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DHWTANK

DHWTANK constructs an object representing one or more unfired water storage tanks in a DHWSYS. DHWTANK heat losses contribute to the water heating load.

wtName

Optional name of tank; give after the word “DHWTANK” if desired.

Units Legal Range Default Required Variability
63 characters none No constant

wtMult

Type: integer

Number of identical tanks of this type. Any value \(>1\) is equivalent to repeated entry of the same DHWTANK.

Units Legal Range Default Required Variability
x \(>\) 0 1 No constant

Tank heat loss is calculated hourly (note that default heat loss is 0) --

\[\text{qLoss} = \text{wtMult} \cdot (\text{[wtUA][wtua]} \cdot (\text{[wtTTank][wtttank]} - \text{[wtTEx][wttex]}) + \text{[wtXLoss][wtxloss]})\]

wtUA

Type: float

Tank heat loss coefficient.

Units Legal Range Default Required Variability
Btuh/oF x \(\ge\) 0 Derived from wtVol and wtInsulR No constant

wtVol

Type: float

Specifies tank volume.

Units Legal Range Default Required Variability
gal x \(\ge\) 0 0 No constant

wtInsulR

Type: float

Specifies total tank insulation resistance. The input value should represent the total resistance from the water to the surroundings, including both built-in insulation and additional exterior wrap insulation.

Units Legal Range Default Required Variability
ft2-oF/Btuh x \(\ge\) 0.01 0 No constant

wtZone

Type: znName

Zone location of DHWTANK regarding tank loss. The value of zero only valid if wtTEx is being used. Half of the heat losses go to zone air and the other goes to half radiant.

Units Legal Range Default Required Variability
Name of ZONE 0 No constant

wtTEx

Type: float

Tank surround temperature.

Units Legal Range Default Required Variability
oF x \(\ge\) 0 70 No hourly

wtTTank

Type: float

Tank average water temperature.

Units Legal Range Default Required Variability
oF \(>\) 32 oF Parent DHWSYSTEM wsTUse No hourly

wtXLoss

Type: float

Additional tank heat loss. To duplicate CEC 2016 procedures, this value should be used to specify the fitting loss of 61.4 Btuh.

Units Legal Range Default Required Variability
Btuh (any) 0 No hourly

endDHWTank

Optionally indicates the end of the DHWTANK definition.

Units Legal Range Default Required Variability
none No constant

Related Probes: