Quick Plumbing Advice re Hot Water Copper Cylinder

ronan45

Just curious, i have a plumber in next week and wondering is there any merit in upgrading my current one of these

https://www.goodwins.ie/p-20756-copper-cylinder-indirect-36-x-18.aspx

to this

https://www.goodwins.ie/p-1167-insulated-copper-cylinder-indirect-900x450mm-36x18.aspx

Any Views?

Wearb

While the factory insulated ones are about twice as good at holding the heat, that heat is usually beneficial in the airing press and also some of the heat loss is retained within the fabric of the building.

Unless you have a history of cylinders leaking at regular periods, I would keep the existing one.

Sleeper12

The factory insulated cylinder will lose less than 1degree of heat over night. You will recoup your investment within 5years or so.
For me the insulated cylinder beats the other one hands down.

John T Carroll

ronan45 wrote: »

Just curious, i have a plumber in next week and wondering is there any merit in upgrading my current one of these

https://www.goodwins.ie/p-20756-copper-cylinder-indirect-36-x-18.aspx

to this

https://www.goodwins.ie/p-1167-insulated-copper-cylinder-indirect-900x450mm-36x18.aspx

Any Views?

If NO lagging jacket fitted a 150 Litre copper cylinder will lose a mind boggling 7243 Kwh/year...0.83 Kwh/hour....4.7C/hour as what you have in effect is a upright copper rad. but will result in a very hot press.
With a "loose" lagging jacket fitted the numbers become 1679 Kwh/year...0.19 Kwh/hour...1.1C/hour.
With factory fitted (new cylinder) 50 mm insulation the numbers are 772 Kwh/year...0.1 kwh/hour...0.5C/hour.

Obviously the first figure will be greatly reduced if there are piles of clothes piled/packed all round it but it would be no harm (if not already done so) to drape a insulation jacket over it, not easy in a already installed cylinder if fitted in the hot press.

Wearb

John T Carroll wrote: »

If NO lagging jacket fitted a 150 Litre copper cylinder will lose a mind boggling 7243 Kwh/year...0.83 Kwh/hour....4.7C/hour as what you have in effect is a upright copper rad. but will result in a very hot press.
With a "loose" lagging jacket fitted the numbers become 1679 Kwh/year...0.19 Kwh/hour...1.1C/hour.
With factory fitted (new cylinder) 50 mm insulation the numbers are 772 Kwh/year...0.1 kwh/hour...0.5C/hour.

Obviously the first figure will be greatly reduced if there are piles of clothes piled/packed all round it but it would be no harm (if not already done so) to drape a insulation jacket over it, not easy in a already installed cylinder if fitted in the hot press.

Good detailed answer.
I had assumed a lagging jacket on the old cylinder. I should have said that in my reply.

Dtp1979

John T Carroll wrote: »

If NO lagging jacket fitted a 150 Litre copper cylinder will lose a mind boggling 7243 Kwh/year...0.83 Kwh/hour....4.7C/hour as what you have in effect is a upright copper rad. but will result in a very hot press.
With a "loose" lagging jacket fitted the numbers become 1679 Kwh/year...0.19 Kwh/hour...1.1C/hour.
With factory fitted (new cylinder) 50 mm insulation the numbers are 772 Kwh/year...0.1 kwh/hour...0.5C/hour.

Obviously the first figure will be greatly reduced if there are piles of clothes piled/packed all round it but it would be no harm (if not already done so) to drape a insulation jacket over it, not easy in a already installed cylinder if fitted in the hot press.

I've seen a customer put a lagging jacket over a 200l joule pressurised cylinder( which are extremely well insulated already. Do you think it'd make much difference?

John T Carroll

Dtp1979 wrote: »

I've seen a customer put a lagging jacket over a 200l joule pressurised cylinder( which are extremely well insulated already. Do you think it'd make much difference?

Hard to say (its like wearing two overcoats) even though it will obviously make some difference, I dont know what Joule's published losses are for a 200L cylinder but if one assumes a loss of 0.45C/hr then the losses would be 24x0.45x200/860 or 2.5 Kwh/24 hrs. As you or Wearb pointed out these losses are usefully absorbed within the house itself except where the cylinder is located in some remote area. The only real savings would then only be in the summer months but I suppose every little bit helps and its all cumulative bearing in mind that hundreds of thousands of households have these cylinders installed. So to answer your question, maybe an extra 0.25/0.5 Kwh/day max in my opinion.

dathi

ronan45 wrote: »

