Solar Hot Water / Heating...

Brock · June 2007

Re: Solar Hot Water / Heating...

Our front load washer uses about 5 gallons per cycle (5 cycles max). If it were me I would just go with either a 5 gallon, or even a 2.5 gallon tank. Then set the washer to "HOT" and it will dump the first 2.5 gallons of hot water in and warm up the cold water passing through it a bit and I am sure it would be at least warm in the end. I find I rarely need to use truly hot water in the washer except when I hit the sanitize button when we have the baby’s “bottom” soiled stuff in there.

Our dish washer it uses about a gallon a cycle (with about 10 cycles). Although I bet the 2.5 gallon could recover between fills and some washers will heat the water to 120F or so no matter what the incoming temp is. I found that out when I turned down our water heater and saw a nice 1000w load. It took me forever to realize it was the washer heating up the water from 110F on each cycle.

BB. · June 2007

Re: Solar Hot Water / Heating...

Dish washers are energy hogs (use as much power per wash as a standard energy star fridge/freezer these days)--but there are many (if not most now?) that will heat the water up to the desired temperature.

Some of the new front load washer too now heat up the water with on-board electrical heaters. And they don't use too much water to boot. (always a trade off between energy usage, water usage and other desires).

I got a top-loader because of the (lack of) room in our garage when the car is parked there. Also splurged and got the top load drier too... Both work great (gas drier had an issue with not lighting the gas flame reliably--manufacturer did eventually replace the whole drier--darn glow-bars...).

-Bill

System2 · June 2007

Re: Solar Hot Water / Heating...

Just sitting here thinking -

What if I "daisy chained" in series all 4 of the 2.5 gallon water heaters and put the dishwasher and washing machine at the end of the loop. Bathroom 1 has the water heater hot outlet teed off to also feed bathroom 2 cold inlet, Bathroom 2 hot outlet also feeds Bathroom 3 cold inlet, Bathroom 3 hot outlet also feeds kitchen sink and teed off for dishwasher and washing machine. If Saturday morning is laundry time, the timers could be set to turn on at that time for the laundry load. I suppose the dishwasher time could be planned also, assuming residents had that discipline.

Do I effectively have 2.5 gallons x 4 or 10 gallons total feeding the dishwasher and washing machine?

I don't know why anyone would "need" hot water for washing machine rinse if you already had hot water wash, but with 10 minute recovery I think I would have another 10 gallons available fairly quickly. I thought everybody used disposable diapers? (Oops, possible political issue.)

I appreciate the issue of chasing pennies, but with the whole house open for a building remodel, and with a small house and no room to spare, I am trying to make the most efficient choices possible, since I will be living with them for a long time to come. Also, I have an enquiring mind and can't leave well enough alone. I always think there is an elegant but simple solution to every problem and all I have to do is find it.

BB. · June 2007

Re: Solar Hot Water / Heating...

No--don't run all of them in serial like that. You would have the cold water inline for all of them and would be just heating/cooling/heating the plumbing.

A thermally blanketed electric hot water heater is pretty darn close to 100% efficiency (in terms of P=I^2 * R). Placing it close to you point of use saves loss of of water/heat to pre-heat the plumbing.

-Bill

System2 · June 2007

Re: Solar Hot Water / Heating...

I don't follow. All water heaters are normally turned off, heating only the water in the tank for 15 minutes or so when the timers call for shower time. All water heaters function in series only when the Saturday morning 7 day timer calls for all to be on at the same time. So, how am I heating all of the plumbing all of the time?

BB. · June 2007

Re: Solar Hot Water / Heating...

If I understand your plan--drawing hot water from kitchen sink will draw water through the piping (and tanks) of the other three upstream bathroom(???). You have the cold water of the round robin plumbing to heat for three bathrooms just running the kitchen sink faucet. If you are drawing hot water only from the kitchen sink (heater on) and the other three bathroom heaters are off--I guess you are not wasting anything other than the loss of hot water from each of the bathroom heaters that is going up to the next heater (1/2 to several gallons of cold water in line being exchanged with luke warm water from heaters turned off)...

If the water in the bath 1-3 heater tanks is at room temperature when you turn on the kitchen sink--then, you are not wasting heat. However, if the tanks are still warm when you use the kitchen sink--you are drawing out warm/hot water and replacing it with cold water--and wasting energy.

If you turn on the elements in all of the daisy chained tanks and draw from the last one for your washer--yes you will have (more or less) the sum of the hot water in all of tanks (plus the tempering provided by any room temperature water in the connecting pipes).

Seems like it would be a lot easier to simply use a local water heater with the washer than running extra pipe (here, new construction requires insulation on hot water pipes).

I don't know--maybe I am not understanding what you are trying to say here.

-Bill

Solar Hot Water / Heating...

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