Cooling with solar energy in India

Two-storey embassy building with pools in the foreground.
A solar cooling system replaces the previous system of the old compression chillers in the embassy building in New Delhi. © FOBL

In New Delhi, temperatures can reach up to 48°C on some days. Therefore, a large amount of energy is required for cooling. In India, most of the electricity used for this purpose comes from coal-fired power plants with high pollutant emissions. The Swiss embassy in New Delhi has found an innovative solution to this problem in line with the 2030 Agenda and the Federal Council's Sustainable Development Strategy 2016–2019.

A new technology for sustainable cooling

In 2014, the previous system of compression chillers was replaced with a solar cooling system. Firstly, water is heated in solar collectors. An absorption chiller then uses this heated water to generate cold, just like a conventional household refrigerator. The system cools most when it is most needed, i.e. when the sun is at its strongest. The heat from the sun is used for cooling, thus beating the heat. Solar cooling also works when the sky is overcast because even diffuse rays can be absorbed sufficiently to produce cooling energy. This efficient system can save 134,000 kWh of electricity and 132 tonnes of CO2 per year in ideal circumstances. This corresponds to the amount of CO2 emissions caused by a person flying from Zurich to the Canary Islands and back 132 times.

Sustainable building

The embassy in New Delhi also distinguishes itself through another innovative feature: when the visa centre had to be rebuilt, a temporary solution was created. The persons responsible opted for a sustainable building method: a new type of cement, developed by the Swiss Federal Institute of Technology in Lausanne (EPFL) in a project funded by the Swiss Agency for Development and Cooperation (SDC), was used for the outer walls. This building material, called 'LC3', combines traditional cement components with limestone and calcined clay. As a result, approximately 30% less CO2 is emitted during production than during the production of conventional cement. Roof insulation, the inclusion of air in the outer walls, and double-glazed windows also ensure perfect insulation of the building. Special rooms for embassy staff and project partners provide excellent conditions for telephone and videoconferencing: numerous flying hours can thus be saved. These measures send out an important message regarding sustainable building in India.

Raising awareness and promoting communication on the subject of sustainability

In addition to major structural measures to improve sustainability, the embassy also attaches importance to sustainable behaviour on the part of its employees. At meetings, for example, it encourages staff to keep printing to a minimum and to use energy-efficient electrical appliances.

Awareness-raising is not restricted to staff: the embassy actively communicates its commitment to sustainability. It has published short videos on energy efficiency measures in the new cooperation office building and on SDC climate protection projects.