rie317
New member
Does anyone know whether it should be possible to instal a calorifier to a Volvo Penta MD2002 sail drive? Any views would be welcome.
Calorifier
- Thread starter rie317
- Start date
vyv_cox
Well-known member
Is this engine fresh water cooled or raw water cooled? In principle it is possible to add a calorifier to either but it's much more effective for Volvos if fresh water cooled. In that case it is simply a matter of breaking into the fresh water circuit before the heat exchanger.
From my reading, but no direct experience, with the raw water cooled version you have to divert the outgoing water from the engine to the exhaust through the calorifier, not a very satisfactory solution as the cold bypass water also goes the same way. This means that the calorifier efficiency is low and it may take a long period of engine operation to warm your domestic water to a reasonable temperature.
From my reading, but no direct experience, with the raw water cooled version you have to divert the outgoing water from the engine to the exhaust through the calorifier, not a very satisfactory solution as the cold bypass water also goes the same way. This means that the calorifier efficiency is low and it may take a long period of engine operation to warm your domestic water to a reasonable temperature.
snowleopard
Active member
not quite that simple...
on raw water cooling there is a constant flow of cold water to cool the exhaust and this results in the output water varying from warm to cold, never hot. the problem is to use only the water that has gone through the block to heat the calorifier. this may or may not be possible depending on the engine type.
on raw water cooling there is a constant flow of cold water to cool the exhaust and this results in the output water varying from warm to cold, never hot. the problem is to use only the water that has gone through the block to heat the calorifier. this may or may not be possible depending on the engine type.
sirius
New member
I have a calorifier connected to my raw water cooled 2003 (similar arrangement). It is not ultimately efficient, and takes a little while of running to heat the water, but it does work. The connection is simple and diverts the cooling water when it exits the thermostat cover, through the calorifier, and back to the exhaust junction.
I believe that fresh water cooled would be better. However, if anyone knows of a three-way valve like the ones fitted to domestic central heating systems in houses, which would only channel hot water to the calorifier I would be very interested.
Simon
I believe that fresh water cooled would be better. However, if anyone knows of a three-way valve like the ones fitted to domestic central heating systems in houses, which would only channel hot water to the calorifier I would be very interested.
Simon
vyv_cox
Well-known member
Re: not quite that simple...
My info is based on an article by PBO's engine expert about two months ago. This states as the later poster said, that water needs to be taken from the top of the thermostat housing. I'm not sufficiently knowledgeable about the Volvo, but on other engines the whole coolant flow merges together at the thermostat, so the flow taken from here would not be hot, as I said, but a mixture of heated and bypass water. The Bukh arrangement is much better, it circulates water between the top and bottom of the block but it needs a separate pump to do so.
My info is based on an article by PBO's engine expert about two months ago. This states as the later poster said, that water needs to be taken from the top of the thermostat housing. I'm not sufficiently knowledgeable about the Volvo, but on other engines the whole coolant flow merges together at the thermostat, so the flow taken from here would not be hot, as I said, but a mixture of heated and bypass water. The Bukh arrangement is much better, it circulates water between the top and bottom of the block but it needs a separate pump to do so.
jleaworthy
New member
The Volvo Part you need is 840775-1. It fits between the thermostat housing and the exhaust elbow and takes water through it only when the thermostat is open ie the engine is up to working temperature. You could of course just take a pipe cutter to the existing pipe in that position and with a couple of elbows save yourself some money but you would have to arrange for axial pressure to be kept upon the pipe as it enters the thermostat housing because there's no clamp. The volvo part is made to the correct length and provides two pipe ends for connection to a calorifier. The water won't be as hot as with a fresh water colled engine but otherwise a calorifier should work OK.
vyv_cox
Well-known member
Do you know how it only takes hot water from the thermostat? Is there a separate route for bypass water to the exhaust?
jleaworthy
New member
Yes there is a separate route. From the water pump the cooling water is taken through the head in a perforated brass tube. It exits at the back of the engine with a little 'S' shaped tube taking this water into the exhaust bend. Cooling water flows through the perforations and around the engine only when the thermostat opens and allows it to exit the head/block and flow through the calorifier if fitted and then into the exhaust bend. Hope this is of use.
rie317
New member
Very many thanks for all the helpful responses to this request - much appreciated! While I note that the water will not be as hot as with a fresh water cooled engine, I think that, combined with an immersion heater for use when hooked up to shore power, it will be the cheapest and most suitable solution.
vyv_cox
Well-known member
Again, no experience with the Volvo, but my raw-water cooled Bukh produced domestic water too hot to put my hand into after about 20 - 30 minutes of motoring.
It is very important to make sure the connections are correct for thermo-syphoning, i.e. the hot coolant water enters the calorifier at the top. Otherwise it is possible to stop the flow completely, not producing hot water and maybe damaging the engine.
It is very important to make sure the connections are correct for thermo-syphoning, i.e. the hot coolant water enters the calorifier at the top. Otherwise it is possible to stop the flow completely, not producing hot water and maybe damaging the engine.