- Contrec 212 BTU Meter is designed to measure the energy consumed in both heating and cooling (air conditioning) systems.
- The instrument is normally supplied complete with temperature probes and power supply and will interface with a wide variety of flowmeters, including positive displacement and inferential water meters, magnetic flowmeters with pulse outputs, turbine flowmeters & paddle wheel flowmeters.
- Contrec 212 BTU Meter measures the temperature in the feed and return flow lines and uses this information to calculate the density and enthalpy of water.
- By also measuring the volume of water flowing in the system, the Model 212 will then determine the energy used. Calculate power as:
P = V x ᵨ x (hTV – hTR)
where P = Power (W)
V = Volumetric Flowrate (m3/sec)
ᵨ = Density (kg/m3)
hTV = Specific Enthalpy (J/kg) at Feed Temperature
hTR = Specific Enthalpy (J/kg) at Return Temperature
- For typical water heating or cooling systems, Contrec 212 design for pressures does not exceed 16 bars.
- The temperature in both the feed and return lines is measured via two PT100 resistance temperature devices (RTDs).
- Four wire RTDs should be a matched pair, Class A to IEC 751 standard to achieve maximum accuracy.
- Contrec 212 complies with OIML R75 and EN1434 standards also include Meter-bus and RS485 (Modbus RTU) communication links.
- BTU Meter includes separate peak and off-peak registers as well as the ability to compute charge and discharge energy in systems where heat may be stored in underground tanks.
- Contrec 212 provides pulse output with programmable pulse width from 10 to 500ms.
- Contrec 212 BTU Meter has a highly accurate built-in real time clock (2ppm typ) also keep track of logging, peak-on/peak-off points, etc.
- After the power failure, the real-time clock is able to keep running for two days hence with ±1 minute accuracy, typically.