Member Info for observer842

@Phimx: "and not even enough electric output to run a power shower - for the 3.2 KW version and only just for the 6.4 kW version and that's as long as every electrical item in the house is switched off"

I find that a bit of an odd statement. It's certainly important that an mCHP can meet all of your thermal needs if you have no other way of meeting them, but the point isn't to also meet all of your electricity needs - it's to reduce the bill, and potentially make money feeding back to the grid if the electricity can't be consumed on site.

I hope there are no pedantics about! "you could transmit the energy instantly to the tap and heat the water there". Ahem, "you could transmit the electricity generated near the speed of light to the tap and heat the water there"

@Phimx: "I would have thought the load there would be fairly constant and also a bit too high for a 15 kW version" The ideal scenario is a fairly constant thermal load of a little over 15kWt. A lot over, e.g. 30kWt, and you'd take 2 (or 3 for 45kWt). Any clearer? (It's about the total cost of ownership)

@Phinx: "Observer: Another thing that doesn't seem to get a mention is the start up energy costs. By that I mean the energy that goes into getting the Charger up to temperature in a stop start environment e.g. domestic"

This has crossed my mind in the past too. For the moment I'm more interested in heavy usage environments (hot water heating in the commercial sector + space heating in colder months), but I'm more than happy to share my thoughts on the start-stop aspects since they are bothering you :-)

There are a few angles to think about. The first angle in all of this is what to do if the boiler is being thermally led and there is no demand for electricity at that point, and vice-versa, the boiler is being electricity led and there is no demand for thermal.

It's going to depend on various factors, not least the efficiencies involved, and whether you can store or transmit to the grid power (thermal or electrical) you can't use. No doubt some clever internet connected algorithms will be able to determine the best course of action for your particular usage patterns, which may obviously include modulation of the ratio if that is appropriate at that time. It's about minimising your operating cost - and potentially even making money depending on feed-in time of use tariffs and subsidies.

In terms of the stop-start aspects. You've no doubt seen both how fast a boiler can come on, and how fast Stirling engines react to heat, we are likely talking a couple of seconds to full peak power, usually a bit longer from a cold start. Either way, electricity demand is typically longer than that for practically all purposes I can think of. I'm guessing you are more concerned with turning on and off of taps? Well it's going to be no real difference to a normal boiler, though in principle, you could transmit the energy instantly to the tap and heat the water there, rather than down a pipe. LoL! I joke, but how do those kettle taps work?

Ob

The point about starting by targeting where it is most economically attractive (commercial setting) is that you can build up volume and experience and hence reduce purchase and maintenance costs before moving into other sectors (residential setting)

LoL. I guess you started writing that before seeing my message. :-) In a commercial setting boilers are chained together in a boiler room. The first boiler, the lead one, can be running pretty much all the time (this would be the Inspirit Charger), the other ones which come on intermittently to supply additional thermal demand are cheapo ones.

Apologises if that sounded terse! Unpacked: let's start by examining the case for a commercial environment: total cost of ownership, NPV, IRR, CapEx, OpEx, etc, and once we have a fairly reasonable handle on that, it's fairly simple to attenuate these values to the residential sector using whatever assumptions we feel are appropriate. If there is no economic case for the commercial sector, then without some seriously heavy subsidies, I find it hard to see that it would work for the residential sector. It should be easy enough to do for the 3.2kW + 15kW, off ~20kW, less so for the 6.4kWe modulation as we don't have the full facts for this! Though it should be easy enough to estimate some extremes and a central case I suppose. Perhaps one for the weekend! ;-)

@Phimx. As I said earlier: "forget about residential for the moment - commercial is where our focus will be on, ideally as a lead boiler in a boiler room so it can be running most of the time."

If commercial isn't economical then neither is residential. Start discussing that, then discuss residential.

@OldBlue - I appreciate the contribution. But it's probably best we base the discussion on what is included in the Align Report: From what I remember they approach the calculation a little more sophisticatedly than you might have realised is even possible! LoL ;-)

I'm in the mood for new threads today! ;-)

@Phimx
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I don't know what the energy rates are at the moment but if you are using it to create electricity at 35 % eff then say at 4p for gas it's costing nearly 12p for your electric not a huge saving on the grid cost - I think. My concern is without storage then the economics of it all are difficult to fathom for the domestic use since the ratios of heat to gas would change during a use cycle. Again no real detail on that aspect. If your using it to provide constant heat, a nursing as they have suggested then since boiler is only 75% eff it doesn't compare with more efficient systems. So I take their claims of paying for itself in 3 or 4 years with a pinch of salt
]===

I highly recommend you read the Align report cover to cover and we can have a chat about it. We'll probably both be able to improve our understanding as if I recall correctly there were a few bits I found challenging! Point being that report was for the 3.0kW version, with recent improvements (reduced cost, doubling of kWe) it should be far more of an economical proposition than it was even in 2016. By the way, forget about residential for the moment - commercial is where our focus will be on, ideally as a lead boiler in a boiler room so it can be running most of the time.

"Inspirit Energy: On the cusp of cogeneration commercialisation & trading at a fraction of replacement IP cost" (13 Jun 2016)
http://www.alignresearch.co.uk/wp-content/uploads/2016/06/Inspirit-Energy-Align-Research-13th-June-2016-Final.pdf

So it is indeed as you suggested @Phimx: even the 3kWe version was able to modulate the ratio of heat to electricity generated. So presumably they've found a method to module this even further to 6.4kWe (at the expense of the thermal). No doubt if we read the patent in depth it would tell us the "how" of this process - I might even know deep down inside, as I have read it cover to cover a long time ago! LoL!

