What is the difference between positive-displacement heat exchangers and semi-positive-displacement heat exchangers?
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What is the difference between positive-displacement heat exchangers and semi-positive-displacement heat exchangers? Are there any other differences besides the location of the water inlet and whether the internal heat exchanger has a shell? Could some experts please help answer this?
Compared to volumetric heaters, semi-volumetric heaters have a smaller tank size and lower weight. The heat transfer capacity per unit volume is 5–8 times that of traditional volumetric heat exchangers and 2–3 times that of the new type of volumetric heat exchangers. The volume utilization rate of semi-volume type is relatively high. Structurally, semi-volumetric heat exchange tube bundles come with a shell, while volumetric ones do not. There doesn’t seem to be any difference elsewhere.
The main difference lies in the heat storage time. For positive-displacement types, it is based on the heat storage capacity over 45 minutes; for semi-positive-displacement types, it is based on the heat storage capacity over 30 minutes. Then, the corresponding water storage volume is calculated based on different heat storage capacities.
Is the reason for the high heat exchange efficiency of semi-volumetric heat exchangers mainly due to the presence of a cylinder inside the heater?
A semi-volume heat exchanger is actually a combination of a rapid heat exchanger and a volume heat exchanger.
Please explain the difference between flow-guided positive-displacement heat exchangers and flow-guided semi-positive-displacement heat exchangers.
For positive-displacement types, it is based on the heat storage capacity over 45 minutes; for semi-positive-displacement types, it is based on the heat storage capacity over 30 minutes.