6.3 HEATING AND COOLING SYSTEMS 138 Central heating appears to have been invented in ancient Greece, but it was the Romans who became the supreme heating engineers of the ancient world with their hypocaust system . What was it? Heat pumps are more common in milder climates, where the temperature does not typically drop below freezing. In colder regions, they can also be combined with furnaces (dual fuel system) for energy-efficient heating on the coldest days. ONLINE RESOURCES New solar technologies HEATING AND HEAT PUMPS The process and system of raising the temperature of an enclosed space to ensure the comfort of its occupants is the primary purpose of heating. Fuels While fossil fuel heating systems are usually cheap to buy, they will cost a lot of money to operate over the following years. Moreover, natural gas and oil depend on the world market, are more polluting and are available only in limited quantities. That is why modern heating systems use renewable energy sources such as solar or heat pumps, which protect the environment more and will cost less in the long run. Heat pumps: an innovative solution Heat pumps draw heat from air, groundwater or layers of the earth. All heat pumps are very energy efficient and work best in buildings that are optimally insulated. They are electrically operated, but, in combination with photovoltaics, they require almost no additional costly energy and offer a self-sufficient system for hot water and heating. Depending on the location , a heat pump is definitely one of the future-proof heating systems. Heat pump basics A heat pump is part of a home heating and cooling system and is installed outside the house. Despite the name, heat pumps do not generate heat: they simply move heat from one place to another. The two most common types of heat pumps are: air-source heat pumps, which absorb heat energy from the outside air, even in cold temperatures, and transfer it to the indoor air; ground-source heat pumps, also called geothermal heat pumps. Below the frost line the depth beneath the ground level at which groundwater freezes the ground maintains a stable temperature year-round that doesn t fluctuate with outdoor air conditions. These pumps use the relatively constant temperature of the earth as the exchange medium rather than outside air. When in cooling mode, a heat pump and an air conditioner are functionally identical, absorbing heat from indoor air and releasing it through the outdoor unit. HOW DO HEAT PUMPS WORK? furnace: caldaia future-proof: all avanguardia insulated: coibentato layer: strato 294 EnErgy MechPower.indb 294 30/01/24 17:10