Dipartimento di Ingegneria Meccanica e Civile Università di Modena e Reggio Emilia

Transcription

1 Object: Report: temperature monitoring and Reference person: Antonio Libbra Client: Barozzi Vernici s.r.l. Revere (MN) Site of investigation: Commitment document: Research contract Notes: Report rev. 1 Report date:

2 Pag. 2/1 Client: Barozzi Vernici s.r.l. Revere (MN) 1. Performed activities This report summarized the activities undertaken to verify the effectiveness of two antisolar coatings applied to cover an industrial building used as a warehouse for logistics site in Landriano (PV). The facility, with a cover characterized by a high ratio between transparent and opaque components and partially covered with a dark bituminous membrane, is affected by the problem of overheating in the summer that makes hard the work for people employed within the building. In this study, in particular, it was investigated the effect of the use of a semi-transparent antisolar paint applied on the transparent components of the cover and of a white paint applied on the opaque components. The coatings were produced by the company Barozzi Vernici di Revere Mantova, client of the measures subject of this report, which wanted to verify experimentally that the paints could be used to give more solar reflectance to the structures, to reduce the temperatures detectable on the cover and to reduce the heat load entering the building. Figure 1.1. Aerial image of warehouse logistics. During the survey was performed a comparison between the surface temperatures detectable in the ceiling of the building at two areas of coverage, one left untouched, the other subjected to paint. Each area of coverage follows longitudinally the space between two supporting beams of reinforced concrete and is flanked on the right and left by a similar area subjected to treatment. In this way, the temperatures read in the central area should not be influenced by edge effects due to

3 Pag. 3/1 Client: Barozzi Vernici s.r.l. Revere (MN) non-treated areas. Each area of coverage identified for the investigation was monitored with temperature probes and subjected to thermographic survey. Figure 1.2. Internal image ceiling analyzed warehouse. In the two sectors have been including the 4 main types of structures present in the covering, in particular (as visible in Figure 2): 1. Reinforced concrete beam 2. Transparent windshield 3. Transparent fiberglass curtain 4. Opaque metal sheet curtain The transparent parts were treated with semi-opaque paint THERMO-LUX (2 layers), while the opaque areas were treated with white opaque paint-thermo GUM (2 layers), (this information was provided by the client).

4 Pag. 4/1 Client: Barozzi Vernici s.r.l. Revere (MN) 2. Thermographic reliefs For the execution of the reliefs has been used a thermal imager NEC-Avio InfReC GEAR 1EX with standard optics with settings:.9 emissivity and temperature 26. The thermographic survey was conducted in the early afternoon of May 3, 212. Main weather parameters during the surveys *: - Temperature 23 - Mean wind speed of 12 km / h - Mean sea level pressure 111 mbar * (source archive ilmeteo.it) 2.1. Results of thermographic investigations The infrared images taken in the areas treated with antisolar coatings show lower peak temperatures compared to surveys conducted in similar areas where there has been no treatment. In particular in areas of skylights the temperatures of the untreated part are approximately from 3 to hotter compared to similar treated zones. In the area opaque curtain sheet approximately 1 to 3. In the areas of reinforced concrete beams from 1 to Comment Although the were carried out on a spring period following an extended cool and rainy period of time and in a day with a not perfectly clear sky, they show a clear difference in temperature between monitored structures in areas with paint and in not treated areas. The same measurements performed on a period not preceded by rains and in typical summer climatic conditions, which permit a reduced night cooling of the cover, may show a greater difference between the two zones even in the load-bearing parts of the structures, with a greater thermal inertia.

5 Pag. /1 Client: Barozzi Vernici s.r.l. Revere (MN) Not treated area. Relief 1 Treated area. Relief 1

6 Pag. 6/1 Client: Barozzi Vernici s.r.l. Revere (MN) Not treated area. Relief 2 Treated area. Relief 2

9 Pag. 9/1 Client: Barozzi Vernici s.r.l. Revere (MN) 3. Investigation with temperature probes 3.1. Methods of measurement The temperature measurements were performed using probes models Lascar Electronics EL-USB-1 and EL-USB-2 of Lascar Electronics. For each of the four types of structures identified in paragraph 1 of this report, in treated areas and in unsprayed zones two temperature probes were placed. For the measurements to a sampling interval of minutes was set. Figure 3.1. Probes under curtain metal sheet, on beam, under transparent elements. The probes in correspondence of the opaque elements, concrete beams and curtain metal sheets, have been positioned through the use of metal anchors, plastic clips and adhesive tape. Those in correspondence of the transparent elements, openable and fixed, have been anchored with adhesive tape to the metal bars used for the support of the fire hoses. The probes were positioned on the day 17/4/212 and collected on 14//212. This period was characterized by typical spring