Just curious, i have a plumber in next week and wondering is there any merit in upgrading my current one of these

https://www.goodwins.ie/p-20756-copper-cylinder-indirect-36-x-18.aspx

to this

https://www.goodwins.ie/p-1167-insulated-copper-cylinder-indirect-900x450mm-36x18.aspx

Any Views?

depends on what other work the plumber is doing if he is changing the boiler then part L of the building regs "material change of use" comes into play and you would need to change the cylinder to comply with regs

corkgsxr

John T Carroll wrote: »

Hard to say (its like wearing two overcoats) even though it will obviously make some difference, I dont know what Joule's published losses are for a 200L cylinder but if one assumes a loss of 0.45C/hr then the losses would be 24x0.45x200/860 or 2.5 Kwh/24 hrs. As you or Wearb pointed out these losses are usefully absorbed within the house itself except where the cylinder is located in some remote area. The only real savings would then only be in the summer months but I suppose every little bit helps and its all cumulative bearing in mind that hundreds of thousands of households have these cylinders installed. So to answer your question, maybe an extra 0.25/0.5 Kwh/day max in my opinion.

It's grand to say it's absorbed in the building but you still loose hot water. If you use the water for showers and stuff I'd say change

nmacc

A few years ago, fitting solar panels on a customer's house, I changed the cylinder on Day 1 for spray-lagged copper cylinder. The original cylinder was not factory insulated, but it had a good lagging jacket and it was surrounded and topped with an old duck down duvet. It was undoubtedly the best alternative to a factory insulated cylinder that I had seen.

The next day the customer complimented me on the excellent cylinder, explaining that it was the first day they had woken up to a full cylinder of hot water in the many years they had lived in the house. Since the solar system wasn't working at that point and the capacity of the new cylinder heated by the boiler coil was only marginally larger than the original cylinder, if at all, the improvement had to be down to the superior insulation. Of course, being a solar cylinder, it had a nominal 50mm compared to the contemporary standard of 25mm.

The argument that a well-insulated cylinder will reduce the performance of the hot press as an airing cupboard is not valid. It's a conversation that I have had umpteen times and even the most skeptical householder has found the results satisfactory.

Well, almost all; there was one exception. That was the lady who ran her unlagged cylinder at high temperature and used her hot press as an alternative to a tumble dryer. Mind you, she wasn't a solar customer, she was my next-door neighbour. Her hot press backed onto a large understairs cupboard in my house. The heat transferred from her hot press, through the thick Victorian rubble wall, was enough for me to dry my clothes for free.

John T Carroll

corkgsxr wrote: »

It's grand to say it's absorbed in the building but you still loose hot water. If you use the water for showers and stuff I'd say change

You can look at it in a few ways.....as I quoted above, a 150 Ltr copper cylinder will lose 1679 Kwh/year with a lagging jacket and 773 Kwh/year from 50 MM factory fitted insulation. ( I calculated the numbers from part of a Part L DEAP S.Sheet). Theoretically you are losing (1679-772), 907 Kwh/annum. Assuming a gross oil/gas cost of €0.055/Kwh and a elect full price cost of €0.17, then the savings are respectively €50/annum & €154/annum.
If one takes a middle of the road approach (which is the way I would cost it) then assume that the extra heat is all lost for 4 months (summer) of the year and "1/2" lost for the remaining 8 months then the "real" heat loss is (907*4/12)+(907*8/12*50%), 604 Kwh/annum with savings of €33/annum & €103/annum. I don't know how much a factory insulated cylinder costs but its easy enough to do the sums then depending on which scenario you accept.

Edit: Just saw that <€200 is the cost of the cylinder so the simple payback is 4years/1.3years in the first scenario and 6years/1.9years in the second so Sleeper12's 5 year pay back is spot on if using oil/gas and even better if using full cost electricity for all or part of the time.

John T Carroll

nmacc wrote: »

Well, almost all; there was one exception. That was the lady who ran her unlagged cylinder at high temperature and used her hot press as an alternative to a tumble dryer. Mind you, she wasn't a solar customer, she was my next-door neighbour. Her hot press backed onto a large understairs cupboard in my house. The heat transferred from her hot press, through the thick Victorian rubble wall, was enough for me to dry my clothes for free.

I know a couple with a "open plan" hot press upstairs (2 bedrooms) the hot press is more or less open on three sides and they have a 100 Litre single coil unlagged copper cylinder and NO rads upstairs, they have a back boiler downstairs for donkeys years and 3 rads, they use free issue turf/wood as fuel and have a lovely cosy warm house for as long as I can remember. Are they worried about heat losses, the DEAP, thermal efficiency or whatever you are having yourself? NO. Are they right, YES, 100% IMO.

As is often said, "Its no good knowing the cost of everything and the value of nothing"