Arduino Based Shower Regulator


Via Ryan Chan on

It may not seem like it, but the shower is easily one of the most wasteful appliances in a home and expends great amounts of water and energy.

According to Home Water Works, the average flow rate of a shower is 2.1 Gallons (7.94L) per minute; this with an average shower time of 8.2 minutes results in 17.2 gallons (65.1L) used per shower or 51.6 gallons (195.3L) used in an average American household (3 people) per day. This makes it the third largest water user in a home.

The numbers are even more surprising if you look at the energy use. According to Skidmore College, the average shower uses 440 BTUs (0.13 kWh) to heat one gallon (3.78L) of water. This means that about 2.2 kWh are used in a single typical 8.2 minute shower and 6.6 kWh used per household per day! According to the US Department of Energy, this makes up 17% of total home electricity usage.

With the US EPA’s estimate of 0.000703 metric tons (1.55 pounds; 0.7 kg) of CO2 per kWh, this results in 3.4 pounds (1.54kg) of CO2 per shower and 10.2 pounds per household.

However, the recommended shower time is only 5 minutes according to Green Lifestyle Changes – this cuts water use by 6.7 gallons (25.4L), power use by 871Wh (That’s enough to power 174 CFL bulbs for an hour!), and CO2 emission by 1.35 pounds (0.6 kg) per shower. This is where the Shower Regulator for the Intel Earth Day Challenge comes in which would limit the shower time to 5 minutes or to whatever time the user chooses.

In one 365 day year, this would save 2,455.5 gallons (9,295.1L) of water (enough for a person to drink for about 13 years) and 317.9kWh or 492.7 pounds (223.5kg) of CO2 per person, resulting in 7,366.5 gallons (27,885.2L) of water, 953.7kWh of power, and 1,478.2 pounds (670.5kg) of CO2 saved per household.

How Does it Work?
1- The solenoid valve is closed when the device is powered off so no water can flow if the regulator is not running.

2- The valve opens when the device is powered on; the user can turn on the water now.

3- The regulator allows the water to warm-up for 20 seconds (is adjustable) indicated by 1 beep.

4- After warm-up, the regulator begins the shower timer for 5 minutes (is adjustable) indicated by 2 beeps.

5- The regulator will give 1 beep warnings 1 and 2 minutes before the shower is over.

6- Once the shower time is completed, the device will automatically close the valve, stopping the flow of water. The user can turn off the water and the regulator now. This is indicated by a continuous beep.

Read more.


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