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Mini Powerstation In The Home To Cut Energy Bills By £500?


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HOLA441

http://www.dailymail.co.uk/news/article-2810404/Boiler-generates-electricity-cut-power-bills-500-Mini-power-station-provide-heating-hot-water-fuelling-generator-appliances.html

  • Flow Energy say their boilers could lead to normal power stations closing
  • New device uses gas to heat liquid similar to coolant used in refrigerators
  • Vapour then causes mechanism to spin - acting as mini-electricity generator
  • Firm say 20 million of its boilers would save UK consumers £4billion a year

A new boiler could slash energy bills for families by turning their homes into mini power stations.

The gas boiler – designed by a British firm – provides heating and hot water, while also fuelling an electricity generator to power household appliances.

Its maker claims that as well as making electricity bills cheaper, the boiler may eventually allow conventional power stations to be closed.

The company, Flow Energy, said it will provide the boilers – the first of which are due to be installed early next year – without householders paying for them up-front.

Instead the firm will be paid over five years through a monthly supplement on bills. Crucially, this supplement should be cancelled out by savings on electricity as households generate their own power.

This means energy bills will be no cheaper to begin with – but once the initial five-year contract is up, families will start to see considerable savings.

They will use some of the electricity themselves, while any excess can be put into the National Grid. Flow claims households could eventually save £500 a year through a combination of lower electricity bills and selling excess energy.

Sounds too good to be true. I wonder how reliable these boilers will be and how efficient will they be at turning gas into electricity. Also if the price of gas goes up "how" cheap will the electricity be then?

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HOLA442

http://www.dailymail.co.uk/news/article-2810404/Boiler-generates-electricity-cut-power-bills-500-Mini-power-station-provide-heating-hot-water-fuelling-generator-appliances.html

Sounds too good to be true. I wonder how reliable these boilers will be and how efficient will they be at turning gas into electricity. Also if the price of gas goes up "how" cheap will the electricity be then?

It's an interesting idea, but I'm guessing there's a flaw somewhere. I assume the principle is that rather than directly heating the water (high heat capacity) you use the gas to heat a liquid with a low heat capacity/heat of fusion and let the expansion of the resulting gas do the work. As the energy is taken from the gas by the turbine it cools and recondensed and gets put around the loop again. Edited by frozen_out
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HOLA443

It's an interesting idea, but I'm guessing there's a flaw somewhere. I assume the principle is that rather than directly heating the water (high heat capacity) you use the gas to heat a liquid with a low heat capacity/heat of fusion and let the expansion of the resulting gas do the work. As the energy is taken from the gas by the turbine it cools and recondensed and gets put around the loop again.

You took the words right out of my mouth !!

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HOLA444
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HOLA445
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HOLA446
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HOLA447

The basic idea behind micro CHP is sound: use the waste heat from local electricity generation to heat your house.

I'd say the disadvantages are the complexity of the plant, and the small scale -- which generally reduces the efficiency of heat engines, and the fact that perhaps you don't want to generate much heat in the summer.

If you compare getting your heat and electrical power from a micro CHP, versus electricity generated in a large combined cycle gas power station -- or even one which supplies heat to an industrial process, where your heating needs being supplied by independently burning gas, say, then I doubt micro CHP is worth it.

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HOLA448

Clearly a huge success then, as I've never heard of it!

They are used a lot on commercial premises anywhere they generate excess heat and would normally vent it off. Think big office heating systems of in industrial sites, waste heat from furnaces/ovens etc...

Small scale chp has been available for a while, they just cost more to buy and install, so not many people go for them, tending to go for heat pumps instead it seems.

Edited by Squeeky
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HOLA449
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HOLA4410

Doesn't seem to be much novelty in the tech similar to aircon, heat source devices do that, whether the turbine can reaqlly extract that much from the exhaust seems somehwat unlikely but you;d have to be a themodynamics bod to work that out. Nice that you could generate electriciy and hating from the same unit, shame it is fossil fuel based. 500 quid a year over 5 years, not cheap but not stupidly expensive, depends on reliability of the turbine, could be another way to chip a few more pounds off.

