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Heat exchangers are elements that transfer heat from one fluid to another, with the purpose of greater or better use of that heat. Table of Contents Rotary exchangers Static exchangers Enthalpic exchangers Sensible heat exchangers There are multiple types and applications of heat exchangers , so to narrow the field of view a little, we will refer to exchangers in which the two fluids do not mix with each other, so that the heat is transferred through a solid wall, in which its sides are bathed by the respective fluids. From the definition itself, the types of exchanger can be deduced according to the fluids involved; they can be: gas/gas, gas/liquid and liquid/liquid. Being a blog about ventilation and heat recovery technologies, we will narrow the vision even further: we will discuss the main types of heat exchangers used in both domestic and commercial heat recovery units. Therefore from now on we will refer to air-air exchangers . Based on their construction, in heat recoverers we find two large groups of heat exchangers: dynamic (rotating) and static (plate).
Rotary exchangers They consist of a wheel equipped in its axial direction with multiple small diameter ducts parallel to each other. This wheel is divided in half so one air flow circulates through its upper semicircle and the other through its lower semicircle. The wheel is powered by a small reduction motor that moves it at slow speed (- rpm), the fluid (A), which in winter is the extraction fluid, from the upper semicircle, when passing through the wheel ducts, transfers them heat; When the wheel rotates, when these conduits are in Armenia Email List the lower semicircle, they in turn transfer it to the other fluid (B), the inlet fluid. Rotary heat exchanger Rotary heat exchanger This type of heat exchangers are widely used, especially for large air flows . Its efficiency can exceed %, which means that flow A in the figure communicates more than % of its heat to flow B. Static (plate) exchangers They consist of very thin aluminum or plastic plates, parallel to each other, in which the extraction air flow alternately circulates on one side and the inlet air flow on the other. Through these plates the heat passes from one flow to the other. This type of exchangers adopt two different construction forms: cross-flow or counter-flow . cross flow.
These exchangers have a square section, so that the air flows cross the heat exchanger in perpendicular directions as illustrated in the figures below. Cross flow exchanger Cross flow exchanger This type of exchangers are widely used in domestic appliances , they are appreciated for their simplicity and relatively moderate cost. Its performance can exceed %. Do you know our new range of CADB-HE heat recovery units? get information here Counterflow In this type of exchanger, the air flows travel through parallel and opposite paths inside , hence the name counterflow. Counterflow exchanger Counterflow exchanger Counterflow exchangers have higher performance than crossflow exchangers. Also its cost is higher. They can exceed % performance. Given that energy efficiency regulations are becoming more demanding every day, these exchangers are increasingly used . Depending on their functionality, heat exchangers can be enthalpic or sensitive. Enthalpic exchangers They are exchangers that, in addition to transferring heat from one air flow to the other, are also capable of transferring humidity . They are widely used in hot and humid climates to save energy in air conditioning. The heat recoverers that equip this type of recoverers are called energy recoverers . Sensible heat exchangers This type of exchangers only recover sensible heat , without transferring humidity from one air flow to the other. In Europe they are, by far, the most used. The fact of being enthalpic or sensitive is perfectly compatible with the construction modalities mentioned above, so both rotary and cross-flow or counterflow plates can adopt the enthalpic or sensitive modalities.
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发表于 2024-2-15 17:22:48