Net Heat Measurement on Chiller Application to Verify the Total Refrigaretion

KROHNE Vortex meters can be used for measurement of net heat exchanged through the chillers thus giving an idea of the efficiency of operation of the chillers as well as verification of the total flow through the system.

Benefits to the user

Efficiency

Efficiency of the chillers would be known and measurements compared with the theoretical TR capacities.

Diagnosis

Would serve as a diagnostic tool for the health of the chillers. In case there is a problem with the chillers, there would be a gradual reduction in the TR capacity which would be otherwise undetected.
This would enable the user to take the corrective action much before the chillers require any major repairs necessitating a major shutdown causing loss in production.

Leakages

Any leakages of the cooling media can be detected and eliminated as the flow rate is measured and any abnormal fall in the flow rate can be detected and leakages of the cooling media can be effectively eliminated.

Optimisation

Optimisation of the chiller capacities in a multiple chiller scenario could be done wherein fewer chillers may be used depending on the production necessity and thus this would result in lower electricity consumption and usage.

Reduced Cost

The number of components in a conventional system would include meters at the inlet and outlet, temperature transmitters at the inlet and outlet and a computer to calculate the net heat exchange and therefore the TR capacity but in our system, only the VFM 5090 alongwith a flow computer would suffice thereby substantially reducing the cost of the system.


Higher Accuracy/Lower Maintenance

The accuracy of the single TR meter and a temperature transmitter is substantially higher than using multiple systems and maintenance of a single system is much easier than multiple systems.

Principle of operation

The conventional system of net heat measurement would involve the following:

	Meters would be positioned at the inlet and outlet of the heat exchanger and temperature transmitters would also be positioned at these points as perthe diagram below.
	The net heat which is removed by the heat exchanger is as below:

Inlet heat = mass flow rate x specific heat capacity of cooling media x temperature at outlet

Similarly

Outlet  heat = mass flow rate x specific heat capacity of cooling media x temperature at outlet

Net heat = Outlet heat ? Inlet heat

= mass flow rate x specific heat capacity of cooling media x difference in temp(outlet ? inlet)

The above calculations would be done in a separate computer which would then be connected to the meters.

By using the VFM 5090 NHM net heat meter the above system can be replaced by just using a temperature transmitter at the outlet. The inbuilt temperature sensor of the meter would measure the temperature at the inlet and the temperature transmitter supplied at the outlet would give the outlet temperature. The calculations for the net heat would be done in the meter itself and displayed to the end user .

In case special requirements such as calculation of the Total Refrigeration are required this can be done directly as well. The benefits to the user are enormous as below:

Cost of using separate components is saved resulting in substantial cost savings.

	Cost of wiring, installation etc are saved
	Accuracy of separate components as in the conventional system is very low due to addition of different components of the system.
	Maintainence of the conventional system is high but in the VFM, this is saved as there are only two components available.

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