whatcharterboat
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Continued from "More design ideas / questions"
Dontpanic42 said
Bruce, Sorry for sounding dumb but what does the “lower 48” mean?
I’ll just throw you some info on diesel heating systems now and maybe this will help. Also I must emphasize that any installation that differs from the manufacturers recommendations should be checked with them before going ahead blindly. And that this post will refer only to Webasto’s products that we have used and may not specifically apply to others or other brands.
LOL. Same here and our propane (LPG) systems in Australia are nowhere near as advanced as in the States. Not the stoves and hot water systems but the propane storage itself . In Aus we don’t have tanks > just bottles. So storage is more limited. LPG is still the norm here for camping but we stopped installing it in our motorhomes about 3 years ago and haven’t looked back.. We also use alcohol yacht stoves/ovens as an alternative to the diesel cooktops depending on the clients’ preference but I’ll concentrate on the hot water systems for now.
Terms I’ll use:
diesel furnace : heats coolant and normally has a pump attached or built in
calorifier : a storage tank with 1 or 2 coolant / heat exchange circuits passing through it
dual top: one unit that combines a furnace , watertank and fan and does NOT heat coolant
space heater: a radiator/fan combo similar to a normal under dash unit.
A typical “diesel furnace” based hotwater system comprises of a furnace that draws diesel prefererably straight from the vehicles fuel tank. (BTW best practice is to install a separate pick up in the main tank as opposed to a “T” into the main fuel line.). However there is nothing wrong from running a separate tank for the furnace supply if you need to set it up this way to allow for removal of the camper or if we are talking about a camper trailer/caravan.
Typically the furnace heats coolant in a circuit, which can run through a calorifier and the trucks cooling system. As an example in an FG this circuit can simply be “T”ed in parallel with the factory cabin heater. Also a space heater can easily be plumbed in parallel with the calorifier (BTW if you do this put an isolation “Gate” valve in series with the space heater so that it can be shut off in summer OR so the coolant can be fine tuned to flow more or less through the heater or calorifier).
So what we now have is an engine, furnace and a calorifier/space heater in a circuit. When the engine runs the coolant heats the calorifier and the furnace remains off. When the furnace runs it heats the calorifier AND the engine so you have your pre heat for cold climates/sub zero starting. The tricky bit is isolating the engine from the circuit, so that when you don’t need the engine pre heat you aren’t losing coolant heat through the engine block when you are camped up but still retain the engine coolant heating when you are traveling.
2 or more ways to do this. Firstly you can isolate the truck with manual valves but this is a bit off a hassle to do all the time or alternatively you can use solenoid valves. More than a couple of hundred bucks each here and you need 2 of them. (BTW make sure you get the “normally closed” or “normally open” bit right so that the valves are energized only when the ignition is “on” and not drawing power when your camped up. So when you are driving the engine is IN the circuit and when you are camped the engine is OUT of the circuit.
If engine pre heat is not a priority, another option is to use a dual circuit calorifier. This gives you an engine coolant heating through one circuit of the calorifier and the furnace runs through the other circuit. The down side here, although minor, is that you have to have a separate coolant header tank for this circuit. With the first option, of course, the engines’ radiator is in effect the header tank and point of fill.
The calorifiers come in a big range sizes from 10 litres up and we have even used a straight heat exchanger (about the size of a brick) with no storage tank at all and this was still successful.
While this next option may not be the most efficient, it is probably the one we do most of and particularly suits short stays and fairly constant travel rather than periods camped up. That is to simply have a calorifier “T”ed in parallel with the engine. If you pull up in the afternoon clients tell me that they still have hot water for a shower the next morning and if it’s necessary you can run the engine for 20 minutes to give you enough heat for a shower. Sure that’s a lot of fuel just for a shower but do the math. You’re charging batteries at the same time and saving the cash outlay of the furnace. Not the way I’d go but simple all the same. I’d prefer to camp up for long periods.
Actually I spoke to the guys at Watts2c (See thread “Simple electrical system for expedition vehicles) regarding development of a new water-cooled DC Genset and the possibility of plumbing a calorifier into its’ coolant circuit. This would be another way to possibly eliminate the furnace say if the genset was to run for ½ an hour a day.
The last common option is to run a Dual Top. We haven’t used one yet but I’m sure they have a place. They don’t run coolant at all and heat the water directly. Also they have 2 hot air outlets that can be ducted into the vehicle for space heating. So a bit of co-generation going on there. Very compact and have a tank built in.
Some other points to make here are that the calorifiers all have an electrical heating element built in so that if you pull into a vanpark or a mates’ place you can run off electricity for awhile and the other point for now is that if you are going to run a calorifier especially plumbed into the engine then fit a thermastically controlled temperature kit to it as a safeguard. These are an adjustable valve that goes on the hotwater outlet of the calorifier and mixes with coldwater to give set output temperature..Very simple to set up but well worth it. If the engine has provided the heat the temps can get very hot and vary so its’ not as simple as dialing down the thermostat on the furnace.
If you could follow all that you’ve done well cause I went to sleep about 3 paragraphs ago. Open for questions but like I said I’m sure there are guys a lot smarter than me around here but this stuff works really well in our climate here and I know all the clients are happy not having to worry about gas.
Hope this helps Bruce. Guess Texas climate would be similar to here too.
