Search results

Accra, the capital city of Ghana, is seeing high-rise buildings springing up with extensive glazing. Given the challenges of the country concerning energy provision, guaranteeing comfort in buildings and sustainability aspects, this trend is questionable and worrying in this pandemic era. Therefore, the purpose of this paper is to evaluate how glazing types and their properties could reduce cooling loads and provide comfort by following the recommendations set by the Ghana Green Building Council (GHGBC) after the Green Star of South Africa, as well as other references found in literature.

Indoor thermal conditions were monitored to evaluate prevailing indoor conditions. Using a simulation application, various options were probed based on the Green recommendations and others found in literature to improve thermal comfort within the structure. Moreover, a questionnaire survey with observation was undertaken with 250 architects to understand the basis of decisions taken when specifying glazing for buildings.

The results indicate that cooling loads increased by 2% when the GHGBC after the Green Star of South Africa recommendations were applied. However, the use of the recommendations of previous research conducted in Ghana could reduce cooling loads by 38% to save energy. Suggested strategies of air velocity up to 1.0 m/s as well as thermal mass, comfort ventilation, conventional dehumidification and air-conditioning were found to be means to improve indoor comfort. Furthermore, the architects revealed that around 40% of multi-storey buildings are 70%–100% glazed. Of all the buildings, 62.4% was found to be glazed with single pane windows, making them use so much energy in cooling. Additionally, the survey underlined the client’s preference, cost and functionality as the three main bases for the choice of glazing in multi-storey office buildings.

A significant contribution of this study to the body of knowledge is the provision of empirical evidence to support the fact that due to climate difference, each country needs to undertake more experimental research works to be able to come out with standards that work. Thus, the GHGBC after the Green Star of South Africa does not necessarily work within the climatic context of Ghana.

As the global population keeps increasing with its associated urbanisation and climate change issues being experienced in various degrees worldwide, there is the need to find mitigating measures to improve thermal conditions within spaces. The study aimed to evaluate green roofs to determine whether they could provide thermal comfort within residential buildings.

Forty-two-year weather data were retrieved from the Kumasi weather station to establish the pattern of the climatic variables. Furthermore, an experiment was conducted by constructing test cells to determine the potential of vegetation/green roofs on temperature development within spaces. This approach led to a simulation-based exploration of the thermal performance of the test cells to probe variables that could lead to the reduction in temperature after the models in the software (design-builder) had been validated.

The results on the 42 years (1976–2018) weather data showed a significant (p = 0.05) mean temperature increment of 2.0 °C. The constructed test cell with Setcreasea purpurea (Purple Heart) vegetation showed an annual mean temperature reduction of 0.4 °C (p = 0.05). In addition, the exploration using the simulation application showed combinations of various soil depth (70–500 mm) and leaf area indices (leaf area index of 2–5) having a potential to lower indoor temperature by 1.5 °C and its associated reduction in energy use. The option of green roofs as a valuable alternative to conventional roofs, given their potential in mitigating climate change, must be encouraged. A survey of occupants in six selected neighbourhoods in Kumasi showed varying subjective perceptions of several green issues (24–98%) and increases in temperature values because of the loss of greenery in the city.

Empirical data that point to the significant reduction of indoor temperature values and a subsequent reduction in energy use have been unearthed. Therefore, built environment professionals together with city authorities could invest in these sustainable measures to help humanity.

Given the climatic context and economic challenge of Ghana in its developmental strides, energy use of office buildings continues to be a task on the economy. Therefore, the study was about finding measures that could reduce cooling loads in 10 office buildings. The paper presents the outcome of a long-term study of the thermal conditions in a selected number of office buildings in Accra and Kumasi, Ghana.

Through long-term monitoring of environmental data, the buildings were consequently modelled in a simulation application. Thereafter, a validation of the simulation models (using regression coefficients, r² of 0.53–0.90) was undertaken towards finding measures to reduce cooling loads.

The results showed various potentials of efficient lighting, thermal mass, night ventilation, insulation to attic floors, efficient glazing, blind deployments, etc. in reducing cooling loads in the range of 2–17.5%. By combining the potential measures to study their synergistic effects on the loads, 35, 39 and 38% improvements were achieved for the low-rise, multi-storey and fully glazed office buildings.

These potential measures ought to be incorporated in the design, specification, construction and operation of Ghanaian office buildings to reduce the burden on the economy and the environment. Now more than ever, there is the need for climatic regions to come up with empirical data that could help relieve the world's economies from the post-pandemic stress.