Predicting thermal loss through building envelopes taking into account changes of material moisture content

Introduction. The important way to improve the efficiency of residential building heating systems is to use thermal insulation materials in exterior building envelope. At the design stage, the choice of insulation is based on predicting heat loss through the walls using standard methodologies that do not take into account changes in the thermophysical properties of the materials during operation, such as changes of humidity during the heating season. The purpose of this paper is to develop the methodology for predicting heat loss through exterior building envelope, taking into account changes in the moisture content of the thermal insulation materials during operation.

Materials and methods. The proposed methodology is based on the mathematical model of heat and moisture transfer in the four-layer building envelope, which was developed using the authors’ experimental data on the dependence of thermal conductivity and moisture conductivity coefficients from sorption moisture content for typical thermal insulation materials. The structure under consideration consists of an internal lime plaster layer; a brick (or concrete) wall; thermal insulation material and an external facing layer. The methodology for predicting thermal losses was implemented in the COMSOL Multiphysics 6.2 software package.

Results. Studies of the thermotechnical characteristics and heat losses for the four-layer envelope structure with IZOVOL, TEHNOPAS PROF, PENOPLEX COMFORT thermal insulation materials were carried out on the example of residential buildings of mass construction in Lugansk. The conducted thermal imaging survey of insulated envelopes for operated buildings is consistent with the results of calculations according to the proposed methodology.

Conclusions. The developed predicting methodology ensures the accuracy increase of determining the heat loss of heating systems through exterior building envelopes, taking into account changes of the materials moisture content during operation. The application of this methodology allows assessing the energy efficiency and economic feasibility of using standard insulation materials in building envelopes.

1. Nigumann E., Kalamees T., Kuusk K., Pihelo P. Circular renovation of an apartment building with prefabricated additional insulation elements to nearly zero energy building. Journal of Sustainable Architecture and Civil Engineering. 2024; 34(1):22-34. DOI: 10.5755/j01.sace.34.1.35674

2. Vysotsky D., Tatyannikov D. Comparison of insulation options for a production building during reconstruction. PNRPU Bulletin, Applied ecology. Urban development. 2020; 2(38):57-67. DOI: 10.15593/2409-5125/2020.02.04. EDN ZNLRPP. (rus.).

3. Belikov K.E. Comparison of the thermal insulation properties of various types of insulation for the construction of private residential buildings. Scientific Journal of Young Scientists. 2021; 3(24):33-38. EDN NXFZDI. (rus.).

4. Wang Q. Thermal insulation performance analysis of high rise building envelope based on finite element analysis. Thermal Science. 2022; 26(3 Part A): 2361-2372. DOI: 10.2298/tsci2203361w

5. Kolosova A.S., Pikalov E.S. Modern effective thermal insulation materials on inorganic base. International Journal of Applied and Fundamental Research. 2020; 9:64-75. EDN CTMUIL. (rus.).

6. Kolosova A.S., Pikalov E.S. Modern effective thermal insulation materials on organic base. International Journal of Applied and Fundamental Research. 2021; 4:74-85. EDN TUZZKY. (rus.).

7. Gamayunova O., Musorina T., Petrichenko M., Goremikins V. Warming of panel houses in various climatic zones. Proceedings of EECE 2019. Energy, Environmental and Construction Engineering. 2020; 253-263. DOI: 10.1007/978-3-030-42351-3_22. EDN BGWXUO.

8. Zubarev K., Gagarin V. Mathematical modeling of heat and moisture regimes of building for the facade thermal insulation composite system with mineral wool insulation. Smart Innovation, Systems and Technologies. 2022; 625-634. DOI: 10.1007/978-981-16-3844-2_54

9. Zubarev K. Gagarin V. Heat and moisture transfer in building enclosing structures. Lecture Notes in Networks and Systems. 2022; 257-266. DOI: 10.1007/978-3-030-80946-1_26

10. Sokolov V., Krol O., Chernikova I., Tsankov P., Salukvadze G. Modeling of Aerodynamic Characteristics of Ventilation Systems Based on Object Decomposition. Lecture Notes in Civil Engineering. 2025; 509-519. DOI: 10.1007/978-3-031-80482-3_48

11. Malygina O.A. Development of mathematical models of definition heat and humidity conditions of building enclosing structures with nonstationary heat flow. Modern problems of civil protection. 2024; 3(52):93-104. EDN NNKWXJ. (rus.).

12. Zaitseva K.V., Titunin A.A., Gnedinа L.Yu., Ibragimov A.M. Heat and mass transfer in a multi-layer glued wooden beam: formulation of the problem. Industrial and Civil Engineering. 2015; 8:21-27. EDN UGYVTT. (rus.).

13. Kuzina V.V., Eremkin A.I., Koshev A.N., Ponomareva I.K. Mathematical modeling of temperature and velocity fields in convective flows from the heated surface of a heater. Regional Architecture and Engineering. 2025; 1(62):183-191. DOI: 10.54734/20722958_2025_1_183. EDN JQAPWL. (rus.).

14. Pavlova M.O., Zaharov V.A., Kvardakova A.M. Study of heat loss through a window slope. Structural Mechanics and Analysis of Constructions. 2023; 3(308):36-45. DOI: 10.37538/0039-2383.2023.3.36.45. EDN RIIGPA. (rus.).

15. Suchilin V.A., Kochetkov A.S., Gubanov N.N. Modeling in COMSOL Multiphysics of energy saving of typical housing and communal services buildings during reconstruction and repair. Plumbing, Heating, Air-Conditioning. 2020; 6(222):44-50. EDN SWRRLH. (rus.).

16. Parfenov G.I., Smirnov N.N., Yablokov A.A., Pyzhov V.K. Simulation of applied heat and air exchange problems in the COMSOL Multiphysics program. Ivanovo, 2023; 132. (rus.).

17. Tsvetkov N.A., Khutornoy A.N., Tolstykh A.V., Kolesnikova A.V. A physico-mathematical model of heat and moisture transfer in building envelopes shaped heat timber. News of Higher Educational Institutions. Construction. 2017; 2(698):12-20. EDN YTPOMP. (rus.).

18. Musorina T.A., Zaborova D.D., Petritchenko M.R. Mathematical apparatus for determination of homogenous scalar medium thermal resistance. Vestnik MGSU [Monthly Journal on Construction and Architecture]. 2019; 14(8):1037-1045. DOI: 10.22227/1997-0935.2019.8.1037-1045. EDN ANCYIM. (rus.).

19. Korniyenko S.V. Improving methods of temperature and humidity calculation in enclosing structures. AlfaBuild. 2020; 1(13):1-6. DOI: 10.34910/ALF.13.1. EDN QJXQQH. (rus.).

20. Gagarin V.G., Kozlov V.V., Zubarev K.P. Analysis of the zone location of maximum moistering in the wall system with different thickness of insulation layer. Housing Construction. 2016; 6:8-12. EDN WFAXGN. (rus.).

21. Kornienko S.V., Chesnokova O.G., Chesnokova V.D., Zhurbenko M.D. Dynamic modeling of heat and moisture transfer processes in multilayer fences. Bulletin of the Volgograd State University of Architecture and Civil Engineering. Series: Construction and Architecture. 2021; 4(85):29-40. EDN CEHHWH. (rus.).

22. Gagarin V., Pastushkov P., Reutova N. Usage of calculated definition of the operating humidity of thermal insulation materials. Building and Reconstruction. 2015; 4(60):152-155. EDN UAXPEH. (rus.).

23. Perekhozhentsev A.G. On the potential of humidity, rationing and calculation of heat and humidity characteristics of external fences of buildings. Bulletin of the Volgograd State University of Architecture and Civil Engineering. Series: Construction and Architecture. 2023; 3-4(92):39-48. EDN JRSXZX. (rus.).

24. Sokolov V. Diffusion of Circular Source in the Channels of Ventilation Systems. Lecture Notes in Networks and Systems. 2019; 278-283. DOI: 10.1007/978-3-030-04792-4_37

25. Malygina O.A. Analysis of the thermal properties of the outdoor the enclosing structure according to the results of field tests. Modern Problems of Civil Protection. 2024; 2(51):129-139. EDN EDFZBP. (rus.).

26. Sokolov V. Hydrodynamics of Flow in a Flat Slot with Boundary Change of Viscosity. Lecture Notes in Mechanical Engineering. 2021; 1172-1181. DOI: 10.1007/978-3-030-54817-9_136

27. Malygina O.A., Zasko V.V. Experimental determination of the thermal conductivity coefficient of thermal insulation materials in a wet state. Proceeding of the Donbas National Academy of Civil Engineering and Architecture. 2024; 5(169):5-14. DOI: 10.71536/vd.2024.5c169.1. EDN MTXSIN. (rus.).