Grantee Research Project Results
Final Report: Developing a Wireless Device for Monitoring Water Usage for Hotel Showers
EPA Grant Number: SU835935Title: Developing a Wireless Device for Monitoring Water Usage for Hotel Showers
Investigators: Johannes, Tyler
Institution: University of Tulsa
EPA Project Officer: Page, Angela
Phase: II
Project Period: September 1, 2015 through September 30, 2017 (Extended to August 31, 2018)
Project Amount: $74,999
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet - Phase 2 (2015) Recipients Lists
Research Category: Sustainable and Healthy Communities , P3 Awards , Pollution Prevention/Sustainable Development , P3 Challenge Area - Safe and Sustainable Water Resources
Objective:
There is no question that water scarcity on the planet should be a significant concern to all humans, especially as the world's population continues to grow. Given that water is a valuable and limited resource used by all industries and individuals, it is extremely important that society embraces efforts to maximize the efficiency of its water usage. In the United States and around the world, a significant amount of commercial water usage occurs in the hotel industry. Most hotels do not monitor individual guest water usage and, as a result, millions of gallons of potable water are wasted every year by hotel guests who use more water than they really need. New applications powered by smart technology and hotel policies can help increase awareness of water conservation efforts and help reduce careless water consumption in hotels. One potential application intended to solve this problem has been the Hydrosense project.
The Hydrosense project sought to develop a commercially viable wireless device for monitoring water use from the showers of hotel guest's rooms. The goal of this project was to design, build, and market a device that could fit onto both new and existing hotel shower fixtures while at the same time being capable of wirelessly transmitting hotel guest water usage data to a central hotel accounting system. This device, paired along with a hotel reward or incentive program and a strong marketing campaign promoting the environmental benefits of limiting water waste could have a small, yet significant impact in reducing the amount of water heating and unnecessary water usage in the hotel industry. The intent of this project was to market this device to the hotel industry as a cost saving mechanism that would promote water conservation at the same time.
At a high level, the objective of the Hydrosense project was to develop a small sized, low cost, modular device that could fit on any hotel shower fixture. This device was to be designed to have wireless capability and be self-energized through a generator powered by the shower's stream.
The hope for this project was to give hotels and their guests information about individual rooms' shower water usage. This information could help hotels and guests conduct their own conservation efforts, being mindful of how much water they actually consume. While the potential applications of information and data such as these would be particularly useful in areas that have a limited water supply, it's application that could be implemented in hotels anywhere.
The key design goals for the Hydrosense device consisted of:
Developing a physical device that could connect to new and existing hotel shower fixtures while minimally obstructing the flow of water.
Developing a self-powered device capable of accurately transmitting typical shower flow rate data wirelessly to a central hotel computer with little outside maintenance.
Summary/Accomplishments (Outputs/Outcomes):
Our original design effort focused on fabricating a 3D printed device that would function as a small generator. This original design had a radially rotating impeller with power generation components lying outside the flow path of the fluid. However, the project team was unsuccessful in building a reliable generator small enough to fit inside the limited space of the device's enclosure or shell. Because of this, our team proceeded to make some design modifications. We custom built a 3D printed shell that can be added as an extension to the base of most purchased low flow generators. This shell extension protrudes from the base of a typical low flow generator and can be seen in Figure 1. This 3D printed shell encloses the coil windings of the generator along with all the other necessary device electronics. These electrical components include our Wemos Microcontroller, rechargeable battery, and the electrical connections between the components. This system configuration is the last iteration of our Hydrosense all-in-one device. When tested, this all-in-one device provides information about flow rates to our remote MySQL database which can be accessed with an internet connection to our server.
