An Agent Based Model of Household Water Use
Abstract
:1. Introduction
2. Materials and Methods
- Water use fixtures and appliances are represented in the model environment;
- Individual decision-making processes are represented with a combination of heuristic and stochastic rules;
- Agents interact with their environment (controllability of fixtures and appliances and household level tasks);
- Adaptive behavior is implemented through strategy selection.
3. Model Description
3.1. Elements and Structure of Domestic Water Use System
3.2. Entities, States, Variables and Scales
Variable | Value | Description |
---|---|---|
Global Variables | ||
Laundry stock | ≥0 kg | State variable. Describes how much laundry is left to wash. kg of laundry/day = 1.3—agent intention to save water. |
Dish stock | ≥0 plate sets | State variable. Describes how many dishes are left to wash. |
Hours | ≥0 h | |
Days | ≥1 day | |
Weeks | ≥1 week | |
Agent Variables | ||
At-home? | true/false | State variable. Describes if agent is at home or not. It is assumed that working agents spend twice as little time at home as non-working agents. |
Working? | true/false (GUI) | Agent employment status. |
Current action | sustenance/eliminate/bodyCare/cleanClothes/dishWash | Agent’s current state. |
Plan | State variable. Describes how the agent is thinking of doing the current action. The plan is a random draw from the bcstrategy (body care strategy), wcstrategy and eatstrategy lists. | |
Body care strategy | NA/shower/wash under faucet/get substitute/take a bath | Agent body care strategy, which depends on agent’s age group and employment status. Children tend to have more baths, employed agents more frequent showers. |
Agent Variables | ||
WC strategy | NA/excrete/urinate | The proportional need to excrete and urinate is 1:4. |
Eat strategy | NA/drink/cook/eat commercial prepared food at home/eat elsewhere | It is assumed that average agent has three meals and four drinks per day (7 events). |
IntentionToSaveWater | See function (1). | |
Patch variables | ||
Water liters | L | Liters of water consumed through each fixture and appliance. |
Times use | integer | Frequency of using each fixture and appliance. |
Variable | Value | Description |
---|---|---|
Household | ||
No. agents | x (GUI) | Number of household members |
Household type | family with kids/family without kids/co-housing/living alone | |
No. agents under 12 | x (GUI) | Number of children |
No. agents over 63 | x (GUI) | Number of seniors |
No. agents working/studying outside home | x (GUI) | Number of hours agent spends at home. It is assumed that an agent studying/working spends eight hours less at home than others. |
Care for environment | 0.0–5 | Care for environment by the agent, where 0 = no care and 5 = maximum care. |
Environment | ||
Water meter | true/false | True if household water is metered, otherwise false |
Water saving campaigns | true/false | True if the household is exposed to water saving campaigns. |
Agent habits | ||
Sustenance | 0.4375 times/h | Frequency an agent eats/drinks, based on Wilkes [24]. |
Eliminate | 0.5 times/h | It is assumed that average agent has 8 toilet visits per day. |
Body care kids | 0.0794 times/h | Frequency agents under 12 clean body, based on Wilkes [24]. |
Body care adults | 0.0856 times/h | Frequency agents clean body, based on Wilkes [24]. |
Body care seniors | 0.0637 times/h | Frequency agents over 64 clean body, based on Wilkes [24]. |
Clothes wash | 1.3 kg/day | Amount of laundry an agent generates per day, estimation by author. |
3.3. Overview of Processes and Specific Timing
4. Results and Discussion
4.1. Description of the Experiments
- single—a person living alone, having a busy life style, i.e., working fulltime outside home,
- couple—a retired couple, spending most of their time at home, and
- family—a family with two children, two of the members of the family working or going to school full-time outside home.
4.2. Model Validation and Sensitivity Analyses
Domestic Water Consumption (L/cap./day) | NL (1) | Model NL | USA (2) | Model USA |
---|---|---|---|---|
Cooking & Drinking (Kitchen Tap, USA all taps) | 8.8 | 20.2 | 41.3 | 15.5 |
Washing (NL Kitchen Tap & Dishwasher, rest dishwasher only) | 6.8 | 2.0 | 3.8 | 3.3 |
Bathing (Bath & Shower) | 52.3 | 96.0 | 48.4 | 101.1 |
Laundry (Washing Machine) | 17.2 | 7 | 56.8 | 43.5 |
Toilet Flushing (Toilet) | 37.1 | 24.9 | 70 | 73.3 |
Other Indoor Usage (Mostly Tap) | 5.3 | 0.9 | 6.1 | 0.27 |
Total | 127.5 | 151.0 | 226.4 | 237.7 |
4.3. Differences in Water Use per Household Type
4.4. Contribution of Selected Behavioral Factors to Different Water Use Levels
4.4.1. Daily Schedules: Time Used at Home
4.4.2. Agent Incentives to Save Water
4.4.3. Social Norm of Cleanness
4.5. Discussion
5. Conclusions
6. Further Research
Acknowledgments
Conflict of Interest
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Linkola, L.; Andrews, C.J.; Schuetze, T. An Agent Based Model of Household Water Use. Water 2013, 5, 1082-1100. https://doi.org/10.3390/w5031082
Linkola L, Andrews CJ, Schuetze T. An Agent Based Model of Household Water Use. Water. 2013; 5(3):1082-1100. https://doi.org/10.3390/w5031082
Chicago/Turabian StyleLinkola, Lilli, Clinton J. Andrews, and Thorsten Schuetze. 2013. "An Agent Based Model of Household Water Use" Water 5, no. 3: 1082-1100. https://doi.org/10.3390/w5031082