Frequently asked questions
In general, the various cooling principles apply to the following applications:
- Air-to-air: Cooling of enclosed spaces. Examples include small rooms, electronics cabinets, enclosures
- Direct-to-air: Direct cooling of objects such as lasers, electronics, or medical samples
- Liquid-to-air: Cooling of liquids or gases, or, when used the other way around, cooling of a space where the hot side of the Peltier cooler is cooled by a liquid
- Direct-to-liquid: Cooling of objects such as lasers, electronics, or medical samples; in this case, the heat is transferred to a coolant.
These are the general applications associated with each cooling principle. Variations are possible. If you are unsure which cooling principle best fits your cooling challenge, please feel free to contact us.
The required cooling capacity depends on the application, the cooling principle, and environmental factors. Below are several scenarios and the information needed:
Air-to-air cooling of a space:
- Ambient temperature (hot side of the cooler)
- Desired temperature inside the space (cold side of the cooler)
- Dimensions of the space
- Insulation material and thickness (needed when cooling below ambient temperature)
- Any heat generation inside the space
The formula used is:
P = λ · A · ΔT / d
where:
- P = transferred power [W]
- d = thickness of the material [m]
- A = surface area of the material [m²]
- ΔT = temperature difference across the material [K]
- λ = thermal conductivity of the material
Direct-to-air / Direct-to-liquid:
- Ambient temperature / coolant temperature
- Desired temperature of the object
- Any heat generation of the object
- Dimensions of the object
- Insulation material and thickness, if the object needs to be cooled below ambient temperature
Direct-to-liquid:
- Coolant temperature
- Desired temperature of the object
- Any heat generation of the object
- Dimensions of the object
- Insulation material and thickness, if the object needs to be cooled below ambient temperature
We are happy to calculate the required cooling capacity for your application. Please contact us so that we can provide a free calculation tailored to your needs.
Our standard coolers are not suitable for outdoor use. However, we can easily make our coolers suitable for this purpose. The steps we take are:
- Replacing the fan(s) with a fan that has the appropriate IP rating
- Modifying connections (relocating them to the interior/dry side or using a suitable connector)
- Sealing cable entries
- Depending on environmental factors (e.g., a marine environment), using alternative materials
- If desired, adding a protective cover
Do you have an application in an outdoor environment or other specific requirements? We can adapt our coolers accordingly. Please contact us to discuss the options.
By reversing the polarity of the Peltier elements, they operate in “reverse.” This makes it possible to heat spaces, objects, liquids, or gases. The Peltier elements transfer heat from one side to the other, while also generating heat from the power they consume. These effects combine, resulting in an efficiency with this heating method that can exceed 100%. This makes it more efficient than conventional heating methods such as resistive wires or heating foils.
There are several ways to control the temperature:
- On/Off control: This is the simplest method, but due to the thermal inertia of many systems, it is also the least accurate. Accuracy varies per application but is generally no better than ±1°C. Rapid cycling of the Peltier elements increases thermal stress on the modules, reducing their lifespan. A good rule of thumb for on/off control is to maintain at least 60 seconds on / 60 seconds off as switching times.
- Voltage/Current control: This is the most efficient method for controlling Peltier modules and can be very precise when combined with proper PID control. However, the required hardware control makes this method more complex.
- PWM (Pulse Width Modulation) control: Most microcontrollers have built-in PWM outputs, making this a simple software-based solution. With proper PID control, it can also achieve high accuracy. There are specific requirements for PWM control to reduce thermal stress and prolong module lifespan. The base PWM frequency should be at least 5 kHz. PWM control is less efficient than voltage/current control because the Peltier module always draws maximum power at each duty cycle. The higher the PWM frequency, the less this effect occurs and the higher the efficiency.
We have a range of standard controllers in stock. Would you like to know which control method is suitable for your application? Please contact us for more information.
As the temperature difference between the hot and cold sides of a Peltier element increases, the available cooling capacity decreases linearly. For our standard coolers, the maximum achievable temperature difference (ΔT) depends on the model and typically ranges between 40–45°C. At this maximum ΔT, no cooling capacity is available, so this temperature difference cannot be reached in practice. Our datasheets include a graph showing cooling capacity versus ΔT.
With our special cascade coolers, a higher ΔT can be achieved. We offer two standard models:
- Air-to-air: CA-050-AAC-24
- Direct-to-air: CA-060-DAC-24
Please contact us for more information.
Both technologies have their advantages and disadvantages, but thermoelectric technology truly excels in enabling small-scale cooling applications that would be impractical with a compressor-based system. Examples include cooling individual integrated circuits, thermally cycling a test tube, or cooling a small enclosure.
Thermoelectric modules are also particularly strong in applications that require both heating and cooling under varying operating conditions; the system can easily switch to the desired mode simply by reversing the current polarity. Additionally, thermoelectric systems can be mounted in any physical orientation and still function correctly.
Another advantage of thermoelectric systems is that they do not require evaporating chemicals, which can be harmful to the environment.
Resistive elements generate heat solely from the power dissipated within them. Thermoelectric elements, on the other hand, not only provide this I²R-heating but also actively pump heat into the thermal load, making them potentially much more efficient than resistive heaters.
The lifespan of a Peltier cooler depends on several factors, with the control method being the most important, as it can cause thermal stress on the modules. Manufacturers often specify lifespan in terms of the number of on/off cycles, assuming the module is on for 60 seconds and off for 60 seconds. Under these conditions, the lifespan is around 100,000 cycles. Shorter cycle times negatively affect the lifespan.
With voltage/current control or a well-implemented PWM control, temperature cycles are smaller, which positively influences the lifespan.
It is also important that the modules never become too hot, so adequate cooling on the hot side must always be ensured.
Our experience with customer applications shows that the lifespan is long (>5 years), regardless of the type of control method used.
We always keep a plentiful stock of parts for our standard coolers, resulting in a lead time of approximately 2–3 weeks.
For custom coolers, the lead time depends on the type of modification. We aim to use as much as possible from our existing stock to keep delivery times as short as possible.
Request a quote for more information.