1.3.7 Installation of mixing valves in the outlet of the DHW tank
Description
A thermostatic mixing valve mixes cold and hot water, generally with a temperature differential of at least 7°C, in order to obtain mixed water at a stabilized temperature, avoiding in this way losses of hot water while adjusting the temperature with the tap.
Benefits
Increase the hot water storage capacity
Perfect for thermal or photovoltaic solar hot water heating because of increase in storage capacity
A mixing valve can make tap temperatures safe even when running a water heater at maximum temperatures
Mixing valves may be better regulation of the temperature of the hot water at the tap compared to thermostats that turn water heating on and off
Limitations
Running water heater at increased water temperatures may cause increased amount of calcification to precipitate out of the water requiring more frequent cleaning and shorter element life
Increase water temperature in tank will mean more stand-by loss
Increase installation space
Economic assessment
The retail cost of the valves at some of the larger retail chains is just under 100 €. A plumber may charge 100-200 € to install it.
References and best practices
Energy efficient controls for multifamily domestic hot water: www.energy.gov/sites/prod/files/2015/01/f19/ba_webinar_dentz_ansanelli_1-21-15_0.pdf
Domestic hot water systems: www.aspe.org/sites/default/files/webfm/ContinuingEd/CEU_221_Mar15.pdf
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CHARACTERIZATION
Environment or playable world:
Residential
Academic
Offices
All
Carried out by:
Public building users
Owners
Operators
All
Reduce consumption of:
Heating
Cooling
DHW
Lighting
Electric devices
Type of driver:
Physical environmental
Contextual
Psychological
Physiological
Social
Time framework:
- Short term
- Long term
Type of measure:
- Envelope
- HVAC
- DHW
- Lighting
- Electrical devices
- Other
