4.33 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=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) –
\[\text{qLoss} = \text{wtMult} \cdot (\text{wtUA} \cdot (\text{wtTTank} - \text{wtTEx}) + \text{wtXLoss})\]
wtUA=float
Tank heat loss coefficient.
| Units | Legal Range | Default | Required | Variability |
|---|---|---|---|---|
| Btuh/oF | x \(\ge\) 0 | Derived from wtVol and wtInsulR | No | constant |
wtVol=float
Specifies tank volume.
| Units | Legal Range | Default | Required | Variability |
|---|---|---|---|---|
| gal | x \(\ge\) 0 | 0 | No | constant |
wtInsulR=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=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=float
Tank surround temperature.
| Units | Legal Range | Default | Required | Variability |
|---|---|---|---|---|
| oF | x \(\ge\) 0 | 70 | No | hourly |
wtTTank=float
Tank average water temperature.
| Units | Legal Range | Default | Required | Variability |
|---|---|---|---|---|
| oF | \(>\) 32 oF | Parent DHWSYSTEM wsTUse | No | hourly |
wtXLoss=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: