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• Solar energy and PCM are used to augment the indoor steam curing process. • Mathematical model of the curing process is developed. • Comparison with experiments confirms the accuracy of the mathematical modelling. • Benefits of the proposed technology are quantitively demonstrated. Steam is used to provide heating and moisture in the curing process for the production of precast concrete (PC) construction elements. The generation of steam requires large amounts of fossil fuels. This study considers the incorporation of solar thermal energy into the steam curing of PC construction elements for reducing the need for fossil fuels and associated CO 2 emissions. For this purpose, the board made of composite phase change material covers the inner surface of the main sun-facing wall in the heating & curing building. The PCM board is heated by sun rays and accumulates thermal energy during the PCM's phase transition, and this energy then is released to the indoor environment of the building, reducing the amount of steam required to maintain a certain level of temperature during the curing process. The energy consumption simulation software, EnergyPlus, and two physical models (built on the scale of 1:3) were used to study the effects of two different PCMs on the thermal performance of such new type of heating & curing buildings. Composite PCMs considered were GH-33 and GH-37 with 33 and 37 °C melting temperatures developed by the research team. The theoretical and experimental results are in good agreement and demonstrate that, compared to the GH-33, GH-37 PCM increases the temperature of the inner surface of the main sun-facing wall and the upper surface temperature of the PC construction element by 3.4 and 1.4 °C, respectively. The heat accumulation and discharge rates also were greater by 62%. For the investigated design of the building and given location in China, the deployment of studied PCM wall panels results in a reduction in the annual energy consumption and CO2 emissions by 58.6 GJ and 5 tons, respectively. The method developed for applying solar energy and selecting PCMs for augmenting steam curing of PC construction elements can be deployed in different geographical regions. [ABSTRACT FROM AUTHOR]

Prefabricated concrete (PC) components require curing at the specific environment after being cast for the concrete to harden to the required levels over a certain period of time. Currently, steam curing is used as the major technique in concrete production. However, this method is highly energy consuming and requires large amounts of fossil fuels. Analysis of thermal process parameters in PC curing and thermal properties of phase change materials (PCMs), developed by the research team at Beijing University of Technology for the greenhouse applications, resulted in the development of the conceptual design of passive solar PC steam curing buildings with on-wall PCM heat storage. The process of selection of the PCM for installation on the inner surface of the main sun-facing wall of solar passive curing buildings is described. The selection is the result of the evaluation of suitable PCMs using the simultaneous process of transient energy consumption simulation with the deployment of EnergyPlus software and one-dimensional unsteady heat transfer modelling across the thickness of the thermal storage. The EnergyPlus simulations were calibrated against experimental data obtained in the curing building in Hebei Province, China. Theoretical simulations for such the building demonstrate that a GH-37 PCM panel with a thickness of 50 mm is suitable for such the application. The temperature range of phase transition for the GH-37 PCM is between 37.4 and 43.5 °C with latent heat equal to 227.5 kJ/kg. Compared to the same case but without PCM, the monthly and nocturnal average temperature of the inner surface of the main sun-facing wall increases by 1.3 °C and 2.7 °C, respectively. The heating load is reduced by 6.4, 5.8, 3.4 and 2.9 GJ in spring, autumn, summer and winter periods, respectively. The amount of annual steam consumption is reduced by 4.7%. • The design concept of solar-assisted PC curing room with PCM was proposed. • Mathematical model of the PC solar-assisted curing room with PCM was carried out. • The selection of a suitable PCM and its optimal thickness was carried out. • The proposed design solution provides annual energy saving of 4.7%. [ABSTRACT FROM AUTHOR]