Medium-temperature water (MTW) systems have operating temperatures ranging from 250°F to 350°F (120 to 175°C)and are designed to a pressure rating of 125 to 150 psig (860 to 1030 kPa [gage]). High-temperature water (HTW) systems are classified as those operating with supply water temperatures above 350°F (175°C) and designed to a pressure rating of 300 psig (2000 kPa [gage]). The usual practical temperature limit is about 450°F (230°C) because of pressure limitations on pipe fittings, equipment, and accessories. The rapid pressure rise that occurs as the temperature rises above 450°F (230°C) 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 systems and distinguishes them from low-temperature water systems operating below 250°F (120°C). See Chapter 13 for basic design considerations applicable to all hot-water systems.
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
ISBN: 978-1-947192-52-2 (for I-P versions of chapters)
ISSN: 1078-6066 (for I-P versions of chapters)
Citation: 2020 ASHRAE Handbook — HVAC Systems and Equipment
Product Details
- ISBN(s):
- 9781947192522
- Number of Pages:
- 8
- Units of Measure:
- I-P
- File Size:
- 1 file , 310 KB
- Product Code(s):
- D-S152020IP
