With the recent drought in the Western Cape, many citizens are taking extreme measures to conserve water at home and work, which is where adults spend most of their time. However, little consideration is given to the place where our children spend the bulk of their awake and water-consuming hours – school. When we realised this, we enquired about a local school’s water and energy bills, and we were shocked to learn that a typical school’s water and energy bill ranges between R 40,000 and R 60,000 per month. The bills are more or less split in half by water and energy costs. Just put this in context, each of the schools we looked at using the same amount of energy per day as 20 households combined, and the same amount of water as 40 households combined. What was even more surprising to us, was that the schools get their bills for a period only two months after the water was consumed. This was a clear opportunity to use our generic water and energy metering and control solutions to make a real difference in the community, which is especially important given the state of our education system’s finances.
Initially, we tackled electricity. Most schools pay for energy consumed during the month (same as the average house pays for kWh “units”), as well as the maximum peak load through the month (measured in kVA). For the first school we looked at, energy made up roughly half of the energy costs, and the single highest peak is seen during the month, the other half. To manage the energy consumed, we installed heat traps on the eight geysers and equipped them geysers with our Geasy intelligent geyser controllers. To manage the peak load, we put all the geysers on individually tailored schedule control that would ensure that hot water is delivered where it was needed which the peak load is kept away from where it was not. To better understand the full picture, we also used Geasys to measure and control the power consumed by the swimming pool pumps. Finally, we installed one of our SHEM real-time three-phase meters on the municipal supply into the school, which allowed us to understand at any instance what the school’s electrical load looked like. We used this information to notify the principal’s office whenever the load reached our targeted maximum, and also when one of the three phases came near the tripping level – when the power trips, the municipality is paid to turn it back on again. We were able to reduce the energy by 19%, saving roughly R 3,000 per month without breaking too much of a sweat. The exact savings on the peak load is difficult to quantify since the school has been expanding and building, but our estimates are that we are reducing the load by about 8kVA, saving another R 2,000.
Then we moved on to water, with which we were dumbstruck by the results. We installed one of our minutely updating smart water meters on the municipal water supply to understand in real-time what the water was for any given time of the day. This allowed to quickly establish that there were losses seen during the night. We were able to identify the sources of those losses, and to consistently reduce them from 9kL per day to 1kL per day. We also presented the results to the teachers and explained to them what measures to take to save water at the school. As an intervention, we presented the summary to the teachers during break times on the TV screen in the tea room, put summarising posters on the walls next to the bathrooms – see here. We also developed “top trump”-like play cards which we handed out to the children in foundation phase, to ensure that they also engage with the figures and are aware of the scale – see here and here. Comparing with May 2016, the consumption is down by well over 350kL, a reduction of R10,000 per month. Average consumption per weekday is now at 12kL per day. At one stage during the process, the builders struck a supply pipe and did not notify the right people — We were able to identify the problem within 24hrs, saving 300 kL of water.
Author: Thinus Booysen
Editor: Arno Scholtz