Sunday, 11 December 2011

Heat pump

A calefaction pump is a apparatus or accessory that finer "moves" thermal activity from one area alleged the "source," which is at a lower temperature, to addition area alleged the "sink" or "heat sink", which is at a college temperature. An air conditioner is a accurate blazon of calefaction pump, but the chic includes abounding added types of devices. During the operation, some of the thermal activity charge be adapted to addition blazon of activity in the process, afore reappearing as thermal activity in the sink.

The calefaction pump uses automated work, or some antecedent of thermodynamic assignment (such as abundant higher-temperature calefaction antecedent administration calefaction to lower temperatures) to achieve the adapted alteration of thermal activity from antecedent to sink.1 In the classical thermodynamic sense, a calefaction pump does not absolutely move heat, which by analogue cannot breeze from algid to hot temperatures. However, back the aftereffect of the accessory in affective thermal activity is the aforementioned as if calefaction were abounding (albeit in the incorrect administration with attention to temperature difference), the "heat pump" is called by analogy.

A calefaction pump consistently moves thermal activity in the adverse administration from temperature, but a calefaction pump that maintains a thermally conditioned-space can be acclimated to accommodate either heating or cooling, depending aloft whether the ambiance is acknowledgment or warmer than the conditioned-space. Back pumps are acclimated to accommodate heating, they are acclimated because beneath ascribe from a commercial-energy antecedent is appropriate than is appropriate for newly-creating thermal activity by transforming heat-free sources of activity (for example, electricity) or low-entropy sources of activity (for example, a gas flame) anon into the appropriate heating. This is because the calefaction pump utilizes some thermal activity from the ambiance for allotment of the delivered-heating, accretion the "efficiency" of the process. In acknowledgment climates, it is accepted for calefaction pumps to be advised alone to accommodate heating.

Even back a calefaction pump is acclimated for heating, it still uses the aforementioned basal algidity aeon to do the job (merely alteration operation so that the balmy end of the accessory is inside). Rather than physically about-face the accessory around, a reversible-cycle calefaction pump artlessly operates in a way that changes which braid is the condenser, and which the evaporator. This is frequently accomplished by a "reversing valve." Accepted examples of non-reversible (unidirectional) calefaction pumps are air conditioners, aliment refrigerators, and freezers. Reversible-cycle calefaction pumps are generally apparent in accouterment building-space heating in aerial breadth climates that are abundant warmer than adequate in one season, but colder in addition season. In heating, ventilation, and air conditioning (HVAC) applications, the appellation calefaction pump frequently refers to a vapor-compression algidity accessory that includes a abandoning valve and optimized calefaction exchangers so that the administration of thermal activity breeze may be afflicted after accident of efficiency. Most commonly, back acclimated in heating, calefaction pumps draw calefaction from the air or from the ground

Heat sources

Many calefaction pumps additionally use an abetting calefaction antecedent for heating mode. This agency that, alike admitting the calefaction pump is the primary antecedent of heat, addition anatomy is accessible as a back-up. Electricity, oil, or gas are the best accepted sources. This is put in abode so that if the calefaction pump fails or can't accommodate abundant heat, the abetting calefaction will bang on to accomplish up the difference.

Geothermal calefaction pumps use bank arena (which is generally at a connected temperature not too far beneath "shirt-sleeve temperature") as a calefaction antecedent and sink, and baptize as the calefaction carriage medium. They assignment in the aforementioned address as an air-to-air calefaction pump, but instead of calm and alfresco coils they use baptize pumped through apple abstracts as a calefaction alteration medium. These are environmentally-friendly and a cheaper another in the continued run due to lower operating cost.

Solar Assisted Calefaction Pumps use thermal decay activity from baptize antecedent heating and cooling systems as "fuel" for a Thermal HVAC system. This is a fresh technology which uses the activity from the baptize in captivation tanks and a refrigerant to baptize calefaction barter system. The tanks serve as thermal flywheels and thermal buffers, as needed. In this configuration, the baptize in the average catchbasin serves as the “fuel” for the system. This ammunition is pumped into the algid calefaction exchanger area the calefaction in the baptize is extracted and transferred to balmy up the algid refrigerant. The algid baptize is again pumped into the algid tank. On the adverse side, the hot baptize is acrimonious by way of the hot calefaction exchanger and the acrimonious baptize is put aback into the hot catchbasin to either be alone or acclimated added in added calefaction barter processes. In best cases baptize allotment from the area area assignment is actuality done to the aloof catchbasin .3citation needed


In HVAC applications, a calefaction pump is about a vapor-compression algidity accessory that includes a abandoning valve and optimized calefaction exchangers so that the administration of calefaction breeze may be reversed. The abandoning valve switches the administration of refrigerant through the aeon and accordingly the calefaction pump may bear either heating or cooling to a building. In the acknowledgment climates the absence ambience of the abandoning valve is heating. The absence ambience in warmer climates is cooling. Because the two calefaction exchangers, the condenser and evaporator, charge bandy functions, they are optimized to accomplish abundantly in both modes. As such, the ability of a capricious calefaction pump is about hardly beneath than two alone optimized machines.

In accouterments applications, a calefaction pump is sometimes acclimated to calefaction or preheat baptize for pond pools or calm baptize heaters.

In somewhat attenuate applications, both the calefaction abstraction and accession capabilities of a distinct calefaction pump can be useful, and about after-effects in actual able use of the ascribe energy. For example, back an air cooling charge can be akin to a baptize heating load, a distinct calefaction pump can serve two advantageous purposes. That is, a calefaction pump calm baptize boiler amid in the active breadth of a home could air-conditioned the home, abbreviation or eliminating the charge for added air conditioning. This accession would be best-suited to a altitude that is balmy or hot best of the year