Another wierd C&G level 2 exam question

[richardindorset]

On my course I'm amazed how little quizing of the students there is by the tutors. No "gather round everyone, look at Fred's install here. What's wrong with it?" or "Can anyone tell me what the difference is between a TT and TNS system?" etc. We just to the worksheet questions...

Anyway going back to the original question, on another forum I posted it on, someone said that ASHP was not a valid answer because its not a micro-generation system...

I don't agree, but could that be what C&G were getting at? (One of their classic trick answers)

 

[ericmark]

A square of sides 4cm and 6cm has an area of: 24ml, 24cm³, 24cm² 24cl.

So that will be (4 + 6)²? as clearly a square has two equal sides and the word 'and' is same as a + so 10m² is the answer, the point however is the answer will be some thing ² but the cm is not a ISO unit so should not be used anyway.

As to the question in this case, I would agree not straight answer however, anything which moves must have some parts which can wear, so more have a finite life, this life may be very long, however it must have a limit.

However maintenance is not limited to parts which wear out, clearly a pressure vessel must be tested at regular intervals, and electronic capacitors we know have a limited life. So looking at the question.

Which one of the following micro-generation systems requires the least maintenance once installed?
a) Micro-combined heat and power – These are in the main a boiler with a Stirling engine, and it does not state if the boiler is supplying a pressure vessel but many do, so we need it consider it will need a service once a year.
b) Air source heat pump – These have been around for a long time, it does not qualify what sort of air source heat pump, if for cooling, heating, or both, or is a integral unit or has separate units, the main problem with the split units is the failure of the condensate scavenger pumps, which if they fail can bring a ceiling down, they are not required with heat only, but again one has to assume an annual service before each summer period.
c) Biomass – These are solid fuel burners, and we must expect a build up of soot, tar excreta so must need the highest maintenance, OK user maintenance, but still maintenance so easy to rule this option out.
d) Solar thermal – This one must assume is the heating of domestic hot water, in theory these should run year in and year out without any maintenance, installed on a flat roof with the tank on stilts above the panels as done in countries like Turkey, these can run as my daughter well knows trouble free for years. However in the UK these do not have tanks on the flat roof, so they need pumps to circulate the water through the panels, I know from my father-in-laws install they are prone to getting air locks should the pump not cut in at the correct time. I think this is the option expected to have least maintenance, however in real terms it required quite a lot.

So we can rule out Biomass, but as to the other three it would require a study to see which required the most, and one must also consider number of maintenance personal, clearly if it required two people for safety then the maintenance is doubled. But as to the three systems in their basic form, i.e. with the Solar thermal installed on a flat roof with header tank above the solar array, this must require the least.

However this is a general engineering question, not an electrical one, as the Solar thermal has no electrical parts, also the Micro-combined heat and power may be a boiler with a Stirling engine, but could also be a generator with the cooling water being used as with most narrow boat installations.

I know there is a piece of string down the centre of a cable, so the answer to how long is a piece of string is equal to one tenth of a nautical mile, however a nautical mile is not a fixed length, it depends where one is, as the earth is not round like a ball, and when flying a nautical mile is longer than when in a boat, so the question is like asking how long is a piece of string. 185 to 241 yd is quite a big variation.

As to RAE showing ones age, it does not exist any more, my son passed it and he is 46 now, it was not long after that you needed to take three courses with marked course work to get licence, so much quicker with an exam.

 

[Notch7]

I have my ASHP serviced on the same schedule as my refrigerator

cool answer

 

[Notch7]

One maths question last year for age 13 was: A square of sides 4cm and 6cm has an area of: 24ml, 24cm³, 24cm² 24cl.
Later the stats were given;
for their class of 28: 24ml=2, 24cm³= 11, 24cm²=7 24cl=8 and
for the year of 9 classes: 24ml=37, 24cm³=71, 24cm²=76 24cl=55

I dont understand any of this

a square is a special rectangle, as it has 4 equal sides

so what does "a square of sides 4cm and 6cm" mean?

its teaching children the wrong meaning to words

 

[robinbanks]

cool answer

Thanks! Originally it was lardger but ended up too wordy. I did manage to make it a bit shorter but Carnot compress it any more

 

[richardindorset]

So that will be (4 + 6)²? as clearly a square has two equal sides and the word 'and' is same as a + so 10m² is the answer, the point however is the answer will be some thing ² but the cm is not a ISO unit so should not be used anyway.

As to the question in this case, I would agree not straight answer however, anything which moves must have some parts which can wear, so more have a finite life, this life may be very long, however it must have a limit.

However maintenance is not limited to parts which wear out, clearly a pressure vessel must be tested at regular intervals, and electronic capacitors we know have a limited life. So looking at the question.

