Fin Rads

[Big COL]

On the old forum Oliver requested for any information on fin rads. Having just completed our new 70' trad on which I designed, specified and installed all the electrical and plumbing requirements I am only too pleased to pass on any information that may be helpful. My first encounter with fin rads was on our first boat which was a 47' Colecraft build and Colecraft fitout, the heating consisted of a single pipe fin rad system coupled to an aldi boiler and was very efficient on that length of boat. We had this boat stretched by 13' and an extensive refit was undertaken. At the same time the aldi was removed and replaced with a diesel stove with backboiler and a pump added, along with alterations to the calorifer to automatically control the water tempreature. This was necessary as you cannot control the heat source on the type of oil fired stove that is normally used on narrowboats. On commissioning the new system it immediately became apparent that there was a problem, with the stove running the lounge would be at a comfortable temperature but the flow out of the boiler was only just warm. The stove had a 5kw rating - 3kw to space and 2kw to water. Although the pump was controlled by a pipe stat that woudn't start the pump until the boiler had heated the water to the required tempreature, when it did start it moved the water through the system so fast that there was no time for any heat pick up as it passed through the boiler. To overcome this I slowed the pump using a variable resistor and eventually managed to balance the system so it was working satisfactorally.

 

As all this was taking place I had ordered a 70' sailaway from Colecraft as a liveboard. I had some serious reservations on the heating system that I was intending to use, I was intending to copy the system from our old boat but this had thrown up a few questions as to the suitabilty of this for a liveaboard, mainly the availability of hot water on tap without the need to run the engine, or having to light a stove just for this purpose. A rethink was required and the only alternative was an independant bolier that was controllable for both hot water and heating. This didn't leave much choice as the erberspacher and others of similar design were at the time getting a considerable amount of bad press. I was about to order a Kuranda when I spotted an ad for a new heating system for boats called Hurricane - a Canadian system distributed by Calcutt Boats. I arranged to visit Calcutt and was immediately impressed by this system - firstly it comes as a complete system, easy to fit, totally controllable for both hot water and heating with a 9.4kw output and fully self diagnostic . 1st problem solved. For rads no one will ever convince me that there is anything better than fin rads - they are positioned in the correct place, at floor level, so as to obtain maximum heat circulation, they are neatly positioned so they are unobtrusive and if you select the right ones far more efficient than normal domestic rads. To improve the efficiency on the rads I searched for a manufacturer of a two pipe system where both the flow and return are in the fins - this way you get the benifit of any heat left in the return. I found a company called Claytons in Coventry who make rads for trains, coaches, etc, They come as a complete unit with a kickproof cover as part of the construction, all you have to do is screw them in position. They come in lengths of 1,2,3 meters and can easily be coupled together if longer lengths are required. Claytons they will also calculate what exactly you require if you send them a layout drawing of your boat. From memory the output is along the lines of 500watts per meter of radiator. To finish these off we had the boatfitter fit a 3'' shelf over the top for the full length of the rad which dovetailed into the boxing which covers the pipes, so from a standing position they are disguised without interfering with the heat output. I also ran a complete loop from the back of the boat across the front and down the other side leaving the pipes exposed where they pass through cupboards and under beds so as to combat any condensation

 

Now fully commissioned this system has far exceeded my expectations. I know I was in a fortunate situation with this boat and wasn't constricted by a budget as the equipment that I have used tended to be more expensive but it's a once in a lifetime build for me so I tended to overlook the cost factor and with the end result I'm pleased I did.

 

Sorry to be so long winded with this but I feel that my experiences may be of some help as the colder weather gets closer and people think of upgrading their heating systems. Reading this may give them an insight into any pitfalls, the major one being controlling the heat to where you actually want it so you remain comfortable. Clayton's contact details: Clayton Transportation Climate Control, tel: 02476 691916, email: clayton@btconnect.com (no web site)

[Jon]

Thanks very much for such a detailed reply. Once all discussion on this topic is complete, I will move it to the content forums.

 

Many thanks,

 

Jon

[Oliver]

Colin

 

Thanks a lot for all of this – sorry we didn’t get to speak, but I think this will be very useful for a lot of us (plus I don't think I would have got all this down correctly)

[charles123]

I am also considering skirting radiators as I dont like the look of "house panel radiators" the nearest I can find are similar to Finrads (see URL) these come out at about £100 per 2m length

 

Anyone know where to source the original Finrads

 

http://heatandplumb.com/acatalog/Perimeter_Heating.html

[Gary Peacock]

I don't have the prices to hand but we use finrads supplied to us by Aquafax they could be worth a try. sales @aquafax.co.uk or 01582568700

 

Cheers

 

Gary

[ChrisPy]

I'm hoping to use a gravity circulation system. I suppose that finrads are out of the question because the water has to drop down through the radiator as it cools, in order for natural circulation to occur. Am I right?

