TEC High Efficiency Thermo Electeric Cooler
Thermoelectric systems are solid-state devices that directly convert electrical energy into temperature differential without the use of gases, compressors or any other moving parts.
A standard thermoelectric system consists of:
- Cold side and hot side heat sink assemblies with or without fans
- Thermoelectric (Peltier) cooling modules
- Temperature controller
- Power supply
The only moving parts are fans, which make thermoelectric systems more compact, reliable and quiet relative to conventional compressor based cooling systems.
A basic element of the thermoelectric system is the Thermoelectric Module (TEM), which actually operates as a heat pump.
The TEM is a solid-state semiconductor device made of two thin ceramic plates with a large quantity of semiconductor elements sandwiched between the plates.
Two types of semiconductors, P and N types, are used in the module. They are connected electrically in series and thermally in parallel in such a way that all cold junctions are placed on one plate and all hot junctions on the opposite plate. Electrical current passing through the junctions absorbs heat energy on the cold junctions, which is then dissipated on the hot junctions.
To ensure the TEM’s cooling performance, the heat energy should be efficiently dissipated from the hot plate to the surrounding atmosphere.
Heat Pipe & Vapor Chamber Technology
The Need
Trends towards higher speed, higher power consumption and denser packaging of electronic components, have generated a need for effective Thermal Management solutions. The reliable performance of the component and long life are directly related to effectively controlling its junction temperature within specific limits.
In special applications, due to enclosure miniaturization, there is a need for an effective cooling solution that removes high heat flux by a very small heat exchange element. Due to the height limitation, even the most efficient air cooled heat sinks, not to mention liquid coolers, are insufficient. The only way to solve such a problem is to transport the heat from the component to an outer area, where cooling fins can be located. In some cases, in order to dissipate the heat produced by a component, it is necessary to spread it uniformly throughout the heat sink’s base plate.
The Solution – Heat Pipes or Vapor Chambers
The best solution for isothermal heat transfer is to utilize a Heat Pipe or a vapor chamber. Heat Pipes & vapor chambers have an inherent thermal conductivity which, if properly designed, can reach more than 1000 times that of copper the same size. A Heat Pipe or vapor chamber consists of a vacuumed sealed metal container (usually copper or aluminum), whose inner surfaces are made of a capillary wicking material. Inside the container is a small quantity of liquid, usually water, under its own pressure, that enters the pores of the capillary material, wetting internal surfaces. Applying heat at any point along the surface causes the liquid to boil and enter a vapor state. When that happens, the liquid picks up the latent heat of vaporization. The gas, having a higher pressure, moves inside the sealed container to a colder location where it condenses. Thus, the gas gives up the latent heat of vaporization and moves heat from the input to the output end of the Heat Pipe or the vapor chamber. Due to high efficient heat transfer by phase transformation, heat fluxes inside a Heat Pipe & vapor chambers are considerable and temperature gradients are very small.
In themselves, Heat Pipes or vapor chambers do not function as heat sinks or cold plates. They can be part of a complete cooling solution, designed to move the heat efficiently from the heat-generating device to another location where an air or liquid stream can take the heat away. Heat Pipes & vapor chambers can be designed and manufactured in various shapes and sizes to fit the customer’s specific needs and requirements.
Heat Pipes & vapor chambers Advantages
Ability to relocate the heat sink away from the device that needs to be cooled.
Reduced volume and weight.
Reliability – Long product life (more than 10 years), no moving parts.
Ability to operate in any environmental conditions, including the absence of gravitation.
Uses no outside power for heat transfer
Double Check’s Capabilities
Double Check’s expert engineers provide you with a complete Heat Pipe or vapor chamber based cooling system, designed to fit your exact requirements. A typical design process includes the following stages: Analysis of the actual thermal problem – in order to define the required solution. The data gathered in this phase enables our engineers to estimate the parameters of the suitable Heat Pipe or the vapor chamber (such as working liquid, case material, tube diameter, porous capillary structure and case wall thickness). In order to define the cooling fins’ structure, we need the following data: number, dimensions and power dissipation of each component to be cooled, maximum allowable component’s case temperature, maximum ambient air temperature, and air convection conditions. Based on this information, Double Check can obtain the characteristics of the suitable fins’ parameters.
Complete Custom-Made Solutions
Continuous innovations in the Power Electronic Packaging industry demand equally continuous improvements in Thermal Management. The design time cycles are decreasing in view of the competitive marketplace. Moreover, modern thermal demands may require the combination of one or more cooling technologies. Double Check has it all! Its strong multi-disciplinary engineering skills enable Double Check to offer complete, reliable, cost-effective and highly efficient solutions for various applications. Double Check specializes in design and production of a range of Thermal Management products, among which are: Heat Sinks, Cold Plates, Thermoelectric Systems Heat Pipes and vapor chambers. Double Check is prepared to apply any Thermal Management discipline to meet your requirements.
