Has anyone heard of Micro Combined Heat and Power units. I am made to believe that these are boilers that also generate their own electricity and are highly efficient. I know of 2 suppliers atthe moment only which are Powergen's Whispergen and BG's Microgen.
Any advice?
Faz
The Whispergen is available in NZ. A stand alone CHP Stirling engine unit. The Whispergen produces 1kW and heat as a byproduct. Sigma of Norway produce a 3kW unit, not available yet.
The Microgen is a wall mounted unit producing 1kW and there will be a combi version too. And is not available yet, but manufacturing is being done in Japan by Rennai.
Gledhill have developed a thermal store, the mCPH, a derivative of the Boilermate, specifically for mating with a CHP unit with a control board to control and mate the two.
Millions of homes are to be built and heavy building at Ashford in Kent and Milton Keynes in Bucks. If all these homes had these then less power stations would need to be built, less power infrastructure which is always overground by pylons (gas is in pipes under). They are about the same efficiency as a condensing boiler, so not attractive to an individual, so subsidy is the only way to kick-start them. With the right control system, Gledhill have developed one, they can be optimised to produce electricity which is 3 to 4 times more expensive than gas. Claims of 25% more efficiency in electricity and gas combined is claimed, beside the environmental spins offs. So they may be worthwhile to the individual. The Microgen will work in a power cut, so fine for remote areas (runs on LPG too). The government is very interested in them and it looks like they will take off.
These units are to be referred to as "Boilers". They are also aimed at the boiler replacement market.
I hadn't realised that they had gone into production yet. I think they're a great idea, but personally, I prefer to avoid 1st generation products. If you are into the "bleeding" edge, then try one. Just make sure you post the results here!
They don't generate much electricity, so you still need a genuine electricity connection. However, they will plod away producing enough for your lights/fridge/freezer/TV, so that you only draw electric current from the mains when you're doing something big, like using the tumble dryer or kettle.
Christian.
Hi,
Gledhill do something designed to use micro CHP, see this post:
cheers, Pete.
They will produce electricity intermittently. When the thermal store is up to temp and no heat is demanded from CH and DHW, then you draw from the grid. It is claimed that over 50% of all electricity will be generated in the home using these units and 25% cheaper to run in both gas and electricity, as you also sell electricity back to the power company.
The peak demand for DHW and CH is at the same time peak demand for electricity on the grid. So, when heating the place, it will power your home up to 1 kW, which is a fair amount of power, and sell any surplus back to the grid.
The Whispergen has been in use in boats for along time. Not first generation with this model.
Personally, mine would rapidly grow a small battery bank, so it could be operated entirely off-grid, in case of power failure, and to provide for larger surges than 1Kw. I'd also be looking at a small gas storage tank that could be plumbed up to the boiler for a mains gas outage too, as well as considering a large thermal store.
The power company is of course the best place to sell back to, much better than a battey bank - if it's working.
A bit of careful design with the heatbank could get better than this. If you have space to oversize the cylinder, you could get it to only demand heat when less than 1/2 full. Then it could be available for electricity until full. I haven't seen the specs, but I presume the CHP's heat output when demanding electricity only would be around 3kW when producing 1kW of electricity, so you could get several hours of electricity out of it before the heat bank is 100% satisfied, requiring the motor to be shut down.
Christian.
This is what Gledhill hope to do. The store literally stores heat that would be otherwise wasted. The CHP Stirling units alone, don't produce that much heat, say compared to a 25kW boiler, so it could trickle charge the store retaining heat while producing electricity. The Microgen has an additional burner to boost the Stirling engine. The control system and sizing of the store is essential in gaining maximum efficiency. The scenarios of calling for electricity and no CH or DHW or DHW calling and no electricity called, ect, have to be thought out. A self adaptive control system remembering the demand of the house, would be likely.
No need. The Microgen can work off the grid giving 1kW 1kW will provide all essential services to a house: fridge, lights, power for CH, DHW, etc.
I'm not sure if you can store natural gas. You can but they may object. It may be cheaper to have a natural gas and an LPG CHP boiler unit. The LPG can be run off large gas bottles as this would be for backup only, so no need for an expensive to buy and rent large LPG tank laying there consuming money.
Good idea. And run very low temp underfloor heating from it.
In your case I assume it doesn't. If you are prone to outages, then the secret is to have as little on electricity as possible. And the appliance you do, make sure they are all very high efficiency models. Running a gas tumble dryer is a start.
1Kw is not enough. A fridge and freezer will easily use 1Kw (if they happen to start at once.) Plus, with the microgen, you need power to start it.
I was more thinking of a couple of large propane cylinders, to cover short outages. (after investigating if I can safely compensate for the different gas properties with different feed pressure, or if I'd need to swap nozzles)
When we've discussed this in the past I've suggested modifying a Honda inverter genset, as this would give a higher proportion of electricity to heat, albeit at the cost of increased pollution.
Problem is that the MTBF on gensets tend to suck a bit. I want one that'll go for at least ten years. I don't think there are many gensets that'll do this. Of course, if you do it right, you can run a conventional generator from gas.
I bet quite reasonable efficiencies could be obtained by running a small immersion heater off the motor if heat, but no leccy is required, assuming thermal efficiency of the system is good enough.
Christian.
Our first Lister went 15 years and 22k hours before it rattled the control box to bits. The alternator and engine are still ok.
It'll be interesting to see how it goes, I think the alternator is built into the flywheel (at least the magnets will be and the coils will be mounted opposite, not like a conventional armature and rotor). So an exchange engine cw flywheel shouldn't be to big a deal. Being gas powered the oil will last a bit longer than a diesel too.
AJH
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