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Title: Evaluating Domestic Hot Water Distribution System Options With Validated Analysis Models

A developing body of work is forming that collects data on domestic hot water consumption, water use behaviors, and energy efficiency of various distribution systems. A full distribution system developed in TRNSYS has been validated using field monitoring data and then exercised in a number of climates to understand climate impact on performance. This study builds upon previous analysis modelling work to evaluate differing distribution systems and the sensitivities of water heating energy and water use efficiency to variations of climate, load, distribution type, insulation and compact plumbing practices. Overall 124 different TRNSYS models were simulated. Of the configurations evaluated, distribution losses account for 13-29% of the total water heating energy use and water use efficiency ranges from 11-22%. The base case, an uninsulated trunk and branch system sees the most improvement in energy consumption by insulating and locating the water heater central to all fixtures. Demand recirculation systems are not projected to provide significant energy savings and in some cases increase energy consumption. Water use is most efficient with demand recirculation systems, followed by the insulated trunk and branch system with a central water heater. Compact plumbing practices and insulation have the most impact on energy consumption (2-6% formore » insulation and 3-4% per 10 gallons of enclosed volume reduced). The results of this work are useful in informing future development of water heating best practices guides as well as more accurate (and simulation time efficient) distribution models for annual whole house simulation programs.« less
Authors:
;
Publication Date:
OSTI Identifier:
1159372
Report Number(s):
DOE/GO-102014-4515
KNDJ-0-40340-04
DOE Contract Number:
AC36-08GO28308
Resource Type:
Technical Report
Resource Relation:
Related Information: Work performed by Alliance for Residential Building Innovation, Davis, California
Research Org:
National Renewable Energy Laboratory (NREL), Golden, CO.
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy Building Technologies Office
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; RESIDENTIAL BUILDINGS; HOT WATER; WATER HEATING; PLUMBING; BUILDINGS RESIDENTIAL; RESIDENTIAL BUILDINGS; ARBI; BUILDING AMERICA; HOT WATER; DOMESTIC HOT WATER; DHW; WATER HEATING; HOT WATER DISTRIBUTION SYSTEMS; DISTRIBUTION SYSTEMS; TRNSYS; HWSIM; PLUMBING; DEMAND RECIRCULATION​; ; Buildings