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2021-12-20

Hot & Cool - Building air conditioning with residual heat

There is a growing demand for comprehensive cooling systems for data storage, in the food sector, in medicine and - especially in times of global warming - for climate-efficient and resource-saving buildings.
Both the Green Cooling Initiative in Kenya, Ghana and the Seychelles and the "Wärmewende 2030" here in Germany are looking for ways to make efficient use of waste heat and natural refrigerants to provide buildings with sustainable air conditioning all year round.

buildings sustainably throughout the year. According to a report by the EU Commission, around 75 percent of all buildings in Europe are energy-inefficient. Under the European Green Deal, money will be made available to renovate existing buildings to increase the number of "zero energy buildings" or "zero energy houses" and reduce electricity costs for consumers.
In New York City, a law will be passed before the end of the year that will ban the use of gas or oil for heating, hot water and cooking in most new buildings. As a result, the city could soon become a pioneer in energy efficiency and fossil fuel use reduction in the United States.
Energy use in city buildings are considered a major contributor to global warming in the world's urban centers. In New York City, buildings account for 70% of the city's pollution. Members of the New York Communities Board for Change, a social housing initiative, are advocating for better insulation in new buildings, which would significantly reduce heating costs for housing units.
Not only on the other side of the pond, but also in Europe, housing construction must be advanced. To ensure that buildings do not become energy guzzlers and that residents have pleasant temperatures in the building all year round, the German Federal Ministry for Economic Affairs and Energy, now: Ministry for Economic Affairs and Climate, recently launched the "Heat Turnaround" 2030 with the goal of a "climate-neutral heat supply."
Throughout Germany, numerous projects for the sustainable use of waste heat have been launched with the aim of using the heat generated by cooling or production processes, among other things, to heat residential buildings.
In the city of Aachen, the waste heat generated by showering or washing clothes is already being used to heat five apartment blocks owned by "gewoge AG". The gas floor heating systems in the buildings have been replaced by a central heat and hot water supply: An exhaust-air heat pump extracts the excess heat from the main collector of the city's wastewater sewer and transfers it to the buildings. This can save 200 tons of CO2 annually.

As the International Energy Agency (IEA) noted in its Renewable Heat 2020 report, most of the energy consumed is still used for heating. Half of it is consumed in industry; the second half in buildings, that is, for heating, water heating and cooking. In the future, it should be possible to use both industrial and waste heat from private households across all areas.
The energy released by waste heat can also be used to cool buildings by subsequently cooling down the water that is fed into the buildings and returning it to the cycle. This system is five to ten times more efficient than traditional air conditioning.
With this in mind, Professor Toby Peters of the University of Birmingham, award-winning developer of a liquid air energy storage system and proponent of "clean cooling," spoke of the need to redesign our heating and cooling systems. Combined with improved building insulation, waste heat pumps can provide a similarly competitive alternative to fossil fuels.