The Thermodynamics of Heat

Thermodynamics has quickly become the hottest bed bug removal method for Tom Jarzynka, senior director of pest prevention quality assurance for Massey Services, in Orlando, Fla.

“When the bed bug issues were ramping up there were two elements of concern. One was the bed bugs are coming. The other was the bed bugs are coming and the treatments that we have aren’t going to kill them,” said Jarzynka. “We jumped in and started looking at (other) solutions.”

His answer was heat. So, for the past 12 years, Jarzynka has been harnessing thermodynamics as a tool in his company’s bed bug removal arsenal.

When building Massey Services’ program, Jarzynka considered how traditional chemical treatments expose a pest to a lethal dose of an insecticide.

“We’ve got an active ingredient that we’re going to put into play. We’re going to expose the target insect to that dose, to that active ingredient, and then we’re going to get a result because of it,” he said. “When it comes to utilizing heat, I looked at heat in the same way. I’m going to take an active ingredient, which is heat energy. I’m going to put it in the place where the bugs are and we’re going to give them a lethal dose of that active ingredient.”

He explained that while traditional chemicals work by affecting the pest’s nervous system, heat works through multiple modes of action including dehydration (which damages the cuticle and nervous system), physical changes to the tissues, damage to internal organs and the loss of endosymbionts, or the good bacteria on pests responsible for life functions, which begin to die at 105°F.

What quickly became the most strategic part of Jarzynka’s heat treatment strategy, however, is manipulating, directing and focusing that heat on target areas. Doing that effectively comes down to the principles of thermodynamics.

HOW HEAT WORKS. The laws of science state that cold is the relative lack of energy in an environment. Heat moves from areas of high energy to low energy. Denser materials absorb heat energy while loose layers insulate. But what does that mean for a thermodynamic pest control strategy?

“When you go into that environment that you are treating, be aware of how that room is put together, what its components are and how each of those elements is going to respond to the input of energy that you add,” said Jarzynka.

When using thermodynamics in a pest control treatment, Jarzynka said his goal is to raise the room temperature to 120°F. The challenge is getting an even distribution of that heat when a typical treatment area, such as a hotel room, has lots of components like the bed, headboard, walls and drapes that all will be affected by the addition of heat energy.

So Jarzynka looked at the three ways heat transfer occurs: conduction, which is the transfer of energy by contact of a liquid or solid material; convection, which is the transfer of energy by circulation or diffusion; and radiation, which is the transfer of energy by infrared waves.

“Those are the three ways that heat is moved. When we first started developing our heat program, these definitions are something we took a hard look at because we wanted to choose the right tool to use in heating the environment,” he said. “Knowing what we know about conduction, convection and infrared energy, we can go through and start eliminating and choosing what tools we’re going to use.”

Jarzynka eliminated radiation first. “It would be a challenge (to use radiation to heat up a hotel room),” he said.

Radiation doesn’t move around or behind obstacles and it provides an uneven distribution of heat, with outer areas absorbing heat and getting hotter while the inner areas are unaffected, which could overheat walls and cause damage. “You could do it, but it doesn’t seem to be a very efficient way of going about heating up a room,” Jarzynka said.

Next up was conduction. Jarzynka’s interpretation of this method was essentially putting an iron to everything affected, which is not exactly effective when dealing with walls, mouldings and room contents. Even on a mattress, the iron would have to remain in contact for an extended period of time before the energy passes through all of the layers, which would cause damage.

Jarzynka found steam conduction a more appealing option, as the water molecules penetrated deeper than the energy from the iron. But it still wasn’t enough.

“Even using steam conduction, you can’t get to all of the parts of a mattress. The surface areas I can do pretty well, but as far as getting good penetration, there might be a tear that would allow bed bugs to get into the mattress. It doesn’t give us a full opportunity to treat as thoroughly as we might like to,” he said. “Conduction by steam might be an option, but there might be a better way to go. That is where we start talking about convection.”

Jarzynka’s main challenge with convection was overcoming stratification. “The heat is going to rise to the top of the room and stay there. You’re going to have hot and cold areas and you’re not going to be successful,” he said. “Well, we eliminated that pretty quickly. All you have to do is bring a fan into the room, add some turbulence and that energy gets distributed pretty well.”

His team arranges the furniture on each job to maximize that turbulence. “Room set up is critical to the flow of energy,” said Jarzynka. “We want to get the energy dispersed within the room in the heated air and we want to get some turbulence top to bottom and no stratification.”

To ensure this was happening, Jarzynka got in touch with his heater manufacturer and tested how positioning the heater differently changed its effectiveness.

“Anytime you can take the air flow and redirect it, you can manipulate the energy,” Jarzynka said. “If you’ve got a spot that’s getting hot or getting cold, it might be a matter of taking a nightstand and turning it a little bit and redirecting some air from here to here and balancing out your distribution of heat.”

ON THE JOB. During each job, Jarzynka’s team monitors the heat distribution with a handheld thermometer, taking snapshots to finding hot or cold areas and adjusting accordingly.

Another challenge Jarzynka encountered was heating the wall voids.

“We believe that by heating the wall voids, we’re taking away the opportunity for reintroduction, so even though we’re heating the room to 120-130 degrees, I want to get lethal temperatures inside the wall voids,” he said. “We know we can get a room hot, what we didn’t know is what’s going to happen along that headboard where bugs might get into that wall void.”

Jarzynka explained two options when it comes to the wall void construction of a room, either sheetrock on each side of an insulation core or sheetrock on each side of a concrete core. This construction can affect how the energy moves.

So, Jarzynka and his team worked with the University of Florida to ensure that their techniques were effective under both circumstances. They built a test chamber and monitored the heat they added to it with heat sensors and an infrared camera, watching how the energy moved into that wall void space through plexiglass. They found they were able to heat that wall void to 123°F in either situation and that the energy actually transfers all the way into any rooms adjoining the space being treated.

In addition to having a technician enter the room every 30 minutes for the first two hours to record temperatures throughout the space, Jarzynka also uses six wireless sensors at different elevations and probes that go into the wall voids.

“We start our clock when all of the probes hit 120 degrees,” he said.

When Jarzynka trains technicians on convection techniques, he likens it to a fish tank filled with energy instead of water, complete with holes where energy can blow out.

“What I want to make sure I’m doing is adding energy faster than it can blow out so it fills the entire room,” he said.

In terms of heat delivery, Jarzynka said any heater can produce energy, but Massey prefers to use electric heat. It works well in the Florida resorts they often treat, which have plenty of electricity to run the heaters. Sometimes they use energy from two or three hotel rooms to get it to where it needs to be.

“Typically a room has one 240-volt outlet coming off of the air conditioner and a number of 120-volt outlets around the room and bathroom,” he said. “Our magic number that we calculated is that we want to have 10,000 to 13,000 watts of energy going into the room so we can fill this fish tank. With that much energy they will overcome any barriers in the room.”

Although that is his standard, Jarzynka added that the unit of measurement doesn’t matter, as long as that standard is hit.

Finally, Jarzynka doesn’t rely on heat alone to do the job. He still integrates inspection, removal and vacuuming, liquid chemicals and a follow-up inspection.

“Heat’s not doing the whole job for us. We have a better chance of success by going through all the stages,” he said.

The author is a Cleveland-based freelancer.