Selection of plate heat exchangers
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For today’s plate heat exchangers, the heat transfer coefficient varies significantly depending on the type of corrugations, as well as the effects of flow velocity and temperature. Some manufacturers can quote prices ranging from 5,000 to 7,000, and even foreign manufacturers can quote 10,000; I think all of this is conditional. If the end temperature difference is only 1°C, what value can the heat transfer coefficient of your heat exchanger reach? Can current plate heat exchangers achieve an end temperature difference of 1°C? Here are the parameters; let’s see if they can be met: heat transfer rate: 2500 kW, inlet and outlet temperature of the secondary water: 7–12°C, inlet and outlet temperature of the primary water: 13–8°C, pressure drop: 60 KPa, fouling coefficient: 0.088. What size should be chosen for the area of this heat exchanger? Can it be achieved?
The heat transfer coefficient of plate heat exchangers isn’t that high, right? What’s being referred to must be some special type of enhanced design; could it be a plate-fin type? And is the pressure drop for plate heat exchangers really that high?
It is possible for the heat transfer coefficient of plate heat exchangers used in specific operating conditions to reach 7000 W/m2*K. With the development of plate heat exchangers in China, their performance is now almost on par with that of foreign-made ones; a temperature difference of 1 degree can be achieved using such heat exchangers. The heat transfer coefficient under the operating conditions you mentioned won’t be too high.
Excuse me, sir upstairs: if a temperature difference of 1 degree is achievable, then if the heat transfer coefficient mentioned by me isn’t very high, the calculated heat exchange area will be quite large – possibly over 1,000 square units. Isn’t that unreasonable?
A terminal difference of 1 degree is only valid in theory; it’s very difficult to achieve in practice. Even if it can be achieved, with a heat transfer coefficient of 5000–7000, 400–600 square units would be sufficient.
Over 1,000 square meters is too much; 400–500 square meters is about right. However, to ensure safety, domestic manufacturers leave a large margin for variations in operating conditions, so it’s not surprising to see values over 1000.
For plate heat exchangers, ordinary manufacturers are neither able to design nor manufacture them. Only equipment selection is possible, so it’s better to provide your parameters to the manufacturer so that they can help with the selection and provide a quote. It’s both accurate and convenient; that’s how we do it.
The heat transfer coefficient has nothing to do with the magnitude of the temperature difference
It is estimated that 2 units need to be used in parallel; generally, manufacturers are not capable of handling such operating conditions. The question posed by the original poster is really tough
For a single heat exchanger, it seems unlikely to achieve a temperature difference of over 5000; a temperature difference of 1 degree was achievable a few years ago, so there shouldn’t be any problem with 1.5 degrees as well. Based on the conditions you provided, do you need help calculating the area? If needed, please leave a message.
For domestic plate heat exchangers, the heat transfer coefficient does not reach such high levels. . Can a temperature difference be achieved once? Please explain it
Heat exchangers with a small temperature difference should use closely spaced corrugations; otherwise, many passes will be required, resulting in high resistance and a large heat exchanger area.
Based on the parameters provided by the poster, using shallow corrugations, commonly known as \"air-conditioning panels\", should theoretically allow for a temperature difference of 1 degree. However, if there are slight fluctuations in the ambient temperature, along with measurement errors, there will definitely be some deviation in reality.