[Greenbuilding] Max Temp Storage Water Heaters+Temperature Sensors

[elitalking]

I am replacing a water heater that is in a location that is inaccessible for servicing.  We have been in the practice of turning the heater on when we are getting ready for a bath to avoid the standby heat losses 

(Energy $$) from continually heating the water.  

 

I want to know the maximum temp that typical storage electric water heater can safely accommodate.  Since we are not storing the heat, the higher temperature is not an energy penalty.  The higher temp allows for a smaller tank.  We are separating the kitchen use from the bathroom.  Tank will located next to the bathtub.  We will have an on off switch at the tank.  

 

Does anybody know of a heat sensor and or sound indicator when the water reaches a set temperature? Currently we allow more time than is necessary because we want to avoid being too cool.  It sure would be nice to know what is going on.  

 

We could use a 20 gal tank for 20 gal bath and set at temp for bath.  However, we use a cistern.  During dry spells (most of the time) we mix creek water in bath to reduce water usage off of cistern.  Results of my spread sheet below show that 20gal bath can be supplied with 10gal HW tank at 185F.  Can a normal temperature relief valve store that kind of pressure-temperature?

 

Bath (gal)  20.0           

Bath Weight (#) 160.0        

Bath Temp (F)    120.0        

Cold Water (gal) 10.0 

Cold Water (#)   80.0           

Cold Water Temp (F)  55.0           

Hot Water (gal)  10.0           

Hot Water (#)     80.0           

Hot Water Temp (F) 185.0   



Thanks for your consideration.

Eli 
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