Flow meters and magnetic meters
These meters are mostly used for measurements that result in printing bills and have relation with customers but are not recommended by any famous company in the world. The reason is deviation meters’ calculations without any physical changes.
Magnetic meters have high energy consumption, so cannot work by battery and for a long time.
According to nature of the operation what is based on magnetic field, it’s enough to put a magnet or something with magnetic field to the meter and then meter’s operation faces disorder. Existence of any magnetic field (e.g. electricity cables,….) influences on operation of the meter.
In the case of using non-metal pipes, it is possible to be disorder in operation of meter because of static electricity.
All equipment must have an appropriate earth connection to prevent effects of environment. Therefore, in the case of any problem in the network, in no time, there will possibly be errors.
And other issues that are in valid scientific articles.
Why shouldn’t water meter be used (instead of flow-meter) to measure domestic hot water?
Base of all differences is because of difference between meter (fluid volume calculation) and flow-meter (flow rate calculation)
Use of turbine water meter with a counter to measure energy of clean hot water is more common instead of flow-meter because of high costs.
Base of this equipment operation is:
- Calculation of total energy for heating hot water in the mechanical room.
- Calculation of domestic hot water volume in every apartment (unit) by turbine water meter and a counter.
- Making ratio (percent) between consumed domestic hot water (calculated by meter at the entrance of each unit) and total energy (calculated in mechanical room)
However, use of this equipment is not scientifically recommended because of following reasons:
According to law, religion and custom, every consumer should pay for consumed energy, not less nor more. Now, this question should be answered that do first floor units, 15th floor units and also other units in other blocks use hot water with the same temperature? The answer is obviously negative since hot water faces temperature drop on the way to units and each unit’s energy should be calculated at entrance of that unit.
Produced hot water in mechanical room has temperature fluctuation during day and night (approximately 4° C) that means consumers use clean hot water (bathroom, kitchen … ) with different temperature at the beginning of day, in the middle of day and at last hours of nigh.
However, in this kind of calculation, energy of domestic water tanks in mechanical room and domestic water volume at the entrance of units calculate during day, and finally, depended on amount of consumed hot water volume, energy cost divides. Due to it is impossible to calculate online (in less than no time) and people have to pay different from the amount that they use.
While reverting pipes of domestic hot water face a problem (operation of fuse, reverting pup of hot water breaks down, thermostat operation of reverting pump of hot water, …. ) consumer has to turn on the tap at least for 5 to 15 minutes to have domestic hot water (especially for bathing) but consumer , according to the calculation method, should pay cost of high temperature hot water for this duration.
Installing temperature sensor next to the meter doesn’t solve this problem. So, it is necessary to use meters with flow-meter to correctly calculate energy since it doesn’t work due to its structure.
Reasons not to install meters on reverting pipe lines of domestic hot water
Measurement principles in the building, having reverting pipe line of domestic hot water inside the units, is based on flow rate differences of input and output domestic hot water of each unit.
Each counter or meter has error, so when the meter measures input and output volume of passing water, measured amount of flow rate is not same(when there is no consumption) and this difference is less or more according to the kind of meter or counter.
Due to this reason, product producer cannot calculate in such buildings or should ignore consumed volume of water if it is less than meter’s error rate. In this case, calculation of water volume with low flow rate, likeleaking and …. , is impossible.
According to kind of technology and feature of ultrasonic meter that can recognize the difference between error and low consumption, only ultrasonic meters are capable to calculate it.
Note: the brand should have this technology and just using an ultrasonic meter is enough.