Study Of Novel Solar Thermal Systems Applied On Residential Building

Solar thermal, as the most mature technology among all currently available solar technologies, is regarded as one of the most feasible renewable solutions for the building application. Truly building integrated solar systems can be a potential solution towards the enhanced energy efficiency and reduced operational cost in the contemporary built environment. However, the current solar thermal system has been identified with a number of problems that would prevent their promotions. To further research and promote the integration of solar thermal technology and architecture, and explore the optimal combination form of solar thermal technology and architecture, several building based novel solar thermal systems are thereby proposed and studied by the author. The content mainly includes:1, To overcome the barriers for the use of solar water heating systems in building, a novel solar facade based loop-heat-pipe heat pump water heating system was proposed. Integrated the loop-heat-pipe, which allows large amount of heat transfer for distances up to several meters and protects the pipes from freezing during winter operation, with an assisted heat pump, the loop heat pipe working fluid could retain at low temperature over the whole operation process, thus ensuring the constant higher solar efficiency.2, A dedicated theoretical investigation into the thermal performance of the novel solar facade based loop-heat-pipe heat pump water heating system was presented. This involved thermo-fluid analyses, computer numerical model development, the model running up, modelling result analyses. It was found that variations in the system configuration, i.e. glazing covers, heat exchangers, and operational parameters, i.e. solar radiation, ambient air temperature, would lead to identifiable differences in the thermal performance of the system. It was suggested that the loop heat pipes could be filled with either water, R134a, R22 or R600a; of which R600a is the favourite working fluid owing to its relatively larger heat transfer capacity and positive pressure in operation.3, The dynamic operational performance of the novel solar facade based loop-heat-pump water heating system using both theoretical and experimental methods was presented. This involved development of a dynamic numerical model; simulation of the operational performance of the system by using the model; test rig construction; and dedicated experiment for verification of the model. It was found that the established model is able to predict the operational performance of the system at a reasonable accuracy. Analyses of the research results indicated that under the selected testing conditions, the average thermal efficiency of the LHP modules and the average coefficient of the performance were 71.0% and 4.93, respectively. The dedicated was also used to evaluate the economic and environmental impact of using this technology in China and Europe, and analyse its possibility for social and public acceptance within these regions.4, To improve the performance of the Trombe wall systems, a novel Trombe wall with venetian blind structure was proposed. This combined system is able to improve the energy efficiency of heat collecting in winter and prevent over heating in summer by switching the working modes of the system. A CFD investigation into the flow and thermal transport of the Trombe wall equipped with venetian blinds was presented. This involved development of a 3-D CFD model and a 2-D CFD model; dedicated experiment for verification of the model; modelling result analyses and conclusion. Based on experimental data, the model was validated and it was able to yield satisfactory predictions. The results indicated that the position of the venetian blind, the width of the air duct and the area of the inlet and outlet vents influence the thermal performance of the system. The Nusselt number and friction factor for Reynolds number within the range of 4173 to 16693 were also achieved.5, For the purpose of creating a building integrated, highly efficient and aesthetically appealing solar heating structure, a novel tile-shaped dual-function solar collector was presented. This tile-shaped collector is designed to integrate the solar collector into the Hui-style building, which can be fixed to the pitched roof and thus enabling improvement of the building’s aesthetic effect and requiring no additional area. A comparative study between the tile-shaped dual-function collector and conventional flat plate dual-function collector was presented. It was found that the tile-shaped collector is able to achieve higher efficiency at higher temperature operation. A complete 3D CFD model in water heating mode was developed. The numerical prediction was validated using experimental data. The results indicated that lower inlet water temperature, higher water flow rate, higher ambient air temperature and lower solar radiation led to enhanced thermal efficiency of the module.6, We designed a two-storey residential building, in which the novel composite solar thermal systems were applied. And the corresponding building thermal model was established. Winter heating performance of the Trombe wall with venetian blind structure and tile-shaped dual-function solar collector in the solar building in Hefei was then simulated and analyzed.