Critical aspects of new domestic static gas meter

To promote the diffusion of smart metering, several National Authorities defined strict roll-out procedures of the existing meters with new smart meters. In such scenario, even if new static technologies in gas metering offer very significant potential (such as digital output, absence of moving parts, direct mass measurement), their reliability in some critical conditions typical of natural gas distribution networks (i.e. zero flow, minimum flow-rate, gas quality changes, presence of dust and contaminants, etc.) still has to be demonstrated. A very promising technology for natural gas domestic measurements is represented by thermal mass flow meters, but, unfortunately, gas quality is expected to significantly affect metrological performance of such meters. The authors conducted several metrological tests aimed to verify the sensitivity of such meter with natural gas quality changes. The results of these tests show a not full reliability when CO₂ content increases and when gas composition varies.