Heat recovery from car radiator.

[brewnog]

I also saved a couple of posts from a forum (no longer online) by a bloke here in the UK who was using a small fiat IDI diesel car engine in a home made CHP unit. He was powering and heating his house and a stable block using chip fat for fuel. I had some email correspondance with him at that time. I could post all that here (there is a fair bit) if that would be of interest.

Personally I think for CHP it is better to start with a fixed speed stationary engine of some type. Preferably some thing which is designed to give good power at low rpm. I know of a few companies offering this sort of system and/or selling components if that is also of interest. I could post some of this information if it would be of use.

Thanks very much for the links Darren. I work with medium sized (500kW - 8MW) CHP systems routinely, and am convinced that there's a huge market for domestic micro cogeneration systems. Any automotive Diesel engine can be easily optimised to run at a suitable speed (1500/1800/3000/3600rpm) for power generation, and with a few simple components can easily be adapted to heat a building. The electricity generated can be sold onto the grid on a peak shaving scheme. When it's economically viable, the engine runs, the electricity is sold, and the house is heated. When it's not, the engine sits unused, and a conventional gas boiler heats the building instead. With the advent of mass biodiesel availability, this would be an extremely environmentally friendly means of power generation and heating.

Just insulate the garage. If the garage is attached to the house the heat lost from the car goes into the garage and slows the heat loss from the house to the garage. No heat exchanger is necessary.

You'll smoke yourself out with exhaust fumes, and while you'll heat the garage, you won't heat the house effectively, or be able to heat water.

 

[DarrenUK]

With the Mercedes engines we were working with (two different engines one from the 70's aone from the 80's) we had trouble geting the governing of the 80's engine correct as the characteristics of the pumps governor would not behave well when coming off loads.

When we invetigated the economics the renewable obligation certificates scheme and another government pay out for heat production made it look more viable when using a biofuel. Cheapest fuel source would be used cooking oil but there was the possibility of running into problems with the waste incineration directive.

Personally I think that the energy density of plant oils make them a great candidate for transportation fuels. The amount currently available is however only a small proportion of our current transportation usage an it would be a shame if due to a skewed market this fuel source was used for heat and power where other more bulky products could do the same job (gasified woodchip?).

I think there is a place for small, bio-oil fuelled, CHP - remote locations etc. and at present and I think for a fair few years the adoption of small CHP systems would be good for promoting the use of bio oils in diesel engines.

Best

Darren

 

[brewnog]

Load rejection can indeed be a big problem, and is one of the reasons electronic control of fueling was adopted so early on engines which could easily have retained mechanical control for a while.

I tend to agree with you regarding the use of plant oils for automotive use due to energy density, but I struggle to imagine the necessary agrigulture and infrastructure becoming widespread enough to support every vehicle on the roads. It'd be nice, but it seems like too much of a step change for us.

I also tend to agree with your comment about more bulkly, less easily stored fuels being used for stationary engines. I particularly support the use of landfill and sewage gas as fuels since burning these actually reduces emissions released to the atmosphere, where burning vegetable oil (whilst carbon neutral) does still produce most of the usual emissions you'd have with a Diesel burn. Woodchip gasification, mine gas, digester gas, it's all good.

 

[DarrenUK]

I'd agree that the production to support current road fuel use (which is growing) of vegetable oil is propably unachievable. Algae could possibly make a big chunk other oil bearing plants also. Currently the feedstock used tends to be eadible oils which is what we are used to growing and cropping and have bred for good yield. There are plenty of other oil bearing plants which could hold potential.

Anyway I don't see a direct replacement of all current road fuel. It's hard to predict the future which is why the shift to biofuels has been relatively slow - people don't want to invest. Maybe the supplies mineral oils will dry up, maybe CO2 regulations will force the shift from diesel and petrol, maybe growing demand for mineral oils will push up the price - maybe any of these will not happen.

I think if supplies of oil start to dry up or get very expensive soon we will see the adoption of a number of different technologies to replace our current road fuel usage. I also guess that transport usage patterns will change. As I say its hard to tell what is going to happen

I do see PPO being useful for fuel somewhere / somewhen because production is very simple just press oil seeds, filter and put it in your engine (at least in the case of rapeseed oil and I expect other feedstocks there is an art to doing this correctly to get good quality fuel - without the right equipment and knowledge to do it properly the oil will be of the wrong chemical composition to burn properly) The by product makes good food / animal feed, in the case of edible oils or fertiliser in the case of non-edible oils.

 

[DarrenUK]

Sorry for the terrible spelling, grammer and sentance composition - I really should spend some time reading what I just typed before posting...

Brewnog,

I'd not come across mine gas before. From what I just read it would be stupid not to use it.

Best

Darren

 

[Artman]

You'll smoke yourself out with exhaust fumes, and while you'll heat the garage, you won't heat the house effectively, or be able to heat water.

Brewnog, then the OP needs to reword his post. He said waste heat. That implies the primary use of the engine is something other than this form of heating. I took this to mean he was placing his car with a hot engine from driving it in the garage and turning it off. Then trying to capture the waste heat from the engine as it cools, which could be done simply as I said, by insulating the garage. This will give the house as much benefit as trying to transfer the heat to the house through a water piping system, without the difficulty of rigging up a radiator, transfer piping, pumps, etc.

Trying to see if it is viable to capture waste heat from radiator of cars(s) to pre-heat water heater and or radiant floor.

 

[Plastic Photon]

Are thermocouples in the engine attached to a space heater out of the question?