Posted by jeff on February 10, 2010, 9:41 am
Ohioguy wrote:
> So from what I'm hearing, having a holding tank to increase the
> incoming water from something like 52 degrees F (the ground water temp
> here year round) to a higher temp when it enters the electric water
> heater would be a way to go. Too bad there is not some simple way to
> get the waste heat out of the drain water from our 3 showers/bathtubs,
> and use some of that to help preheat this water. Sounds like that would
> be too complicated, though.
Google that. It's fairly common. There are even some home brew
devices. Typically it is used to warm the cold water line feeding the
shower.
>
> And then, if I were to use some sort of solar heating system, sounds
> like it would be best to be on from about April 1 to November 1.
No, year round. The efficiency, particularly depending on the type
falls in colder weather. Also, the sun is lower in winter, so there are
tradeoffs. Solar is big in a lot of cold climates. Here, I take
advantage of the deciduous trees losing their leaves and have one
vertically mounted collector. So it is tuned for winter. My solar is
primarily for home heating, the leftover goes for DHW. In the summer,
I'll have plenty of hot water.
> Otherwise, I'd have to rig up some sort of antifreeze based exchanger
> system.
No. Drain back. If you need to go up in height to mount the collector
you will need a closed loop (for reasons in my other post), probably
with antifreeze. There are options even there.
>
> The simplest solution would probably just be to rig up an insulated
> bathtub in the basement, fill it up 2/3 of the way and put a floating
> heat blanket on top of it. Then I could use a solar powered pump and
> some small black plastic tubing with water, & see how hot it gets. If
> it worked, I could just use the sun to heat all of my bath water.
I don't think that is worth your while.
The simplest/cheapest these days is a modified Thomason Trickle Down,
high efficiency to boot. No antifreeze in that. Or a batch heater.
Jeff
Posted by RickMerrill on February 11, 2010, 8:42 am
jeff wrote:
> Ohioguy wrote:
>> So from what I'm hearing, having a holding tank to increase the
>> incoming water from something like 52 degrees F (the ground water temp
>> here year round) to a higher temp when it enters the electric water
>> heater would be a way to go. Too bad there is not some simple way to
>> get the waste heat out of the drain water from our 3 showers/bathtubs,
>> and use some of that to help preheat this water. Sounds like that
>> would be too complicated, though.
> Google that. It's fairly common. There are even some home brew devices.
> Typically it is used to warm the cold water line feeding the shower.
>>
>> And then, if I were to use some sort of solar heating system, sounds
>> like it would be best to be on from about April 1 to November 1.
> No, year round. The efficiency, particularly depending on the type falls
> in colder weather. Also, the sun is lower in winter, so there are
> tradeoffs. Solar is big in a lot of cold climates. Here, I take
> advantage of the deciduous trees losing their leaves and have one
> vertically mounted collector. So it is tuned for winter. My solar is
> primarily for home heating, the leftover goes for DHW. In the summer,
> I'll have plenty of hot water.
>> Otherwise, I'd have to rig up some sort of antifreeze based exchanger
>> system.
> No. Drain back. If you need to go up in height to mount the collector
> you will need a closed loop (for reasons in my other post), probably
> with antifreeze. There are options even there.
>>
>> The simplest solution would probably just be to rig up an insulated
>> bathtub in the basement, fill it up 2/3 of the way and put a floating
>> heat blanket on top of it. Then I could use a solar powered pump and
>> some small black plastic tubing with water, & see how hot it gets. If
>> it worked, I could just use the sun to heat all of my bath water.
> I don't think that is worth your while.
> The simplest/cheapest these days is a modified Thomason Trickle Down,
> high efficiency to boot. No antifreeze in that. Or a batch heater.
> Jeff
Just a reminder: do not run an antifreeze loop inside the potable hot
water tank. (Otherwise a single leak could poison you.) I think there
are non-poisonous anti freezes these days however.
Posted by Rod Speed on February 10, 2010, 1:04 pm
Ohioguy wrote:
> So from what I'm hearing, having a holding tank to increase the
> incoming water from something like 52 degrees F (the ground water temp
> here year round) to a higher temp when it enters the electric water
> heater would be a way to go. Too bad there is not some simple way to
> get the waste heat out of the drain water from our 3 showers/bathtubs,
> and use some of that to help preheat this water. Sounds like that
> would be too complicated, though.
> And then, if I were to use some sort of solar heating system, sounds
> like it would be best to be on from about April 1 to November 1.
> Otherwise, I'd have to rig up some sort of antifreeze based exchanger
> system.
Nope, just automate a drain back system for the winter.
> The simplest solution would probably just be to rig up an insulated
> bathtub in the basement, fill it up 2/3 of the way and put a floating
> heat blanket on top of it. Then I could use a solar powered pump and
> some small black plastic tubing with water, & see how hot it gets.
It wont get that hot in winter without some transparent cover over
the black plastic tubing if you get much snow and ice in winter.
> If it worked, I could just use the sun to heat all of my bath water.
That doesnt work too well if you mostly bath first thing in the morning early.
Its dark here when I get up in summer.
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> incoming water from something like 52 degrees F (the ground water temp
> here year round) to a higher temp when it enters the electric water
> heater would be a way to go. Too bad there is not some simple way to
> get the waste heat out of the drain water from our 3 showers/bathtubs,
> and use some of that to help preheat this water. Sounds like that would
> be too complicated, though.