To make sure laptops don’t burn customers, vendors such as HP and Lenovo have dedicated thermal engineers who use thermal couples and infrared cameras to see how warm each area of a notebook’s exterior gets during various workloads. Their goal is not to get rid of heat altogether, but to keep it away from key touch points that come in contact with users’ bodies.
“A Core 2 Duo [processor] running at 2.8 GHz is going to generate the same amount of heat, no matter whose system it’s in,” Kohut said. “The job, from Lenovo’s perspective, is to make sure it goes out the tailpipes—not on your lap, not on the keyboard.”
Though every notebook has to emit warm air, they don’t all have to be steaming hot. “The more airflow that you have and the lower power that you have, the cooler that air will be leaving the system,” Intel’s Mongia said. “A consumer is always going to experience a situation where the exit air of a laptop will be warmer than the ambient air, but how much warmer really depends on the thermal design decisions that the OEM has made.”
HP’s master technologist and mechanical engineer Mark Ruch explained some of the methods his company uses to deal with hot notebook skins. “We try to change the airflow within the box to bring air across [different] areas,” he said. “We can also put insulating materials between the heat source and the skin.” Ruch also said that HP will occasionally substitute plastic for metal skins while using other materials to minimize temperatures.
Other Cooling Methods
Beyond the exterior, vendors have a number of heat-reducing tools in their arsenals. The CPU and graphics card are cooled by using a heat pipe that moves heat away from sensitive components to a fin-shaped heat exchanger that gets air blown across it by the fan. Other sensitive components may also have heat exchangers on them.
Vents are strategically placed throughout a given system to help cool incoming air as warm air flows out. Meanwhile, software from the vendor—both in the BIOS and directly in the OS—tells the fan when to turn on and how fast to spin. Windows Power Manager also helps regulate the processor and graphics card clock speeds to conserve battery life and reduce heat output. Unlike desktops, most notebooks’ space constraints only allow for one fan. While in some cases that single fan and vent are enough, Lenovo notebooks use two vents to help dissipate heat.
Intel has also developed and shared a number of cooling technologies with notebook makers. Its Laminar Wall Jet technology, available in a number of Acer notebooks, uses specially shaped vents to create a layer of cool air between hot components and the notebook’s chassis. “It’s something that we borrowed from the gas-turbine industry,” Mongia said. “The way that they end up cooling combustion liners and turbine blades in gas turbines is by using a phenomenon called film cooling. If you’re trying to keep your surface cool and block it from something hot, you try to create this little film of air along that surface to shield that surface from the hot gases.”
What You Can Do
It may start with manufacturers, but you can help your notebook stay cool. Start by keeping the bottom vents unobstructed to increase airflow. If you’re using the notebook on your lap and it’s getting too hot, try using it on a flat surface instead. Third-party cooling pads and active fans can help by elevating the notebook and blowing cool air into those vents.
You can also tweak your power plan using either Windows Power Manager or your notebook manufacturer’s bundled utility software. Enable active cooling and choose a balanced power plan over a high-performance one; the less power your components are using, the less heat they will generate. Experiment with battery saving plans, but keep in mind that some low-power settings may also slow down the fan.