300 nm (adapted from [48].). i.e., reflectance (i.e., the fraction of solar radiation reflected by the glass and film system), absorptance and transmi (i.e., the fraction of solar radiation absorbed by the glass and film system), tance (i.e., the fraction of solar radiation passing through the glass and film system), properties for the UV, visible, and thermal ranges. The standard EN 15752-1 refers to the SCF made of adhesive backed polymeric films based on biaxially oriented polyester film, while t he glass products that have an adhesive-backed polymeric film applied are regulated by EN 15775-1 [49]. Their performance depends on the combined effect of the glass substrate and the applied SCF. A critical issue is to reach conditions of overheating and potentia thermal shock breakage, that is increased by the solar absorptance of the SCF. Therefore, their application should be carefully evaluated [50].
Related topics:
Cultural StudiesHeritage ConservationCultural Heritage ManagementTropical Climate VariabilityClimate modelingTropical Architecture
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