on system composition, ranging from 40-70°C for traditional flat plate collectors with desiccant evaporative cooling, to 250°C for Fresnel collectors (a linear concentrating solar thermal collector) with absorption chillers.

In conventional AC systems, the sensible load reduces the temperature of the air until it reaches 100% relative humidity. The latent load then removes the moisture from the air, but this usually results in the air being too cold for thermal comfort, so it must be reheated using additional energy. Humidity (or rather the latent heat that humidity contains) is responsible for a large share of the cooling demand in many countries.

Solar thermal cooling systems with one solid/liquid desiccant wheel could reduce cooling demand significantly, as they do not require extra energy for reheating.

Appliances & equipment

Technology already exists and is readily available to improve the energy efficiency of appliances and equipment. Conventional policy measures can be employed to drive markets to adopt these more efficient technologies and put appliances and equipment on track with the SDS.

Innovation remains important to achieve mass deployment of products with even higher efficiency. Technology improvements include vacuum-insulated panels for refrigerators, heat pump technology for tumble dryers and improved silicon for electronic equipment. Innovation will also be required to continue reducing the cost of manufacturing equipment while improving energy efficiency and related performance. Furthermore, to take advantage of digitalisation benefits, consumer-friendly energy management tools are needed for smart appliances and equipment.

Development of vacuum-insulated panels and insulating materials for refrigeration.

In 2018, global electricity use by residential refrigerators and freezers was around 500 TWh and is expected to rise a further 35% by 2050. The efficiency of residential refrigerators can be doubled through known technology, such as using more insulation (though noticeably reducing useful internal space) and better compressors. The use of effective vacuum-insulated panels (VIPs), however, would raise energy efficiency while also increasing internal refrigerator volume (for the same external area), providing better service for consumers.

High cost of heat pumps in tumble dryers

Tumble dryers use a considerable amount of energy when in operation – globally energy consumption is approaching 100 TWh annually and is expected to more than triple by 2050 as ownership and use expand. Heat pump technology is therefore important, as it can significantly improve tumble dryer energy efficiency.

Data centres & networks

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