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An air source heat pump (ASHP) is a heat pump that can absorb heat from air outside a building and release it inside; it uses the same vapor-compression refrigeration process and much the same equipment as an air conditioner, but in the opposite direction. ASHPs are the most common type of heat pump and, usually being smaller, tend to be used ...
Natural gas is a common-used heat source, therefore, absorption heat pumps are sometimes called gas-fired heat pumps. [11] Also, when other heat sources heat pumps (waste heat for example) are running at the heating mode, they can meet the overload heating requirements of very cold periods in an efficient manner through additional gas boilers. [6]
The main difference between the two is in the compression phase: where the compression heat pump uses an electric compressor, the gas-driven absorption heat pump uses a thermal compressor. [12] The ACHP is obtained by combining the components that are in common and using the electric and thermal compressor in parallel or in series. [3]
Thermodynamic heat pump cycles or refrigeration cycles are the conceptual and mathematical models for heat pump, air conditioning and refrigeration systems. [1] A heat pump is a mechanical system that transmits heat from one location (the "source") at a certain temperature to another location (the "sink" or "heat sink") at a higher temperature. [2]
GCSE Bitesize was launched in January 1998, covering seven subjects. For each subject, a one- or two-hour long TV programme would be broadcast overnight in the BBC Learning Zone block, and supporting material was available in books and on the BBC website. At the time, only around 9% of UK households had access to the internet at home.
The heat flow can be modelled by analogy to an electrical circuit where heat flow is represented by current, temperatures are represented by voltages, heat sources are represented by constant current sources, absolute thermal resistances are represented by resistors and thermal capacitances by capacitors.
Electrical heaters are often used as backup or supplemental heat for heat pump systems. The heat pump gained popularity in the 1950s in Japan and the United States. [14] Heat pumps can extract heat from various sources, such as environmental air, exhaust air from a building, or from the ground. Heat pumps transfer heat from outside the ...
The thermal efficiency of modern steam turbine plants with reheat cycles can reach 47%, and in combined cycle plants, in which a steam turbine is powered by exhaust heat from a gas turbine, it can approach 60%. [4] Brayton cycle: gas turbines and jet engines The Brayton cycle is the cycle used in gas turbines and jet engines. It consists of a ...