Get Started with Boyd Genie

What is Boyd Genie?

Boyd Genie is a free thermal design software application available online. The Genie guides engineers through the thermal solution design process with helpful tips and real-time thermal performance estimates. With the Boyd Genie, it is easy to design and simulate your air cooled heat sink in under 15 minutes.

Once you input your requirements and design parameters, Boyd Genie calculates the most optimum heat sink designs to fit your needs. These design options can be ranked by size, mass, thermal performance, and pressure drop to help you choose the right fabrication and flow rate for your application. The heat sink design tool then walks you through additional customization options such as adding more fins, heat pipes, and flow rates. Lastly, you place your heat sources on the base of your heat sink. Boyd Genie allows for multiple heat sources of varying size and shapes as well as adding uniform heat loads.

After you run your thermal simulation, the Genie offers several next steps for making your heat sink a reality:

Register and use Boyd Genie for free!

Boyd Genie Thermal Design Project Checklist

To optimize your heat sink design and thermal performance and to save time within the Boyd Genie app, it is best to have as much information as possible before you begin designing. Below is a checklist of all the parameters and key considerations that you would need to develop and run thermal simulations for your custom heat sink.

It’s ok to start using Boyd Genie without all necessary information. Boyd Genie saves your progress through every step of the heat sink design process. If you need to pause a project, your inputs will be saved and ready for you when you come back. You may also go back and change inputs as needed up until you choose to run a thermal simulation.

Parameter Checklist

  • Available Volume (Working Envelope) for your heat sink (Length, Width, and Height).
    • Check the Boyd Genie working envelope resource for more information on how Boyd Genie defines this parameter.
  • Total Heat Load across all devices.
    • Learn more about how to calculate dissipated thermal power
  • Size and Placement of Devices on the Base of your Heat Sink.
  • Environmental Temperature and Altitude.
    • Read about some of the considerations you should make for the environmental conditions of your application.
  • Maximum Heat Sink Base Temperature or Heat Sink Thermal Resistance.
  • Maximum Allowable Pressure Drop or Flow Rate.
  • Consider if you will be using Natural or Forced Convection.
    • The Genie will give options to help you decide, but for more information check our post about natural vs forced convection.
    • You may also want to consider if your flow is ducted or has a bypass.
  • Consider if there are any heat sink fabrication types or materials that will not work for your application.

If at any point in the process you require thermal design assistance, Boyd Engineers are available to help. Share custom heat sink designs and questions with Boyd directly through the Boyd Genie App or on our Contact Us page.

Boyd Genie – Frequently Asked Questions

General Boyd Genie Questions

What is the Boyd Genie?

The Boyd Genie is a cloud-based system solver designed to simulate air cooled heat sinks. Input your requirements and parameters into Boyd Genie and it will guide you through designing a manufacturable heat sink with a thermal report. Simulations are free and do not require any licensing fees. There are no minimum or maximum uses, you can use the Boyd Genie one time or over one thousand times in a year.

Why should I use Boyd Genie?

Boyd Genie has a simple web-based interface that helps you build your heat sink, define your conditions, and conducts a thermal simulation within minutes. This free tool is a simplified interface that utilizes the Boyd SmartCFD core software that was designed with decades of empirical thermal management data and correlates significantly with actual performance.

Boyd Genie enables you to conduct fast and reasonably accurate simulations of your air cooled heat sink to help you in the initial discovery and feasibility phases of your project.

Thermal reports, 2D drawings, and 3D models come with each simulation and are available for download in the Next Steps portion of the Genie. You can also request a quote for either for prototypes or production parts directly from the application.

Learn more about How to Download Drawings and Models in Boyd Genie.

What do I need to know before I use Boyd Genie?

The Genie saves your progress as you go so you can pick up and put down a project any time, even if you need to check an input. Please view our Boyd Genie Get Started page for the complete list of inputs and related Boyd Genie articles to help you make the best use of this online tool.

How do I start using Boyd Genie?

You can register and start right away in the Boyd Genie App.

Boyd Genie has handy tips to help you along your project.

If you require more guidance view an in-depth Boyd Genie video tutorial.

Does Boyd Genie have any software requirements?

Boyd Genie works best on the latest versions of Google Chrome, Mozilla Firefox, macOS Safari, and Microsoft Edge. Boyd Genie is also compatible with Internet Explorer 11.

Genie Steps: Project Conditions

I have a range of environmental conditions, what should I tell Boyd Genie?

For conservative results, use the harshest potential conditions that are likely to affect your heat sink. Typically, this means the highest elevation and highest temperature that the devices or complete product will experience.

