STUDY ON ENERGY ZERO BALANCE BASED LIGHTING SYSTEM IN TOILET: ZET lighting system using the energy harvesting technology implement to actual building

In this study, the energy harvesting system for public toilet was constructed that stores electric energy recovered by micro hydropower generator equipped in tap water supplying pipe into battery. This system uses high-efficiency charge / discharge circuit and Purkinje effect visibility adjusted ultra-high-efficiency LED lighting. ZET system was installed to the toilet of disaster affected Tohoku University and confirmed the influence on the lighting energy balance and excretion behavior by demonstration experiment. As a result the following knowledge was obtained. 1. In the gents' toilet despite that the consumption amount is larger than power generation amount, if the number of users and the consumption amount satisfy the predetermined conditions, the lighting energy of zero balance can be achieved by the power generation of additional flashing for cleaning. That is, the balance depends on the relationship between the number of users, how it behaves, and the number of automatically self-flushing. 2. Regarding the frequency of use of urinal, the closest to the entrance was most frequently used and the fewest were next to the urinal nearest to the entrance. Frequency of use of urinal is not dependent on the distance from the entrance, and there is a strong tendency for the users to act not to be next to each other. Regardless of gender, it was confirmed that toilet booth closest to the entrance were frequently used, especially for Ladies' toilet, the trend is remarkable. 3. Gents’ toilet has maximum 240 erroneous detections of LED lighting motion sensor per day without excretory activity, and for Ladies toilets as well. In female toilets, unnecessary detection lights due to lost stances due to booth selection and reconfirmation action after use were found. The toilet plan / equipment plan affects energy consumption of LED lighting. 4. By combining reduction of erroneous detection of entry, reduction of wasteful lighting at the time of use, and controlling how to turn on/off the lighting, the gents' toilet got a prospect that zero energy balance can be achieved even if no daylight use toilet. 5. As a result of utilizing daylight, reduction of erroneous entry detection and wasteful lighting reduction, the energy balance rate of gents' toilet improved significantly. This tendency is the same for ladies' toilet. 6. In ladies' toilet, consumption by lighting in the booth was much larger than that for gents', and it became clear that there is a difference in beh