Cabin heat from engine

[dor]

Had the first real opportunity last week to try out the idea of using the calorifier to act as a heat exchanger between the engine & CH system.

 

I recently fitted a twin-coil calorifier in place of the old single coil one, so I could use the Alde to heat water as well as the engine.

 

I had assumed that if I ran the Alde pump but with the alde itself off, heat would be picked up by the Alde coil and could be circulated through the rads. I didn't expect them to get particularly hot, but enough to take the chill off.

 

Well it has out-performed all my expectations. With four rads in the system, they get too hot to hold your hand on, and keep the cabin very warm, which was much appreciated on some of the cold wet days last week.

 

I've put a full-flow ball valve in between the Alde and the coil, so I can stop the alde trying to heat the hot water when it doesn't need to.

 

I've got a temperature sensor on the calorifier half-way up the side (a cheap digital indoor-outdoor thermometer, with the outdoor sensor up against the tank under the insulation). This will show over 60C after a bit of cruising, and even with the radiators being heated will hold this temperature - I had expected it to take a lot of the heat from the tank.

 

Feeling quite pleased with myself!

[Guest]

Had the first real opportunity last week to try out the idea of using the calorifier to act as a heat exchanger between the engine & CH system.

 

I recently fitted a twin-coil calorifier in place of the old single coil one, so I could use the Alde to heat water as well as the engine.

 

I had assumed that if I ran the Alde pump but with the alde itself off, heat would be picked up by the Alde coil and could be circulated through the rads. I didn't expect them to get particularly hot, but enough to take the chill off.

 

Well it has out-performed all my expectations. With four rads in the system, they get too hot to hold your hand on, and keep the cabin very warm, which was much appreciated on some of the cold wet days last week.

 

I've put a full-flow ball valve in between the Alde and the coil, so I can stop the alde trying to heat the hot water when it doesn't need to.

 

I've got a temperature sensor on the calorifier half-way up the side (a cheap digital indoor-outdoor thermometer, with the outdoor sensor up against the tank under the insulation). This will show over 60C after a bit of cruising, and even with the radiators being heated will hold this temperature - I had expected it to take a lot of the heat from the tank.

 

Feeling quite pleased with myself!

DOR

That is interesting. If i understand you correctly, you are exchchaging heat from the engine via the calorifier to heat your cabin radiators whilst cruising? Additionally you can heat water from the Aldi?

Reason I ask is that I have one of those convector blowers lying idle, and have wondered about connecting that as you have described.

Thanks

[dor]

Hi Cat

 

Yes, it is a fairly conventional twin coil setup as far as I am aware.

 

So the engine is heating the water in the calorifier as normal, then the hot water in the calorifier heats the water in the radiator circuit through the second coil. The alde pump is used to circulate the water, without the Alde itself running.

 

What surprised me was how much surplus heat there must be, as even with the rads at full temperature, it still maintained the temperature in the calorifer.

 

You could always plumb in a rad or convector etc on the calorifier return - that way you you could use the heat even if you only have a single coil calorifier.

Edited May 29, 2006 by dor

[Noah]

Hi DOR

 

I'm supprised that there is sufficient heat exchange between calorifier water and the rad circuit, but now you have proved this successful I will have a go myself with my Webasto's water pump or even a second 12V pump connected in parallel. Was it easy to tap into your Alde pump to switch it on independently? I wonder if a second advantage of this setup would be the ability to provide additional engine cooling in an emergency (for example, if overheating when going against a strong tide or current for several hours)

 

Noah

[dor]

Hi Noah

 

I just turn the Alde thermostat switch on, with the thermostat setting quite high, so that the pump keeps running. The gas control knob is left in the off position.

 

It would be easy as well to run a switched feed to the pump, which would override the thermostat.

[Noah]

Aah, I don't have that facility on my Webasto so I'll have to find out how to switch it's water circulation pump on without it firing up. Otherwise I'll add a separate 12V pump that will by-pass the Webasto boiler.

 

Noah

[elessina]

Dor, We have a twin coil calorifier, and also find that the heat exchange between calorifier water and the rad circuit is much greater than expected. So great is the heat exchange that I am a little worried that the heat may actually do some damage to the installed webasto diesel heater….. It gets very hot!!..... Our engine is a 92hp Perkins with skin cooling, so I guess it produces more heat than a narrowboat engine, and it takes around 2 hours of cruising at 6 knots on a river to produce this high heat transfer.

 

Noah, The Webasto has only recently been installed, and 1st time on, with the heater on 'auto' the webasto pump automatically came on and circulated the water around, I now have it on 'off' and it does not operate. I have a couple of valves isolating the radiators so the webasto currently only circulates through the calorifier (summer hot water heating). The timer I have is a 7 day multi event timer, 'auto' is on timer.

 

I will have to re-check to be sure it circulates on auto, it did it once / first time and I am 99% sure it was not set to come on at that time, but need to check again…… also thinking about it I am sure it was only the water pump running and not the heater, because I remember assuming that the heat had triggered a heat sensor and started the water pump.

 

But I can see it will be useful for spring / autumn cruising as we will get 'free heat' from the rads, and we have a radiator in the wheelhouse which I can turn on separately to all the others.

 

Also noticed some heat transfer into the engine cooling system (very little) when the webasto was on in the winter, but do not want to add any ball valves / isolationg valves in either system as it would be very easy to forget to open them when needed, stopping circulation.

 

Ian

DB Elessina

[dor]

So great is the heat exchange that I am a little worried that the heat may actually do some damage to the installed webasto diesel heater….. It gets very hot!!.

 

Also noticed some heat transfer into the engine cooling system (very little) when the webasto was on in the winter, but do not want to add any ball valves / isolationg valves in either system as it would be very easy to forget to open them when needed, stopping circulation.

 

The way I have set mine up is with two ball valves. One is on the cabin radiator circuit, so i don't have to heat the rads if I want to heat the water from the Alde (and quicker than going round turning off individual rads).

 

The other ball valve is on the circuit to the calorifier, so I don't have to heat the water if I want the Alde to heat the rads. Equally important is that it means I won't take heat from the calorifier after the engine has stopped, as the engine will get the water hotter than the Alde. To avoid the possible problems associated with both valves getting turned off together, I have a radiator in the bathroom which is not isolated by either of the ball valves.

 

I also have a one-way flap valve in the engine-calorifier circuit, to prevent heat loss into the engine at night.