# COMSOL Blog

## App: Studying a Concentric Tube Heat Exchanger’s Dimensions

##### Bridget Cunningham | June 10, 2015

By design, heat exchangers transfer heat from one source to another. When analyzing the efficiency of this heat transfer, it is important to consider the impact of the system’s dimensions. Simulation offers a simplified approach to testing the performance of various designs. With simulation apps, you can now bring this power into the hands of those who are not simulation experts. Let’s get started by exploring the Concentric Tube Heat Exchanger Dimensioning Tool demo app.

### Optimizing Heat Sink Designs with a Simulation App

##### Caty Fairclough | June 4, 2015

Heat sinks are components designed to cool off devices by dissipating heat. They can be used passively or in active cooling systems combined with fans for example. When optimizing heat sink designs, you can turn to simulation for guidance. But what if you could simplify the design process by embedding your model in an app? You can — and the Heat Sink with Fins demo app is here to get you started.

### How Can I Build an Efficient Stirling Heat Pump?

##### Phillip Oberdorfer | April 9, 2015

Stirling engines, or heat pumps, are systems that are able to work on incredibly low temperature differences. In fact, some types of Stirling engines only need human body heat in order to operate. Here, we explore the dynamics of this interesting machine that you can build at home and demonstrate how to model it using COMSOL Multiphysics.

### Using the Boussinesq Approximation for Natural Convection

##### Fabrice Schlegel | April 7, 2015

Today, we compare the Boussinesq approximation to the full Navier-Stokes equations for a natural convection problem. We also show you how to implement the Boussinesq approximation in COMSOL Multiphysics software and discuss potential benefits of doing so.

### Implementing a Thermostat with the Events Interface

##### Walter Frei | February 19, 2015

A thermostat is a device that senses the temperature of a system and uses this information to control the system’s heaters, or coolers, to keep the temperature close to a desired setpoint. While there are many different types of thermostats, we will focus today on one that turns a heater either on or off based upon two setpoints. This is known as an on-off or a bang-bang controller, and it can be implemented with the Events interface in COMSOL Multiphysics.

### Computing View Factors with the Heat Transfer Module

##### Nicolas Huc | January 2, 2015

In the past, I’ve received regular requests for the ability to check the view factors used by COMSOL Multiphysics. How accurate are they? What is the impact of a given parameter (mesh size, radiation resolution, etc.) on their accuracy? Good news: Version 5.0 provides new operators for postprocessing that correspond to the operators used to generate surface-to-surface equations. Allow me to demonstrate how to compute geometrical view factors.

### Intro to Modeling Evaporative Cooling

##### Nancy Bannach | December 8, 2014

When you think of evaporation, you probably think of the cup on your desk that spreads the aroma of coffee or tea. But evaporation is also a process with many industrial and scientific applications, ranging from meteorology to food processing. This blog entry is the beginning of a new blog series on modeling evaporative cooling. Here, we introduce the basic concepts using your coffee cup as an example.

### Rosetta and Philae: A Historic Landing on a Comet

##### Nikola Strah | November 12, 2014

How the sun, solar system, and planet Earth formed and how life began are fundamental science questions that still remain unanswered. Today, we may be one step closer to answering these questions, because the spacecraft Philae, which is aboard the Rosetta, is in the process of landing on a comet for the first time ever. I was able to interview two of the scientists involved in this project to gain insight into how Rosetta’s mission may answer these very questions.

### Designing Electric Vehicles with Magnetic Cooling Technology

##### Bridget Cunningham | October 21, 2014

In a previous blog post, we focused on the growing use of magnetic cooling technology as a safer, more eco-friendly method of refrigeration. Here, we look at how one team of researchers analyzed the potential use of this technology in the design of electric vehicles.

### Green Energy Management for Communication Systems

##### Alexandra Foley | October 17, 2014

The communication network wasn’t designed to carry the amount of traffic that is currently transmitted around the world on a daily basis. With the rapid expansion in data traffic and the exponential growth in high-speed communications, the current network is coming under increasing strain. At Bell Labs, researchers are looking into ways to improve energy efficiency through the use of optimized electronics cooling and energy harvesting technology. Two new energy-savings approaches developed by the group promise significant savings.

### Accounting for Heat in the Design of Lithium-Ion Batteries

##### Bridget Cunningham | October 9, 2014

In the performance of lithium-ion batteries, thermal management is an important element to consider. Through modeling and simulation, you can improve the design process by analyzing how heat is transferred within the energy source.