S15 -- Medium- and High-Temperature Water Heating (SI)

Medium-temperature water systems have operating temperatures ranging from 250F to 350F (120 to 175C) and are designed to a pressure rating of 125 to 150 psig (860 to 1030 kPa [gage]). High-temperature water systems are classified as those operating with supply water temperatures above 350F (175C) and designed to a pressure rating of 300 psig (2000 kPa [gage]). The usual practical temperature limit is about 450F because of pressure limitations on pipe fittings, equipment, and accessories. The rapid pressure rise that occurs as the temperature rises above 450F (230C) increases cost because components rated for higher pressures are required. The design principles for both medium- and high-temperature systems are basically the same. This chapter presents the general principles and practices that apply to MTW/HTW and distinguishes them from low-temperature water systems operating below 250F (120C). See Chapter 13 for basic design considerations applicable to all hot-water systems.

Chapter Table of Contents

System Characteristics
Basic System
Design Considerations
Distribution Piping Design
Heat Exchangers
Air-Heating Coils
Space-Heating Equipment
Instrumentation and Controls
Water Treatment
Heat Storage
Safety Considerations
National and International Safety Standards and Guidelines

ISBN: 978-1-936504-26-8 (for SI versions of chapters)
ISSN: 1930-7705 (for SI versions of chapters)

Citation: 2012 ASHRAE Handbook -- HVAC Systems and Equipment: Chapter 15, Medium- and High-Temperature Water Heating



Product Code(s): D-S152012SI