Introduction to Air-to-Water Heat Pump Systems

This document provides comprehensive insights into air-to-water heat pump (AWHP) hydronic systems, focusing on their application in cooling and heating. It also details the cascade option for systems requiring elevated heating temperatures. The guide is designed to assist engineering professionals, architects, building owners, and technicians in understanding system design considerations, piping, airside requirements, and operational controls.

Trane, a leading manufacturer in the HVAC industry, is committed to disseminating information that promotes effective building comfort system applications. This publication draws upon extensive laboratory research, testing programs, and practical experience.

Key Features and Applications

The guide explores various AWHP configurations, including two-pipe and four-pipe systems, as well as units with partial or full heat recovery. It highlights the Trane® ACX air-to-water heat pump and the Trane® RTWD water-to-water heat pump, detailing their capabilities and applications, such as boiler replacement and high-temperature needs.

Emphasis is placed on system reliability, flexibility, and the impact of outdoor air temperature (OAT) on heat pump performance. Strategies for mitigating defrost cycles and ensuring consistent heat availability are also discussed.

System Design and Operation

The document delves into critical aspects of system design, including building load evaluation, air-to-water heat pump plant sizing, and space heating equipment options. It also covers system configuration, modes of operation, and various system options like auxiliary heating and heat recovery.

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