Thermoelectric Air Conditioners - Frequently Asked Questions
With the following answers we have tried to anticipate most of your questions about air-to-air exchangers. If you have a suggestion or need additional information, please let us know.
1.) What is an air-to-air exchanger?
An air-to-air exchanger is a device for the cooling of air in an electronics enclosure. Our TAC60 units are delivered ready to be easily and quickly mounted. For cooling it uses electrical energy only. The same effects of a traditional compressor system can be obtained without the employment of gas or moving parts (except the fans).
2.) How does an air-to-air exchanger work?
Air-to-air exchangers utilize the Peltier effect whereby the heat is transferred via the flow of current through thermoelectric modules. One part absorbs the heat and, as a consequence, reduces the temperature (cold side) and the other part dissipates the heat to ambient (hot side). Fans are used to move air over heat sinks attached to both the hot and cold sides of the thermoelectric modules.
3.) What are its advantages over a compressor-based system?
There are no moving mechanical parts (except fans) so thermoelectric air-to-air exchangers are extremely reliable with an almost unlimited life span and require no maintenance (except possible fan replacement). "Static" construction makes TE exchangers immune to vibration thus allowing them to be used in any orientation and makes them particularly suitable for the application on moving systems including ships, aircraft and robots.
A thermoelectric air-to-air exchanger does not contain any polluting substances such as CFC or other gases, has a more compact and simple structure than a compressor system and can be easily adapted and mounted.
4.) What are the major components of a thermoelectric air-to-air exchanger?
The heart of the system is one or more thermoelectric modules. The cold side of the module is connected to a heat sink with a fan (forced convection) that absorbs heat from within the enclosure and circulates the cooled air. The warm or "hot" side of the module is connected to another forced convection heat sink that dissipates the heat, absorbed through the cold side as well as the input power to the module/s, to ambient.
5.) How much heat can be transferred with a thermoelectric air-to-air exchanger?
The cooling capacity or Qmax for our thermoelectric air conditioners describes the number of Watts that can be removed from an enclosure without lowering the temperature below ambient (DT=0). This is also known as the nominal cooling capacity. In general, the Qmax value is of most interest for users who don't require cooling but rather simply don't want the air in the enclosure to increase in temperature above ambient.
When cooling below ambient is necessary, the capacity in Watts or Btu/hour decreases the as the exchanger works to provide colder temperatures. See the curves for a particular unit to see how many Watts can be extracted at a given temperature drop.
Each TAC60 is rated for 60 Watts or 204 BTU/h. Simply add additional units, wired in series or in parallel to increase capacity. Contact our technical support for assistance as necessary.
6.) Can a thermoelectric air-to-air exchanger reduce the temperature below that of the ambient?
Most certainly, although we must not forget that the cooling capacity decreases as the difference in temperature between the air inside the enclosure and ambient increases. We must also consider that unless a suitable insulation is provided, the enclosure we want to cool tends to absorb heat from the environment making cold internal temperatures difficult to achieve.
7.) How precisely can a thermoelectric air-to-air exchanger control the temperature?
That depends on the type of control used and where the temperature is measured. Under ideal conditions, a tolerance of ± 0.1° C is possible.
8.) Where is the heat absorbed by the thermoelectric air-to-air exchanger transferred to?
Since heat may not be destroyed, only transferred or distributed it is dissipated into the ambient air surrounding the unit. The warm side of the unit is therefore always warmer than the air to which the heat is being transferred.
9.) Can a thermoelectric air-to-air exchanger be used for heating?
When inverting or reversing the direction of the current flow crossing the thermoelectric elements in the exchanger, the process itself inverts and the heat is moved in the opposite direction. Temperature may also be controlled in the heating mode. For this reason, ElectraCOOL exchangers are excellent in outdoor applications where ambient temperatures vary above and below a target temperature. With a bipolar power supply and temperature controller you can "Set it and forget it."
10.) How do we handle a thermoelectric air-to-air exchanger?
Each exchanger is a ready-to-be-integrated unit and can therefore be quickly installed onto the respective enclosure or machine using only a few screws. TAC60 is designed to be mounted in either of two methods. Most users can simply mount the unit with a set of flanges we supply that allow installer to simply place the cold side of the unit through the enclosure wall, mark the location of the screw holes and drill or use the hardware of your preference.
In the second method, the four (4) screws that hold the exterior fan in place pass through the exterior heatsink and extend into the enclosure. They can be fastened with appropriate nuts. This method is good when space is very limited but not recommended for most users because the entire unit needs to be removed in order to replace the exterior fan.
Then simply connect to a suitable power supply, which may or may not be equipped with a control function.
11.) Must the exchanger be installed in a certain position?
Our exchangers may be mounted in any position as long as the dissipation of the heat is not impeded. The force of gravity does not represent an obstacle.
12.) What is the lifetime of a thermoelectric air-to-air exchanger?
The cooling modules in an exchanger are solid-state with a MTBF over 200,000 hours. The only maintenance required may be the replacement of fan/s.
13.) Is a TE exchanger reliable?
YES - In general operation the only part of our thermoelectric air conditioner that need service are the fans. We use very high quality fans but fans do wear out and will need replacement every few years.
We have thought this through and designed the TAC60 so that fan replacement can be completed in just a few minuets without removing the unit from the enclosure. Simply remove the four machine screws that hold the fan/s in place and gently pull the fan away from the unit. Either a crimp, Amp, Molex brand connector or your specified connector will be exposed for the technician to disconnect and reconnect the new fan.
14.) How much space does a TE air-to-air exchanger occupy?
Our TE units are, in general, extremely compact and occupy less space than a traditional compressor system. Each TAC60 occupies only 4 square inches (100mm square) so they are great for enclosure doors and thin control panels.
15.) What are the protection ratings for exchangers?
Our exchangers are "IP" protection rated according to rules IEC 529.
Standard units are IP20 rated and designed for use in a clean, dry environment. Upgrading to an IP55 rating (protected against dust and against water jet with nozzle) is available at slightly higher prices. This rating is similar to a Nema-4X rating.
Click here for all "IP" ratings and definitions
Click here for all NEMA enclsoure ratings and definitions
16.) What is the lead-time for delivery?
Reasonable quantities in stock. Call or email with your requirements.
17.) I need something different. Can you help?
Thanks to the information made available to us by way of our questionnaire we can put together, without cost or obligation, a first assessment of whether and how you could employ a thermoelectric exchanger to solve your specific problem.
Click here for our questionnaire.
18.) How much does a TE air-to-air exchanger cost?
Like many state-of-the-art products, thermoelectric exchangers are not inexpensive but provide outstanding value. Standard TAC60 units are about $200 USD with significant volume discounts. Outdoor units are about $50 more. Naturally, only you know what the benefits will be when cooling you're electronics or other components as well as the cost in performance and reliability if they are not.
Kindly call or e-mail us with your requirements for a prompt quotation.
Summary of features:
Highly Reliable (Maintenance limited to fan repair or replacement)
Attractive and functional design
Easily adaptable to your needs
Quick and easy installation
Immune to vibration
Reversible (cools or heats)
Precise Temperature Control Available
Operation in any Orientation
Reasonably Compact Size with Small Footprint
Can remove heat from hermetically sealed enclosures
Environmentally Friendly (No gases - CFCs)
Other pages that may be of interest to you include:
ElectraCOOL Thermoelectric Air Conditioner Main page
IP Ratings - (International Protection Code)
Click here for all NEMA enclsoure ratings and definitions
telephone (603) 888-2467
fax (603) 724-6740
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