Water
This simple heating coil model only does sensible heating of the air. The simple heating coil uses the Effectiveness-NTU algorithm and assumes a cross-flow heat exchanger.
Calculation Method
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Default: Capacity
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Typical Range: NA
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Min Max: NA
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Units: NA
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The user can choose either UAMethod or Capacity. If UAMethod is selected, the user must input values for UA of the Coil (and Rated Capacity is ignored). If Capacity is chosen, the user must input a Rated Capacity for the coil. Rated capacity is defined as the heating capacity in watts of the coil at the rating points (i.e., the rated inlet and outlet water/air temperatures defined in the input fields below). The rated capacity is used to calculate a water mass flow rate and a UA for the coil.
To autosize the capacity, choose UAMethod and put autosize as the inputs for U-Factor Times Area Value and Rated Capacity. The program will use the Sizing inputs to size the coil. The rated temperatures are ignored in autosizing. These are used only when the user is specifying coil performance using the NominalCapacity input method.
Rated Heating Capacity
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Default: Auto size
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Typical Range: NA
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Min Max: 0 to 999,999,999
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Units: W, kW, Btuh, Mbh
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The heating capacity of the coil in watts at the rated inlet and outlet air and water temperatures. The gross rated heating capacity does not account for the effect of supply air fan heat. This field is used when the Performance Input Method = Nominal Capacity. This field is autosizable.
Rated Water Inlet Temperature
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Default: 180°F/82.2°C
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Typical Range: 150°F to 200°F
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Min Max: 0 to 999,999,999
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Units: °F/°C
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The inlet water temperature corresponding to the rated heating capacity.
Rated Air Inlet Temperature
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Default: 60.98°F/16.6°C
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Typical Range: 55°F to 70°F
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Min Max: 0 to 999,999,999
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Units: °F/°C
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The inlet air temperature corresponding to the rated heating capacity.
Rated Water Outlet Temperature
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Default: 159.98°F/71.1°C
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Typical Range: 130°F to 170°F
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Min Max: 0 to 999,999,999
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Units: °F/°C
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The outlet water temperature corresponding to the rated heating capacity.
Rated Air Inlet Temperature
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Default: 89.96°F/32.2°C
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Typical Range: 80°F to 100°F
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Min Max: 0 to 999,999,999
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Units: °F/°C
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The outlet air temperature corresponding to the rated heating capacity.
Rated Evaporation Ratio
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Default: 0.5
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Typical Range: 0.5 to 0.6
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Min Max: 0 to 1
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Units: NA
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This is the ratio of convective heat transfers between air side and water side of the heating coil at the rated operating conditions. This ratio describes the geometry and the design of the coil and is defined by:
where:
ηf is the fin efficiency, (dimensionless)
h is the surface convection heat transfer coefficient
A is the surface area