- 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.
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.
- 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)
Cold Side Block
- Cold Side Copper Chiller Block Subassembly Drawing
- Cold Side Copper Cooling Blocks Drawing
- Cold Side Copper Baseplate Drawing
- Heatsink Subassembly Center Brass Reinforcement Bar Drawing
- Cold Side Aluminum Side Support Bar Drawing
- Cold Side Inlet Manifold Drawing
- Cold Side End Block Manifold Drawing
- Nylon 3/8″ Barb to 1/4″ NPT Drawing
- Epoxy Heatsink Hole Plug Drawing
Hot Side Assembly
- Peltier Chiller Thermal Insulation Bottom Plate Drawing
- Peltier Chiller Thermal Insulation Mid Plate Drawing