UPDATE LOG
- 07/26/2018 – Peltier chiller module completed.
- 08/04/2018 – Build details officially completed and released.
- 08/20/2018 – Peltier chiller module officially tested with verified operation in cooling system. Successfully chilled 1.25 gallons of distilled water to 13C in 40 minutes against ambient.
- 08/21/2018 – Peltier chiller module confirmed to chill 1.25 gallons of distilled water to 11C in 40 minutes against ambient.
- 02/09/2019 – Leak found in the peltier chiller module – patched and reinforced with additional JB Weld encapsulation and aluminum sheet reinforcement.
- 09/02/2019 – Peltier chiller module is currently no longer functional and is now obsolete. A new cooling solution is being designed to replace the thermoelectric-based cooling system.
INTRODUCTION
As part of the Closed Loop Peltier Chilled Diffusion Pump Cooling System, the peltier chiller module plays an integral role in reducing the temperature of the coolant required for optimal operation of both the diffusion pump and the water cooled baffle. Based on the technical specifications for the baffle and the pump, ideal temperature levels are stated for optimal performance. Preliminary thermal simulations were also performed on both the diffusion pump and water cooled baffle to determine thermal characteristics of the system and to establish predictions for how the system will behave with cooling.
In order to simplify construction and reduce costs, utilizing common materials, a novel method of creating the cold side block of the module was implemented. By utilizing standard solid copper heatsinks, and creating custom manifold blocks at either end, water flow can be directed and forced between the heatsink fins in a type of “dry-cell” topology. By epoxying the entire assembly together, fabrication is greatly simplified, cost is decreased, and water-tightness is assured when proper techniques are applied. Careful epoxying of the heatsinks, the baseplate, and the manifolds also ensure that water is forced to flow in a zig-zag pattern through the structure to maximize transit time of the coolant through the cold side block to ensure high cooling transfer from the peltier modules. This technique can be very readily adapted to a number of different sized peltier modules based on low cost off-the-shelf components, allowing for a very modular and robust system with large thermal mass and cooling surface area.
In order to maintain a large thermal gradient between the hot and cold sides, the hot sides must be actively cooled. For this system setup, water cooling is the primary method of heat extraction for the hot side. A set of four parallel solid aluminum water blocks, with two peltiers per block, are implemented. The entire module is bolted together between two mdf boards, with XPS thermal insulation foam on the cold side to increase cooling efficiency. MDF was used for the initial bottom and top plate materials due to cost constraints for the initial prototype. However, plastic sheets of the same dimensions and layout would provide a better material selection as a future upgrade to the system. The entire stacked topology allows for ease of manufacturing as well as reduced cost. The basic concept can be used for similar variations of the design, and can be easily modified according to cost constraints, material availability, and performance requirements.
TECHNICAL SPECIFICATIONS
- Type of Cooling: Peltier Thermoelectric
- Number of Peltier Modules: 8
- Peltier Modules: TEC1-12708
- Number of Coolant Passes: 12
- Cold Side Power Requirements (Hot Side @ 25C, Delta T @ 10C, Voltage @ 12VDC): 72W
- Cold Side Cooling Capacity (Hot Side @ 25C, Delta T @ 10C Voltage @ 12VDC): 400W
- Temperature Range During Operation: 0C-25C
- Cold Side Block: Epoxy-Bonded Custom Solid Copper Heatsink-Based “Dry-Cell” with Nylon Manifolds
- Cold Side Inlet: 3/8″ Nylon Barbed Hose Adapter
- Cold Side Outlet: 3/8″ Nylon Barbed Hose Adapter
- Cold Side Manifold Blocks: 1″x1″ Custom Nylon Manifolds
- Hot Side Cooling: Parallel Solid Aluminum Water Block Heat Exchangers
- Number of Hot Side Cooling Blocks: 4
- Number of Peltier Modules per Hot Side Cooling Block: 2
- Thermal Grease: Arctic Silver 5
- Thermal Insulation: 1″ XPS Thermal Insulation Foam
- Epoxy: JB Weld
CAD FILES (.STEP FORMAT)
DATASHEETS
COST ANALYSIS
RELATED SYSTEM LINKS
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Peltier Chiller Module Build Pictures
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Lost Cost Thermocouple Rebuild and Upgrade
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Low Cost Thermocouple Rebuild and Upgrade Build Pictures
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Closed Loop Peltier Chilled Diffusion Pump Cooling System
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Closed Loop Peltier Chilled Diffusion Pump Cooling System Build Pictures
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Steady-State Thermal Analysis of the Edwards EO4 Diffusion Pump
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Steady-State Thermal Analysis of an Optically Dense Water Cooled Baffle