Abstract
The voluntary Water Efficiency Labelling Scheme (WELS) on showers for bathing in Hong Kong is a water conservation initiative of the Hong Kong Special Administrative Region (HKSAR) Government. As shower water consumption has been identified as a potential area for carbon emissions reductions, this study examines, from a five-month measurement survey of the showering practices of 37 local residents, a range of showerheads with resistance factors k = 0.54–4.05 kPa·min2·L−2 with showering attributes including hot shower temperature, temperature difference between hot and cold water supply, flow rate and water consumption and shower duration. A Monte Carlo model is proposed for evaluating the water consumption and carbon-reducing impacts of WELS on showers for bathing at confidence intervals with input parameters determined from the measurement survey. The simulation results indicate that full implementation of WELS rated showerheads with k ≥ 4.02 can reduce water consumption by 37%, energy use by 25% and carbon dioxide (CO2) emissions by 26%. This study is also a useful source of reference for policymakers and practitioners to evaluate the impacts of water efficient showerheads on water consumption, energy use, and CO2 emissions.
Highlights
The Hong Kong Electrical and Mechanical Services Department (HKEMSD) reported that about one-fifth of energy end-use in Hong Kong was for shower water heating [1]
An earlier survey indicated that 98.8% households supported water conservation measures and 36.4% of them were aware of Water Efficiency Labelling Scheme (WELS) [4,6], this study revealed that the usage rate of WELS rated showerheads was not high and further promotion for these showerheads may be required
Strong associations with showerhead resistance factor k were reported for hot shower Strong associations with showerhead resistance factor k were reported for hot shower temperature temperature T0 (p < 0.001, t‐test), temperature difference between hot and cold water supply T0 − Ti
Summary
The Hong Kong Electrical and Mechanical Services Department (HKEMSD) reported that about one-fifth of energy end-use in Hong Kong was for shower water heating [1]. In Japan, residential water supply systems accounted for nearly 5% of total carbon dioxide (CO2 ) emissions and over 50%. Of those emissions came from hot water supply systems [2]. In southeast Queensland, Australia, the average energy consumption from hot showers ranged between 810 and 1246 kWhps1 ̈ year , corresponding to CO2 emissions ranging between 160 and 245 kg-CO2 ps1 ̈ year1 [3]. Improving shower water efficiency can lead to energy savings and carbon emissions reductions. An effective way to increase shower water efficiency is to replace an inefficient showerhead with a water efficient one. To encourage shower water conservation in Hong Kong, a voluntary
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