【Process Area Event – Bizarre Designs – 12】-- Heat exchange issues in the economizer of refrigeration systems
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The diagram below shows a portion of the refrigeration principle diagram for the cooling unit in a certain chlor-alkali plant. After the project was completed, performance analyses revealed that it fell far short of the expected results. The upper part is the liquid storage tank, and the lower part is the economizer. Brief description: Function of the economizer – it subcools the liquid supplied to the evaporator in the shell side, and provides gas to the compressor via the tube side (in short, it is a heat exchanger). Refrigerant used: R22. Structure of the economizer: Horizontal shell-and-tube type. Shell side: Used for the main supply of liquid to the evaporator. Tube side: A portion of the liquid is diverted from this main supply, throttled to reduce pressure, and then exchanged heat with the main liquid stream to become gas, which is then supplied to the compressor. Main topic: As indicated by the red circle in the figure below, this is the liquid inlet for the economizer. Is it advantageous for heat exchange to have the liquid flow in from above and out from above? Poor heat exchange can directly affect the evaporation efficiency of the evaporator and the gas replenishment performance of the compressor, thereby **reducing the energy efficiency of the refrigeration system!
With grills and exhaust vents, the efficiency is not much worse. Doing this is probably to address practical problems on site; it’s not that strange
This post was last edited by YORK Industrial Refrigeration on 2017-8-22 at 12:39. It’s necessary to exhaust air every time the machine is started–what a hassle. Partition? Will the material cost increase? Increase resistance for no reason? With a partition added between 2, won’t there be any flash gas? Is the partition unnecessary? 3 Will real-world refrigeration processes be willing to spend money on an economizer that is expensive and inefficient? Is it still economical? 4 Since there is no partition, is this considered a strange design? Please do not define it as a regular heat exchanger; define it from the perspective of refrigeration equipment. Given his role, he is responsible for supplying liquid to the evaporator; the effect of the flash gas on the refrigeration system is significant. Just imagine those flash gases ending up mixed in the liquid being supplied!
It’s a normal design: what enters is liquid R22, and it vaporizes as it falls, with a small portion remaining in liquid form. This design helps improve the heat exchange efficiency by allowing for faster vaporization of the liquid. In general, compressors are not allowed to operate with liquid inside them, and the main evaporator is also designed in this way; or else the liquid inlet is located at a higher position, but not necessarily at the top
It shouldn’t be considered using a pure liquid medium; you’re on the wrong track
This post was last edited by shijiazhuang on 2017-8-22 21:14 :lol
There are two types of economizers in refrigeration: one is used to supply air to the compressor, and the other is used for supercooling the liquid supply and overheating the return gas; it is also known as a regenerator. Take a look at the picture I sent; above is the liquid reservoir. The liquid flows into the evaporator via the economizer, where a small portion of it is throttled to reduce its pressure. This liquid then exchanges heat with the main supply of liquid in the economizer, turning into gas that is used to feed the compressor. It should be emphasized that the inside of the shell contains liquid, while most of the inside of the tube is gas! There’s too much gas inside the shell – what do you think are the effects of that?
:Lol, I’m sorry – I answered your question based only on my memory, without carefully looking at your drawings
The process in my memory is exactly the opposite of what you’ve described; I haven’t dealt with that thing for a few years now that I’m older