The central part of this building’s cooling system is a solar powered absorption cooling system made up of four 10kW state-of-the-art absorption heat pumps, driven by 90 high performance flat- plate solar collectors able to constantly deliver fluid at up to 95°C, the maximum temperature for the absorption heat pump to work properly. In summer this system is a serious alternative to conventional chillers or heat pumps for providing cold water to the cooling coils as it requires almost no additional energy (apart from the solar energy captured by the solar collectors) to cool the building. The absorption heat pump used at the Almeria building uses a patented technology that allows energy to be stored and instantly delivered later on. This way the system can store energy all along the sunny hours of the day and keep on cooling down the building even after sunset if necessary. It has to be mentioned that the system is designed so that it can store and deliver at the same time. Also, the technology employed allows the input fluid temperature to vary, as long as the temperature difference between the source and the heat sink (in our case a cooling tower for practical reasons) is above 50°C. When considering using solar thermal collectors as a heat source, this is an advantage over conventional absorption chillers that need the input fluid to remain at a constant temperature. The cooling tower can actually be controlled so that the absorption system keeps working even when the solar collectors’ output temperature falls down. On the other side, the system can also be set to take higher temperatures of up to 120°C for some minutes so that, in the end, this system makes it possible to take advantage of all of the available solar energy to produce cooling energy for the building.

Fig. 1. Array of solar collectors on the roof (left) and Absorption heat pumps (right).