What does the Genie mean by “Working Envelope”?

This is the volume you have available for your heat sink. If you don’t have a fixed volume that you are working with, try using the largest preferred volume for your heat sink. Be sure to take into consideration any existing enclosures or ducts as those may dictate specific dimensions available to you.

How does Boyd Genie define depth?

In Boyd Genie, “depth” is the flow length of the fins. In other words, the depth is the direction perpendicular to the heat sink profile.

What does the Genie mean by “Total Load of Devices”?

Your device may be powered by 100 W but is only dissipating 20 W as heat. The 20 W is what the heat sink will need to dissipate, so that is what your input to Boyd Genie should be. Read more about how to determine Total Load of Devices and what values to use in Boyd Genie.

I have multiple devices, what should I input as the Total Heat Source Size?

In the project conditions page, Boyd Genie allows you to customize the size of your device. This is only to get an estimation of the power density and its effect on heat spreading in the base. You should select dimensions that will generate a footprint area equivalent to the sum of the footprint area all the devices will have on your base.

Learn more about determining Total Heat Source Size in Boyd Genie.

Why does Boyd Genie only apply Radiation to Natural Convection cases?

Boyd Genie will only apply the effects of radiation to heat sinks that have no forced flow or are removing heat by natural convection. This is because the effect of radiation is a noticeable portion of heat transfer during natural convection, but negligible in forced convection situations.

Should I use the Maximum Case Temperature or Thermal Resistance of my device?

It depends upon what value you have available to you, but they both will produce a maximum case temperature. If you have neither of these values, the Maximum Case Temperature may be the easier to calculate from the datasheet of your device.

Read about how to Calculate the Maximum Case Temperature of your device.

I only have the Maximum Junction Temperature of my device, how do I calculate the Maximum Case Temperature?

Learn more how to Calculate the Maximum Case Temperature of your device based on your device datasheet’s thermal section.

How do I know what my Maximum Pressure Drop is?

Consider what is producing your airflow. If you aren’t using a fan, you have minimal pressure drop available to you. If you are using a fan or blower, you will need to consider a fan curve (PQ Curve). If you have an air flow for a whole system, you will need to consider the other elements in your system in relation to the fan curve

Genie Steps: Technology Selection

How do I know what my Maximum Pressure Drop is?

Boyd Genie first tries to find a heat sink that meets your project conditions. If Genie cannot find a solution for that Technology/Flow combination, the box in the matrix will be colored red, with the condition that isn’t being met written in red text. Boyd Genie then reduces the amount of material of each Technology/Flow Combination, while still meeting the project conditions.

How do I pick a heat sink type/technology?

This is dependent on your requirements and preference. Within the application, you can have Genie evaluate the technology/flow combinations based on your key requirements such as weight or size. This allows you to choose the technology that best suits your needs.

How do I pick between natural or forced convection?

This is dependent on our application requirements and conditions. Applications that experience debris, require high reliability beyond what a fan would allow, or are extremely noise sensitive would be good candidates for natural convection. Additionally, smaller and lower power applications may not require forced convection.

Read more about the comparison between Natural Convection versus Forced Convection.

Genie Steps: Heat Sink Design

Where are heat pipes placed in the base?

If you have a single heat pipe and single device, Boyd Genie will center the heat pipe on the device.

To see how the Boyd Genie handles multiple heat pipes, see the Heat Pipe Placement in Boyd Genie Page.

Should I have my heat pipe perpendicular or parallel to the fins?

This depends upon the application, but generally the heat pipes should be perpendicular to the fins so the heat pipe can spread the heat more effectively throughout the fins.

What does “Fixed Heat Sink Height” mean?

This option allows you to alter the base thickness or fin height without changing the total set height of the heat sink. This is important when working within a fixed height enclosure or duct. For example: in many server applications, boards must fit within predefined heights, so if a board and its solution need to stay within a 1U envelope, the heat sink height cannot be increased past that height.

Genie Steps: Flow Definition

Do I need a flow bypass for my heat sink?

If you have a fixed duct and your heat sink is smaller than this duct size, then you will have a bypass. Bypasses decrease the amount of airflow through the fins and decreases both the thermal performance (i.e. higher thermal resistance) and the pressure drop.


Genie Steps: Heat Sources

What is a “Uniform Heat Load” and why would I add one to my heat sink?

A Uniform Heat Load in Boyd Genie allows you to account for additional smaller heat sources not worth individually modeling and defining in Genie, but collectively they contribute to the overall heat load. This will distribute the additional heat load uniformly across the heat sink base and offer a more accurate simulation of your heat sink’s thermal performance.

