Thread Number: 72678
/ Tag: Modern Dishwashers
Cold water experiment |
[Down to Last] |
|
Post# 960378 , Reply# 1   10/3/2017 at 08:21 (2,390 days old) by Yogitunes (New Jersey)   |   | |
Checkrate/Likes
 
3    
well this is where you would need a watt meter to determine which is saving you money....
and that depends on areas, sometimes gas is way cheaper than electric....at least in New Jersey it is.... on-demand water heaters are usually more efficient than standard water tanks.... dishwashers can heat their own water, but may take longer to run in order to get the temperature raised.....most times its just boosting temps 10 to 20 degrees....and depending on how cold your incoming water is... plus as a dishwasher cycles, the heating element only comes on for the main wash, and final rinse.....in the mean time, the pre-rinse and regular rinses will be cold, so you would be raising and lowering the internal temp...things like greases and oils could be dissolved and redeposit..... this cold wash attempt would function in a pinch.....can't say it would be something I would do on a regular basis.... your mileage may vary.... |
Post# 960391 , Reply# 2   10/3/2017 at 09:51 (2,390 days old) by combo52 (50 Year Repair Tech Beltsville,Md)   |   | |
Checkrate/Likes
 
1    
It is probably cheaper to let the DW do the heating, but it will probably put a little more wear on the DWs wiring and main motor doing so all the time.
Could you just have a timer on the pump for the hot water loop so it will shut off after an hour or so, so it does not have to keep the loop hot after the DW is through with most of its fill periods. |
Post# 960394 , Reply# 3   10/3/2017 at 10:05 (2,390 days old) by foraloysius (Leeuwarden, Friesland, the Netherlands)   |   | |
Checkrate/Likes
 
2    
I've never seen a loop system with a tankless water heater. Overhere those systems are only used with a well insulated tank water heater and insulated hot water pipes to make it as economical as possible. Tankless water heaters are for hot water on demand, that's what they're best at. Using them for a loop system is a waste of energy.
|
Post# 960401 , Reply# 5   10/3/2017 at 10:41 (2,390 days old) by DADoES (TX, U.S. of A.)   |   | |
Checkrate/Likes
 
1    
There are often discussions about tankless water heaters and circulation loops on a plumbing discussion board that I read on occasion. People want the loops when the water heater is located a long distance (plumbing-wise) from hot water usage points. The advisory always is that the circulation loop is an energy-waster if not insulated extremely well, and of course it negates some of the advantage of tankless if the pump runs continuously. I vaguely recall mention of a tankless brand/model that has a built-in circulation pump. I have a tankless (no circulation pump). It takes 2+ fills for heated water to reach my dishwasher if I don't purge the line first, which I do on occasion depending on winter weather and/or the contents of the load. However, my dishwasher has assured water heating. The main wash and final rinse are extended as long as necessary to reach the target temperatures. I also keep the tankless set at 102°F as the "normal" temperature and raise it temporarily when needed for particular tasks ... but that's a separate discussion. |
Post# 960589 , Reply# 8   10/4/2017 at 14:32 (2,389 days old) by foraloysius (Leeuwarden, Friesland, the Netherlands)   |   | |
Checkrate/Likes
 
     
|
Post# 960617 , Reply# 9   10/4/2017 at 16:36 (2,389 days old) by jkbff (Happy Rock, ND)   |   | |
Checkrate/Likes
 
     
I am going to express my thoughts on this, but this seems like trying to get milk from a crowbar.
Why isn't the circulation pump on a pressure switch with a time delay? Meaning when a valve is opened, the pump circulates until the valve shuts and x amount of time (five minutes) passes before it stops circulating? If you are wanting to shut off the hot water to the house at night and still run your dishwasher, you are going to need a dishwasher that is designed for that type of usage. I would imagine that bosch is capable of doing this, I know the Miele EcoFlex dishwashers are designed for this, but so are their other dishwashers. I would honestly just go the pressure switch / time to off delay route my self. I plan on doing a setup that you have when I finally redo my bathrooms. |