Which one of the following micro-generation systems requires the least maintenance once installed?
a) Micro-combined heat and power – These are in the main a boiler with a Stirling engine, and it does not state if the boiler is supplying a pressure vessel but many do, so we need it consider it will need a service once a year.
b) Air source heat pump – These have been around for a long time, it does not qualify what sort of air source heat pump, if for cooling, heating, or both, or is a integral unit or has separate units, the main problem with the split units is the failure of the condensate scavenger pumps, which if they fail can bring a ceiling down, they are not required with heat only, but again one has to assume an annual service before each summer period.
c) Biomass – These are solid fuel burners, and we must expect a build up of soot, tar excreta so must need the highest maintenance, OK user maintenance, but still maintenance so easy to rule this option out.
d) Solar thermal – This one must assume is the heating of domestic hot water, in theory these should run year in and year out without any maintenance, installed on a flat roof with the tank on stilts above the panels as done in countries like Turkey, these can run as my daughter well knows trouble free for years. However in the UK these do not have tanks on the flat roof, so they need pumps to circulate the water through the panels, I know from my father-in-laws install they are prone to getting air locks should the pump not cut in at the correct time. I think this is the option expected to have least maintenance, however in real terms it required quite a lot.

So we can rule out Biomass, but as to the other three it would require a study to see which required the most, and one must also consider number of maintenance personal, clearly if it required two people for safety then the maintenance is doubled. But as to the three systems in their basic form, i.e. with the Solar thermal installed on a flat roof with header tank above the solar array, this must require the least.

However this is a general engineering question, not an electrical one, as the Solar thermal has no electrical parts, also the Micro-combined heat and power may be a boiler with a Stirling engine, but could also be a generator with the cooling water being used as with most narrow boat installations.

I know there is a piece of string down the centre of a cable, so the answer to how long is a piece of string is equal to one tenth of a nautical mile, however a nautical mile is not a fixed length, it depends where one is, as the earth is not round like a ball, and when flying a nautical mile is longer than when in a boat, so the question is like asking how long is a piece of string. 185 to 241 yd is quite a big variation.

As to RAE showing ones age, it does not exist any more, my son passed it and he is 46 now, it was not long after that you needed to take three courses with marked course work to get licence, so much quicker with an exam.

All valid points but going by the learning material provided, only ASHP and GSHP are quoted as being "fit and forget". Maintenance is not mentioned on solar thermal, so as 'we' are students and not micro-gen service engineers with years of experience, the answer is ASHP. Except its not, apprarently its Solar thermal which therefore, going by the learning material, requires less maintenance than a system that is "fit and forget". Not sure what that would be then.... "fit and forget and it even replaces itself after 10 years"?

 

[JohnW2]

Yes MCQ is a pretty poor way to assess the state of learning.

I suppose that depends upon what one means by "the state of learning". As I've said, MCQs are fine for assessing "prompted recall" - and that may or may not be adequate, depending on the context.

A proper mix of classroom and practical work, which relates to the classroom work with continual assessment by the tutors would be best. Any tutor can pick up who gets it, who is getting it slowly but surely and who is a lost cause pretty quickly.

That is certainly probably the theoretically best method of assessment but, in practice, is not without its potential problems - primarily that an assessment by a single human tutor may, in some cases,be 'biased' by such issues as 'personality clashes' or, worse, various 'prejudices' (based on sex, race, appearance, 'general behaviour' etc. etc.)- and,of course requires that the 'single human tutor' is, reasonably competent and 'fit to assess'!

I hated final technical exams and in the end I devised a way to pass them by simply learning to write out all the required formulas on a sheet of paper. I'd keep doing it until I could just write them all out from memory. When the exam started, I'd just write out my sheet of formulas and then start looking at the questions. After 2 days I would have forgotten all those formulas. It was a completely pointless exercise.

In many fields,it cannot reasonably be expected that people will remember ('for ever') all relevant matters of detail-so,as you imply,simply 'mugging up'such facts immediately before an exam achieves little (other than passing the exam¬!). When I did my A-Levels, many decades ago, we were provided with 'formula sheets' or use during the exams.

'Learning' is not just (or even primarily) a matter of 'learning (and remembering) facts' (as one might learn a poem!). Far more important is learning about underlying basic principles (which will ofen enable one to 'work things out' for themselves), coupled with knowledge of where to find the detailed information when one needs it.

The C&G course I'm doing now is also odd in that the theory lags the practical by months. We covered the theory of 2 plate and 3 plate lighting about 4 months after we'd done it in the practical workshop. It would be much better if the theory was done in the morning and the practical application of it followed immediately after.

That's presumably just a badly-designed course. I've seen a good few which suffer from problems such as you describe.

