Hydronic - Matrix Heaters

[Playtime]

Has anyone found a source of reasonably priced, quiet yet powerful matrix heaters for use with a hydronic system?

I thought I had with this one (which is actually a Kalori one like this but £40 cheaper) but it is not particularly quiet, at least not on the high setting (1.7KW).

The Helios 2000 unit looks good on paper (you have to download the spec), but so did the Kalori. The Helios is also expensive from Espar - is there a cheaper source?

 

[vyv_cox]

I have been searching for much the same thing but with some space constraints. Yesterday I ordered the 2.2 kW one from http://www.t7design.co.uk/index.php?main_page=index&cPath=65 Sounds good, will have to find out in a week or two.

 

[Piers]

We are contemplating having a Webasto hydronic system installed on Play d'eau.

Normally, as the room temperature approaches the required setting, the fans are made to slow down by reducing the drive voltage. This makes the motors hum and buzz.

The new Webasto fans operate in a clever way. The voltage is not reduced but pulsed so there's no buzzing as the fan runs slower. Clever.

 

[rotrax]

We fitted a Webasto Hydronic to our previous boat, a 33ft yacht. We used two small powder coated heated towel rails, one at the end of the galley and one in the heads. We fitted a long narrow radiato under the setee berth. Apart from the Webasto pump it was silent and very warm. It was a mission to bore the teak stringers for the pipes-even good quality bits got blunt pretty quick. Consider not using matrix type heaters-its more complication.

 

[philip_stevens]

I fitted a Kalori Kuba

to our boat. We have an Eber Hydronic system feeding the Kalori, two radiators and the calorifier.

I won it on ebay, so a lot cheaper than advertised. It has got a good output, and not noisy.

Heats the cabin up a lot quicker than the radiators, and switched off and left to the radiators once well warmed up.

 

[Playtime]

I have been searching for much the same thing but with some space constraints. Yesterday I ordered the 2.2 kW one from http://www.t7design.co.uk/index.php?main_page=index&cPath=65 Sounds good, will have to find out in a week or two.

I've looked at that unit as it is powerful and reasonably priced. However, I was concerned that it might be noisy (it takes a lot of air to move 2.2KW) so will be very interested in your feedback when you have tried it.

We are contemplating having a Webasto hydronic system installed on Play d'eau.

Normally, as the room temperature approaches the required setting, the fans are made to slow down by reducing the drive voltage. This makes the motors hum and buzz.

The new Webasto fans operate in a clever way. The voltage is not reduced but pulsed so there's no buzzing as the fan runs slower. Clever.

Sounds good. Do you have a link to these heaters? I've just tried Google but get too many hits to everything else Webasto produce!

BTW - get a binding quote (if you can). There is a lot more work installing a hydronic system than an airtronic (or equivalent). I am part way through installing the hydronic system at the moment; installing an airtronic system 12 years ago was easy in comparison - but maybe it's just an age thing!

 

[Piers]

Sounds good. Do you have a link to these heaters? I've just tried Google but get too many hits to everything else Webasto produce!

BTW - get a binding quote (if you can). There is a lot more work installing a hydronic system than an airtronic (or equivalent). I am part way through installing the hydronic system at the moment; installing an airtronic system 12 years ago was easy in comparison - but maybe it's just an age thing!

I have a pdf, so if you PM me with an email address I'll send it to you. Binding quote? Yes, I have a fixed price in my hands!

 

[David2452]

Though Webasto et al supply matrix heaters they all counsel that they are not the most efficient way to use the coolant heat, radiators are the best possible method if they can be accommodated. The following is an extract from the Webasto marine coolant based install manual. From my own point of view in practise this is certainly true, when these matrix are incorporated into an engine cooling circuit they seem to work well at the higher temperatures present (and these are the temperatures their KWh are based upon so don't expect a 2KWrated one to give you that) but not at the lower temperature of diesel boilers. The Kalori Baikal range of smaller fan assisted rads which are quite small do work well though. Anybody considering a coolant based system should seriously consider specifying (or self fitting) a pressurised system with an auto bleed rather than a header tank based system and certainly steer clear of single line header tanks as initial and subsequent removal of air is far more difficult, the "swirl pot" type of header tank has advantages but does tend to act as a radiator and remove some heat from the system. I am a great advocate of coolant based systems and fit quite a number on narrow boats, wide beams, barges and commercial vessels and think they are really under used in Motor boats and Yachts but like forced air they must designed and installed in a workman like manner and with a full understanding of the whole system to achieve the best result both in performance and reliability.

