Design And Numerical Simulation of One-Phase Liquid Immersion Cooling System For Small-Scale Cryptocurrency Mining Rigs
Restricted (Penn State Only)
- Author:
- Almutairi, Faris
- Graduate Program:
- Mechanical Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- March 14, 2023
- Committee Members:
- Ahm E Rahman, Thesis Advisor/Co-Advisor
Issam Abu-Mahfouz, Committee Member
Rick Ciocci, Professor in Charge/Director of Graduate Studies
Brian Allen Maicke, Committee Member - Keywords:
- Immersion Cooling
Dielectric Liquid
Cryptocurrency mining
Thermal management
CFD
Computational fluid dynamics
heat transfer
ASIC
ASIC miner - Abstract:
- As the world is rapidly transitioning into a digital era, blockchain technology has high potential deployments in many organizations’ digital transformation plans. Blockchain technology, which is the main driver of cryptocurrency as many other digital technologies, requires sophisticated computing hardware to run it, mainly Application specific Integrated Circuit (ASIC). One of the challenges that faces cryptocurrency miners, who are an integral pillar of the network, is efficiency of their hardware. Efficiency is crucial to miners since it dictates how fast and cost-effective they can run their rigs to generate reasonable profit. With high computing scenarios (or what is known as hash rates in the cryptocurrency community) the hardware capability, despite the existence of air-cooling fans, could be limited due to high temperatures. Computing hardware in a datacenter, cryptocurrency mining rig or even in a gaming console produces a tremendous amount of heat that is essentially cooled by forced air through fans. The excessive heat in the ASIC especially in a high hash rate scenario can affect performance and potentially develop micro cracks in the hash boards and lead to failure and disruptive service. Air cooling by fans is energy consuming, noisy and requires air conditioning to remove heat from the ambient. Moreover, air is considered a good insulator and poor thermal conductor. Alternatively, recent developments in dielectric fluids that have superior thermal characteristics over air show a promising future for cooling computing hardware more efficiently. In this thesis, the thermal performance of a dielectric liquid named Bitcool-888 is explored via numerical simulation to study its effectiveness in cooling ASIC miners. This method is known as one-phase liquid immersion cooling. The ASIC miner is one of four immersed in the dielectric fluid that is being circulated in a system of tank, piping, pumps and a heat exchanger. The objective of the simulation is to find the optimum flow rate and inlet temperature that ensures adequate cooling of the ASIC miners at their peak computing power and to compare the performance of air and dielectric liquid. 32 simulations were conducted via ANSYS Icepak to study the dielectric liquid cooling capability for various power densities (1000 W and 1250 W per hash board), inlet temperatures (30 °C, 35 °C, 40 °C and 45 °C) and inlet flow rates (4 lpm, 10 lpm, 15 lpm and 20 lpm). Air performance was examined for one power density (1000 W per hash board), various inlet velocities (2 m/s, 3 m/s, 4 m/s and 5 m/s) and at 30 °C and 35 °C inlet temperatures. The results show that the dielectric liquid is better than air in cooling the ASIC miner, even at high power density, low flow rates and high inlet temperatures. The maximum hash board temperatures particularly were lower in the dielectric liquid case. Air showed higher maximum hash board temperatures in both 30 °C and 35 °C inlet temperatures cases with low to medium velocities.