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Modicon M171 M172 Plc For Hvac And Pumping Applications - Page 2-13 Solutions overview

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Energy management


The energy management function blocks are designed for applications where the machine energy consumption needs to be metered and energy efficiency information is required. The function blocks provide an easy integration of metering devices into the system and offer calculations methods to determine the machine efficiency, COP, or ESEER (1) .


Quick and easy integration


Preprogrammed and fully tested metering functions are provided for a quick and easy integration of energy metering devices and machine efficiency calculation methods.


The function blocks provide an efficient integration of electrical metering devices either connected via Modbus SL or hardwired by using pulses.


A thermal energy calculation function block is embedded to determine the produced thermal energy. With dedicated trending and COP (1) calculation functions, machine efficiency can be monitored and analyzed in detail.


The function block allows the cooling capacity to be calculated without adding a low meter.

Operating principle

A wide range of functions are covered by a comprehensive set of metering function blocks, from retrieving energy information to energy efficiency calculations and trending.


The following function blocks are designed to be used in the Modicon M171/M172 logic controller application:


Digital input pulse totalizer: counts the digital input pulses from an energy meter


Converter of totalized pulses from energy meter: converts the digital input pulses into the consumption


Thermal power calculation: calculates the thermal power, an energy based on the flow (for water chillers)


Coefficient of performance calculation: calculates the COP based on the consumption and the thermal power


Energy meter data trend: Trend of consumption data over time To calculate the thermal energy, a flow meter must be installed in the system and the heat capacity of the medium must be known. Thanks to a new AFB named COPMonitor, which combines 6 other AFBs, the COP can be calculated without the need for a flow meter. The flow is calculated based on the compressor characteristics and the thermal power produced by the machine is calculated based on the enthalpies of the machine. Typical applications


Air and water cooled chillers


Heat pumps


Rooftop units


Compressor racks

(1) COP = Coefficient Of Performance. Efficiency of the chiller or heat pump calculated by the cooling or heating power divided by electrical power consumption. ESEER = European Seasonal Energy Efficiency Ratio: seasonal efficiency of refrigeration equipment, chillers, and air conditioners calculated by the cooling or heating power divided by the electrical power consumption at different loads.


Solutions overview

Application solutions for HVAC Related functions: Energy management

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