Engineering Calculator Platform

PMV/PPD, moist-air, and refrigerant Mollier-diagram tools deployed as a secure AWS serverless web application.

This repository is intended to grow into a collection of engineering calculation tools with a shared web interface and AWS platform.

Architecture

• CloudFront is the public HTTPS endpoint and adds security headers.
• A private, versioned S3 bucket stores the static web application.
• CloudFront routes /api/* to an API Gateway HTTP API.
• Separate Python Lambda functions calculate PMV/PPD and moist-air properties.
• API requests are throttled and validated server-side.
• The moist-air page renders an h-x psychrometric chart as browser-native SVG.
• The Mollier page runs the official CoolProp 8.0.0 WebAssembly build locally in the browser and renders a refrigerant p-h diagram.

The stack deploys independently, so existing calculators can remain available during acceptance testing and migration.

Source layout

• template-deploy.yaml — canonical AWS SAM/CloudFormation template
• functions/pmv/app.py — ISO 7730 Fanger PMV/PPD calculation
• functions/air/app.py and app_release.py — psychrometric calculations and release handler
• web-release/ — canonical static site
• tests_verified/ — regression and validation tests
• scripts/deploy-production.ps1 — AWS CLI packaging and deployment

Validation

python -m pip install -r requirements-dev.txt
python -m pytest -c pytest-verified.ini

The PMV tests include representative values captured from the legacy API. The moist-air tests cover standard conditions, reverse calculation, and invalid-input responses.

The browser chart ports the equations and oblique-coordinate transform from iguchi-lab/psychrometric-chart.

The Mollier tool adapts iguchi-lab/mollier-diagram and vendors the official MIT-licensed CoolProp 8.0.0 JavaScript/WASM binaries. The pinned vendor files and license are stored under web-release/mollier/vendor/coolprop-8.0.0/.

Deployment

Prerequisites:

• Authenticated AWS CLI
• An existing private S3 artifact bucket for Lambda deployment packages

./scripts/deploy-production.ps1 `
  -StackName engineering-calculators `
  -Region ap-northeast-1 `
  -ArtifactBucket your-private-artifact-bucket

The script validates and packages the template, deploys the stack, uploads web-release/, invalidates CloudFront, and prints the HTTPS URL.

Deploy to a parallel stack first and complete acceptance testing before removing legacy resources.