How to perform a physical examination on the heat exchange station?

How to perform a physical examination on the heat exchange station?

To treat a heat exchange station is just like to cure the disease of a person, there is no miracle drug in the world that can guarantee to cure all diseases, every heat exchange station has different body mass and different conditions, so one therapeutic schedule cannot treat all the heat exchange stations, the stations need to be examined meticulously detail by detail to suit the remedy to the case.
Physical examination on the heat exchange station is much simpler than that on human beings, the examination items are no more than temperature, flow, pressure, power and several key points, through these simple parameters, 3 important indicators of heat rate, power consumption and pressure drop were examined, so as to find the crux of the problem of “three highs” of the heat exchange station. Let us see the high-end customized health care services that heating stations can enjoy:
First item of the physical examination: cardiac function examination – circulating pump health state
The circulating pump is a key equipment for transmission and distribution of the heat exchange station, and its health state directly affects the heat supply effect and operating cost of the heat exchange station. The efficiency of the water pump is an important indicator to measure whether the model selection of the heat exchange station is reasonable and whether the operation is economical.
At present, most of the water pumps operated in some thermal companies are rather big in model selection, low in efficiency and need to be removed and replaced. Why? Isn’t that a waste removing water pumps of the just finished heat exchange station? In fact, it is not a waste, to continue the use is the biggest waste. What we need to do is to let the efficiency of the water pump fit the existing operating conditions and be close to the optimum efficiency as far as possible by examinations and measurement. The optimization of water pump efficiency is one of the most reliable ways to reduce power consumption for heat-supply enterprises, because inefficient pumps seem not to affect the current operation, but they actually waste a lot of energy and operating costs.
Here is another misunderstanding, that is, overthrowing the original model selection, directly reducing the lift and replacing large pumps with small ones will be okay. This is definitely wrong, because the heat exchange intra-station systems are roughly the same, but every heat exchange station has a different anfractuous courtyard heating pipe network, reselecting the model of the circulating pump before the courtyard heating pipe network is adjusted to balance will still lead to low efficiency and high power consumption. This is also the primary cause of large and unreasonable model selection of the water pump in design, as well as a common problem in heat-supply enterprises.
Most water pumps operate in a low efficiency range for long term. If this is the case, replacing the pump as soon as possible is the best choice.
After the efficiency of existing circulating pumps is examined, through reasonable model selection and replacement, more energy-saving water pumps will significantly reduce the operating cost, earn back the equipment cost for heat-supply enterprises in a few months, benefit the enterprises for long term, and achieve the optimum energy-saving effect, even the electric charge saved in one heating period can be enough to buy several water pumps.
Examination method: water pump efficiency test

Second item of the physical examination: gastrointestinal system examination – health status of the heat exchanger
In addition to circulating pump, heat exchanger is most likely the equally important equipment in the exchange station, which is equivalent to human body’s digestive organs. Heat exchanger can easily cause overly large pressure drop due to unreasonable area match and model selection, overly large import& export local resistance, blockage and scaling, thus increasing intra-station resistance loss and electricity consumption in operation of the circulating pump. Through detailed examination and optimization of the heat exchanger and the import& export pressure drop in the station, the loss due to local resistance of the heat exchanger can be effectively reduced. The difference between the value under large pressure drop and that under optimized pressure drop can be more than ten meters.
Besides, by calculating the logarithmic mean temperature difference between the import and export temperatures of the heat exchanger, the current health state of the heat exchanger can also be quickly judged by the heat exchange efficiency, higher heat exchange efficiency can effectively reduce heat consumption, otherwise, heat consumption will increase.

Examination method: pressure drawdown test and terminal temperature difference test of the heat exchanger
Third item of the physical examination: the excretory system examination-the health state of the dirt separator
Like the heat exchanger, as the filtration and excretion system of the heat exchange station, the dirt separator is more likely to be blocked by brick, broken tiles, fiber bag and other peculiar objects.
Examination method: pressure drawdown test of the dirt separator
Fourth item of the physical examination: circulatory system examination-the health state of the user branch
With the gradually increasing covered area of the heat transfer station, due to problems in branch design and construction quality, overly small pipe diameter of some branch, overly large specific frictional resistance and poor circulation can easily occur, thereby increasing power consumption of the circulating pump and making regulation on the courtyard heating pipe network difficult. Most heating companies only know the branch with bad effect and the corresponding thermal station, but they do not know the root cause. They do not know the extent of the influence, or the specific frictional resistance, or the method for reasonable optimization. Maybe no one has considered these issues carefully.
Pressure drawdown test and analysis of the secondary network branches of the heating stations should be carried out in time, so as to make targeted reasonable optimization, efficiently reduce power consumption and heat consumption and enhance the heat supply effect.




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