A Case Study on the Assumption of Mean Radiant Temperature Equals to Indoor Air Temperature in a Free-Running Building

Abstract

Thermal comfort is basically affected by environmental (mean radiant temperature, indoor air temperature and relative humidity and air velocity) and personal parameters (clothing value and activity level). Mean Radiant Temperature is the most complicated parameter among all thermal comfort parameters due to the difficulty of measurement and calculation processes. Calculation methods are not preferred by the researchers because of the complexity of obtaining angle factors while the measurement methods require very expensive devices such as globe thermometers and radiometers. On the other hand, assumptions are commonly used in thermal comfort studies because of their simplicities. One of the most frequently used assumptions expresses the equality of mean radiant temperature to indoor air temperature. However, the accuracy of this assumption needs further experimental research in order to evaluate thermal comfort, especially in free-running buildings. To this aim, this study proposes to determine the accuracy of the assumption of mean radiant temperature equals to indoor air temperature in a free-running building where Adaptive Thermal Comfort approach is applied in summer condition. Environmental parameters are measured via objective sensors, while adaptive thermal comfort is assessed by a software program. The statistical results show that there are significant deviations between two parameters in summer conditions for a free-running building.

Keywords

• Adaptive Thermal Comfort
• Free Running Building
• Globe Thermometer
• Indoor Air Temperature
• Mean Radiant Temperature

Project Number

yok

References

1. [1] ASHRAE 55, 2017, Thermal Environmental Conditions for Human Occupancy
2. [2] ISO Standard 7730, 1994, Moderate Thermal Environments-Determination of the PMV and PPD Indices and Specification of the Conditions for Thermal Comfort, International Standards Organization, Geneva, Switzerland.
3. [3] Fanger, P.O., 1970. Thermal comfort. Analysis and applications in environmental engineering. Thermal comfort. Analysis and applications in environmental engineering.
4. [4] Nicol, F. and Humphreys, M., 2010. Derivation of the adaptive equations for thermal comfort in free-running buildings in European standard EN15251. Building and Environment, 45(1), pp.11-17.
5. [5] De Dear, R.J. and Brager, G.S., 2002. Thermal comfort in naturally ventilated buildings: revisions to ASHRAE Standard 55. Energy and Buildings, 34(6), pp.549-561.
6. [6] Wagner, A., Gossauer, E., Moosmann, C., Gropp, T. and Leonhart, R., 2007. Thermal comfort and workplace occupant satisfaction—Results of field studies in German low energy office buildings. Energy and Buildings, 39(7), pp.758-769.
7. [7] Pfafferott, J., Herkel, S., Kalz, D.E. and Zeuschner, A., 2007. Comparison of low-energy office buildings in summer using different thermal comfort criteria. Energy and Buildings, 39(7), pp.750-757.
8. [8] CEN EN 15251, 2007. Indoor Environmental Input Parameters for Design and Assessment of Energy Performance of Buildings Addressing Indoor Air Quality. Thermal Environment. Lighting and Acoustics. European Committee for Standardization. Brussels, Belgium.

