Heating and air conditioning

Setting an air conditioner 1°C higher can reduce the amount of electricity used by up to 10%. (5)

Heating and cooling account for 50- 60% of energy consumption in hospitals and offices. (8)

Fearing an energy shortage during 2017 and 2018 summers, the Tunisian Electricity and Gas Company (STEG) has asked the population to take measures and to pay particular attention to air conditioning. Air conditioning alone accounts for nearly 50% of national electricity consumption in Tunisia, and the number of air conditioners almost quadrupled between 2009 and 2013, from 400,000 to nearly 1.5 million units. “We are going to make consumers aware of the need to ensure, when purchasing an air conditioner, that it corresponds perfectly to their real needs, and that it does not consume energy, by consulting the energy label. Consumers should also set the air conditioner to 26°C, since each degree lower than this results in 6 to 12% more energy consumption. They should also avoid opening doors and windows when the air conditioner is on.  He should only turn on the air conditioners in places where it is strictly necessary.” (17)(18)

The Iranian city of Yazd is home to a system of ancient engineering marvels that includes an underground refrigeration structure called a yakhchāl and an underground irrigation system called qanats. Among Yazd’s ancient technologies is the wind sensor, or bâdgir in Persian. These remarkable structures can often be seen above the roofs of Yazd. They are often rectangular towers, but can also be found in circular, square, octagonal and other ornamental shapes. Air entering the structure is pushed down due to the change in buoyancy of the air with temperature – warmer air tends to rise above the colder, denser air. This channels cooler outside air to the building below. Sand or debris settles at the bottom of the tower. The warm indoor air rises and leaves the building through another tower or opening, helped by the pressure inside the building. (19)

The University Hospital of La Reunion Island will be installing the innovative SWAC (Sea Water Air Conditioning) technology in Saint-Pierre. This project is unique in the world in terms of its size and environmental benefits, with a substantial reduction in electricity consumption of up to 90%, i.e. 10 GWh per year, the equivalent of the consumption of a town of 6,000 inhabitants, and savings on cooling management costs of at least 10%. The technology consists of pumping cold water from great depths (around 5 degrees at 1000m) and transferring the cold contained in this water to the hospital’s air conditioning network by means of a heat exchanger. The seawater that comes out of the heat exchanger (at about 12°C) is then returned to the ocean at a depth appropriate to its temperature and without impact on its environment. Commissioning is scheduled for 2023, for a contractual period of 20 years. The investment represents an amount of €45 million, co-financed by the European Regional Development Fund (ERDF) and the French Agency for Ecological Transition (Ademe). (20)

The Cannes hospital system allows a maximum difference of 6°C between indoor and outdoor temperatures. Radiators have been removed in technical corridors where doors are often open. Presence and movement detectors regulate lighting. A software program monitors consumption and alerts in case of over-consumption. Energy-intensive water fountains have been removed; staff are now consuming tap water. An awareness-raising process has been undertaken with staff using posters in the premises and information in the internal newspaper, for example about temperature settings in each room. The energy bill fell by 10% in 2015. (21)

Energy management plan at the Lille Hospital Center

In November 2022, the Lille University Hospital deployed an extensive energy management plan to rapidly reduce its energy consumption while ensuring that it would not affect the quality of care provided. The heating set point has been reduced to 19°C from 20°C, and in the rooms to 21°C from 22°C. The doors of the care access services described as “energy sinks”, will eventually be equipped with automatic closing systems. According to the Director, “these measures should enable us to reduce our consumption by at least 7%, which means 2 million euros less on the bill, the equivalent of the consumption of 600 families in less than a year. ” This approach is not new, since between 2011 and 2021, the hospital has managed to reduce its gas bills by 15% and its electricity bills by 14%, while its activity has continued to increase. The air conditioning system, for example, was replaced by much more efficient and energy-efficient cooling units. (22)(23)

During 2022-2023 winter, office temperatures in the State of Fribourg was limited to 19°C and hot water was cut off, unless necessary. Staff were forbidden to compensate with private heating. The canton of Berne opted for a temperature of 20 °C in offices and common rooms, 17 °C in multipurpose rooms and workshops, 13 °C in empty buildings and rooms, and 7 °C in warehouses and garages. The temperature in hospitals and care homes was set at 23 °C in the canton of Geneva. In the canton of Valais, it was requested to set boilers temperature in public buildings between 50 °C and 55 °C. Similar recommendations were made to municipalities and private companies. (24)

Conducted since 2009 in the canton of Geneva, the GeniLac project aims to replace air conditioners as well as oil and gas boilers with hydrothermal energy. GeniLac is part of the canton’s climate strategy and is being implemented by the Services industriels de Genève (SIG). Water from the lake is used to heat and cool buildings. “This resource represents an almost inexhaustible and local energy reservoir. The water is drawn from a depth of 45 meters and is at a constant temperature all year round. It passes through mechanical exchangers to be used directly to cool the buildings in summer. In winter, this water is used to produce hot water thanks to the heat pumps, which run on 100% renewable electricity, which considerably reduces CO2 emissions. » (25)

The Cidrerie de Domagné in Brittany changed its cooling system by replacing its eleven compressors with an ammonia-based technology. This action allows both to anticipate the ban on certain refrigerant gases by 2030 and to reduce the energy bill. By combining its impact with the efforts made elsewhere, particularly in heat recovery, Domagné has reduced its gas and electricity bills by 7% over five years, saving 530 tons of carbon equivalent or 550 return flights between Paris and New York each year. (26)