4.4. Simulations of World of Showers B

Figure 4.11 shows typical simulated behaviour of temperature at the two shower heads over a period of two minutes (120 seconds). Shower-takers both begin too hot and inadvertently end up in an endless cycle of conflict and discomfort. Neither shower-taker is able to achieve a condition of stable and comfortable 25 °C water, despite the intention of both to do so. Instead of converging, the water temperature in both showers exhibits persistent fluctuations, sometimes reaching peaks of almost 35 °C and troughs of less than 20 °C. The strong coupling of the shower worlds is evident in the way temperature movements mirror each other – when the temperature is high in your shower (line 1), it is low in shower 2 (line 2), and vice versa.

Figure 4.11. Typical simulation of two interacting showers in World of Showers B

Such a world is confusing and frustrating for decision makers. Well intentioned actions to stabilise temperature (and so increase comfort) have the perverse effect of inducing instability. Moreover, no amount of time spent changing the tap setting will improve the situation. Each shower-taker adopts an adjustment strategy and mindset appropriate to a single shower, reinforced by visual cues that confirm they are in a single shower world – separate cubicles, a single tap to adjust, no awareness of the other shower or its occupant (just like the functional or regional stovepipes that shape mindsets in organisations).

An effective way to improve performance is to reduce the pipeline delay and to increase the patience of the hidden shower-taker (by increasing the time to adjust the tap). Reducing the pipeline delay makes each shower more responsive to the comfort needs of the shower-takers. Increasing the time to adjust the tap mimics a hidden shower-taker who reacts more gradually to any temperature gap and so reduces internal competition for hot water. The combined effect of these two design changes is to reduce coupling between the two showers so each shower-taker feels more in control of their own destiny. The effective dynamic complexity of the shower system is reduced and World of Showers B behaves more like World of Showers A, with the water temperature in both showers converging quickly to the desired 25 °C as shown in Figure 4.12.

Figure 4.12. Simulation of two interacting showers in a redesigned World of Showers B with pipeline delay reduced from 4 to 2 seconds and time to adjust tap increased from 5 to 10 seconds