Steve Lusardi wrote:

If you use a water cooled muffler as a heat exchanger to heat your fresh
water, at some point your freshwater tank will be hot enough.

Just curious, no one mentioned using the exhaust waste heat
for domestic water heating. I have never seen such an
installation and suspect it is pretty rare since for the
reasons you mention it is a cumbersome means to avoid using
heat from the coolant.

Rick

Rick,
If you use a water cooled muffler as a heat exchanger to heat your fresh
water, at some point your freshwater tank will be hot enough. You now must
have a mechanism to dump the absorbed exhaust heat or damage will occur
somewhere in the system. Most colorifiers use the engine's cooling water
circulating through an imersed exchange coil in the hot water tank. In that
way, the engine's cooling system itself is the energy dump. If the exhaust
system is used, another mechanism must be found.
Steve
"Rick" wrote in message
nk.net...
Steve Lusardi wrote:

If you use a
fresh water exchanger and your hot water tank is up to temp and you
continue
to run the engine, the exchanger overheats. So you need auxillary
cooling,
when your heat demand is low. I guess there is no free lunch.

??? Are you suggesting there are systems out there that use
the domestic hot water system as a heat sink for the engine
cooling requirements? Or that someone would install a heat
exchanger that is rated at a lower temperature than the
operating temperature of the engine cooling circuit?

Something is missing here.

Rick

That means a big boat.

Thanks to all posters for feedback.
I have the luxury of a big cat and big battery bank.

I'm not worried about the fridge , it's maybe 300W/24 hrs average in tropics
and half of this in the north.

As for the cooker- two hot plates at 1KW each seems a lot but given you use it
for 1 hour/day it translates to something like 2kW/24 = 83 Watts average @ 24
hrs and I think it's well worth it given the safety,cost, convenience and
simplicity advantages.

Same goes for coffee maker etc.

I did do my math before posting here and I understand how amps/watts etc add up.
I agree higher voltage would be nice but we are stack with 24V and don't expect
to be running generator at all times. Also we have luxury of designing
everything from scratch as the boat is being built and can acommodate locations.
In other words instead of long thick wires we can make them short for equipment
which consumes a lot of ampers. I'm trying to be smart but not always
conventional with this.

I agree electric heater might be the most energy hungry element, especially if
the water has to be retained and temperature maintained in the tank for 10
people onboard.

This is something that I'm considering to built around hybrid solution.

I came accross this Webasto heater:

http://www.navstore.com/pdf/webasto/Webasto%20TSL17.pdf

What do you think?

Another thing is - I'm wondering if we need a water tank at all? It takes lost
of gallons to shower 10 people- it cost money and space. I remember seeing in
some country (not US) showers with built in electric heater element which will
simply just warm up water passing through a piece of the size of grapefruit.

Regards M

On Sun, 11 Jan 2004 22:34:28 GMT, misia
wrote:

I agree electric heater might be the most energy hungry element, especially if
the water has to be retained and temperature maintained in the tank for 10
people onboard.

================================================== ====

To cruise with 10 people in the tropics, you're going to need a water
maker and lots of power. You might as well spring for a decent sized
generator with 110/220 volt power and not worry about finding 24 volt
appliances or stove fuel.

I agree. We actually will have the Spectra watermaker and these are extremely
efficient. I owned one for 5 years on a 31ft boat and with 5 people 2 120W solar
batteries are able to maintain it to provide enough water daily.

If we use spectra, the watermaker will consume approx the same amount of kwh as
the fridge.

We will have the generator as well

M

"Wayne.B" wrote:

On Sun, 11 Jan 2004 22:34:28 GMT, misia
wrote:

I agree electric heater might be the most energy hungry element, especially if
the water has to be retained and temperature maintained in the tank for 10
people onboard.

================================================== ====

To cruise with 10 people in the tropics, you're going to need a water
maker and lots of power. You might as well spring for a decent sized
generator with 110/220 volt power and not worry about finding 24 volt
appliances or stove fuel.

I agree. We actually will have the Spectra watermaker and these are extremely
efficient. I owned one for 5 years on a 31ft boat and with 5 people 2 120W solar
batteries are able to maintain it to provide enough water daily.

If we use spectra, the watermaker will consume approx the same amount of kwh as
the fridge.

We will have the generator as well

M

"Wayne.B" wrote:

On Sun, 11 Jan 2004 22:34:28 GMT, misia
wrote:

I agree electric heater might be the most energy hungry element, especially if
the water has to be retained and temperature maintained in the tank for 10
people onboard.

================================================== ====

To cruise with 10 people in the tropics, you're going to need a water
maker and lots of power. You might as well spring for a decent sized
generator with 110/220 volt power and not worry about finding 24 volt
appliances or stove fuel.

On Sun, 11 Jan 2004 22:34:28 GMT, misia
wrote:

I agree electric heater might be the most energy hungry element, especially if
the water has to be retained and temperature maintained in the tank for 10
people onboard.

================================================== ====

To cruise with 10 people in the tropics, you're going to need a water
maker and lots of power. You might as well spring for a decent sized
generator with 110/220 volt power and not worry about finding 24 volt
appliances or stove fuel.

"misia" wrote in message
ail.from.there...

I agree electric heater might be the most energy hungry element,
especially if
the water has to be retained and temperature maintained in the tank for 10
people onboard.

This is something that I'm considering to built around hybrid solution.

I came accross this Webasto heater:

http://www.navstore.com/pdf/webasto/Webasto%20TSL17.pdf

What do you think?

I did not check your link, but what you might want to ask your engineer for
would be a design for a water-to-water (Glycol based)heat exchanger to keep
your shower water HOT. This could be done with off-the-shelf electric
components if you have the space, and need only be configured to your space
by your architect and engineer. The electric would be your seldom-used
backup, and you could have your choice of 120, 240, or custom voltage
standard mount heating elements (check off-the-grid, solar, and wind power
resources for these items).

Rob
*
*
*

The exchanger you mention is the engine exhaust exchanger or engine cooling
system exchanger? Do you maybe have any links to practical solutions?

I have found 24V water heater heating elements which could be used as auxiliary.

Regards M



I came accross this Webasto heater:

http://www.navstore.com/pdf/webasto/Webasto%20TSL17.pdf

What do you think?

I did not check your link, but what you might want to ask your engineer for
would be a design for a water-to-water (Glycol based)heat exchanger to keep
your shower water HOT. This could be done with off-the-shelf electric
components if you have the space, and need only be configured to your space
by your architect and engineer. The electric would be your seldom-used
backup, and you could have your choice of 120, 240, or custom voltage
standard mount heating elements (check off-the-grid, solar, and wind power
resources for these items).

Rob
*
*
*

The exchanger you mention is the engine exhaust exchanger or engine cooling
system exchanger? Do you maybe have any links to practical solutions?

I have found 24V water heater heating elements which could be used as auxiliary.

Regards M



I came accross this Webasto heater:

http://www.navstore.com/pdf/webasto/Webasto%20TSL17.pdf

What do you think?

I did not check your link, but what you might want to ask your engineer for
would be a design for a water-to-water (Glycol based)heat exchanger to keep
your shower water HOT. This could be done with off-the-shelf electric
components if you have the space, and need only be configured to your space
by your architect and engineer. The electric would be your seldom-used
backup, and you could have your choice of 120, 240, or custom voltage
standard mount heating elements (check off-the-grid, solar, and wind power
resources for these items).

Rob
*
*
*