Energy consumption for hot-water supply in warm regions in Japan amounts to more than 30% of the whole household. Thus it is essential to save energy consumption of hot-water supply. In recent years, it has been high efficiency by advancing high efficiency hot water supply system and hot water saving faucets. On the other hand, there are few cases studies factor behind using satisfactorily hot water saving shower head.
In this study, we focus on the hot water saving shower head. The first target is to grasp the relation of feelings and physical properties through some experiments. The second target is to confirm the effect of water saving shower head in actual bathing. Furthermore, we consider the flow rate which can use the shower head not to harm feeling of satisfaction.
We studied the relation of feelings and physical properties through some experiments in Chap. 3 and Chap. 4. We heard 6 types of feelings (volume, spread, momentum, density, bias of spray range, form of grain) and satisfaction when subjects adjust the optimum flow rate. As a result, feelings of volume and momentum were high relation with satisfaction. Also, we found that low volume and high momentum could be dissatisfied factor. The feeling of volume was a strong correlation with all grain surface area of shower, and over 100 mm2 all grain surface area not could be dissatisfied factor. The feeling of momentum was correlation with spray force from one hole of shower head, and under 0.02N spray force from one hole could not be dissatisfied factor. Also, it was revealed that large bias of spray range tend to be dissatisfied factor.
We conducted an experiment to confirm the effect of water saving shower head in actual bathing. Table 5 shows the experimental method in Chap. 4. As a result of experiment, it was clear that hot water consumption is reduced with a flow quantity reduction effect in the actual bathing without spreading use time by the use of water saving shower head. Also, temperature of hot water did not change. Therefore, using water saving shower head enable us to reduce energy of hot-water supply. Furthermore we compared hot water consumption at every washing act (shampoo, body wash, Facial cleansing, other). As a result, hot water consumption during shampoo was the maximum percentage of all washing act, and second was other act.
Finally we suggested that we need at least 7.0L/min flow rate if we use the shower head not to harm feeling of satisfaction in Chap. 6.