Regards John.
Dontpanic42 said
Bruce, Sorry for sounding dumb but what does the “lower 48” mean?
I’ll just throw you some info on diesel heating systems now and maybe this will help. Also I must emphasize that any installation that differs from the manufacturers recommendations should be checked with them before going ahead blindly. And that this post will refer only to Webasto’s products that we have used and may not specifically apply to others or other brands.
LOL. Same here and our propane (LPG) systems in Australia are nowhere near as advanced as in the States. Not the stoves and hot water systems but the propane storage itself . In Aus we don’t have tanks > just bottles. So storage is more limited. LPG is still the norm here for camping but we stopped installing it in our motorhomes about 3 years ago and haven’t looked back.. We also use alcohol yacht stoves/ovens as an alternative to the diesel cooktops depending on the clients’ preference but I’ll concentrate on the hot water systems for now.
Terms I’ll use:
diesel furnace : heats coolant and normally has a pump attached or built in
calorifier : a storage tank with 1 or 2 coolant / heat exchange circuits passing through it
dual top: one unit that combines a furnace , watertank and fan and does NOT heat coolant
space heater: a radiator/fan combo similar to a normal under dash unit.
A typical “diesel furnace” based hotwater system comprises of a furnace that draws diesel prefererably straight from the vehicles fuel tank. (BTW best practice is to install a separate pick up in the main tank as opposed to a “T” into the main fuel line.). However there is nothing wrong from running a separate tank for the furnace supply if you need to set it up this way to allow for removal of the camper or if we are talking about a camper trailer/caravan.
Typically the furnace heats coolant in a circuit, which can run through a calorifier and the trucks cooling system. As an example in an FG this circuit can simply be “T”ed in parallel with the factory cabin heater. Also a space heater can easily be plumbed in parallel with the calorifier (BTW if you do this put an isolation “Gate” valve in series with the space heater so that it can be shut off in summer OR so the coolant can be fine tuned to flow more or less through the heater or calorifier).
So what we now have is an engine, furnace and a calorifier/space heater in a circuit. When the engine runs the coolant heats the calorifier and the furnace remains off. When the furnace runs it heats the calorifier AND the engine so you have your pre heat for cold climates/sub zero starting. The tricky bit is isolating the engine from the circuit, so that when you don’t need the engine pre heat you aren’t losing coolant heat through the engine block when you are camped up but still retain the engine coolant heating when you are traveling.
2 or more ways to do this. Firstly you can isolate the truck with manual valves but this is a bit off a hassle to do all the time or alternatively you can use solenoid valves. More than a couple of hundred bucks each here and you need 2 of them. (BTW make sure you get the “normally closed” or “normally open” bit right so that the valves are energized only when the ignition is “on” and not drawing power when your camped up. So when you are driving the engine is IN the circuit and when you are camped the engine is OUT of the circuit.
If engine pre heat is not a priority, another option is to use a dual circuit calorifier. This gives you an engine coolant heating through one circuit of the calorifier and the furnace runs through the other circuit. The down side here, although minor, is that you have to have a separate coolant header tank for this circuit. With the first option, of course, the engines’ radiator is in effect the header tank and point of fill.
The calorifiers come in a big range sizes from 10 litres up and we have even used a straight heat exchanger (about the size of a brick) with no storage tank at all and this was still successful.
While this next option may not be the most efficient, it is probably the one we do most of and particularly suits short stays and fairly constant travel rather than periods camped up. That is to simply have a calorifier “T”ed in parallel with the engine. If you pull up in the afternoon clients tell me that they still have hot water for a shower the next morning and if it’s necessary you can run the engine for 20 minutes to give you enough heat for a shower. Sure that’s a lot of fuel just for a shower but do the math. You’re charging batteries at the same time and saving the cash outlay of the furnace. Not the way I’d go but simple all the same. I’d prefer to camp up for long periods.
Actually I spoke to the guys at Watts2c (See thread “Simple electrical system for expedition vehicles) regarding development of a new water-cooled DC Genset and the possibility of plumbing a calorifier into its’ coolant circuit. This would be another way to possibly eliminate the furnace say if the genset was to run for ½ an hour a day.
The last common option is to run a Dual Top. We haven’t used one yet but I’m sure they have a place. They don’t run coolant at all and heat the water directly. Also they have 2 hot air outlets that can be ducted into the vehicle for space heating. So a bit of co-generation going on there. Very compact and have a tank built in.
Some other points to make here are that the calorifiers all have an electrical heating element built in so that if you pull into a vanpark or a mates’ place you can run off electricity for awhile and the other point for now is that if you are going to run a calorifier especially plumbed into the engine then fit a thermastically controlled temperature kit to it as a safeguard. These are an adjustable valve that goes on the hotwater outlet of the calorifier and mixes with coldwater to give set output temperature..Very simple to set up but well worth it. If the engine has provided the heat the temps can get very hot and vary so its’ not as simple as dialing down the thermostat on the furnace.
If you could follow all that you’ve done well cause I went to sleep about 3 paragraphs ago. Open for questions but like I said I’m sure there are guys a lot smarter than me around here but this stuff works really well in our climate here and I know all the clients are happy not having to worry about gas.
Hope this helps Bruce. Guess Texas climate would be similar to here too.
Regards John.
I see the solution being to install it in a diving bell