horizontal thermal store

OK so it is probably a contradiction in terms but I have a *space* issue.

I made a decision to use underfloor heating, thermal store, system boiler and the old garage as a kitchen diner for an annexe we are constructing. What I failed to realise is that *garages* are really too narrow to accept all the bits of tackle that housewives consider essential.

One possible saving has been to consider fitting the thermal store in what will be a very modest (minuscule) loft. I don't have the actual dimensions yet. Browsing through various offerings looking for short/fat versions, I came across a horizontal store!

How serious a problem would this cause? I vaguely remember stratification being discussed here. I have no current ambition to use any alternative energy source .

regards

Reply to
Tim Lamb
Loading thread data ...

Stratification still occurs in a 2' tall container

NT

Reply to
NT

OK. I suppose I am concerned that I might be spoiling the heating and hot water system in order to squeeze in another chunk of electrical white goods:-(

regards

Reply to
Tim Lamb

That's interesting - I'm likely to be trying to put a thermal store in our loft in the next year or so - and something short and fat (other than me) could be very useful.

Do you lose much over a vertical store though?

Reply to
PCPaul

In message , PCPaul writes

From the lack of response, I guess our *experts* are elsewhere:-)

I'm going to support BT by telephoning DPS of Epsom later. I'll post anything useful I learn.

regards

Reply to
Tim Lamb

What make? Does it have a DHW plate heat exchanger.

Reply to
Doctor Drivel

If you put it in your loft:

1) you may need to reinforce the loft as water is heavy 2) any heat loss will be wasted through the roof (no insulation is perfect) [g]
Reply to
george (dicegeorge)

In message , Doctor Drivel writes

It might have done, if I could get any sense out of DPS.

The current plan is to use a big combi:-(

By hanging the floor joists (150mm and about 2m long for those concerned about heavy water) I can achieve a space of 1050mm x 400mm or 900 x 680 etc. given by the roof pitch of around 30deg.

Access for plumber could only be through a ceiling hatch and standing on steps which may not be acceptable.

regards

>
Reply to
Tim Lamb

How many baths, showers? Look at the wall mounted ATAG 51kW and the Ethos

54kW combis. They do two bathrooms. These have weather compensation that can be set to cope with UFH - that's if you only have UFH. The W-Bosch floor mounted Highflow 550 does two bathrooms too.
Reply to
Doctor Drivel

Why do you need a thermal store, Tim. What's wrong with just a nice big pressurised hot water tank, with a 2ft square footprint?

Reply to
The Natural Philosopher

Nah. My neighbour got a pressurised tank in the same converted woodstore the boiler already occupies. No thermal store, just lots of high pressure hot water.

Converted the boiler to run full pressure CH as well at the same time.

No header tanks any more, no shower pumps.

MMm. that's not room enough for much of a tank..

I think its time to build an insulated outhouse..

Reply to
The Natural Philosopher

It is clear you do not know the benefits of thermal storage.

A lot is wrong with them:

Unvented Cylinder blasts:

formatting link
formatting link
?v=GF_Wrm-Ns0IAn exploding water heater ripped apart a north Phoenix home Thursday morning.

Video from Air15, near 40th Street and Thunderbird Road, showed a hole in the roof of the garage, a pile of rubble, and debris blown out into the neighborhood.

The water heater ended up on a sidewalk about two blocks away, across from a school.

Fire spokesman Victor Rangel said the temperature and pressure valve malfunctioned, sending the water heater skyrocketing.

Nearby residents were evacuated as a Southwest Gas crew and agents from Alcohol, Tobacco and Firearms investigated. Neighbors were allowed back into their homes after about two hours.

Many neighbors described the sound of a bomb, with windows shattering, walls shaking, and in one home pictures falling off walls.

A neighbor's wall was damaged by the explosion, which also broke windows in a house across the street.

One woman who lives two blocks away said the blast knocked all the pictures off her walls.

Click related link to right to see a water heater explosion.

Most of the damage occured to the house next door and directly across the street. However debris from the blast could be seen in yards and on roof tops.

According to Phoenix firefighters, the owner of the house was asleep when the blast ripped apart his garage about 5 a.m.

Red Cross relocated the homeowner.

No one was injured. [luckily]

Rangel said he's never seen this happen and he'd spoken to several plumbers who had heard of hot water heaters exploding, but had never seen it happen.

He said homeowners need to keep up with the maintenance of water heaters; sometimes the T and P valves become corroded or have been installed improperly.

Rangel suggests having the units checked by a professional, especially for people buying homes that have gone through foreclosure. A home bought after a foreclosure might not have gone through an inspection, especially in a short sale.