To calculate the flow rate, we had originally used an Ardunio microcontroller and later changed it to a Wemos microcontroller in order to solve the problem caused by the insufficient space available within the shell enclosure. Switching microcontrollers reduced the space needed for the electronics by 25%. While this also helped reduce the power consumption, our team continued to have trouble powering the Wemos microcontroller board directly from the current produced by the generator as the water flowed through the system. To design around this problem, our team decided to add a rechargeable battery to power the microprocessor. This means that the device's generator is now connected to the rechargeable battery that powers our microcontroller. The current produced by the generator is then used to recharge the battery and extend the runtime of our system.
While the generator by itself can provide enough power for the Wemos microcontroller to execute the computer program that calculates water volume consumed, it does not provide enough power to send that information over WiFi to our remote MySQL database. Our engineering team worked hard to figure new ways to lower the power requirements of the microcontroller in order to build a system that could rely solely on a generator without an additional battery, but unfortunately, we were unable to implement a working solution to this issue. Ultimately this was very problematic because the Wemos Microcontroller consumed battery power faster than it could be recharged. Therefore, the system was not fully self-powered as originally intended.
Our project was successful in developing an underlying embedded software that allowed our Wemos microcontroller to have wireless transfer of data from the device to a database hosted on a server using the Transmission Control Protocol (TCP). While we were able to transmit data from what could be considered a stand-alone shower unit to a central hotel database, we were not able to generate data that accurately described the actual water flow rate.
After many design changes, our team attempted to accurately correlate fluid flow to power generation from our device's generator as the main method to measure water consumption. Our team experienced issues with the integrity and quality of the data being sent wirelessly from our device to the database. The lack of accuracy of this data was perhaps the largest and most upsetting setback. Our team pursued this strategy because during the 2016-2017 academic school year, we were confident that we could relate the voltage and current being produced by the device generator to provide an accurate estimate of the actual water flow. Using the clock on the microprocessor we took the current, voltage, and time variables to calculate the total water consumed, eliminating the need for an additional flow meter linked to our device. However, we were never able to build a mathematical model that accurately, precisely, and consistently related this voltage/current output to actual water flow.
Our device was tested by attaching a purchased flow meter in line with our Hydrosense system. Doing so allowed us to compare the results generated by our prototype device to the actual water volume consumption rates displayed by a LCD screen attached to the purchased flow meter. For purposes of comparison between the actual water volume used (purchased flow meter) and the reported water volume used (Hydrosense system), ranges of total water volumes were tested against each other. In these tests, the measured water flow data being reported by our device was always significantly less than the actual flow rate values read from the purchased flow meter, thus indicating that more work is needed to develop a more accurate Hydrosense device.
Conclusions:
While our team faced setbacks to our original goal to develop a completely self-powered water monitoring device, our team built an all-in-one device capable of wirelessly transmitting data with the help of a rechargeable battery connected to the device's generator. While our team was very close to delivering a fully functional device, the main issue with our final device was that the water flow data being reported by our device was significantly less than the actual flow rate values. The amount of deviation would vary depending on the length of time used to test our device. As such, the device did not meet its original goal of accurately measuring flow rate seen in typical shower usage. Additionally, due to issues our team encountered in trying to power the circuit with the generator, our design was not a self-powered device since it used a rechargeable battery that had to be changed or recharged frequently.
While this project did not conclude in a commercially viable device that was first envisioned in the original P3 proposal, it has served as an important educational tool for both the students that have worked on the project and the numerous elementary and middle school aged children that have participated in outreach projects led by the student members of this project team. The student team members would like to highlight that they have learned new mechanical, electrical, and software design considerations and techniques necessary to build smart devices. This valuable research experience in building an internet of things system has provided many of them with valuable engineering, design, and leadership lessons that have been instrumental in their interviews for a wide range of industries and graduate programs.
This project involved 10 undergraduate students and 1 MBA student.
Journal Articles:
No journal articles submitted with this report: View all 1 publications for this projectSupplemental Keywords:
Water conservation, Urban water planning, Sustainable water management
Progress and Final Reports:
Original AbstractP3 Phase I:
Developing a Wireless Device for Monitoring Water Usage for Hotel Showers | Final ReportThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.