10 Pag. 1/1 Client: Barozzi Vernici s.r.l. Revere (MN) conditions, with sunny days alternating with rainy days. As shown in Figure 4, only the days between 8 and 12 may have been sufficiently sunny to allow an increase of temperature and a comparison of the collected data. Figura 3.2. Weather conditions during the investigation period (source:

11 Pag. 11/1 Client: Barozzi Vernici s.r.l. Revere (MN) 3.2. Results of measurements performed Zona NON trattata Zona trattata 1//212 : 3//212 : 11//212 : 13//212 : Figure 3.3. Temperature measurements on concrete beam area 6 Differenza di temperatura: Non trattata - Trattata //212 : 3//212 : 11//212 : 13//212 : Figure 3.4. Temperature difference between the treated area and untreated area on concrete beam area

12 Pag. 12/1 Client: Barozzi Vernici s.r.l. Revere (MN) Zona NON trattata Zona trattata 1//212 : 3//212 : 11//212 : 13//212 : Figure 3.. Temperature measurements on transparent screens area 6 Differenza di temperatura: Non trattata - Trattata //212 : 3//212 : 11//212 : 13//212 : Figure 3.6. Temperature difference between the treated area and untreated area on transparent screens area

13 Pag. 13/1 Client: Barozzi Vernici s.r.l. Revere (MN) Zona NON trattata Zona trattata 1//212 : 3//212 : 11//212 : 13//212 : Figure 3.7. Temperature measurements on curtain metal sheets area 6 Differenza di temperatura: Non trattata - Trattata //212 : 3//212 : 11//212 : 13//212 : Figure 3.8. Temperature difference between the treated area and untreated area on curtain metal sheets area

14 Pag. 14/1 Client: Barozzi Vernici s.r.l. Revere (MN) Zona NON trattata Zona trattata 1//212 : 3//212 : 11//212 : 13//212 : 1. Figure 3.9. Temperature measurements in transparent fiberglass curtain area 8 7 Differenza di temperatura: Non trattata - Trattata //212 : 3//212 : 11//212 : 13//212 : Figure 3.1. Temperature difference between the treated area and untreated at the transparent fiberglass curtain area

15 Pag. 1/1 Client: Barozzi Vernici s.r.l. Revere (MN) 3.3. Comments on the collected data The measurements made through the use of temperature probes confirmed what anticipated by the thermographic surveys. In particular in the areas of coverage are characterized by the presence of transparent components (fiberglass fairings and panels), the temperatures taken in areas not treated with antisolar paint come to be up to more than 6 warmer than those detected in similar treated areas. In the areas of coverage characterized by the presence of opaque elements, such as concrete beams and sheets, the temperatures of the untreated areas are up to about 3 C higher than those detected in similar treated areas These values were measured in typical spring weather condition, with not particularly high mean temperatures and with a strong temperature differences between day and night, which allowed the structure to dissipate during the night the heat accumulated during the day. In a more typical summer condition is reasonable to expect higher temperature differences between treated and untreated areas, not only on the transparent elements, but also on the opaque elements with greater thermal inertia, as concrete beams. Having treated only a small part of the coverage of a sector of the shed does not have allowed to perform temperature measurements at man height in order to detect differences between treated and untreated areas. However, on the basis of the measured data, assuming to be able to monitor two integers warehouses, one of which subjected to treatment with antisolar paints and the other not treated, it is possible to predict that, with the same boundary conditions such as ventilation and quantities of goods present in the shed, the temperature differences at man height could be found proportional to those found on the ceiling between areas subjected to antisolar painting treatment and untreated areas. The presence of ventilation (natural or forced) in the two hypothetical sheds could harmonize air temperature at man height, but it would not remove the so-called "hot head effect", ie the sensation of thermal discomfort felt in presence of thermal radiation from an overheated wall especially annoying when coming from the ceiling to the people's heads. In these cases, the recommended solution is, in fact, the use of coating materials with high thermal emissivity and high solar reflectance.