Are we in a bubble?

[agg221]

15 minutes ago, skyhuck said:

You are obviously a very clever chap.

 

Maybe you can answer a question my dad keeps bringing up. Apparently capacitors are much better alternative to batteries, why are they not used?

I can try 🙂

 

Capacitors are used, but do a different thing. If you think of a battery as a thin walled tank, like an unpressurised domestic water tank and a capacitor as being like water-type fire extinguisher. Think of the water as being like energy. For a given weight, the domestic water tank holds a lot more water (energy) than the fire extinguisher can, due to the weight of the cylinder itself to take the pressure. When you turn both on, the pressure in the fire extinguisher means it empties very fast whereas the water tank can only drain slowly.

 

What that means in practice is that you use a capacitor when you want to get energy in or out very quickly. They are used for regenerative braking for example. However, if you want steady energy delivery for transport you want the highest possible energy density (Wh/kg). Capacitors will give you less than 1Wh/kg, supercapacitors up to around 15Wh/kg whereas the batteries in the current generation Tesla will give you over 250Wh/kg.

 

Hope that helps!

 

Alec

[agg221]

5 minutes ago, openspaceman said:

The SMRs are derived from the power plants which were used in subs.

I can't comment.

 

Alec

[openspaceman]

2 minutes ago, skyhuck said:

My dad recons he saw a documentary in which Elon Musk put on in a car instead of the batteries, it increased the range and could be charged in 10minuets. He reckoned he was prevented from using them by the US government. This is all hearsay from my 79year old father.

Check out super-capacitors, some people use them instead of lead acid car batteries.

 

As Spud says they can be charged and discharged much quicker than a  EV battery and they have near infinite charge discharge cycles.

 

The saying is while you think of EV batteries in terms of kilowatt hours super capacitors are more megawatt seconds.

 

They will likely be used in transport as they can soak up sudden charges where a conventional EV battery cannot absorb all of the charge the regeneration could  give out, so place the super-capicitor to absorb the huge spike and feed the main battery at a rate it can take to catch up.

[Commando]

Going back to the original post. As someone who's recently tried to get someone in for a job I'm surprised how hard it's been. There's not a local tree business I'm aware of and those that are a bit further out don't seem to have a web site and just rely of facebook/mobile.
 
I've spoken to a couple of neighbours and they ended up getting people in from 30 miles away which seems daft for small jobs.
 
It's not a wealthy area but there's lots of second homes and a good number of large roadside ash showing signs for dieback.
 
Plenty of work for someone with a MEWP I'd have thought.

Ain’t that the truth Paul! I’ve been trying to get contractors in to quote for work, all who are currently flat out busy, most don’t even to respond to a call or text.
It won’t be forgotten when these plentiful times finish....as they always do[emoji106]
Surely a short “sorry mate I’m flat out” text ain’t too much to ask for?

[Martin du Preez]

The work load is surely unprecedented. I put it down to a couple of factors (domestic)

1.people have nothing else to spend there money on so are completing bigger projects (no holiday)

2. Working from home, being at home more. Where I am the majority of people work in London and are only about on weekends so now this is all bugging them.

3. Stamp duty break has driven the housing market nuts, we are carry out works in so many new homes people have recently bought.

4. On the commercial side for site clearances and fencing on development sites. All the developers I know have said they are just rushing like mad to knock up as many houses as they can before the housing bubble bursts which is they feel is imminent.

It’s going to be interesting to see what’s going to happen to all these new start up firms when this workload disappears. What’s going to happen to the firms who have financed so much gear under the impression it’s going to last?

[Paddy1000111]

6 minutes ago, Martin du Preez said:

It’s going to be interesting to see what’s going to happen to all these new start up firms when this workload disappears. What’s going to happen to the firms who have financed so much gear under the impression it’s going to last?

I think the small start up firms may not be hit as hard as the bigger firms. Small start-ups have small overheads, less kit on lease as a lot is second hand, less staff etc as they rely on freelancers. It will obviously separate the wheat from the chaff but I think the bigger companies that have bought lots of new kit, taken bounce backs etc etc will be hit hardest. I don't think they will go under but I think they will make redundancies and hand back kit moving forward

[Mesterh]

2 hours ago, agg221 said:

I can try 🙂

 

Capacitors are used, but do a different thing. If you think of a battery as a thin walled tank, like an unpressurised domestic water tank and a capacitor as being like water-type fire extinguisher. Think of the water as being like energy. For a given weight, the domestic water tank holds a lot more water (energy) than the fire extinguisher can, due to the weight of the cylinder itself to take the pressure. When you turn both on, the pressure in the fire extinguisher means it empties very fast whereas the water tank can only drain slowly.

 

What that means in practice is that you use a capacitor when you want to get energy in or out very quickly. They are used for regenerative braking for example. However, if you want steady energy delivery for transport you want the highest possible energy density (Wh/kg). Capacitors will give you less than 1Wh/kg, supercapacitors up to around 15Wh/kg whereas the batteries in the current generation Tesla will give you over 250Wh/kg.

 

Hope that helps!

 

Alec

Interesting stuff. 

 

 

[skyhuck]

8 minutes ago, Paddy1000111 said:

I think the small start up firms may not be hit as hard as the bigger firms. Small start-ups have small overheads, less kit on lease as a lot is second hand, less staff etc as they rely on freelancers. It will obviously separate the wheat from the chaff but I think the bigger companies that have bought lots of new kit, taken bounce backs etc etc will be hit hardest. I don't think they will go under but I think they will make redundancies and hand back kit moving forward

But then all the redundant staff will start taking your work.

[Paddy1000111]

1 minute ago, skyhuck said:

But then all the redundant staff will start taking your work.

And the vicious circle continues, same as every industry I guess. If you're a plumber, you don't get an apprentice so they take over your company when you retire, you're just training the competition! 

[doobin]

7 hours ago, skyhuck said:

But then all the redundant staff will start taking your work.

Plenty of staff, whilst capable of their job, would not be cabable of saving for their first chainsaw, let alone taking your jobs.