[Richard Bustens]

Hi Gary

I have been in contact with Claytons and they supply Aqufax with there product,

I am concidering putting in these rads as well ,and clayton will make up with any terminations that you require for your piping also put a u bend on the end rad to send the flow back, BUT im'e not convinced,,,,, as i feel that instead of giving up the last bit of heat on the return i feel that it is more probable that the colder water will pick up heat from the rads and decrease the eficancy not increase it and am waiting for claytons to confirm this.

It may be better (in my oppinion) to feed both pipes with hot water and run a independant return.

Just my thoughts.

[Big COL]

Richard

 

Its the cumulative heat that the fins throw out, I have used both systems, and have used Claton's fin rads on my current boat. They are the most efficient rads that I have ever used. I have no connection with Clayton so there is no sales pitch here, they are just an extremely good product and easy to fit. I would stress that you send Clayton a layout and let them do the calcs, they do it for free, I checked their calculations for my boat and they were not trying to oversell.

 

best regards

Colin

[John Orentas]

Colin.

 

As Richard suspects, having the return pipe built into the radiator. On the face of it you have all the makings of an efficient heat exchanger. The cooler water returning will pick up heat from the hot going out.

 

But perhaps there is a bit more to it.

 

John Squeers

[Big COL]

John

 

I agree it does look that way, but I think it works by the difference in conductivity of the metals involved with the flow being the top pipe and made of copper, the aluminium fins conduct the heat up and away from the return and whatever heat remains in the return is collected and conducted up towards the flow. On my system the return is getting progressively cooler the more rads it passes through therefore the heat has been captured by the rads. If it was working as a heat exchanger you would expect the return to get progressively hotter. I am sure you will agree the physics here, but the explanation is my assumption, all I have to go on is my own system.

best regards

Colin

[John Orentas]

Chris.

 

Don't rule out complely the use of Finrads on a naturally convecting system. For such a system to function, the first requirement is for fairly large diameter pipes to avoid frictional losses. The second more difficult one is to induce the hot water from the stove to rise by virtue of it's reduced mass and fall as it cools to maintain a constant circulation.

 

Imagine the hot stove outlet pipe with a constant rise towards the rear of the boat, at the end of the pipe on the same alignment is fitted a one mtr. Finrad unit. The outlet of the 'rad drops vertically downwards and then returns to the stove horizontally via as many 'rads as are required.

 

Draw it out on paper, it should work, an added bonus is that all but the rearmost one the Finrads are horizontal and at a low level.

There would be a definate advantage if the rising hot pipe was insulated.

The Finrads and other pipes should be say 1.25" dia minimum.

 

The system will require a high level header tank fed by a 1" dia pipe.

 

John Squeers

Edited November 13, 2004 by John Orentas

[Richard Bustens]

Hi John and rest

I spoke to Clayton's and they are genuine i think.

But i still think for the max performance they need to be both pipes as feeds and a seporate return.

The pipes are 22mm.

[timboharticus]

Re: Gravity systems.

 

Suggest run 28mm pipe uphill 1:40 to top of panel rad then from bottom of rad return downhill via fin-rads.

[ChrisPy]

John, Tim: thanks for the advice. It seems to work on paper, looks good. A lot neater than ugly panel radiators occupying good wall storage space.

 

Has anybody out there tried it?

[Big COL]

Richard

 

Just thinking out loud, and not being critical, as I am sure you you have thought this through, but for the benefit of the others that are following this thread and may decide to replicate your system here are just a few thoughts that crossed my mind.

 

If you were to use both pipes through the rads as the flow, what size of pipe would you need to use from the boiler to the first rad,where it divides ? It would have to be larger than 22mm or you gain no advantage. You are doubling the surface area for the collection of heat on the flow so you must increase the available heat or the last rads on the system will never get hot. What is the size of the separate return ? This should be equal to the pipe that you use on the flow.

Also what size boiler are you using ? If you make the system more efficient to give off a certain quantity of heat the boiler has to be capable of remaking that heat, at the the very least - at the same rate, if it cannot do this you will have to balance the system and any advantage will have been lost. As you know you can only get out what you put in,the boiler output should be the first thing to consider when designing a system. If it is not capable of producing the heat then this system will not work. There are not many boilers on narrowboats that I can see supplying the make up temperature to run a system of this design.

