14 June 2002
HOT WATER LOAD ESTIMATIONS
B-1. The feasibility analysis requires that the designer estimate the thermal energy
loads for a facility on a daily or monthly basis. Although the economic feasibility of the
solar project is not usually dependent on the estimated hot water load, this value is
important when determining the size of the system to be designed.
B-2. Since solar energy systems are not designed to supply the full hot water demand
of a building, average values should be used for the hot water estimate. This is in
contrast to sizing conventional water heating equipment, which typically is sized
according to an expected maximum or design load. Table B-1 lists a variety of service
hot water applications and the average amounts of water required on a per person
basis. The value given for industrial buildings is that required for personal use by the
workers. It does not include possible process water heating applications that may exist.
Other applications not listed in Table B-1 should be evaluated by considering existing
buildings with similar applications.
Table B-1. Estimated Average Hot Water Loads for
Gallons per day
Type of Building
(Liters per day)
Office buildings and similar facilities
Barracks w/ dining facilities
Barracks w/o dining facilities