Solar Immersion and Hot Fill Washing Machine

NobbyTucker

I'm working on a new solar PV installation and have opted for a hot water cylinder and Solar Immersion Controller (a Solic 200).

I would like to connect a washing machine to fill from the hot water cylinder and make the best of the 'free' hot water. The problem I am finding is a lack of options, as most washing machines now seem to be cold water fill only.

There is one company producing hot fill washing machines www.Ebac.com but they do not have an integrated version to fit my kitchen. I have emailed the Energy Saving Trust but no answer.

Any ideas please? Thanks

DullGreyGuy

They seem to have gone out of fashion for both washers and dishwashers... looking at a high end brand its only their £2,500+ models that take a hot water feed. Even then it's only on a hot wash that it makes a massive difference. The difference on a cool wash is small (0.2KWH per wash)

Alnat1

30C washes are now the new normal, better for the planet, so need minimum water heating. We do a "boil up" cleaning cycle every couple of months and choose a sunny day to do it.

Probably not worth all the extra spend on an expensive hot fill machine unless you do frequent very hot washes but I doubt you'd get ROI over the machine life.

NobbyTucker

DullGreyGuy said:

They seem to have gone out of fashion for both washers and dishwashers.

We have taken the plunge on an energy efficient dishwasher, having refused one for years on energy/water waste grounds. With a fill of 9 litres, it is less than a sinkful.

We do 4 low temperature loads and one high each week, so I wanted to try!

Ebac hot fill machines are from £499 so affordable but do not have an integrated version.

Exiled_Tyke

When I enquired about this issue (some years ago) the point was made to me that for many homes (mine included) hot-fill appliances were a waste of time (and money) because of running so much cold water into the machine before it gets to the hot.  With modern appliances using even less water than before this probably even more of an issue now.   If you have a hot tap right next to the machine you could run the cold water through first but I'm pretty sure I wouldn't remember to do this. 

QrizB

NobbyTucker said:

Any ideas please? Thanks

I have a cold fill machine but, for at least six months of the year, can do laundry when the sun shines without significant electricity import. And my array is quite small by modern standards.

Taking ETs comments about cooled water in the hot fill line into account, and the prevalence of 30 or 40 degree washes, this is likely to work for you too.

BossBob

It is a case of playing Apollo 13 and working out what you can use with what, and when, without tipping the inverter into pulling current from the grid. While I do have the added advantage of a battery, I can do laundry OR wash dishes. Once the grill/oven is up to temperature for croissants I can then make coffee or tea, but not before. I see the occasional spike as the grid takes the load before the inverter takes over but only used 5.28kWh for the whole of May and the highest daily use 0.34kWh.

NobbyTucker

Thanks everyone!

I was planning on running the sink tap before putting the washer on, but it is a good call that in the middle of a sunny day, there is likely to be only low/no electric draw from the grid.

With no economic integrated hot-fill machines available anyway, an energy efficient cold-fill seems like the way to go. Thanks again!

silverwhistle

I fill a watering can (without a rose!!) with hot water and put that in my machine via the soap tray. Running the tap first to get to temperature goes to watering the garden. It knocks about 15 minutes off an 80 minute cycle.

Lovesolar

Good to hear of your solar immersion heater plans, NobbyTucker. A recent letter in New Scientist pointed out that heating hot water is a cheaper and more efficient way of storing solar energy than batteries - yet the correspondent didn't seem to know that this had already got going in domestic settings!

Of course, there comes a point we might want to install batteries, too (for electronics, washing machine motors etc). But heating water uses a lot of energy, and is - after space heating - normally the largest user of energy in the home, so storing solar power as hot water makes great sense. Routine charging of electric cars might change this ratio, I guess.

Silverwhistle, I'm fascinated to know that you've got something to work with your watering can and a hot tap! I looked at this some years ago, and talked to a manufacturer about it (having told an elderly couple with solar hot water to do the watering can trick). They told me that this was not possible to do via the drum, with the door open, because the machine always pumps out any residual water in the machine before it fills it. And then if you pour the hot water in via the soap tray, that water is competing with the cold feed which is coming in (which shuts off when it detects that it has put in the right amount of water for the load - in many machines). At best, then, you get a proportion of hot water into the machine mixed with the cold feed. But your post suggests that something has worked, because the shorter running time indicates that the machine has spent less energy heating up the water, because you have warmed it already with your watering can.

Sounds crazy, but I shall try the same with a simple, homemade solar water heater, set up in the garden! 

If someone really knew what they were doing (which I don't), it seems to me possible to sort out some kind of piping and valve so that solar hot water could be diverted through the cold feed, temporarily, to fill the machine - though the feed must be at the correct pressure for the machine. This might well break some kind of regulations, of course...

Re hot-feed washing machines, in March 2024 Zanussi said they were developing new ones that could be used with solar hot water (but apparently not yet on sale).

paul991

A company in wales still  manufactures hot feed  water washing machines but unless your on a old FIT PAYMENT i doubt you would save much