This section describes the building descriptors for hot water recirculation systems. The baseline building has a recirculation system when the proposed design does. This is one aspect of the water heating system configuration (see above).
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Recirculation System Name |
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|---|---|
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Applicability |
All recirculation systems |
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Definition |
A unique descriptor for each water heating recirculation system |
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Units |
Text, unique |
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Input Restrictions |
Where applicable, this should match the tags or descriptions that are used on plans such that a plan reviewer can make a connection |
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Baseline Building |
The naming convention of the baseline building shall be similar to the proposed design |
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Pumping Power |
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|---|---|
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Applicability |
All recirculation systems |
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Definition |
The electric demand of the pumps when the recirculation system is operating. This input is a function of the flow rate, the pumping head, the motor efficiency, and the pump efficiency. Some software may allow each of these factors to be separately entered. |
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Units |
Watts (W) |
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Input Restrictions |
Pumping power shall be consistent with the piping configuration, flow rate, and equipment specified on the construction documents |
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Baseline Building |
Pumping power in the baseline building shall be the same as the proposed design unless specific measures are included in the proposed design to reduce the pumping power. Example measures could include reducing pumping head by oversizing distribution piping or specifying premium efficiency motors or pumps. |
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Schedule |
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|---|---|
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Applicability |
All recirculation systems |
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Definition |
An on/off or fraction schedule that indicates when the recirculation system is expected to be operated |
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Units |
Data structure: schedule, on/off or fraction |
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Input Restrictions |
The schedule for operation of the recirculation system shall be consistent with the design intent of the system. Hotels, hospitals, and other 24x7 institutional buildings will typically have a system that runs continuously. The schedule should be consistent with the controls called for on the construction documents: no control (runs constantly), timer control, temperature control, timer/temperature control, or demand control. |
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Baseline Building |
Recirculation schedules for the baseline building shall be the same as the proposed design |
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Piping |
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|---|---|
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Applicability |
All recirculation systems |
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Definition |
The heat loss rate of piping for recirculating systems. This may be defined separately for pipe that is exposed to outdoor conditions, indoor or semi-heated conditions, or buried underground conditions. |
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Units |
Btu/h-°F specified separately for outdoor, indoor, or buried locations |
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Input Restrictions |
In accordance with Standard 90.1-2019, Section G3.1.3.6, piping heat losses are not modeled for the proposed building |
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Baseline Building |
Piping losses shall not be modeled for the baseline building. |