State Industries 317913-000 manual Introduction to Commercial Water heating, Parameters

Index

l. Introduction To Commercial Water Heating	Pages
Parameters	2-3
What is Hot Water?	3-4
Evaluating Water	4

ll. Principles of Sizing
Hot Water Demand	5
Profiles of Operation	5-6
lll. Equipment Performance
Recovery Capacity Tables	6-7
Storage Capacity And Tank Efficiency	7
Gas and Oil - Fired Tank Type Heaters	8
Electric Tank Type Heaters	8
Auxiliary Tank (Unfired)	8
Heater Recovery Plus Storage Tank Equals Demand	8
Heater Recovery And Storage Tank Performance Comparison	9
When Using Electricity to Heat Water	10
Estimating Water Heating Costs	10
lV. System Types And Application
Design Objectives	11
System Types	11
Tank Type Water Heater Systems Using Gas, Oil and Electricity	11-12
Creating The Successful System	13
Sizing Without Prepared Information	13-14
One Temperature System	14
Two Temperature System	15
Field Assistance	15

This guide is different than most produced by the water heating industry. Instead of just referring you to prepared sizing information the guide shows you how it’s done. Then, when new model heaters are

Foreword	introduced or applications are different, you will have the information necessary to proceed on
	your own with confidence.
	You will learn how to evaluate water characteristics which could affect system life and
	performance, develop a profile of system operation to establish demand and recovery periods,
	size energy and storage requirements to meet system demands and, all told, create a
	successful commercial water heating system.

I. Introduction to Commercial Water heating

Parameters

A water heater is an appliance for supplying hot water for residential or commercial use other than space heating. The maximum outlet water temperature for a water heater is 210°F ( 98.5°C).

Water heaters are sometimes called boilers and may be so labeled. This is because the gallon capacity of the tank and/or the energy input is above a level for which some codes require ASME (American Society of Mechanical Engineers) construction. Essentially the requirement applies when the water-containing capacity is in excess of 120 gallons or the heat input is above 200,000 Btuh (58.6 kw). Caution, some local inspectors interpret the code to mean including 120 gallons and 200,000 Btuh. The “boiler” requirement can cause cost escalation or system rejection if not taken into consideration by the system designer. One way that more expensive heater costs are often avoided is by combining several “smaller” heaters into a system instead of one large unit.

The term water heater and water heating system is used interchangeably in this technical guide. The water heating system may consist of one or more water heaters installed individually at points-of-use or manifolded together to form a central system. Some systems are comprised of water heater(s), with or without storage, hot water storage tanks, circulating pump, related piping and controls.

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