Water heater warnings and tips from the Phoenix Fire Department Most of the time, your water heater just sits where it's been placed, quietly doing its job. But unlike your family pet, if it's unhappy it's not going to walk to the door and bark and scratch. It could just suddenly blow up like the one that exploded this morning near Thunderbird Road and 38th Street.

What? You didn't know that your water heater could be so lethal? It can be if a tank has been improperly installed, if hazards have been allowed to develop over time, if it has been improperly vented, or if the pressure relief valve has been tampered with.

Here are some safety tips to use when operating your hot water heater:

--------------------------------

Explosion lifts off roof

Tue, January 08 2008

Roof blown off house and then brought back down on to the bungalow after hot water tank causes explosion

A HOME in Pamber Heath was wrecked this afternooon (Monday) after the roof of the bungalow was lifted by the force of an explosion.

Firefighters from Tadley and Basingstoke rushed to the scene at 12.10pm, after what was though to be a gas explosion at the private bungalow in Silchester Road. It was later discovered to be caused by an electric hot water tank.

Luckily no-one was at home at the time and no-one was hurt.

Upon arrival, firefighters discovered the explosion had caused extensive damage to internal and external walls and the roof.

Hampshire fire spokesman, Mark Jones, who attended the scene, said the bungalow was now "uninhabitable" following damage to internal and load bearing walls. "The roof was blown off and came back down on the house, as all the tiles were loose," he said. "And there's a big outwards bow in one of the outside walls."

According to Mr Jones the cause was an electric hot water tank, which got "hotter and hotter" after an emersion heater had been left on, with the water turned off. Incident commander, Tony Evans of Basingstoke Fire Station, decided not to the evacuate the surrounding properties, which were not damaged in the blast. He said he was confident there would be no more explosions.

Hampshire Fire and Rescue Service's Urban Search and Rescue team, which is trained to rescue people from collapsed buildings and to stabilise unsafe structures, was put on standby but not required.

Reply to
Doctor Drivel

In message , Doctor Drivel writes

One bath, one shower, underfloor and some rads.

50 KW would stretch my gas supply. There is an existing 25KW boiler serving the rest of the house and I see the gas meter is rated at 6cu.m.

regards

Reply to
Tim Lamb

In message , The Natural Philosopher writes

The requirement is for an annexe which may have occasional tenants. I am trying to avoid annual inspection charges.

regards

>
Reply to
Tim Lamb

In message , Doctor Drivel writes

I suppose avoiding electric immersion as a heat source overcomes most problems.

Back to the original issue.... can one have a short fat thermal store?

regards

Reply to
Tim Lamb

I don't annually inspect mine.

Reply to
The Natural Philosopher

Yes, its called a pressurised hot water tank ;-)

Reply to
The Natural Philosopher

Definition: Thermal Store - has an internal DHW take-off coil Heat Bank - has a DHW plate heat exchanger and pump.

People get them mixed up.

An integrated heat bank, CH & DHW, is very different to an unvented cylinder. It is not a direct replacement, although there are DHW only heat banks/thermal stores. It offers so much more. In most cases it is foolish not to use an integrated heat bank/thermal store.

Thermal Stores/Heat Banks are far superior to unvented cylinders - and safer. Read below....

Advantages of Thermal Stores/Heat-Banks

- Instant high pressure hot water - When the store has reached temperature, or just the top of the store in a heat bank, water is delivered instantly at the taps.

- High mains water pressures - At up to 10 bar using a heat bank plate heat exchanger, compared to 3.5 bar maximum with most unvented cylinders.

- Very high water flow-rate - The high-end heat-banks have a flow-rate up to

45 litres/min.

- Long efficient boiler burn - Eliminates boiler on-off cycling increasing efficiency and boiler longevity.

- Maintains a Low Return Temperature Promoting Condensing Efficiency - using high efficient plate heat exchangers the return temperature from the plate s guaranteed to be very low. The bottom of the cylinder get very cool while the top can be 70C to 75C. Even is the store is set to 80C, 80% plus of re-heat time the boiler is condensing.

- Boiler Operates in the Ideal Hydraulic Environment - Using a blending valve the flow/return of the boiler can be kept to the ideal heat exchanger temperature differential. This maintains greater efficiencies. The boiler operates at optimum performance in the ideal hydraulic environment.

- May combine the output of the stored water and the boiler - The boiler and energy in the store may be combined to increase output. This in effect makes the cylinder larger.

- Superb Neutral Point For Combining Different Heat Sources - Provides for linking a variety of directly connected heat sources providing a brilliant neutral point: boiler, wood stoves, electric immersion, solar panels, heat pumps, etc, can all be connected to the one cylinder.