Extract
"Try to avoid installing blower boxes as they are not really suitable for use with these types of heater. The problem is that nobody manufactures a blower box specifically for hot water applications. The technology is derived from air-conditioning where it is desirable to have a long winding flow across the matrix to evaporate all the gas and to dehumidify the cabin. To use this same technology for heating will never work effectively as we need a buffer of water at each end of the matrix so there is parallel flow across the whole of the matrix and therefore a small Δt, (delta t, the temperature
difference between the flow & return). With the standard air-conditioning derived units the Δt will be unacceptably large by the time the liquid has exited the matrix because of the distance the liquid has to travel."

 

[Piers]

Though Webasto et al supply matrix heaters they all counsel that they are not the most efficient way to use the coolant heat, radiators are the best possible method if they can be accommodated.....Anybody considering a coolant based system should seriously consider specifying (or self fitting) a pressurised system with an auto bleed rather than a header tank based system

The Webasto hydronic system being specified for Play d'eau will be pressurised as you advise above. There's only one place where a rad can be fitted, so matrices will have to be used where needs be. We are also having a demist system installed.

 

[David2452]

I have been searching for much the same thing but with some space constraints. Yesterday I ordered the 2.2 kW one from http://www.t7design.co.uk/index.php?main_page=index&cPath=65 Sounds good, will have to find out in a week or two.

The ratings for those are quoted based on a higher temperature of coolant than a diesel boiler will give so don't expect the quoted KW in practice.

 

[David2452]

Oh, and another thing never use TRVs on radiators they cause too much cycling, fit a manual valve and balance the system manually by measuring the temperature drop across the load and adjusting each one to try to get about an 8 - 12 deg C across each rad, obviously it is best to start by restricting the ones nearer the boiler a bit more than the furthest away.

 

[David2452]

The Webasto hydronic system being specified for Play d'eau will be pressurised as you advise above. There's only one place where a rad can be fitted, so matrices will have to be used where needs be. We are also having a demist system installed.

Where they have to be used, they have to be used and I do when there is no room, but they are definately second choice for efficiency. It is a shame boat floors have to be removable otherwise underfloor would save space, I did one on the upper floor of a big boat and it was a real success.

 

[bendyone]

I have a proper one in the front cabin and a home made one in the rear. The one I made using a golf heater core and 2 x 6 inch computer fans, works just as well as the brought one if not better. I made it to fit in a limited space I had.
Basically a wooden box with 2 "house" vent grills all about 2 inches deep.
Works for me.

 

[lw395]

I think blown air from matrices does have its attractions.
When you go below cold and damp mid channel after your watch, some warm blown air is great. When the boat has got damp due to lots of wet people, blowing some air around with the hatch open is very effective.
It's a different case to your motor yacht with indoor steering or your liveaboard.
Cars have heater matrices for a reason.

As others have said, the simple physics is you have to move a lot of air over a lot of surface area to get 2kW or whatever out of a matrix.
My first effort involved the heater from a VW Polo, which did the business, but the fan drew over 10A at full chat.

Question for David2452, is it normal to have the engine in circuit with hydronic systems?
I found it the best way to reduce cycling on my boat, and took the view that the heat in the engine 90% found its way into the cabins eventually.

There must be a lot to be said for a boat designed around a heating system, as opposed to trying to retrofit one into a yacht that still has racing pretensions!

 

[David2452]

Question for David2452, is it normal to have the engine in circuit with hydronic systems?
I found it the best way to reduce cycling on my boat, and took the view that the heat in the engine 90% found its way into the cabins eventually.

If by normal you mean do many boats have it then the answer is no, however, and I speak mainly of vessels that use the motor as primary, indeed only means of propulsion then it is a really good idea to gain free heat, larger, commercial vessels and narrowboats usually use a heat exchanger rather than having direct connection to the engine cooling system for a couple of reasons, loss of engine coolant due to heating system failure and the fact that engines use a 50/50 anti freeze wheras to get best efficiency coolant based heating is normally run at 25% as glycol is not as good a heat carrier as water. There are all sorts of ways to incorporate them, a favourite of mine is a solid fuel stove with boiler incorporated, Webo on a timer for morning shower and warmth on waking up then cheaper heat and reduced wear on the Webo from solid fuel and a focal point in the day / evening, of course much of this is inapropriate for a small yacht but there is more to good heating than just sticking in an ex BT Eber and hoping for the best. As I said in another thread, it's a real shame Webasto don't develop and sell the RV comi water / forced air system for marine use.