Behavioural End-use Stochastic simulator (BESS) – fixed and sampled
The behavioural model provides simulation of water use using the Behavioural End-use Stochastic simulator (BESS) of Thyer et al. (2011). BESS stochastically simulating individual end-uses (outdoor, shower, washing machine, toilet, tap etc) at the household scale at sub-daily time steps using algorithms which probabilistically simulate an individual household’s use of common household water-using appliances. The conceptual framework for BESS is provided as follows:
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For outdoor water, the behavioural model uses monthly varying, average daily values, which can be input by the user - similar to the average daily model. For the sub-daily outdoor water use, the daily values are evenly distributed throughout the day. Future versions of the behavioural model may incorporate the behavioural impact daily weather has on outdoor water use variability (Micevski et al, 2011).
Diurnal Pattern
The statistical distributions used by BESS to generate the sub-daily indoor water use are based on the end-use study of Roberts et al. (2005). Users are encouraged to check that the predicted water use statistics provided by BESS match their expectations. BESS uses a diurnal variation to vary the probability of water use events occurring throughout the day. It disaggregates the daily demand data to a sub-daily time-step using a non-dimensionalised diurnal pattern.
Fixed Behavioural
Sampled Behavioural
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The behavioural water use model configuration with sampled appliances and occupancy allows you to specify random sampling of occupancy and appliance types, for each household, from statistical distributions.
Using the behavioural model with sampled appliances and occupancy is only recommended when you are simulating a larger number of households (> 400) and you do not want to set the appliance types /occupancy for each house.
Sample size requirements
If you specify sampled appliances and occupancy, you must specify a minimum number of houses in order to provide a statistically-reliable sample of the household occupancy and appliance type.
Due to random sampling in any particular Urban Developer run, the percentage of houses actually sampled for each household occupancy and appliance type (the sampled percentage) will not be exactly the same as what you specify (the true percentage).
For example - if you specify only 10 houses, with a true probability of 0.2 for 3-Star showers and 0.8 for 1-Star showers, the chance of the sampled percentage being very different (eg: 0.5 3-Star and 0.5 2-Star) is much greater than with a large sample size.
The recommended minimum number of 400 houses ensures that for true percentages greater than 10%, the sampled percentage of houses is within 30% of the true percentage for 90% of the time.
You can specify a number of houses smaller than 400, but should be aware that the sampled percentage of household occupancy and appliances types may be different than the percentage you originally specified.
Sampled appliances and occupancy configuration
Select Configure
Average Behavioural
For Water Use nodes set to behavioural mode, there are two options for specifying their configuration.
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