9. [9] Van der Linden, A.C., Boerstra, A.C., Raue, A.K., Kurvers, S.R. and De Dear, R.J., 2006. Adaptive temperature limits: A new guideline in The Netherlands: A new approach for the assessment of building performance with respect to thermal indoor climate. Energy and Buildings, 38(1), pp.8-17.
10. [10] Kántor, N. and Unger, J., 2011. The most problematic variable in the course of human-biometeorological comfort assessment—the mean radiant temperature. Central European Journal of Geosciences, 3(1), pp.90-100.
11. [11] Wang, Y., Meng, X., Zhang, L., Liu, Y. and Long, E., 2014. Angle factor calculation for the thermal radiation environment of the human body. In Proceedings of the 8th International Symposium on Heating, Ventilation and Air Conditioning (pp. 447-455). Springer, Berlin, Heidelberg.
12. [12] JOKL, M.V., 2015. 4 New Thermal Comfort Standards of the Czech Republic. Standards for Thermal Comfort: Indoor air temperature standards for the 21st century.
13. [13] ROWE, D., 2015. 24 Warm and Sweaty: Thermal Comfort in Two Naturally Ventilated Offices in Sydney, NSW. Standards for Thermal Comfort: Indoor air temperature standards for the 21st century, p.48.
14. [14] Itani, M., Ghaddar, N., Ghali, K. and Laouadi, A., 2020. Development of heat stress charts for older people under indoor environmental conditions. Energy and Buildings, 224, p.110274.
15. [15] Dawe, M., Raftery, P., Woolley, J., Schiavon, S. and Bauman, F., 2020. Comparison of mean radiant and air temperatures in mechanically-conditioned commercial buildings from over 200,000 field and laboratory measurements. Energy and Buildings, 206, p.109582.
16. [16] Guo, H., Aviv, D., Loyola, M., Teitelbaum, E., Houchois, N., and Meggers, F., 2020. On the understanding of the mean radiant temperature within both the indoor and outdoor environment, a critical review. Renewable and Sustainable Energy Reviews, 117, 109207.
17. [17] Koch, W., 1962. Relationship between air temperature and mean radiant temperature in thermal comfort. Nature, 196(4854), pp.587-587.
18. [18] McIntyre, D.A. and Griffiths, I.D., 1972. Subjective response to radiant and convective environments. Environmental Research, 5(4), pp.471-482.
19. [19] Lin, B., Wang, Z., Sun, H., Zhu, Y. and Ouyang, Q., 2016. Evaluation and comparison of thermal comfort of convective and radiant heating terminals in office buildings. Building and Environment, 106, pp.91-102.
20. [20] Catalina, T., Virgone, J. and Kuznik, F., 2009. Evaluation of thermal comfort using combined CFD and experimentation study in a test room equipped with a cooling ceiling. Building and Environment, 44(8), pp.1740-1750.
21. [21] Chaudhuri, T., Soh, Y.C., Bose, S., Xie, L. and Li, H., 2016, October. On assuming Mean Radiant Temperature equal to air temperature during PMV-based thermal comfort study in air-conditioned buildings. IECON 2016-42nd Annual Conference of the IEEE Industrial Electronics Society (pp. 7065-7070). IEEE.
22. [22] Köppen-Geiger Climate Classification, 2009. Retrieved March 3, from http://koeppen-geiger.vuwien.ac.at/ (Access Date: 30/11/2020)
23. [23] EN 16798, 2019. Energy performance of buildings - Part 1: Indoor environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality, thermal environment, lighting and acoustics.
24. [24] Extech Instruments 42530, http://www.extech.com/display/?id=14256, (Access Date: 30/11/2020)
25. [25] TESTO 425 - Compact Thermal Anemometer, https://www.testo.com/en-UK/testo-425/p/0560-4251, (Access Date: 30/11/2020)
26. [26] ISO 7726, 1998. Ergonomics of the Thermal Environment-Instruments for Measuring Physical Quantities.
27. [27] Camacho, A., Rodrigues, M.T. and Navas, C., 2015. Extreme operative temperatures are better descriptors of the thermal environment than mean temperatures. Journal of thermal biology, 49, pp.106-111.
28. [28] Kazkaz, M. and Pavelek, M., 2013. Operative temperature and globe temperature. Eng. Mech, 20(3/4), pp.319-325.
29. [29] Allen, M.P., 2004. Understanding regression analysis. Springer Science & Business Media.
30. [30] Dekking, F.M., Kraaikamp, C., Lopuhaä, H.P. and Meester, L.E., 2005. A Modern Introduction to Probability and Statistics: Understanding why and how. Springer Science & Business Media.
31. [31] Schechtman, E. and Sherman, M., 2007. The two-sample t-test with a known ratio of variances. Statistical Methodology, 4(4), pp.508-514.
32. [32] Rumsey, D. J., 2016. Statistics For Dummies, 2nd ed., John Wiley & Sons, Nashville, TN.
33. [33] Bughrara, K.S., Arsan, Z.D. and Akkurt, G.G., 2017. Applying underfloor heating system for improvement of thermal comfort in historic mosques: the case study of Salepçioğlu Mosque, Izmir, Turkey. Energy Procedia, 133, pp.290-299.
34. [34] Walikewitz, N., Jänicke, B., Langner, M., Meier, F., and Endlicher, W., 2015. The difference between the mean radiant temperature and the air temperature within indoor environments: A case study during summer conditions. Building and Environment, 84, 151-161.