A comparative study on optimum insulation thickness of walls and energy savings in equatorial and tropical climate

The increase outdoor temperature acts directly on the indoor climate of buildings. In Cameroon, the energy consumption demand in the buildings sector has been rapidly increasing in recent years; so well that energy supply does not always satisfy demand. Thermal insulation technology can be one of the leading methods for reducing energy consumption in these new buildings. However, choosing the thickness of the insulation material often causes high insulation costs. In the present study, the optimum insulation thickness, energy saving and payback period were calculated for buildings in Yaounde´ and Garoua cities, located in two climatic regions in Cameroon. The economic model including the cost of insulation material and the present value of energy consumption and the cost over a life time of 22 years of the building, were used to find the optimum insulation thickness, energy saving, and payback period. Materials that extruded polystyrene were chosen and used for two typical wall structures (concrete block (HCB) and compressed stabilized earth block wall (CSEB)). The early cooling transmission loads, according to wall orientations and percentage of radiation blocked were calculated using the explicit finite-difference method under steady periodic conditions. As a result, it was found that the west- and east-facing walls are the least favourite in the cooling season, whereas the south and north orientations are the most economical. Although wall orientation had a significant effect on the optimum insulation thickness, it had a more significant effect on energy savings. In equatorial region (Yaounde´), for south orientation, the optimum insulation thickness was 0.08 m for an energy savings of 51.69 $/m2. Meanwhile, in tropical region (Garoua), for north orientation, the optimum insulation thickness was 0.11 m for an energy savings of 97.82$/m2

Impact of climate change on demands for heating and cooling energy in hospitals: An in-depth case study of six islands located in the Indian Ocean region

This research was conducted in order to assess the impact that climate change has on the demands for heating and cooling energy in hospitals in six cities located in six countries in the Indian Ocean region. Three scenarios (B1, A1B, and A2) of the Intergovernmental Panel on Climate Change (IPCC) were applied in the undertaking of this work. The hourly outdoor data relating to air temperature, wind speed, relative humidity, radiation, and atmospheric pressure recorded over the last 30 years were used as inputs by Meteonorm software to enable the forecasting. The averages obtained in all the 18 models used in the IPCC report 2007 were included in the Meteonorm software and applied for assessing the future climate. The Energy-Plus software was used for assessing the thermal performance of hospitals under natural ventilation, then the energy demand during five periods (past, current, 2030, 2060, and 2090). Thermal insulation was utilized as a passive strategy for reducing cooling and heating energy consumption in the hospitals. Results showed that the use of an envelope of thermal insulation in hospitals was one of the solutions that allowed a reduction in the energy consumption for cooling and heating while increasing the thermal comfort within the hospital. Moreover, by 2090, the ventilation system was recommended in all these hospitals for improving the quality of indoor air, since the heat rate was very high. In the cases of the six islands in the Indian Ocean, each of them represented by one city, the annual energy demand for cooling will increase between 17.1 and 25.4% by 2030; 34.6 and 50.2% by 2060; and 60.8 and 95.1% by 2090. With the use of passive design as a strategy, the annual mean thermal performance of hospitals is predicted to increase to 184% by 2060, while 40% of the cost of cooling energy will be saved. Despite this, the outdoor climate will be 5% harsher in Victoria than in other cities by the year 2090

A review on energy consumption in the residential and commercial buildings located in tropical regions of Indian Ocean: A case of Madagascar island

The aim of this research is to review the status and current trends on energy consumption, but also to assess the cooling energy in some buildings in Madagascar. To achieve this objective, but due to a lack of data regarding energy consumption in buildings in this region, experimental and subjective studies were carried out in 1272 residential buildings and 51 commercial buildings, distributed in 12 cities in the tropical region of Madagascar. A specific questionnaire was designed to collect these data. A total of 1323 questionnaires were distributed during dry and rainy seasons. The results showed that energy consumption varied by both function of design and occupants' behaviors. Cooling energy demand was the highest in modern buildings, while 60% of occupants found their environment uncomfortable. Good indoor air and optimal worker’s performance were watched in buildings with local materials. Although Madagascar has an important source of renewable energy, electricity production remains heavily dependent on more than 80% of fossil fuel sources