The objective of this project was to reduce the energy costs for mail sorting centres throughout the UK. The study identified two opportunities to significantly reduce running costs: evaporative cooling, and optimising their roof light percentage.

The optimal percentage of glazing of any building can be determined based on five factors: building usage patterns, heating demand, cooling demand, glazing specification, and the artificial lighting demand. Based on a complex thermal model it was possible to determine that for the mail sorting centres which were studied, the optimal percentage of roof lights was 15%. By modifying their warehouses to have the optimal percentage of roof lights, the mail sorting centres could reduce their energy consumption by approximately 20% per year.

Mail sorting centres have a lot of large equipment which generate a significant cooling demand. With the proposed evaporative cooling system water is sprayed on the large roofs of the sorting centre at night and, through the cool evening temperature, the water is cooled down to approximately 12 degrees Celsius. This 12 degree water is stored in a large tank and is used for cooling the next day. The installation of an evaporative cooling system would have a return on investment within the first year of operation and is predicted to save 99% of the energy costs for cooling.