Over five years ago now I was on top of a brand new high school in Southern Minnesota looking over the barren roof. Modern HVAC equipment has been centralized leaving roofs pretty much empty. One option to cover the rooftops is Solar PV, but for organizations that serve food, such as schools, the best option may be to grow the food for their cafeterias on-site utilizing hydroponics.
Hydroponics allow for growing without soil, meaning crops can grow virtually anywhere, provided water, nutrients, and light. Plants get exactly the right amount of water and nutrients and, since the growing season is year-round if placed in a greenhouse, yields can be 10-20 times the amount per land area depending on the crop. Again depending on the crop, 60-90% less water is used.
Growing on-site reduces the food-mileage to zero, however that doesn’t necessarily remove the carbon-footprint. A lot of electricity is used to grow the crops and depending on distance from the normal source of food and source of electricity GHG emissions could go up, or they could go down significantly. Typically, areas in the Northeast would see a dramatic decrease in carbon-footprint.
While a school was the initial inspiration of the idea, there are a lot of vertical markets that could use hydroponics: healthcare, K-12, Universities, Stadiums, and any other vertical market served by the food service industry.
I actually started a company to do this, but didn’t have much success selling the idea. Mostly the problem was the business skills and financial backing I lacked. From trying to sell this idea for a year or so, though, there’s lots of obstacles to maneuver from the customer side. First is finding a customer that will like to be the first to do this. Next is to find one that is willing to invest immediately. I didn’t want to deal with the growing of the food, just selling the development and installation of the hydroponic systems. The payback for the customer can range from 1 to 5 years depending on the crop, location, size of system, etc. There’s other business plans that might work, though, such as leasing the system or installing on-site and contracting the food.
For me, personally, this is a dream and I took a job where I still have the possibility of promoting this idea. It’s going to be a long winding road, though!
For more reading on hydroponics, this is a great article in this months National Geographic on the tremendous work being done by the Dutch. “This Tiny Country Feeds the World.”
Comment on “Connected Rooftop Units Learn to Maintain and Monitor Indoor Air Quality.”
Great Find! From my perspective, as an Energy Engineer that worked with RTUs for several years, there’s a lot of opportunity for improvement in RTU technology. Also, these units cover virtually all vertical markets and this technology can be marketed to those. The best opportunity would be to retrofit existing units with IoT controls. Again, great find!