Having said all this if all the criteria were met then you will have on hell of a system, may be too good for a well insulated narrowboat. Still you could always rename the boat to Richard's Sauna.

 

best regards

Colin

[Richard Bustens]

Hi Col

Ive got a eberspacher 10kw .

I think i am going to use 22 mm to feed and return, the only restriction will be that the water in the rads will flow through slower than just feeding one and that may remove more heat from the water, also i am only having them in the kitchen and lounge as the boatmans and dining room have eberspacher blown air rads and im'e only putting the towel rail in the bathroom.

[timboharticus]

Regarding the balancing of backboiler output etc. to rads the aim should be to get a flow temp of 70-80 degrees.

 

Pipes give off about 25 Watts per metre

 

Typical back boiler is about 2kW

 

Suggest isolation valve to rad to allow quicker heating of calorifier.

[John Orentas]

I think we are all at cross purposes here, where did the calorifier come from ? The original enquiry was for a convection only heating system using Finrads.

 

John Squeers

[timboharticus]

It seems sensible to me to use the heat from the back boiler for heating water.

 

Once the water is up to temp the heating will increase, or could use isolating valves to choose between heat/ water.

 

I am considering a separate summer hot water system using gas.

Would need to change over using valves.

 

Please advise, in the BSC is it ok to use gas water heater in series with calorifier.

 

I understand that it is advisory to have warning labels because water could get veryhot.

[ChrisPy]

Having thought it through, I'm considering 28mm pipework from the Bubbles or Refleks stove which will be located against the front bulkhead, rising to a single panel radiator 10metres away in the rear bedroom. (vent/expansion tank connected at this point). All flow directed into top connection in the radiator, and out at the bottom, where the piping will run horizontally back along the boat passing through two one-metre finrads.

 

It's all or nothing (no way to divert the flow) but I suppose heating the whole of a well insulated boat is logical, rather than just one or two zones. KISS principle applies.

 

Wiil it work?

[Big COL]

Having thought it through, I'm considering 28mm pipework from the Bubbles or Refleks stove which will be located against the front bulkhead, rising to a single panel radiator 10metres away in the rear bedroom.  (vent/expansion tank connected at this point).  All flow directed into top connection in the radiator, and out at the bottom, where the piping will run horizontally back along the boat passing through two one-metre finrads.

 

It's all or nothing (no way to divert the flow) but I suppose heating the whole of a well insulated boat is logical, rather than just one or two zones.  KISS principle applies. 

 

Wiil it work?

<{POST_SNAPBACK}>

[Big COL]

Chris

 

Some questions, firstly why go for a gravity system - kiss applies also to a fully pumped system and allows the pipes to be low down and can be far more versatile. Secondly do they make fin rads in 28mm, which they will need to be on a gravity system?

If 28mm fin rads are available then I can see no reason why this should not work, remember that when you come into the panel rad at the top , the return connects at the bottom diagonally opposite. This is also a good position to connect the feed from the header tank and then take the vent/bleed off from the other top connection directly above it.

 

Best regards

Colin

[ChrisPy]

Chris

 

        Some questions, firstly why go for a gravity system - kiss applies also to a fully pumped system and allows the pipes to be low down and can be far more versatile. Secondly do they make fin rads in 28mm, which they will need to be on a gravity system?

          If 28mm fin rads are available then I can see no reason why this should not work, remember that when you come into the panel rad at the top , the return connects at the bottom diagonally opposite. This is also a good position to connect the feed from the header tank and then take the vent/bleed off from the other top connection directly above it.

 

Best regards

Colin

<{POST_SNAPBACK}>

 

I don't want the noise or additional complication of electrics and pumps.

 

thanks for your advice. I'll check on finrads for 28mm pipe.

[John Orentas]

Back to the thread. I have found a range of 'Finrads'. In various lenghts, aluminium fins 75mm on copper pipe.

 

C.A.K. Tanks Ltd. (Caravan accessories) Kenilworth.

 

Mainly a mail order company.

 

WWW.caktanks.co.uk

 

www.sales@caktanks.co.uk Orderline

 

Tel 0870 757 2324

 

Fax 0870 757 2325

 

Richard . There are some geometric compex looking, Bed / Seat Hinge units.

 

Lots of other bits and bats for ideas

 

John Squeers

Edited November 20, 2004 by John Orentas

[Richard Bustens]

Hi John

Are you sure about the web address it seems to be a dead link?