Contains controls used to view prescriptive option
compliance results for the Service Water Heating portion of the ASHRAE 90.1
(2010) requirements.
Water heating requirements are specified in section 7 of
the ASHRAE 90.1 (2010) standard, and include general and mandatory provisions,
the Prescriptive Path and the Energy Cost Budget Method compliance path
options.
Tip: You can
open the
Results Viewer
utility to step through the calculations for displayed results
by selecting the result value and clicking for more information (as prompted).
Setting | Description |
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Service Water Heating
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Displays prescriptive results for the service water heating
systems in the project building. Service water heating is the heating of water
for domestic or commercial purposes other than space heating and process
requirements.
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Water Heaters
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Displays prescriptive results for the water heater
systems in the building. Qualifying water heaters are those heated vessels
which provide hot water for a use that is external to the heating and cooling
systems of the building.
-
Equipment type – Lists all the water heater types in the building. Water heater
types can be electric heaters (including heat pump water heaters and
instantaneous heaters), fuel-fired storage heaters (gas or oil), fuel-fired
instantaneous heaters (gas or oil), fuel-fired pool and spa heaters. Heaters
must be of a certain size to qualify based on definitions in the standard.
- Input
Rating – Lists the rated power input for each water heater.
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Sub-Category or Rating Condition – Lists the performance requirements for each
water heater in the building.
- Volume
– Lists the volume of each water heater vessel.
- Energy
Factor or Et – Lists prescriptive results for the factors that determine water
heater thermal efficiency for each water heater in the building. Et refers to
the combined effects of thermal efficiency and standby losses based on a
standardized DOE (US Department of Energy) test in which the ratio of thermal
energy transferred to the water (by the heater) to the energy input (required
by the heater) is measured.
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Rated – Lists the DOE energy factor for each water heater in the building.
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Required – Lists the required energy factor for compliance with the standard
for each water heater.
- Standby
Loss – Lists prescriptive results for the factors that determine water heater
standby loss for each water heater that serves to provide heat for spaces and
water. To comply, the standby loss should not exceed the maximum value
calculated by using the definitions and required tests specified in the
standard. The requirements are intended to regulate the use of these types of
systems for water heating alone after the heating season is over. Energy is
wasted in these systems because they are utilizing an oversized boiler (sized
to concurrently heat spaces and service water) during those times of the year.
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Rated – Lists the rated standby loss determined by tests in the factory or the
field as required by the standard for each eligible water/space heater in the
building.
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Required – Displays the calculated maximum standby loss for each eligible each
eligible water/space heater in the building.
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Pass/Fail – Displays an overall result of the building’s compliance with the
Service Water Heating requirements prescribed by the standard.
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