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HOLA4411

What do you do with waste heat from your computer?

My central heating system thermostat takes care of that. My bath water heats just that tiny bit quicker since the room radiators shut down sooner. So indirectly yes, the computer heats the bath water if home insulation is good.
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HOLA4412
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HOLA4413

Could see this as being good if you had a swimming pool that needed heating in the summer as well.

I was once asked to devise a house cooling system to dump heat to a swimming pool, with sunlight as the power source and no moving parts except the coolant. Turns out Einstein had a patent for that (Nov 11, 1930)

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HOLA4414

They are using the organic rankine cycle to generate the electricity which uses a principle similar to how air con works. The Baxi units that others have referred to use a sterling engine which is very costly to build and notoriously reliable. The other alternative the fuel cell is also unreliable and very costly. So I think the technology is right one if they can make it reliable.

The real issue is economics and payback. The unit will cost more than an ordinary boiler (double or treble?) but to get a good payback you need to have the unit on 24/7 for a large period of the year. Even in winter most homes switch of their heating at night when everyone is in bed and during the day when people are out at work. In Spring and Autumn your heating is continually switching on and off as the demand to bring the house up to a comfortable temperature is lower. However, in Summer (in effect mid April to mid Sept) the only time this unit will be running is when there is a hot water demand. In addition there is the question of how much electricity the unit will generate. Base load in a home is probably 1/2 kW consumption above that has to be sold back to the grid but the FIT for CHP is far less generous than PV.

Flow Energy seem to be getting round this by putting the unit in at low cost and making the householder pay for it via electricity which you must buy through Flow and a finance package. Flow receive the FIT payments. They state that everything will work out OK at the end of 5 years. Now here's the rub if the flow CHPs are unreliable or electricity generation falls below target then Flow will end up going bust. However, if they have there economics right then they will revolutionise home heating and electricity generation.

My money is on them going bust.

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Guest UK Debt Slave

Interestingly, I worked as an engineer for a company developing a micro CHP boiler for the domestic market

I was employed by this company for about 3 years. I actually took the job figuring it would be a good idea to take a full time position rather than being self employed because I knew the financial crisis of 2007-2008 was just around the corner.

My prediction was correct!

After a short time working there, it became apparent that the whole thing was a complete scam.

The share price was around £3 in 2006, a year before I joined the company. When I left the company in 2010, it was 0.08p

This company spunked about £100 million of investors' money developing a product that was neither green, nor efficient. It was the most amateurish ludicrous work experience I have ever had. Between 2006 and 2010, the workforce expanded from about 25 people to about 130 people and during this time, not ONE single product was ever delivered to market.

The directors of the company all walked away with multimillion golden handshakes for ABJECT FAILURE

It was in one word................. DISGRACEFUL

Edited by UK Debt Slave
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HOLA4417

My central heating system thermostat takes care of that.

Some like it hot. Most of us, for most of the year, wouldn't find that useful.

Interestingly, I worked as an engineer for a company developing a micro CHP boiler for the domestic market

After a short time working there, it became apparent that the whole thing was a complete scam.

So it wasn't actually developing a CHP product, it was going through the motions to collect from suckered investors and public slush funds. And perhaps employees, if it folded owing you money and/or with an ugly stain on your CV.

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HOLA4418

I was looking at the Honda CHP which puts out 1KW electricity and 2.5KW of heat as part of an offgrid set up here in Oz. I reckon with 5KW of solar panels, 1000a/h of batteries and a Honda CHP you have a pretty good offgrid arrangement other than a limited supply of LPG / CNG for the CHP and Gas Oven. There is also enough electricity to supply a fair bit of juice for a plug in Hybrid.

