Warm and happy in Winter

[Kjeld Holm]

My idea is to use waste heat from the motor while driving, as a little heating in the cabin !?

For example with the Trige motor and 48V, there should be plenty of wasted heat to increase the temperature several degrees in the cabin
(Other engines could also be used, but here it is just a benefit with a less efficient motor ;-)


In theory it is not neccesary to heat up the whole cabin, but only around the driver

Estimated 30 - 35% Trige motorlosses:
Max: 36V x 120A x 0.35 efficiency = 1386W (50% = 693 W)
Max: 48V x 120A x 0.35 efficiency = 2016W (50% = 1008 W)

Average: 36V x 60A x 0.30 efficiency = 648W (50% = 324 W)
Average: 48V x 60A x 0.30 efficiency = 864W (50% = 432 W)


Of course, not all waste heat can be used for heating because the engine will still heat up, but maybe 50% of the motorlosses, corresponding to approx. 300 W - 1000 W, could be usefull !?

Some Twike-drivers already exploiting motor-waste heat to supplement the removal of dew from their frontwindow

A radial fan / centrifugal fan is god for blowing through a hose and also have exhaust air throug the side. So it can be placed on top of the right battery, just to the right of the Trige motor-exhaust and suck warm air in and blow it out through a flexible hose.
A hole must be drilled through the wall at the right side of the seat, for the hose. Maybe the hose can be put under the seat and out to your feet/legs, through a new hole next to the batt-charger cooling fan.

A 2.5 - 3 cm high radial fan will fit nicely when there are approximately 7 to 8 cm. between battery and battery/motor cover.

The idea is only sutiable for closed batteries: Gel, Vliess and lithium, so corrosive gases are not blown into the cabin.

A brushless fan motor is probably also a must, so there is no risk of ignition of any battery fumes

Maybe carbon / copper dust from the commutator will be a problem into the cabin !? (A brushless Cityel-motor would be better)

Maybe you need to make a little winter protection below the Trige engine cooling blade, so the warm exhaust air does not mix too much with coold fresh air from below, but keep the warm air in top of the battery box / engine compartment

Likewise, there could be made an extra hole at the left side of the seat, for a soft hose going to the motor air intake. So the engine will partially get heated air from the cabin in winter, which would further increase the temperature in the cabin !?


What do you think of the hole idea, Do you think it can increase the temperature usefull in the cabin, or have I missed something?
Is there maybe corrosive gases too from closed batteries as well ?

Ideeas only get really good, when more people put their thoughts in it too !


NB: I have just dismounted a discarded PC-projector and it had 6 brushless 12V motors inside !!!
Luckly one of them was a good 9.6 W radial engine as in the picture/drawing, so I hope to get the idea testet soon

Have fun and keep cheerful and warm ;-)

 

[Sascha Meyer]

Hi Kjeld,
many el-driver already had this idea, using the motor heat for warming up the cabin. Sounds good, doesn´t it? With cupper heat spreader, one could collect motor heat and transport it with heat pipes into the cabin. One could easily build heat pipes out of cupper pipes, fiilling them with ethanol. This could transport warmness better than just a ventilation, i suppose? And you wouldn´t have the probs with bad smelling air, except after a good danish bean soup. :joke:

Greetings from Germany, Sascha

 

[ba0547]

Hello Kjeld,

i think the heat energy of the engine would not be enougth to heat the cabin of the vehicle. the bottom of the "engine room/battery area" must also be closed anyway.

maybe in your case you have more heat than in my case.

best regards to skive from cold bavaria, harald.

 

[jbl]

I think it is much easier to use a more efficient motor like the Perm and to use a fan heater driven by the saved energy to direct the warmth exactly to the place where you want it to go.

Regards, Jochen

 

[Halreuther]

Moin Mädels,

ich wiess ja nicht, was Ihr so denkt, was Ihr an Temperaturen
aus dem alten Motor kitzeln könnt...

Ich bin heute morgen bei +1°C Motortemperatur losgefahren.
Nach 7 km angekommen hatte der Motor ne Temperatur von 13°C.
OK - wärmer als die Umgebung... aber von "Heizen" kann da doch
wohl keine Rede sein - oder ?

Grüßle - Thomas

 

[Kjeld Holm]

Hi all Heat eksperts

Today my first testdrive with a piece of cardboard with radial fan on top of a hole in the cardboard: The air from the fan was very cold the first 3 km with hi speed and several stops. And after that the fan-air only felt not so cold. And after my trip the motor was only a littel warm :-( so maybe like Thomas have measured, only (13°C - 1°C )= 12°C rise in temperature

But in summer i could not keep my hand on the Trige after several trips and that means about > 60 °C - 20°C ambient = about +40° temperature rise, so let us see with closed bottom and maybee partly recirculated cabin-air...

So Yes Your idea of closing the bottom of the motor-room is a must and first step. And could maybe reduce dust/spraywater from the street too !?

Of cause 300 - 1000W can not heat up the whole kabin in winter, but only a little warmer around the driver or the seat is maybe better than nothing !?

"Heat pipes" is maybee a good idea without with bad air in the cabin, but how to get the heat in the tube and out again is that not quite slow? Directly moving the warmed air by a fan is very cheap and simple

Yes a Perm + electric heat form the batteries is very elegant and simple, but not cheap solution if you have a Trige.
In denmark I think switching from Trige to Perm cost about 2500¤, if you do the job yourself. And the idea was to use wast energy, so it did not reduce our range/km.

Or better Perm + Electric heat and 200Ah Li-bats, if money is no isue ;-)

:xcool:

 

[Kjeld Holm]

Hi Sebastian

Yes of cause the batteryes ned some ventialtion especially when charging

I have had another look around the motorcompartment yesterday and yes it is a good idea anyway to get the bottom of the motorcompartment closed a little, to keep out water, dust, small stones and saltspray. But yes it need a lot of woork to fix it nicely.

Regarding cabin-heating, your solution sounds nice

If using motorwast heat should have a chance i now think the motor itself must have its own enclosure-tube a little larger than the motor housing. The air intake in left side must be airtight in connection with the cabin and the air outlet in right side must also connect to the cabin via the fan, then most of the motor wastheat could transfer to the cabin. But this again needs some pioneer work ;-)

And in summertime the air-in- and outlet needs to be switched to outside air

I do not think heating the 100Kg batteryes, with the motor while driving, is is fast enougt anyway. This heat must build up from inside of the battery, from the current running in them.

:xcool: