Heat pumps and thermal energy
Heat pumps are devices that transfer thermal energy from a lower-temperature source to a higher-temperature sink, and they can serve both heating and cooling functions. This versatility makes them integral to various applications, from household refrigerators and freezers to larger industrial systems. The operation of heat pumps relies on a transfer fluid that moves heat, with a compressor providing the necessary power to facilitate this transfer. There are three primary types of heat pumps: air source, water source, and ground source. Air source heat pumps extract energy from the ambient air, often requiring supplementary heating in colder climates due to reduced efficiency. Water source heat pumps draw energy from bodies of water or dedicated networks, taking advantage of stable groundwater temperatures for enhanced efficiency. Ground source heat pumps use a system of underground pipes to exchange heat with the earth, benefiting from consistent ground temperatures for effective heating and cooling. While heat pumps are efficient, they are typically suited to low-temperature heating applications, making them ideal for buildings designed for such systems.
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Heat pumps and thermal energy
Summary: Heat pumps transfer thermal energy between a lower-temperature source and a higher-temperature sink and can also be reversible, performing both heating and cooling functions.
Heat pumps include a wide range of devices, ranging from refrigerators and freezers to large industrial units. All heat pumps, however, transfer thermal energy between a lower-temperature source and a higher-temperature sink. The process can also be reversed, allowing a single heat pump to perform both heating and cooling functions. A transfer fluid is used to transport the heat from the source to the sink, with a compressor providing the necessary power. The three major types of heat pumps are air source, water source, and ground source heat pumps. Air source heat pumps use the ambient energy in outside air or an exhaust air stream for heating or cooling. In colder climates, a supplementary heat source is often included, as the heat pump’s efficacy drops significantly in cold temperatures. A refrigerator or freezer is a type of air source heat pump, with the colder temperatures inside the compartment acting as the source and the air in the room as the heat sink.
Water source heat pumps use energy from water in the ground, on the surface, in seawater, or from dedicated heat pump water distribution networks that can serve individual buildings or entire cities. In many areas, groundwater temperatures are relatively constant year-round, allowing the heat pump to operate at high efficiency for both heating and cooling. Ground source heat pumps (GSHPs) are similar to water source units but use a vertical or horizontal collection grid to transfer heat to the earth. Again, these units can be very efficient with the appropriate ground temperatures. Heat pumps are generally limited to relatively low heating temperatures, confining their use to buildings that are designed for low-temperature heating.
Bibliography
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