E-Thesis 43 views
Optimisation of solar thermally driven building cooling and heating system / ENOCK EBBAH
Swansea University Author: ENOCK EBBAH
Abstract
Buildings account for about 30% of global final energy and 28% of total energy sector emissions. Applying solar heat for cooling could reach 1.5 EJ per year, accounting for nearly 17% of energy use for cooling in 2050. Almost half the worldwide building energy demand is for space and water heating....
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Swansea University, Wales, UK
2024
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| Institution: | Swansea University |
| Degree level: | Doctoral |
| Degree name: | EngD |
| Supervisor: | Jewell, E. and Elvins, J. |
| URI: | https://cronfa.swan.ac.uk/Record/cronfa68365 |
| Abstract: |
Buildings account for about 30% of global final energy and 28% of total energy sector emissions. Applying solar heat for cooling could reach 1.5 EJ per year, accounting for nearly 17% of energy use for cooling in 2050. Almost half the worldwide building energy demand is for space and water heating. Solar thermally driven diffusion absorption cooling and heating systems present the opportunity to sustainably meet the growing building cooling and heating energy demand. This research describes how improving a building's thermal envelope design and adopting solar heat capture technology can reduce a building's heating and cooling energy demand. TRNSYS simulation software has been used to determine the cooling and heating demand of a thermally efficient (TE) building in four climatically varying locations in India, Tunisia, Russia, and the UK. The building design criteria varied, including the thermal characteristics of the building envelope material and the use of a solar heat capture device fitted to a diffusion absorption cooling system. The results show that the TE building has less combined heating and cooling loads than that constructed using local building regulations for the four climatic locations, except in India, where insulative properties lead to a requirement for additional cooling. A solar-driven diffusion absorption cooling system, modelled with the EES modelling tool and compared with experimental data, could reduce the TE building cooling energy consumption by 70% for India and Tunisia climatic locations and TE building heat energy demand by up to 28% for Russia and the UK climatic zones. The economic analysis demonstrates that while energetically compelling, local fuel costs mean the energy and CO2 impacts are not immediately translated to short-term financial benefits. The solar collector and storage design indicates that the mass flow rate, collector area, and buffer tank volume influence the cooling engine’s generator temperature. Also, the solar collector achieves the optimum 190-205 °C temperatures with up to 10 kg/hr mass flow rates. Using a small buffer store of 2 litres/ m2 of solar collector area, the solar fraction was between 40-65 %. On the other hand, a cold energy storage design, with tank sizes between 120-500 litres, provides adequate cooling energy throughout the year, with a latent heat medium (eutectic water-salt solution) storing more than three times the energy and less heat loss than sensible heat storage (ethylene glycol and water mixture). The discounted payback times for Tunis, New Delhi, Volgograd, and Swansea are 12.7, 6.8, 0.8, and 2.1 years, respectively, compared with residential air source heat pumps, reported to have paybacks between 3 – 15 years. |
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| Item Description: |
A selection of content is redacted or is partially redacted from this thesis to protect sensitive and personal information. |
| Keywords: |
diffusion absorption cooling, TRNSYS, solar cooling and heating, XCPC solar collector, solar design, thermal energy storage, cold thermal energy storage. |
| College: |
Faculty of Science and Engineering |
| Funders: |
Solar Polar Ltd, M2A, Swansea University, Coated, WEFO |