Warning: This story involves maggots

How consistent, cool, rental air helps raise protein-rich feed supplement

Flies. They can ruin a camping trip, a picnic, or a day on the lake pretty quickly. But for one business in Ohio, black soldier flies, or at least their larvae—maggots, that is- -are their stock in trade. Despite what you or I may think about flies, one thing can’t be disputed: Their larvae are an excellent source of protein. In fact, according to this Washington Post article, “Black soldier fly larvae can make thousand-fold more protein than terrestrial animals or other plants.”

We are not suggesting that you serve fly larvae to your budding athletes at home—not yet at least—but they are an excellent source of feed protein for livestock and even fish farms.

Here’s how it works: Female black soldier flies lay several hundred eggs at a time. Within just a few days, the larvae are hatched and begin feeding on just about whatever organic matter they can find, gaining the fat stores they would normally be used for the rest of their adult lives. But in the case of companies harvesting the protein, this is where the story ends. Once they are nice, plump larvae, but before they turn into flying adults, they are killed off to be added to animal feed and fish feed as a rich protein supplement.

A black soldier fly larva can consume twice its weight in food every day. On its 14-day journey from hatchling to pupa, a single larva will grow nearly an inch long and increase its weight by a factor of 10,000.

But while they are in that growth mode between hatching and adulthood, they are particularly vulnerable to temperature. In the summer months, there were 30-degree swings in outside air temps—no bueno for these adolescent flies. Too warm or too cold and an entire brood—and profits--could be lost. Our customer was in growth mode, and their operating facility didn’t have adequate temperature control for the entire facility, and because they were still growing, they didn’t want to shed capital to invest in the HVAC infrastructure for such a short window of time each year. 

In working with the customer, we identified three critical goals: 1. to supply a system that could deliver up to 50,000 CFM of 100% outside air to their building; 2. the incoming air needed to be at a consistent temperature of 65°F-69°F; 3. the volume of air needed to be adjustable to help balance the pressure in the building.

Here’s how we approached the problem: To create the cooled air, we installed one of our Rental-Ready air-cooled chillers. We coupled that with a pair 100-ton air handling units with variable speed drives to control the volume of air introduced into the building and balanced that with outgoing air from the exhaust fans. To maintain a consistent temperature, each air handler was outfitted with bypass valves, that could be engaged when outside air was cool enough to supply air to the building.

Our client recognized that not only was our engineered solution a good fit based on their budget but noted that we were the only outfit that was able to single-source all of the equipment required for the solution. Less supplier equals fewer headaches.