It is common to install devices in the kitchen to promote air recirculation.
Recirculation is a concept that comes from circulation , a term that refers to the process of circulating . Circulation, on the other hand, is associated with movement, transit or traffic, whether of vehicles, currency, fluids, etc.
The concept of recirculation is linked to re-boosting the circulation of something within the same circuit or system . Air, water and blood, for example, are some of the things that can be recirculated.
Types of recirculation
Air recirculation can be carried out in a kitchen . There are hoods that take in the air, filter it and then expel it again, always within the same room. In this way, the air is never sent outside. The case of extraction is different, which consists of capturing the air from the kitchen to expel it from the room.
There are buildings, on the other hand, that have hot water recirculation systems. This allows hot water to flow out of the tap immediately, as the hot water circulates constantly through the pipe. To achieve this recirculation, a pump is installed that constantly brings cold water to a heater and then back to the pipe. This way the water is always hot.
In the medical field, recirculation is the process in which blood that has already been dialyzed passes through the dialyzer again during a dialysis process. This means that dialysis loses its effectiveness because it is being carried out again on already treated blood.
Water recirculation time is an important variable in the dynamics of a pool.
The concept in the pools
There is a concept associated with swimming pools called water recirculation time , or turnover in English, and it is the time in hours that a given purification system takes to treat a quantity of water equivalent to the volume of the pool to which it is connected. This value is related to several factors, which must be known to understand why it is high, low or acceptable, depending on the case.
For example, two key points to consider in order to know how efficient a purification system can be are the dimensions of the pump and the filter, which are the two basic components of a simple system; if the pump has a high flow rate but the filter is small, the time will not be proportional to the size of the pump, since the filter will not be able to take advantage of its capacity, and the same would occur in the opposite case.
Recirculation in a chemical reactor
Another area where recirculation takes place is a chemical reactor , a device capable of accommodating a specific chemical reaction . It has a design that maximizes the selectivity and conversion of the reaction, ensuring the lowest possible cost. Among the different types of chemical reactor is the recirculating plug flow reactor.
First, plug flow reactors (also known by their acronym PFR ) operate in a steady state; that is, their properties at a given moment are maintained over time. Reactors that include recirculation without a separator device take a portion of the output stream and direct it to the inlet of the equipment, so that mixing is favored (in fact, the benefits are greater the greater the recirculation).
It is important to note that in a perfectly mixed reactor, which does not provide an outlet stream, recirculation would offer no advantage, since mixing would have been completed by the time the system wanted to divert some of the flow . A related concept to these devices is the recirculation ratio , which is symbolized by the letter R , and is defined as the ratio of the flow rate returning to the flow rate leaving.