Add Appliance/Load and similar elements

[shorowit]

Similar to what's available for plug/fuel loads and lighting.

New elements:

• ClothesDryer: Load (0-2, electric or fuel)
• ClothesWasher: Load (0-1, electric) and HotWaterLoad
• Dishwasher: Load (0-1, electric) and HotWaterLoad
• Freezer: Load (0-1, electric)
• Refrigerator: Load (0-1, electric)
• Dehumidifier: Load (0-1, electric)
• CookingRange: Load (0-1, electric or fuel)
• Oven: Load (0-1, electric or fuel)
• HotWaterDistribution: HotWaterLoad
• WaterFixture: HotWaterLoad

Available enumeration choices are:

• Electric units: "kWh/year" or "W" (same as used for plug loads)
• Fuel units: "therm/year" or "Btuh" (same as used for fuel loads)
• Hot water units: "gal/day" or "gal/year"

Notes:

• Water usage can be confusing when dealing with hot water end uses (e.g., dishwasher) vs mixed water end uses (e.g., showerhead or faucet). Need some documentation to ensure consistency. @jmaguire1 suggests using water use at the fixture temperature and not including distribution losses.
• I excluded units of gpm (gal/min) from HotWaterLoad because A) water fixtures already have a FlowRate element and B) no one probably cares about the flow rate of hot water use for things like dishwashers or clothes washers.