a recent article from advanced thermal solutions, inc. (ats), a thermal engineering design and manufacturing company based in norwood, mass., explains the steps and calculations that are necessary for providing localized cooling using liquid cold plates.

the article outlines calculations for measuring pressure drop, thermal resistance, and heat transfer in cold plates. (advanced thermal solutions, inc.)

as the article noted, it is more efficient, particularly with high-powered components, that the liquid inside a cold plate is transferred to areas that need to be cooled. this requires several design considerations, including adjusting for a lower volumetric flow rate than if a cold plate was entirely filled.

“to analyze the problem, we first have to calculate how much flow is going through the cold plate, and evaluate the pressure drop of the flowing fluid,” the article explained.

the article continued with a series of pressure drop, thermal resistance, and heat transfer calculations for an intricate, drilled hole design.

“the drilled hole design shows effective convection heat transfer between 7,000 and 27,000 w/m²k for the range of flow between 0 and 7.56 l/m (2.6 gpm),” the article continued. “the press-fit tube design on the other hand shows a lower effective heat transfer coefficient of between 6,000 and 17,000 w/m²k.”

it added, “this is mostly due to the interfacial resistance and tube wall conduction. in the drilled design example, these two resistances do not exist. in a real application, the pumping of fluid is constrained by the pump and its characteristic curve.”

the calculations presented in the article could be applied to other designs seeking to more efficiently use liquid cold plates to provide localized cooling of electronics.

“the above analytics show that the performance of a cold plate for localized cooling can be calculated using a simple analytical tool,” the article concluded. “the designer then has to consider such factors as weight, manufacturing, cost and thermal performance to decide the best option for his or her design. the characteristic of the pump has a paramount effect on the design and cannot be neglected.”

read the full article at https://www.qats.com/cms/2018/01/16/how-to-achieve-localized-cooling-with-cold-plates.