2017 ASHRAE Annual Conference

An analytical study is carried out to assess the impact of corrections to nominal test conditions on the measured energy factor for residential water heaters. While test conditions are specified in the method of test, the difficulty in exactly achieving these test conditions in the laboratory necessitates a computational approach to correct the results to nominal conditions. This paper examines the magnitude of those corrections for a range of water heaters of various fuel type, heating method, and size across a number of potential draw volumes during a 24 hour simulated use test.

The impact of the high power requirements of large residential tankless electric resistance water heaters on electric system distribution wiring, transformers, breakers, and other equipment is an area of concern for both electric utilities and builders. This study analyzes how probable and worst case diversified electrical demand of large (28 kW) residential tankless electric water heaters compares to that of 4.5 kW storage water heaters in residential applications as a function of number of households on a given electrical distribution circuit.

Information on hotel hot water use patterns has been limited until now, resulting in most hotel hot water systems being designed using extremely old hot water use data (45-80 years old) that predate the introduction of water and energy efficient fixtures and appliances. In recognition of this fact, ASHRAE funded research project 1544 “Establishing Benchmark Levels and Patterns of Commercial Hot Water Use – Hotels” to both develop a monitoring methodology that could be duplicated by others to collect hot water use data from a larger number of hotels and to obtain updated hot water use information from at least two hotels. This paper compares hot water use results collected for a “travel” hotel which had neither meeting rooms nor food service and a “business” hotel which had both.

This is the fifth paper in a series of technical papers written to describe results of ASHRAE research project 1544. This paper builds on information presented in the project final report, the three previously published papers to present information on using the updated data to select water heating systems for hotels of any desired size and compares results of this sizing method to other hotel hot water system sizing methods described in the ASHRAE Service Water Heating Handbook Chapter through the use of examples.