Introducing Psychrometrics CLI

Today, I’m releasing a command line application that is built on top of my swift-psychrometrics package, that I open sourced over 2 years ago.

The application consists of many calculations / conversions for psychrometric properties of an air stream. The tool works for both imperial and metric units. The application will work natively on macOS, but can also be ran through a docker container on other platforms.

Why

I spend a lot of time in my terminal, because I can work so much more efficiently. I discovered many years ago that the more I can do using simple applications and keyboard over a mouse and a web browser or native application the more I can accomplish. I understand this is intimidating for many who think they are “not good with computers”. I can assure that was me several years ago, I would only encourage you to not be afraid and give it a shot. We are at a time in society where it is easier than ever to get informed and learned new skills.

Installation

For complete installation instructions, you can view the github repository.

The following instructions are based on using macOS.

Open your terminal application.

Personally, I use iTerm2 , however you can use the default Terminal app. Found at /Applications/Utilities/Terminal.app.

Install Homebrew

We use Homebrew for package distribution of the pre-built application binaries. You can follow their instructions to install.

Tap our custom formula tap.

brew tap swift-psychrometrics/formula

Install the psychrometrics application

brew install psychrometrics

That’s it!

Usage

I will run through a couple of the commands that are supplied with the application and show what you can expect the outputs to be.

Properties

The following command will output a bunch of the psychrometric properties of an air stream. There are several ways to call it, but generally you will supply the dry bulb temperature and the relative humidity.

Below, we calculate the psychrometric properties based on 75°F and 50% humidity.

psychrometrics --dry-bulb 75 --relative-humidity 50

Dehumidifier Sizing

If you’ve read some of my recent articles on calculating the dehumidifier size required based on the latent load , the application also ships with a calculation that will do this for you and has the ability to calculate it at different coverages that you can supply.

For example if we’ve done a load calculation and determined that we have a latent load of 4,334 BTU/h then we could run the following command to see what size dehumidifier is needed for 100%, 85%, and 70% of the latent load.

psychrometrics dh size --coverage 100 85 70 --verbose 4334

Pounds of Water Removed

I also recently wrote an article about calculating the pounds of water removed from an air stream given the grains of moisture removed.

Below is an example of calculating the pounds of water removed per hour based on the example in the article (14 delta-grains)

psychrometrics dh pounds-removed --delta 14 --cfm 797 --verbose

Help

You can use --help option to show help and the list of commands provided.

If you have any questions then feel free to email or message me. I hope some of you may find this application useful.