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HOLA4419

I was looking at the Honda CHP which puts out 1KW electricity and 2.5KW of heat as part of an offgrid set up here in Oz. I reckon with 5KW of solar panels, 1000a/h of batteries and a Honda CHP you have a pretty good offgrid arrangement other than a limited supply of LPG / CNG for the CHP and Gas Oven. There is also enough electricity to supply a fair bit of juice for a plug in Hybrid.

Surely the average aussie is ideally placed to go 100% solar, if only storage worked well for you. Isn't anyone flogging you a wide range of storage ideas from gyroscopes to plain heat reservoirs, in addition to regular fuel cells?

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HOLA4420

The main issue with domestic CHP is that it has low thermal power (typically 5-10 kW). This compares to regular domestic boilers in the 28-38 kW range. This gives poor responsiveness with long warm up times.

Many of the newer ones get around this by including a normal high power gas burner as well, for when hot water is required, or when the timer comes on first thing in the morning and before you get in from work. As a result a substantial proportion of the heating is done with the auxiliary burner, not the generator.

These systems work best where a home or building is occupied all day and/or you have space for large amounts of thermal storage.

Once you price in bulky and expensive thermal storage, and estimate the auxiliary heat requirements, plus higher purchase costs and maintenance requirements, then things don't look so attractive (especially if you have to sell energy at wholesale rate without a feed-in tariff)

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HOLA4421

Surely the average aussie is ideally placed to go 100% solar, if only storage worked well for you. Isn't anyone flogging you a wide range of storage ideas from gyroscopes to plain heat reservoirs, in addition to regular fuel cells?

It is - solar output in Perth in the depths of winter (July) is 60% of peak output in the summer (January) when leccy demand is likely to be at its highest anyway due to A/C costs.

However Australia is a very conservative place - despite electricity being at least 50% more expensive double glazing is virtually unheard of.'Wouldn't work here mate'

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HOLA4422

The main issue with domestic CHP is that it has low thermal power (typically 5-10 kW). This compares to regular domestic boilers in the 28-38 kW range. This gives poor responsiveness with long warm up times.

Many of the newer ones get around this by including a normal high power gas burner as well, for when hot water is required, or when the timer comes on first thing in the morning and before you get in from work. As a result a substantial proportion of the heating is done with the auxiliary burner, not the generator.

These systems work best where a home or building is occupied all day and/or you have space for large amounts of thermal storage.

Once you price in bulky and expensive thermal storage, and estimate the auxiliary heat requirements, plus higher purchase costs and maintenance requirements, then things don't look so attractive (especially if you have to sell energy at wholesale rate without a feed-in tariff)

A well insulated domestic 3-4 bedroom house should not need more than an 18kw boiler. In any case no matter how big the boiler heat output will be limited by radiator size and design. My last 2 4 bedroom houses in the UK had 15KW and 12KW condensing boilers.

I think the Honda CHP unit with 2.5KW heat output is ideal for a house built to Passivhaus standards with minimal heat demand.

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HOLA4423
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HOLA4424

I was looking at the Honda CHP which puts out 1KW electricity and 2.5KW of heat as part of an offgrid set up here in Oz. I reckon with 5KW of solar panels, 1000a/h of batteries and a Honda CHP you have a pretty good offgrid arrangement other than a limited supply of LPG / CNG for the CHP and Gas Oven. There is also enough electricity to supply a fair bit of juice for a plug in Hybrid.

Without thinking too much about it, I'd say you'd need to triple that battery capacity, otherwise most of your solar output would be wasted. Mine is 600ah and I only have 600w of panels. Don't forget discharge depth too. Of course if you're charging a hybrid too then that's a bit different.

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HOLA4425

Without thinking too much about it, I'd say you'd need to triple that battery capacity, otherwise most of your solar output would be wasted. Mine is 600ah and I only have 600w of panels. Don't forget discharge depth too. Of course if you're charging a hybrid too then that's a bit different.

Doesn't have to be a battery. Anything that'll hold energy will help. So, for example, if you have an old-fashioned but properly-lagged hot water tank, that's some more solar energy you can use.

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