Do I need to include an interface resistance?

If you’re looking for quick answers and a general sense of how your heat sink will work, you can omit a thermal interface resistance. Otherwise you should include an interface resistance in your Boyd Genie Simulation. Unless there is something that prevents you from using any thermal interface material (TIM) in your application, you should always include TIM between your heat source and your heat sink.

Where am I placing my heat sources when I move them around on Boyd Genie?

The grey box represents the board or mountable area that the heat sink will cover.

Language Selection in Boyd Genie

Making Thermal Design Speak Your Language

While physics and math are constant between cultures globally, the language we use to discuss these concepts aren’t always the same. That’s why Boyd Genie has a few languages for users to select. The Genie is intended to make thermal management and design more accessible and enabling more languages was an obvious choice.

Change your language before you start simulating. Your thermal reports are generated in the language that is saved to your account when you simulate.


How do I change my language setting in Boyd Genie?

First: Log into Boyd Genie!

Next: Select the “User Options” icon in the upper right-hand corner of your screen.

“User Options” is the person icon up in the top right-hand corner

Now select the option “Edit Profile.” This will bring you to your account details.

Once you are on the page labeled “Edit Your Account,” you’ll see “Language” as your first drop down menu selection.

Click the drop down menu and select your preferred language. Your default language will be switched over to your new selection. You need to save these changes by going to the ”Update” button. Click the button to save your language selection.

Make sure you save your language before you simulate to make sure your thermal report will have these new language settings.


Heat Sink Drawings and 3D Models with Boyd Genie


How to Download Heat Sink Drawings and 3D Models in Boyd Genie

Boyd Genie can generate heat sink drawings and 3D models of the heat sink you simulated in a project. Drawings and 3D models are available for immediate download after simulation and come in .dxf and .stl files respectively. Solution Reports can be downloaded after simulation as well.

Downloading Boyd Genie Heat Sink Models Step by Step

After you have simulated your heat sink and reviewed your results, Boyd Genie presents you with several options for Next Steps in your project. One of those options is to Download Project/Solution Files.

These download options include:

  • Solution Report: A summary of your results and all your simulated conditions
  • Project File: The full heat sink design and parameters that you can use in the complete Boyd SmartCFD software
  • 3D Printable File: The 3D model of the heat sink you simulated
  • 2D CAD Drawing: A 2D drawing of the heat sink profile you simulated

By clicking either the 3D or 2D download options, you will be prompted to confirm the download of the files.


Boyd Genie Heat Sink Drawings

Boyd Genie heat sink drawings are simple but have enough detail for your in-house machinist to fabricate a prototype quickly for you to use in testing. Dimensions not depicted on the profile drawing are listed in the notes above the title block. These heat sink drawings come in .DXF format and can be opened by a variety of CAD packages. Keep the file for your records and feel free to add any notes you need or contact Boyd Engineering for more guidance.

Boyd Genie Heat Sink Models

Boyd Genie generates a simple 3D model that utilizes the heat sink profile and length that you used in your simulation. The Genie produces 3D models in a .STL format. Feel free to use it in your product assembly files to complete your product design.


Sharing Heat Sink Models and Re-simulation

Previously simulated heat sink design projects whose drawings retain their solution and files when shared with another Boyd Genie user.

Keep in mind that these files are unique for each simulation, so you will need to redownload the heat sink drawing and model downloads for every separate simulation. In other words, if you simulate the same project under 5 different sets of conditions, each simulation will have its own set of downloads.

Try downloading your heat sink models in Boyd Genie.

Environmental Conditions Range for Thermal Calculations


Consider Where and How your Product Will Be Used

When starting a new application, it’s critical that you determine the environmental conditions your end device will live in. Your environmental conditions will affect how easily your product might reach maximum case temperature. Or maybe your user is in contact with your device and you need to design a safe touch temperature.

In many cases, the application is clear on what temperature range your device may be subject to. It may only require straightforward lab conditions (23-25°C at sea level) to perform well. Other times the application may need to accommodate extreme or harsh environments, which will drastically influence the end user’s experience with your product.

Most of the time you, the thermal designer, don’t have the capacity to control what the end user will do. Think of how you treat your poor smartphone all day; you constantly use it throughout the day, so you are generating heat and draining the battery. You may store it in your pocket next to your own body heat and no airflow to help cool it down. While your end application may not have such high demands as a smartphone, the environmental conditions your device will experience are critical to the overall performance and longevity of your end product.

After you have taken a moment to consider what temperature and altitude you expect, you might find that you have a large range of conditions.

