Domestic Hot Water (DHW) is the water used for handwashing, dishwashing, showers, and other similar purposes. DHW is separate from the main heating system water (if present) in a building as the water must be potable and once used it leaves the buildings via the drainage systems, typically returning to municipal sewer systems.
DHW is generated by heating cold water from a buildings water supply, sometimes called city water. There are several methods of heating this water that cove.tool supports
Electric
These are typical in homes and use an electric element to heat incoming water
System Efficiency is 0.75
VR-Boiler
These are standard efficiency fired boilers for DHW. If you have limited information about the projects design VR-Boiler is a conservative assumption.
System Efficiency is 0.61
Gas Boiler, HR-Boiler
These are high-efficiency gas boilers which will save energy compared to VR-Boilers.
System Efficiency is 0.75
Co-Generation
This covers DHW generation via a combined heat and power (CHP) system. These are most typically at a very large scale and overall not very common.
System Efficiency is 0.9
District Heating
This covers DHW generation via a district or campus connection
System Efficiency is 0.9
Heat Pump
This a newer technology for DHW generation which utilizes an electric heat pump. These provide the highest efficiency for DHW generation.
System Efficiency is 1.4
Steam
This covers DHW generation via steam boilers. Less common in modern buildings.
System Efficiency is 0.61
Illustration of a standard domestic VR-Boiler and the smaller instantaneous counterpart.