Evaporative Cooling

Why you need this guide

• Address soaring cooling demands sustainably: As climate change drives up cooling needs, standard refrigerant-based air conditioning is becoming an unsustainable burden on the power grid. Evaporative cooling uses up to 75% less energy.

• Eliminate hazardous refrigerants: Move away from chemical refrigerants with high Global Warming Potential (GWP) and ozone-depleting risks by utilizing nature's ultimate refrigerant: water.

• Navigate complex water management: While highly energy-efficient, these systems consume water. This guide teaches you how to optimize water use, implement proper purging strategies, and prevent scale buildup.

• Mitigate severe health risks: Improperly designed or maintained evaporative coolers can become breeding grounds for bacteria. This guide provides strict, actionable protocols for Legionella prevention and overall bio-growth control.

What’s inside the guidebook

As a brand-new addition to the REHVA Guidebook series in 2026, this manual covers the absolute state-of-the-art in adiabatic cooling technology, including:

• Advanced Hybrid Configurations: Detailed breakdowns of multi-stage Indirect/Direct Evaporative Cooling (IEC/DEC) systems that push performance boundaries even in humid climates.

• Latest Global Standards: Full integration of the newest 2024 and 2025 rating and testing standards from Eurovent, ANSI/ASHRAE, and EN ISO 16798-1.

• Modern Control Strategies: Deep insights into variable frequency drives (VFDs), enthalpy-based control logic, and automated water management for maximum efficiency.

• Detailed Performance Simulations: Real-world data comparing the energy, water, and comfort outputs of evaporative systems versus traditional DX refrigeration across various climate zones.

What you will gain

Whether you are designing for a residential building, a large industrial facility, or a sensitive data center, this guidebook equips you with:

• A practical, step-by-step sizing procedure for Direct (DEC) and Indirect (IEC) evaporative systems based on peak sensible cooling loads and psychrometric charting.

• Clear criteria for selecting wetted media (fiber, rigid, packaged) versus water spray and ultrasonic atomization systems.

• Comprehensive guidelines on supply air distribution, including duct sizing, seasonal dampers, and preventing winter heat loss.

• The ability to conduct accurate Life Cycle Cost Analyses (LCCA) and Environmental Life Cycle Assessments (E-LCA) to prove the financial and environmental viability of your designs to clients.

• A complete framework for system commissioning, periodic maintenance, and winter shutdown to ensure decades of reliable operation.

A trusted REHVA publication

Developed by leading international experts and based on the latest research, REHVA Guidebook 35 delivers reliable, industry-aligned guidance.