The vehicle above is a familiar sight — a big yellow bus built to carry students back and forth to school. (Funny how people will refuse to fund transit — but they’ll fight to get a school bus stop that works for their kids.) They’re utility working vehicles. No one expects them to be flashy or stylish — just to provide reliable transportation day in and day out for years. School fleets rack up millions of miles with them.
You may have noticed something different?
Lately a lot of school buses are turning up with white roofs — because that helps (a little) to keep them from becoming solar cookers. Ventilation inside is primitive — you get whatever airflow can come in through open windows and roof hatches, and if the bus isn’t moving, you’d better hope for a breeze. The driver is lucky to have a fan — usually old-school, looking like something from the 1930’s, a motor with what looks like a boat propellor inside a wire cage. Better than nothing.
We can do better, and when temperatures starting hitting triple digits day after day, we may have to. Traditionally school buses (and schools) have gotten away without air conditioning because of the rationale schools are only in session in the cooler months, because AC and electricity is expensive, because “kids (and teachers) have it too easy these days.”
Well, cooler months ain’t what they used to be, so here’s an idea. School buses have those big roofs. How about we cover them with solar panels and use that power to run an air conditioning unit? Kids (and drivers) trapped inside a bus would find it a blessing, especially on longer routes. And there’s additional reasons to do this.
Here’s some design considerations:
- Make it low profile, so clearance isn’t an issue. Put the panels on the roof, but put the AC components down below — a lot of buses have storage lockers on the lower level. This would make maintaining them easier — especially if mounted on slide-out trays/pallets and making them interchangeable modules.
- Make it autonomous and automatic, so it could operate without needing the bus motor to be running or anyone on board. Envision controls that would register when enough light was available to run the system, and a thermostat to switch it on when temperatures inside the bus hit a certain point. Otherwise, it could draw on bus power when the bus was being operated if necessary.
- Take battery systems into account. Would it be worth the weight penalty to carry around batteries to power the system after dark? Even if the AC isn’t running, the solar panels could still be charging those batteries during the day — and if it’s an electric bus, they could be charging the batteries for that as well.
- Sitting in the school bus parking yard, those buses could be hooked up to send excess power from the panels into the grid — or provide mobile power when parked somewhere else (see below).
- Make the system modular so it would possible to use them to retrofit current buses. There are only a handful of school bus makers in the US so it shouldn’t be hard to come up with some standard kits.
- Factor in Wright’s Law— the more of these systems that get built, the cheaper it will get — by a significant amount, just from the experience gained from doing it.
Beyond hauling school kids back and forth, adding this capability to school buses would make other things possible.
- Think about emergency situations. When a heatwave lasts for weeks, these buses could be used as mobile emergency cooling shelters. Given the push to build car-charging stations everywhere, a bus could be plugged into one to run the AC even when the sun was down.
- When a weather event like tornadoes or hurricanes take out the grid, these buses could be mobile emergency power sources for people who need to charge phones and flashlights, and for emergency workers who need power and a place to cool down and shelter during breaks.
- If there’s a need for a mass evacuation, this would make it possible to move people at a higher level of comfort, reducing stress.
- Think about increased value for fleet operators. Companies that supply buses to schools on a contract basis often charter them out to other groups. Buses with AC are going to be a lot more attractive for people who need a shuttle service or want to take a group somewhere.
The climate emergency is going to force us to think outside the box and question the way we’ve always done things — or should if we are going to respond as capably as we must. Biden’s infrastructure investments are already having a big effect on the roughly 500,000 school buses in America. Adding this capability to them would be a force multiplier.
For that matter, it would seem to be a no-brainer to add solar panels to school buildings to power AC during the hotter months, feed excess power into the grid otherwise, and use them for a microgrid that would turn the schools into emergency centers with power in the event the grid goes down. It can make a real difference.
What do you think?
The panels on the bus make nice cool air,
Nice cool air,
Nice cool air,
The panels on the bus make nice cool air,
All through the town!