Last week, Urban Blooms installed a series of moisture and temperature sensors into our Ohio State, Howlett Hall, Living Wall Installation. These sensors will be collecting and storing data every 15 minutes through an Arduino microcontroller. This data is then automatically imported into an Excel spreadsheet and is made available for our team to analyze.
This data will be summarized in a Living Wall Sustainability Report which will be published at the end of the year.
The above graph shows the temperature of the sun exposed brick wall on Howlett Hall (AMBIENT TEMP) compared to temperatures at the top of the garden (GARDEN TOP TEMP), temperatures at the bottom of the garden (GARDEN BOTTOM TEMP), and temperatures of the brick wall behind the garden (WALL TEMP). While outdoor temperatures were relatively cool over the past week, with a weekly high of only 81 degrees. This data shows that there is up to a 30 degree drop in temperatures between the brick wall exposed to the sun and the brick wall behind the garden, as you will see in the next graph, that difference in temperature equates to real time energy and cost savings.
This graph shows the amount of money saved in every 15 minute interval. The area beneath the blue line would be the total savings. While it was a relatively cool and overcast week significant savings were still noted; for example, on August 12th there was a high of only 77 and we still see a average savings of .05 cents every 15 minutes during the day. Thus our small display garden still saved the university $2.12 on that cool, overcast Wednesday. Over the course of the cool, overcast, 5 days this data is showing, Our Living Wall saved the university $9.08 in AC Costs.
This data extrapolated over the course of the summer equates to $270 in saved energy costs!
From this data we can also estimate that the garden should save approximately $400 in heating costs over the winter. Giving an estimated yearly savings of $670 for this 32 square foot garden. This represents an ROI of 4.9 years, which means, by just having this garden installed on Howlett Hall for 5 years, the university will save in energy costs the entire cost of the installation!