Thermal Range

Temperature Range might be somewhat difficult to define, since you may have an upper and lower limit. We’ve seen consumer applications that need to survive from high temperature environments around 100°C, outside in the hot desert at 41°C, and other applications that need to function at -40°C. Space applications have a much wider temperature range, depending on sun exposure.

Then the next key is to determine what temperature to use in your simulation or calculations. We recommend using the highest temperature in your range first. If the simulations determine your heat sink cannot perform well enough in this case, then the heat sink is inadequate for your application.



Altitude might not be on our radar for consideration when we’re determining the environmental conditions our products will experience. But altitude defines how much atmosphere is available for heat transfer. Less dense air at higher altitudes decreases the rate of heat dissipation through air cooling, so heat can build up faster but is typically exposed to colder temperatures.

Most consumer applications will be at or near sea level, but you may want to consider higher altitude conditions for cities such Mexico City or Denver, Colorado with significant populations. Many aerospace and defense devices need to withstand higher atmosphere conditions. Products meant for extreme hikers may be another time where altitude is an important parameter to consider.

Trying Out Your Environmental Conditions Range in Boyd Genie

For a better idea of how your heat sink will behave over the environmental temperature range, we recommend two other cases for initial consideration. One case should be at room temperature at sea level and another should be at your lowest temperature and highest altitude. Most users will probably be at the former condition and running this case will give you a good idea of what most of your end users should expect. Running the latter case can help give you an indicator of the other extreme your system will experience. You can test these cases out in the Boyd Genie heat sink design tool if you’re developing an air cooled heat sink. This tool allows you to estimate the performance of your heat sink in each case and compare against your maximum allowable device temperature. If your system meets your thermals at all of these cases, your solution should work well for the environmental conditions range.

Applying Thermal Interface Material in Boyd Genie


How Boyd Genie Handles Thermal Interface Material

Thermal Interface Materials come in many types, options, and thermal conductivities. Because of this, Boyd Genie simplifies the user input for thermal interface material (TIM) as interface resistance. Boyd Genie also allows you to define the TIM for each heat source. Since the Genie supports up to 10 individual heat sources, it means you have up to 10 different inputs for interface resistance. When a heat source is selected in the positioning diagram graphic user interface (GUI), the heat source should highlight in yellow. You should also see the geometric dimensions on the right above the heat source GUI update to the heat source you’ve selected.

On the side of the GUI, the heat source section for that selected source will also update with the dimensions and other specifications applied to this heat source. On the bottom of this section, Boyd Genie has an input to account for interface resistance from using a thermal interface material on that source. If you need help determining what TIM you need or what your interface resistance is, please contact Boyd Design Engineers.

Boyd Genie will apply the thermal interface resistance across the whole footprint of the selected heat source as defined by the Length and Width you input in this section. When using Boyd Genie, don’t forget about using thermal interface material as it is a critical portion of a thermal management solution. This small part of your thermal solution can have a big impact on your product’s overall performance. Try out TIM application in Boyd Genie or view more Boyd Genie resources to make the most of our online heat sink design tool.

Working Envelope and Heat Sink Design Volume


How to use Boyd Genie’s Working Envelope to input your Heat Sink Design Volume

In the “Project Conditions” page of Boyd Genie, there is a box that asks you the “Working Envelope.” This term refers to the heat sink design volume.

Consider this as the volume available for your heat sink in the application you’re simulating. Boyd Genie defines your working envelope in terms of where your air flow comes from.

Envelope Width

The width of the working envelope refers to the dimension perpendicular to your air flow that runs along the length of your heat sink base. You may want to consider any ducts or bypass flow you will need for your application in this dimension as well.

Envelope Height

The envelope height is the distance above your heat sources that is available for your heat sink design. Typically the height refers to the thickness of the base plus the height of your fins and any additional flow bypass you might include above the fin tips.

Envelope Length

Length in Boyd Genie refers to the flow length of the heat sink or the length that air will flow along the heat sink. Length also refers to how long the fins are on the heat sink.

Defining Heat Sink Design Volume

In retrofit applications, these dimensions may be already defined, as you may be trying to fit a new heat sink into an existing duct or enclosure. Those would be the dimensions you use for your Working Envelope. New applications have more flexibility in your available heat sink volume. For cases like these, use the volume that is your preferred volume. You can return and increase and decrease your volume size after checking what options the “Technology Selection” page calculates before you simulate your heat sink design.

Allow the Heat Sink to be Smaller

You have the option to ask Boyd Genie to recommend heat sinks that are smaller than your defined working envelope. Genie will first meet your thermal design constraints that you defined in the Project Conditions page. Then it will reduce the size of the heat sink until it cannot meet the thermal and flow parameters you set. You’ll see a red box in the Technology Matrix if Boyd Genie can’t meet your requirements. If the Genie can’t make a heat sink within the technology manufacturing limits, the box will be greyed out. Explore custom heat sink design volumes and working envelopes with Boyd Genie.

Boyd Genie Heat Source and Heat Sink Orientation


Heat Source Location

In Boyd Genie, you can add devices to your heat sink before simulating thermal performance. Boyd Genie has a graphical user interface (GUI) for heat source placement on your heat sink, but an important thing to consider is how your heat sink is oriented in relation to the GUI.

If you take a heat sink resting on your desk with the base resting on the surface, pick it up, make sure the fins are oriented vertically and press it to the screen where the GUI is, that’s how your heat sources and heat sink are placed in relation to each other.

Thermal Interface Material Placement

If you add thermal interface resistance to your heat sources, they will be placed in between the heat source GUI and your heat sink. For more information on thermal interface materials, what they do, and how to use them in Boyd Genie, see our Boyd Genie Thermal Interface Material post.

Air Flow Orientation

Standard forced convection applications have flow coming from the bottom of the screen going towards the top. If you chose fixed impinged air flow, that air flow would come from your direction (in front of the computer screen) straight down on top of the fins.

In natural convection simulations, vertically oriented heat sinks are oriented just like the hypothetical heat sink you’re holding up to the screen.


Heat Pipe Placement in Boyd Genie


Boyd Genie Heat Pipe Options

Boyd Genie gives the option of adding embedded heat pipes into the base of your heat sink. Genie takes your device layout into account when determining heat pipe placement. This method approximates what Boyd Engineers would do, which is to focus heat spreading at your heat sources.

Boyd Genie’s parent software, Boyd SmartCFD, can implement more complex swept heat pipe geometry which reflects how we can apply heat pipes in the real world. To keep Boyd Genie fast and simple, it can only insert straight heat pipes that extend from one end of the base to the other.

In case you’re looking for more uniform spreading, we can simulate a vapor chamber in Boyd Genie by applying a Uniform Heat Load. This way you can conduct a rough comparison to assess if your application requires heat pipes or vapor chambers.

Otherwise, there are 4 different ways Boyd Genie will place heat pipes in your base depending on the number of devices and number of heat pipes you include in the base.

Single Heat Pipe with a Single Heat Source

For single heat sources, heat pipe placement is straightforward. Genie will line up the center of the device and the center of the heat pipe in the direction you selected. You can select that heat pipe axis runs in the same direction as the fins along the flow length of the heat sink or perpendicular to the fins along the width of the heat sink.


Single Heat Pipe with Multiple Heat Sources

For single heat pipes and multiple devices, Boyd Genie will place that one heat pipe in between the two sources. If you have multiple devices that do not line up on the same heat pipe and both require some level of heat spreading, you should consider including multiple heat pipes in your base.


Multiple Heat Pipes and a Single Heat Source

Placements with multiple heat pipes and multiple heat sources are a little more complex, so Boyd Genie makes some assumptions. The Genie evenly distributes the number of heat pipes you’ve included in your design over the widest dimension you have placed heat loads.

For a single heat source, Genie tries to group multiple heat pipes all under the heat source. Boyd Genie limits how close it places each heat pipe, so if there are more pipes than can fit under the device, the heat pipes are grouped together around the center of the heat source. This means that if the Genie can’t place all the heat pipes over the heat source, it places them as group centered over the heat source.


Multiple Heat Pipes and Multiple Heat Sources

Again, Boyd Genie will evenly spread out multiple heat pipes across multiple heat sources. The farthest width occupied by heat sources is the width that Boyd Genie will spread the heat pipes across. If there is a gap between your devices, that gap is considered part of the width the pipes will be spread across. While this may not always yield a layout an Boyd Engineer would select, it does give you a better idea of how heat pipes can improve base spreading for your heat sink.

If you’re concerned the gap between devices is too large and you’re not getting heat pipes under your base, try increasing the number of heat pipes you include. In fabrication, heat pipes can take U-shaped geometries and act as two heat pipes. Also, the jump in cost between a couple embedded heat pipes and a few more is typically offset by added performance.


Heat Pipe Placement for Uniform Heat Sources

Adding a uniform heat source won’t affect your heat pipe layout. Since adding that load isn’t changing where your heat load is concentrated, altering the heat pipes won’t accomplish anything different. In general, uniform heat loads are what heat pipes are aiming to approximate anyways.

Try out embedded heat pipes in Boyd Genie.

Have questions? We’re ready to help!