Contrec 212 BTU Meter is designed to measure the energy consumed in both cooling(air conditioning) and heating systems.
The temperature probes and power supply are optional to Contrec 212 and interface with a wide range of flowmeters, including positive displacement and inferential water meters, magnetic flowmeters with pulse outputs, turbine flowmeters, etc. paddlewheel flowmeters.
Contrec 212 BTU Meter measures the temperature in the supply and return flow lines and uses this information to calculate the enthalpy and density of water.
By 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 supply 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 and 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 type) also keeps track of logging, peak-on/peak-off points, etc.
- After the power failure, the real-time clock can keep running for two days hence with ±1 minute accuracy, typically.