Using phase change materials and efficient coldless air conditioning systems to optimize the heat management in telecom shelters

Telecom shelters are widely used either for mobile phone base stations or for placing xDSL equipments close to the customer. As the power dissipated by the equipments grows tremendously throughout the generations, heat management becomes an important concern. According to the politic of sustainable development of France Telecom, a study has been led in order to optimize the conception of telecom shelters. In fact, most of the shelters available on the market are very light buildings that have not been thought to limit the effects of external temperature and sun radiation nor to cope with the high internal heat dissipation. This study explores several ways to achieve the conception of an efficient telecom shelter: - Coldless air conditioning system: the methods use fan with an appropriate regulations to control the temperature in the room, - Using phase change materials to highly improve the thermal inertia: phase change materials (PCM) need a lot of energy to turn from a solid state to a liquid state. Thus, if the phase temperature is cleverly selected, the increase of temperature of the room can be limited. The PCM can be directly part of the construction materials (melt in gypsum wallboards or in cement, lime or gypsum mortars) or placed in heat exchangers. - Choosing construction materials carefully selected regarding their physical properties Firstly, simulations have been made to optimize the choice of material properties and to find rules of conception (regarding thermal inertia and insulation). As the effects of PCM are very hard to compute, experimental investigations have been performed. The final goal is to construct a model that can represent the thermal response of a real shelter with a coldless air conditioning system, and PCM.