Worth a new thread! Key quotes below:

"Double take" (25th November 2008)
https://www.theengineer.co.uk/double-take/
===[
The Stirling engine used in Disenco’s system is a two-piston beta type where heat from the boiler turns linear motion into rotary motion, then produces electricity from a generator, using a rhombic drive.
...
Alan Dale, Disenco’s chief executive, said the company aims to target domestic and small business markets. ‘Because it generates up to 3kW of electricity and modulates [changes the proportion of electrical versus thermal energy generated] it fits into three to four-bedroom houses and heat-led SMEs, such as a nursing homes, which keep the heating on for much of the day, or a hairdresser’s where there’s a constant demand for hot water,’ he said.
...
Once the first HomePowerPlant is in production, Disenco plans to develop a wall-mounted version, then decide whether to develop bigger or smaller versions — down to 1kW or up to 6kW — for different-sized properties. With some further work on the Stirling engine, it could also work as an air conditioning unit.
]===

Note the following:

"Product Update" (26th Apr 2019)
https://www.lse.co.uk/rns/INSP/product-update-wokuuge4igv0i2t.html
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The drive system will consist of a single offset crank, leading to less components and more cost efficiencies,
]===

@Phimx. Found it thanks!

https://www.theengineer.co.uk/double-take/

Here is a tip if you want to find something on the web. quote it: "Disenco intends to have HomePowerPlant in production by the third quarter of 2009" took me straight there.

@Phimx
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Just thought of another interpretation, how about a smaller version of the casting itself the resulting cast is the same size engine casing. Only the casting is smaller, I guess it would save a bit of money somewhere.
]===

That's something I hadn't thought of! I'm currently swaying towards the scenario where we have demonstrated a 6.4kWe version (2000 hours), and we were (now perhaps mostly complete?) working on reducing the costs associated with it. e.g. bio-degradable plastic housing and 3D printed metal casting. Last year we hadn't put all things together into a test unit - presumably we have or are very close to now? I think the latest is from March: "At the start of 2020 Inspirit Energy set up the manufacturing and testing site in Poland in readiness to implement the manufacturing and testing of the charger unit. The facility is set up for the manufacturing and testing of our developing technology.", with the June update saying the Polish partner: "... will therefore be able to assist with the testing of our microCHP boiler technology again."

@Phimx
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Oh and burning more gas is bit like cheating isn't it. We have squeezed more out but forgot to mention we used more gas doing it.
]===

I've got no problem whatsoever if we have used more gas to double the electrical output if the systems efficiencies remain the same. Even if the system efficiency in this configuration were to drop from the 90's to 80's or even 50's (!) it may still be a more economical proposition overall than the fixed 3.2kWe proposition, especially if the 6.4kWe is also able to produce 3.2kWe + 15kWt simultaneously off approximately 20kW in! :-)))

Keep up the good research and ideas.

Ob.

Discussing this deserves a new thread!

A couple of interesting quotes that caught my eye:

"Select Committee on Innovation, Universities, Science and Skills Written Evidence - Submission from Disenco Energy plc" (January 2008)
https://publications.parliament.uk/pa/cm200708/cmselect/cmdius/216/216we88.htm
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The appliance modulates and produces between 12kW to 18 kW thermal (heat) and up to 3kW electrical energy
...
Clean Micro Combined Heat and Power (m-CHP)

At current the majority of m-CHP appliances are powered by natural gas, which provides a good, highly efficient interim solution. Due to the depletion of natural gas and the medium term need for renewable technology other thermal energy sources are being considered. It is therefore expected that future Disenco Stirling engines and associate appliances will be designed to accept a variety of clean genuinely renewable fuel sources to power the appliance.

These are expected to include, but not limited to:

Bio gas.

Wood chip (eg short rotation coppice).

Liquid bio fuels (eg oil from plants).

Solar (Disenco existing Patented Hot Platelet End—Heater Head).

In essence any renewable heat source can be considered, as a Stirling engine simply requires heat to function.
]===

@Phimx - I think with your latest find it's unquestionable that the 3.0kWe was simultaneous to the 15kWt: "The simultaneous nominal output of the appliance is 15kW thermal energy and 3kW electrical energy from approximately 20kW input of either natural gas or LPG.". Note they used the word "approximate" when describing the 20kW.

Do we know if the system efficiency increased when 3.0kWe went to 3.2kWe or did it stay the same and either the 20kW input increased slightly, or the output thermal decreased slightly? I suppose it doesn't really matter now as the 3.2kWe to 6.4kWe conundrum is more important! ;-)

@Phimx - are you able to provide a link for "Some words by Disenco mentioned they would or could or had in their power the ability to develop their engine to give a 6 kW and a smaller 1 kW versions."?

Wow, your're on fire today @Phimx! I recommend everyone take a good read:

"Select Committee on Innovation, Universities, Science and Skills Written Evidence - Submission from Disenco Energy plc (January 2008)
https://publications.parliament.uk/pa/cm200708/cmselect/cmdius/216/216we88.htm

I'll add it to the beginning of the "history", next time I update! ;-)

Not surprising @MB - we practically just declared we are going to stop selling them! ;-)

An excellent post @Phimx! I'll reply later.