- Cylinder may be smaller for a similar performance - smaller cylinders than unvented cylinders.

- Cylinder at low pressure - Unlike an unvented cylinder vented stores do not store water at high pressures. Even pressurised heat banks operate at 1 bar cold, and rarely get above 2 bar.

- Fast cylinder recovery rate - When the boiler is connected directly to the heat-bank, and not via an indirect coil, the recovery rate is rapid. Although in some cases a boiler may heat the heat-bank via an indirect coil, reducing the recovery rate.

- Legionella bacteria virtually eliminated - The Legionella bacteria cannot survive in the high temperature sealed conditions of a heat-bank.

- No scale build-up in heat-bank - Containing primary and not secondary fresh water, there is no scale build-up inside the heat-bank cylinder.

- Cold water storage eliminated - No need for cold water storage tanks.

- No G3 certification to fit - Unvented cylinders require an approved fitter to install. Heat banks, pressurised and vented, require none and can be DIYed. Also vented thermal stores required no G3.

- Solar heating storage - Water heated via solar panels may be stored in the heat-bank via a solar coil.

- Easy maintenance - If an external plate heat exchanger requires cleaning or replacing it is a matter of draining down the heat-bank, or closing isolating vales, and unscrewing the plate heat-exchanger. In some rare instances plate heat-exchangers are fitted directly inside the heat-bank preventing on-site maintenance.

- Easy to improve hot water flowrates - By simply adding additional plate heat-exchangers in parallel, hot water flow rates may be improved. Retrofit additions are possible if extra bathrooms or showers are installed. This is impossible with unvented cylinders.

- Stored water vessel need not be cylindrical - As no internal coil is used for hot water heat transfer the stored water vessel may be any shape, as opposed to a thermal store which has to be cylindrical for maximum efficiency. This has advantages where space is limited.

- No Annual Service Charge - Unvented cylinders require an annual service of between £60-£100. Thermal stores and Heat Banks are service free.

- Thermostatic Radiator Valves can be on all Rads - No wall thermostat required and TRVs on all rads when the CH circuit is taken off the store cylinder and an auto modulating speed Grundfos Alpha pump used.

- Cheaper, Smaller, Simpler Boilers May Be Used - The large buffer of stored water means that a boiler sized for average use, not peak use, can be fitted.

- Larger Boilers may Be Used Without Fear of Boiler Cycling - A larger boiler can be used to reduce the cylinder size or give rapid heat recovery rates or both.

- Full Electric Backup of CH and DHW - An immersion Heater(s) can be fitted in the cylinder that will give CH and DHW backup very cheaply.

- Vented Thermal Stores/Heat Bank Eliminate Explosion risk - Unvented cylinders have an explosion risk. This is not a problem with vented thermal stores/heat banks.

formatting link
?v=GF_Wrm-Ns0I- Pressurised Heat Banks Don't Need Annual Service - No G3 unvented certification for fitting or annual service is required if a heat bank is pressurised and uses a plate heat exchanger.

Disadvantages of Thermal Stores Heat-Banks

- The store needs be near full temperature to supply baths - Before any hot water is drawn off, the store must be up to temperature. Many later versions use a blending valve on the return to the boiler to ensure only up to temperature water is pumped into the store by the boiler. This prevents agitation of the stored water, and aiding heat stratification within the store giving useful hot water at the top of the store within a short time. The water is heated only in one pass through the boiler.

- Lower water temperatures with fast flow-rates - As with Combi boilers, fast flow-rates through the plate heat-exchanger results in lower water temperatures. This is not so pronounced with heat-banks as with internal coil thermal-stores. This also applies to combi's. With a heat bank, larger or extra plate heat exchangers can be easily fitted to increase flow rates. Sized up properly this is not an issue in real world operation.

- Needs more inhibitor - A minor added cost.

Advantages overwhelmingly to thermal stores/heat banks.

Reply to
Doctor Drivel

The Remeha Avanta plus 39C combi is ideal for you. A well priced quality boiler. It will fill the bath fast enough and great showers. It is quiet too. It has integral weather compensation. Some rads? How many? In bedrooms? The rads could be oversized and run at lower UFH temps. Remeha have just bought out Baxi. Do Google on this group for "Broag".

Reply to
Doctor Drivel

It is best you have a square one to maximize the space up there. However in your case I would go for a quality combi as your DHW needs are not great.

These make stainless stores and make to order. Give them your sizes and they make it - square or cylinder.

formatting link

Reply to
Doctor Drivel

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.