Environmental concerns worldwide (climate change, global warming, etc.) are pushing to reduce the consumption of fossil fuels. The building sector is responsible for a third of greenhouse gas emissions (40% in France). In tropical countries, the main share of energy consumption in buildings is due to air conditioning systems. Indeed, in a resort of high standing, 60% of energy consumption is due to air conditioning. In the Indonesian context, which welcomes growing real estate projects on more or less isolated islands, it becomes important to put in place passive or autonomous buildings and the corresponding energy solutions. The energy efficiency of buildings is based on two pillars: an efficient building's design and on the effectiveness of the air conditioning system to achieve energy independency in a tropical environment. Considering the decreasing cost of PV cells, the solution to reduce the energy consumption of air conditioning proposed in this article covers a vapour-compression refrigeration system electrically powered by solar cells. To avoid the use of electric batteries, not sustainable in terms of carbon footprint (construction and recycling of batteries) and to overcome the problem of intermittency of solar energy, the choice fell on a variable speed compressor and a storage in a mixture of fatty acids (derived from coconut oil) as phase change material embedded in expanded graphite. The work also focuses on the energy performance of the storage system. This study describes the context and the air conditioning system chosen as a solution for a sustainable resort application in a tropical region. The design and characterization of the coupled PCM and compressed expanded graphite in a latent heat thermal energy storage is also detailed. It uses a TRNSYS simulation for the assessment of the cooling demand. Calculations for a prototype of 25 m 2 apartment showed that with a chiller of 8000 W and a surface of 14 m 2 of photovoltaic panels, it is possible to cool a hotel bedroom with solar energy. The consortium members work jointly at designing and optimizing the system: Indonesian members are focused on the PCM storage and French members are more dedicated to the hygrothermal behaviour of the hotel bedrooms.

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A cooling tower is a unit that helps the process of heat dissipation. Thus, thermal effectiveness is a vital variable for cooling tower performance. Scale precipitation can obstruct thermal effectiveness of the heat exchange unit due to its natural high thermal resistance properties. The ozonation process is expected to decrease the potential of scale precipitation thereby improving cooling tower thermal performance. Cooling water is circulated from the tower before ozone and UV rays are applied. This study aims to determine the characteristics of the effects of ozonation on the overall thermal fouling resistance of forced draft type-counter flow-closed system cooling towers and the quality of water circulation by using the Practical Ozone Scaling Index and Langelier Saturation Index methods. Water quality from closed system cooling towers is determined by conducting laboratory tests. The results obtained from this study indicate that when ozone is present the overall thermal tower resistance of the closed system cooling towers is reduced by 7 x10-6 m2K/W. Ozone can also improve the water quality of closed system cooling towers.

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