Utveckling av en ytmonterad fördelningsmätare som underlag för individuell debitering av vattenförbrukning i fastigheter
The master thesis, conducted at Metrima AB, concerns the development of a non-intrusivedistribution meter as a basis for individual tap water billing in apartments.The project is conducted in response to the market interest in individual tap water billing inapartments as an answer to environmental concerns regarding water consumption. Due to thehigh installation cost of traditional water meters, a new method of determining waterconsumption, without having to cut water pipes, is proposed.The proposed method distributes the total water consumption for an apartment complex toindividual apartments according to distribution meters, measuring water run-time, in eachapartment. The water run-time is estimated by measuring the water pipe?s outward vibrationsand temperature changes.A test environment was established and a prototype built, using a tilt- and vibration sensor forvibration sensing and a precision temperature sensor to measure temperature changes. As bothsensors work well in the test environment, further testing was done in 3 apartments for aduration of 5 days. As the vibration sensor is extremely sensitive to the water pipe?smanufacturing material, size and construction, the sensor is of little use and hence discarded.The temperature change is, therefore, solely used for estimating the water run-time.Mathematical methods based on E.S. Page?s cumulative summation theory is applied to bothan unaltered and a time differentiated temperature signal. From tests conducted from 051128to 061019, distribution accuracies reached ± 14,33 % and ± 13,60% respectively, which isconsidered acceptable for a low cost meter. Conclusions cannot be drawn from the result fromtest apartments as too little data was gathered. A correlation between actual waterconsumption and water run-time can, nonetheless, be observed.As a further development of the prototype, a wireless solution is suggested and necessary tofurther reduce cost.