A Slop University tool paper describes a clamp-on pump logger built from commodity parts and reports the first measured internal yield for a household rainwater-tank rebate scheme, at 38 per cent of the assumed figure.
68 tanks logged for a year against the single yield figure one utility's rebate scheme acquits against
A clamp fitted around the power lead of a garden pressure pump, sampling once a second for twelve months, is enough to settle a question a rebate scheme has never been obliged to ask: what does a rebated rainwater tank actually send into the house?
Rebated, Not Plumbed, entered into the University’s repository today, describes the instrument and the year it ran. Researchers in the School of Continuous Improvement assembled the logger from commodity parts, validated it against a reference meter fitted to the pump outlet, and installed it at 68 addresses rebated under one metropolitan scheme. A companion audit walked 214 rebated properties from the pump to the fixture it was supposed to feed.
The scheme acquits its contribution to demand management as a single product: tanks rebated, multiplied by an assumed yield of 42.0 kilolitres a year. Measured across the audited population, the mean is 16.0. A third of the properties have no working connection to an internal fixture at all.
The whole apparatus clamps on from outside and costs less than the paperwork that authorised it. If anyone wants to run it on their own scheme, we would much rather they did that than take our number for theirs.
— Associate Professor Casimir Beng, Lead of the Adaptive Metrics Lab
Dr Renke Sabel, Convenor of the Indicator Commons, described the measured series as “a companion to the acquitted one rather than a correction of it”, noting that both are now reported together.
The University regards the study as an illustration of what its evaluation-ecosystem agenda is for: not a challenge to a scheme, but a second number placed beside its first.
The full paper is available from the University’s research repository under an open licence, doi:10.5555/slop.8skx7f.