Liquid Cooling Plates
Cool Technology Solutions: Cold plates for Microprocessors, Power Electronics (Diode Modules, IGBT), Thermoelectric Modules, and Laser
Our specialty is development and implementation of various Submerged Jets Cooling Technologies including our own main technology: Swirling Jet-Steams™. Unique cold plates, heat exchangers, and heat sinks that utilize these break-thru patent-pending technologies allow pushing your electronic equipment beyond any conventional performance limits and reliability boundaries.
Download performance specifications
Performance Specifications
Challenges of heat dissipation in power electronics, microprocessors and lasers pose serious hurdles in the ongoing efforts to improve performance. Changes in component specifications and complexity have required transitions in cooling methods: from air to liquid, then liquid to multi-phase, and then back to air.
During the last decade, along with usual and anticipated rise in the dissipated heat, a new challenge has arisen: high heat density. Today this is the most serious challenge and the biggest obstacle in the development of new electronic devices.
Fig. 1a and 1 b present comparative analysis of changes in overall dissipated heat and its density using Intel XEON µP-Family processor as an example.
As one can see, maximum dissipated heat remains practically constant within the 90 to120 W range . Moreover, at some point during the transition to multi-core processors, one can see a slight decrease. Heat density, on the other hand rises continuously.
Anticipated increase of number of cores in processors will only cause this trend to continue, if not accelerate. Developments in power electronics exhibit the same trend: miniaturization of active elements of diodes and IGBT’s causes an increase in heat density.
Cool Technology Solutions, Inc. has developed Swirling Streams nozzle designs which do not require additional mechanical devices, and has perfected utilization of such streams within liquid heat exchangers.
Swirling of liquid streams is more complicated and less studied phenomenon. Swirling Jet Stream Technology is not a classical method based on swirling of jets streams with intermixing and turbulization of liquid streams with the help of injected gas. This technology is based on quasi-swirling, and utilizes rectangular or oval nozzles and uneven profile gaps to create dynamic jet streams (Fig. 3)
Fig.3 Hydrodynamic jet-streams flow
These figures show forming of turbulized flow within 1 to 5 nozzle calibers, It is seen clearly that jet are swirled at the significant distance from the nozzle (located to the left) and are not jet separation effects;; instead they prove that turbulization inside the heat exchanger indeed takes place.
Capabilities to localize heat exchange are determined by ejection effects created by secondary nozzles aimed onto areas with maximum heat fluxes. This allows the creation of zones of high turbulization and destruction of the wall boundary layer. Stream formation is highly dependent on the shape and geometry of the nozzle, therefore formation zone can vary significantly, from 2.5 to 8 nozzle’s calibers.
Interaction of cold plate microstructure with laminar rectangular flow creates local swirling streams along heat transfer surface; this phenomenon is especially effective for handling of local hot spots, since such micro turbulizations not only allow to significantly increase average heat exchange across the whole surface, but prevent local overheating as well. Ability to effectively control such local overheatings is the main task of localized heat dissipation.
Such artificial turbulization at Reynolds numbers up to 350 allows to drastically increase the efficiency of cold plates and heat exchangers.
Fig. 4 and 5 present comparison of various methods utilized in design of modern of cold plates.
Fig. 4 Thermal Performances (based on Thermal resistance)
Fig. 5 Hydraulic Performance (based on pressure drop)
The most promising benefit of the implementation of this method is hot spot management. Drastic improvement of the temperature splash in the hot spots, results in significant increase in overall system reliability. Fig. 6 shows comparison of aforementioned methods taking into consideration not just the average overall thermal resistivity, but local resistivity in the hottest spots. Swirling Jets-Stream is very effective way of dealing with local hot spots.
Clearly local heat dissipation at the source, i.e. within the 3D structure of the chip is most preferred. However, so far such methods are in a preliminary research stage, and not likely to be available in production for some years.
It is important to mention that thermal resistance is always defined relatively to average overheating of the whole heat dissipation surface. When hot spots are present such a parameter is not always the best in determining heat exchange characteristics.. Therefore it is important to determine thermal resistance for spots with a maximum T junction for heat dissipation. Thermal resistance calculated for Tj for areas with maximum hot spots will really characterize and define the most capable method of localized heat dissipation. Comparison of various methods of preventing local overheating is presented in Fig. 6
Technology’s Ability to dissipate heat from a local hot spot
Fig.. 6 Max Thermal Performance for Max Heat Flux based on Local Thermal Resistance
Fig. 7 and 8 present temperature distribution fields at the power board carrying 6 IGBT’s 50 W each using standard pin-fin structure cold plate and plate utilizing Swirling Jet Streams. Comparison shows that even at the modest liquid flow of 1.8 GpM gain is very significant.
Pictures below exhibit efficiency of an approach. Thermal distribution modeling for IGBT modules uncovers decrease of almost 30% in hot spots temperature influx compared with best market cold plates with micro channels.
