| 摘要 |
Advanced electronic metering of natural gas consumption is a new opportunity in the recent free market economy of the utility sector in the US and Europe. Real-time continuous measurements facilitate our awareness in the consumption of a non-renewable energy resource, which is a first step towards taking energy saving measures in domestic and commercial buildings. We here disclose a real-time desktop information system for natural gas consumption based on a new wireless electronic flow-meter. The meter is drift-free by subjecting thermal anemometry to a novel modulation technique. It uses a dynamical flow-interface to control the exposure of a thermal flow-sensor to a streaming medium. A discrete modulation of the flow perturbs the total heat-flux from the sensor to the medium. The relative perturbation, normalized to total heat-flux, creates a Nusselt number which is a function only of the Reynolds number of the flow. The medium temperature can be estimated on the basis of a similar factorization of the total heat-flux. Our method hereby measures both volume- and mass-displacement. In the preferred embodiments the interface consists of a by-pass configuration with micro-flow switches, controlling micro-jets applied to a silicon integrated flow-sensor. The device hereby forms a cost-effective and robust alternative to current approaches for electronic flow-metering. Its output is readily provided to a desk-top computer using existing wireless interfacing, serving energy-analysis and energy-saving strategies.
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