 

[Harry Bloomfield]

'Learning' is not just (or even primarily) a matter of 'learning (and remembering) facts' (as one might learn a poem!). Far more important is learning about underlying basic principles (which will ofen enable one to 'work things out' for themselves), coupled with knowledge of where to find the detailed information when one needs it.

Learning, simply provides you with the essential tools, a starting point, from which useful decisions can be made.

 

[Harry Bloomfield]

The C&G course I'm doing now is also odd in that the theory lags the practical by months. We covered the theory of 2 plate and 3 plate lighting about 4 months after we'd done it in the practical workshop. It would be much better if the theory was done in the morning and the practical application of it followed immediately after.

Some courses are entirely theoretical, with no practical. The modern RAE is like that, all you can expect is the mock papers,

 

[JohnW2]

Learning, simply provides you with the essential tools, a starting point, from which useful decisions can be made.

Exactly, and it's certainly not primarily about learning a list of facts,parrot-fashion.

 

[SUNRAY]

So that will be (4 + 6)²? as clearly a square has two equal sides and the word 'and' is same as a + so 10m² is the answer, the point however is the answer will be some thing ² but the cm is not a ISO unit so should not be used anyway.

Well clearly the 4 answers given are 24 so clearly the dimensions of the quadrangle are 4 by 6 and regardless of ISO units cm is being taught regularly.
My gripes with this are:
The incorrect description of the quadrangle,
The level of education for 13 year olds and he horrendous results with only 25-30% being able to work out guess a simple area correctly.

 

[JohnW2]

The level of education for 13 year olds and he horrendous results with only 25-30% being able to work out guess a simple area correctly.

Indeed, that's pretty extraordinary, and clearly not really acceptable.

I feel sure that, at that age, I and the vast majority of my contemporaries would have known which of a list was the correct unit for an area. Goodness, I was only one year older than that (i.e. 14) when I did O-Level Maths!

 

[ebee]

Indeed, we could leave schooldays behind when we were not much more than toddlers back then and get an apprenticeship or a shop job or join the army.
Yep 14, 15, 16 you knew yer formulas, could add up etc in yer head and figure things out, you could repeat up to the 12 times table and could cross the road observing safe practice. You knew that if you climbed a high tree for conkers that if you fell you could break yer legs or worse and not blame anyone else for your stupidity.

You would, instinctively, not walk across a glass sheet 5 storeys up or stick yer fingers near mains voltage because there was an RCD present, you would not drive at 100mph round a blind bend because your car has crumple zones, you just would not do it.
It was not an alien planet, it was the Earth where we still live today.

We did not have "Smart Phone Zombies" suddenly appear in the path right in front of our cars, buses, trains.

"Oh, let`s put a safety device in then we can all act like idiots!" seems the motto for today.

 

[ericmark]

I can still remember 2πNT/33000 is the formula for brake horse power, it is now useless as we have gone metric. But when I used a dynamotor it did not read in horse power so we had to calculate all the points to make a graph.

I have re-read the question and clearly not air source heat pump, it is not a generator, the others can generate heat, but the air source heat pump only transfers energy it does not generate it, so is not an option.

Solar thermal also transfers, it does not generate, solar voltage generates, but not solar thermal.

Biomass is a little open, I know my daughter lived in a house designed to be heated with biomass, however it was no longer heated by keeping cows down stairs, but this was a common method in the middle ages, cows generate a lot of heat, but as to maintenance was this to run the heating system or to ensure food production?

But I am sure they are not talking about that type of biomass generation, it hardly matters if one burns wood, or coal, they both come from same source, just one is compressed. However charcoal and coke are products of wood and coal, and in both cases the material has been processed to remove the nasty stuff. One hopes in a proper way catching the nasty stuff like creosote, but processed fuel can have the advantage of low maintenance. To burn wood or any other plant material the temperature needs to be very carefully controlled to avoid particular emissions, NOX etc. But burning processed fuel does not have the same draw backs.

Biomass does not even need to be veg, I produce heat as a byproduct when I brew my beer, keeping yeast as pets! But the maintenance I consider is down to production of booze, not the byproduct of heat.

But considering the options it must be a) Micro-combined heat and power. @SUNRAY One maths question last year for age 13 was: A square of sides 4cm and 6cm has an area of: 24ml, 24cm³, 24cm² 24cl. the only answer is cm² as rest not area, so with your question is has to be a) Micro-combined heat and power or c) Biomass as the other two do not generate they only transfer.

However it has taken me some time to realise this, and I would say that's a sneaky question, as one is not really considering that when taking an exam.

 

[JohnW2]

.......................... "Oh, let`s put a safety device in then we can all act like idiots!" seems the motto for today.

That is, indeed, the bottom line of the mindset we have been discussing!

Kind Regards, John