Investigation of a compact unglazed solar thermal façade for building integration

Abstract

In order to achieve the global carbon emission reduction target, it is expected to become essential for higher fraction of locally available renewable energy sources in energy mix, other than significant reduction of fossil energy consumption. Solar energy is one of the most promising renewable sources locally with various building applications. In addition, the Solar Thermal Facade (STF) system demonstrates a real sense of building integration that can be a potential solution towards energy efficiency improvement and operational cost reduction in contemporary built environment. This thesis presents a comprehensive investigation into a novel com-pact unglazed STF system that possesses the advantages of compact structure, economical cost and high feasibility in architectural design. The entire study follows in the basic methodology of combined theoretical and experimental analysis, including procedures of critical literature reviews, optimal concept design, theoretical study, analytical model development, prototype system construction, laboratory-controlled evaluation, techno-economic feasibility analysis and a design strategy for its application. Under the baseline testing condition, the collector efficiency factor F’, heat removal factor FR and channel flow factor F’’ were respectively high up to 0.993, 0.992, and 0.985, leading to a relatively high thermal efficiency at about 63.21%, exhibiting a better thermal performance. And the maximum theoretical possible useful heat gain capacity (intercept FRαp) of such STF at the given operating conditions was about 96.20%. And the mean slope (FRUL) was as much as about -13.06, representing a sharp decreasing trend of this SFT’s thermal efficiency against the (Tin-Ta)/I complying with the feature of no glazing cover attached in the front. So in case of current design, such STF could match the applications of heating load for pool heating, domestic hot water and radiant space heating in those areas with warm air temperature and sufficient solar radiation. Moreover, the techno-economic feasibility study identified that the overall contributions of the STF application in a reference residential building consist of direct solar thermal generation, indirect HVAC load reduction and savings in operation cost. Additionally, the financial outputs from the dedicated business model in Shanghai stated that: the proposed STF system was a profitable investment project with positive overall revenue and acceptable payback period within 6 years; and three different investment schemes have individual advantages in terms of investment risk, payback period and financial output. Lastly, the BIM associated STF design strategy was raised for building performance research in architectural practice. It is ultimately about the evaluation of multiple STF alternatives against different design priorities and the associated STF design information sharing with others to reduce duplication, minimize errors, streamline processes and facilitate collaboration towards sustainable STF integration. The entire research is expected to configure a technical breakthrough in the subject for the widespread market penetration of the STF technology, a feasible solution for solar thermal technology in future building application, as well as an advanced multi-functional STF development. The research outcomes of this study will conduce to the promotion of such a building integrated solar thermal technology, enrich low-carbon building design strategy, and thus contribute to achieving the domestic and international targets for energy saving, renewable energy utilization, and carbon emission reduction in the building sector.

Date of Award	1 Mar 2017
Original language	English
Awarding Institution	Univerisity of Nottingham
Supervisor	Tong Yang (Supervisor), Llewellyn Tang (Supervisor) & Yupeng Wu (Supervisor)