Pic.7 Temperature field simulation with micro channel Structure for cooling IGBT module
Results: •Max. Temp of IGBT = +105°C ∆T = +20°C Rth=0.4
Pic.8 Temperature field simulation Swirling Jet-Streams Structure for cooling the same IGBT module Results: •Max. Temp of IGBT = +99°C ∆T = +14°C Rth= 0.28
Fig. 7 and 8 show that maximum temperature Tj onto IGBT is 105ºС and at coolant’s temperature of 85ºС is 20ºC higher coolant’s temperature at the dissipated power of 50 W. Utilization of Swirling Jets Technology allows to keep maximum temperature Tj onto IGBT at only 97ºC, bringing temperature differential between IGBT and coolant to 14ºС or almost 35% better.
Here are some different examples of the cold plates for microprocessors and power electronics.
Fig. 9 a) Cold plate CTS-V-series for cooling microprocessors
b) Cold Plate CTS – W- series for cooling IGBT modules
Conclusions:
1) The main tendency in the market of microprocessors and power electronics – increase in the density of heat flows.
2) Increase in the density of heat flows requires new cooling methods, capable not only of managing significant amounts of heat integrally but at the same time be effective in handling local hot spots on the surface of these elements.
3) One of the most promising methods is development of cooling devices with artificial turbulization of flow with small hydraulic resistance and losses
4) Described here method of artificial turbulization Swirling Jet-Streams, developed and offered by the company Cool Technology Solutions, Inc. offers optimistic hope to be capable of handling effectively not just integral heat dissipation, but also local heat dissipation from the local hot spots of electronic components and devices.
TEG Thermo Electric Generator
Thermoelectric cooling
Thermoelectric Cooling Heating Plate for Thermal Testing
Specification Rev 02
- General description
Thermoelectric Cooling/Heating Plate is designed for thermal testing of the electronic components and assembles at wide temperature range from -45 C to 115 C and consists of the following main components:
- Bench top unit with cold/hot plate and control panel with temperature display allowing set of controlled temperature
- Liquid chiller with power supply/control box
- Flexible hose connecting between chiller and bench top unit
Mechanical performance
- Overall dimensions of the bench top unit: 360 x 375 x 80 mm
- Overall dimensions of the chiller: 325 (W) x 550 (D) x 700 (H) mm (including power supply/control box)
- Hose dimensions: diameter- 60 mm, length – 2 m (optionally 3m)
- Cold/hot plate dimensions: 200 x 250 mm
- Electrical performance
- Input voltage: 230 VAC, 50 Hz
- Input current: 7A
- Thermal performance
- Cold/hot plate temperature range: -45 C … 115 C
- Maximum heat dissipation of the component
to be tested: 40 Watts - Cooling time from 25 C to -45 C : 20 min
(at chiller’s liquid temperature range: -10 C … -15 C without components power dissipations) - Heating time from 25 C to 115 C: 20 min
(at chiller’s liquid temperature range: -10 C … -15 C without components power dissipations)
- Communication
- Communication with PC: RS485
- Connector type: USB
- Length of the communication cable: 2 m
Heat Sink
The right choice of fins type and material of heat sink is the most effective way to build right solution for passive cooling
There are different types of fins having different thermal, pressure, mechanical characteristics and cost: extrusion, bonded fins, folded fins, stacked and skived fins. Each type has its advantages and limitations.
Thermal technologies are continuously improving and we always take care to be at the forefront of technology. In many cases we combine heat sinks with heat pipe or vapor chamber to reach optimal performances.
We at Double Check design heat sinks exactly meeting your thermal and economical requirements. We do this after collecting all the required thermal and engineering data, using thermal calculations and simulations to maximize performance. We provide customize solution for you, manufacture, prototypes and supply production quantities on a regular basis.
As part of our service, we offer to our customers optimization of the heat sinks that they are currently used in their products. Performance Improvement will upgrade your product and give you an edge in the market over competitors and even open up additional markets.
We will be happy if you will contact us to get a quote for heat sink either that you currently use in order to reduce cost and improve performances or thermal solution for your new product.
We at Double Check specialize in the development and design of thermal management systems, serving many customers worldwide from various industries.
Our experienced, innovative and interdisciplinary team own strong, thermal, thermoelectric, manufacturing skills dedicated to providing you with the services that suite your application and requirements.
Our services include the use of:
- State-of-the-Art Thermal Analysis
- Heat Pipes and Vapor Chamber Design
- Phase Change Materials (PCM) and PCM based Heat Exchangers
- Thermoelectric System Design and Development
- Heat Sink Design and Development
- Testing and Evaluation of Thermal Management Systems
- Arrangement of Research Projects for Cooling of Electronics
- Telecommunications indoor/outdoor applications.
- Large to Small Enclosure Cooling Using: Air Conditioning, Heat Exchangers, Phase Change Materials
- and/or fully passive systems Liaison with CFD and Heat Sink Manufacturers