On Monday, April 14, 2014 10:07:45 PM UTC+1, John Williamson wrote:
On 14/04/2014 20:35, wrote:
On Sunday, April 13, 2014 8:49:24 PM UTC+1, wrote:
I'm talking about 150W element heating 5 litres of water through 45C,
the unit costs ~£250 and requires 27Ahr from cold which takes about an
hour. I don't know how well it is insulated to keep warm during the
shift. So I may get more heat from the exhaust or a diesel heater but
the capital cost wouldn't warrant it.

Why would one spend 250 on a diesel heater when heat can be harvested from the exhaust with metal & rubber pipe?

Because running the engine creates noise and pollution which many people
find annoying. Because it's cheaper to run a diesel powered heater than
the engine used for moving the vehicle. Because the diesel powered
heater starts heating the water immediately without first having to heat
many kilogrammes of metal. Because with today's efficient diesels, they
take ages to start getting warm enough to make a difference to the water
temperature in a calorifier.

I wont quibble with the noise. Its the coolant circuit that takes time to heat up though. Most heat is lost via exhaust, not coolant.

However, it's the electric water heater that's costing £250, a diesel
heater costs over £500 fitted. Installing a calorifier run off either
exhaust heat or engine cooling water costs even more.

How would it cost over 500 to bend some pipe and tack it on to the manifold?


NT