The 2021 ASHRAE Handbook—Fundamentalscovers basic principles and data used inthe HVAC&R industry. Its more than 1,000 pages cover basic principles suchas thermodynamics, psychrometrics, and heat transfer, and provide practicalguidance on building envelope, indoor environmental quality, load calculations,duct and piping system design, refrigerants, energy resources, sustainability,a new chapter on climate change, and more. Climate data for over 9000 weatherstations worldwide are provided as a separate download (approximately 700 MBzip file).